# Philip Duclos Fire Eater



## CFLBob (May 12, 2018)

I don't envision this as a build thread, because I have so little to contribute, but I could use some help with questions as I muddle through my build of this engine, from "The Shop Wisdom of Philip Duclos".  

I'm going by the book, and now making the second part, which is the cylinder.  After cutting to finished size, cutting the fins, turning the shoulders, and drilling the bore up to the biggest drill bit I own (1/2"), the next operation is to bore it to size.  The plans say to bore it to 1.00 - which is funny because that's only two decimal places.  The piston's drawing says to turn it to 0.9980 to 0.9985.  Four decimal places.  

The piston isn't ready to fit to the cylinder because the order of the build (in Duclos' book) has me build the cylinder and set it aside.  The piston is a few parts in the future.   

I bought a CRS steel bar for the piston (the drawing says "bronze, cast iron, or CRS"), 1" diameter, which is really a bit undersized at 0.9990 to 0.9984.  I figure when I put that in my lathe to do the turning, I'll lose more than .001 just turning it in the lathe.  I don't know what my 3-jaw chuck's runout is, but .001 is way too good for a 3-jaw.  

What I'm thinking is to bore the cylinder to something smaller than 1.000, then turn the piston to size.  Say I bore it to .990 or .980.   I shouldn't have to go as far as .980, but just to make sure I can turn the piston to the right fit.  The only problem I see is that I bore the cylinder without knowing what size I can make the piston.  

Does that seem like the right approach?  


CFL Bob


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## Cogsy (May 13, 2018)

It's always easiest to size a piston to a bore size rather than the other way round. At least that's what I find. As it can be very difficult to measure a bore to a high level of accuracy (precision is easy, accuracy is much harder) you cut your bore then when you get close to size as you're turning the piston, you can test fit it to the bore while it's still mounted in the lathe. And I don't see 0.020" making much power difference to the engine so the slightly smaller bore should be perfectly fine.


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## CFLBob (May 13, 2018)

Cogsy said:


> It's always easiest to size a piston to a bore size rather than the other way round. At least that's what I find. As it can be very difficult to measure a bore to a high level of accuracy (precision is easy, accuracy is much harder) you cut your bore then when you get close to size as you're turning the piston, you can test fit it to the bore while it's still mounted in the lathe. And I don't see 0.020" making much power difference to the engine so the slightly smaller bore should be perfectly fine.



Thanks.  I was thinking that was the right way to go.  

I have experience with one engine, a wobbler, and with that one, I cut the piston (12L14) and hand fit the cylinder onto the piston, like you say.


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## jchevy (May 13, 2018)

When I built this engine I found the best material for the piston was graphite.


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## el gringo (May 14, 2018)

jchevy said:


> When I built this engine I found the best material for the piston was graphite.


I have built three engines of this type and graphite pistons give excellent results. Self lubing also.
Ray M


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## CFLBob (May 14, 2018)

jchevy said:


> When I built this engine I found the best material for the piston was graphite.



The piston has a hole in the middle of the top.  It looks like it's threaded for the wrist pin but I don't see where he calls out the thread, just that it's a #29 drill.  I think that's 8-32?  Can you tap graphite?


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## CFLBob (May 14, 2018)

el gringo said:


> I have built three engines of this type and graphite pistons give excellent results. Self lubing also.
> Ray M



Three?  I'd love to see some pictures of them.


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## jchevy (May 14, 2018)

The piston is drilled and countersunk for a flat head screw , the screw attaches to another part inside the piston which the wrist pin attaches to . I hope this makes sense .


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## CFLBob (May 14, 2018)

It makes sense, I just don't see it in the book.  It looks like the pin is threaded and either screws into the piston or that nut on the side?


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## el gringo (May 14, 2018)

CFLBob said:


> Three?  I'd love to see some pictures of them.



[ame]https://www.youtube.com/watch?v=FhfXnPnCidM[/ame]

[ame]https://www.youtube.com/watch?v=dd-Ytq-OJ5k[/ame]

[ame]https://www.youtube.com/watch?v=GMqkD0Bua28[/ame]

[ame]https://www.youtube.com/watch?v=MIxq9sohs9c[/ame]


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## Brian Rupnow (May 14, 2018)

I have the same book and the same article. The threaded portion of the "wrist pin yoke" goes right thru a hole in the piston and gets a #6-32 nut on the far side of the piston. The nut is setting there in the picture you posted, and there is one #6-32 nut called up in the bill of materials. A #29 drilled hole is 0.136" diameter. A #6-32 thread is 0.136" diameter. It'll go thru if you hold your breath.---Brian


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## jchevy (May 14, 2018)

I guess I tapped the part that holds the wrist pin and used a screw to hold the piston on for what ever reason , both ways should work .


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## CFLBob (May 14, 2018)

el gringo said:


> https://www.youtube.com/watch?v=FhfXnPnCidM
> 
> https://www.youtube.com/watch?v=dd-Ytq-OJ5k
> 
> ...



Very cool.  I like your modification to the support pedestal on the  Duclos engine.  Mine seems like it should press on, although I haven't tried to press it on in case I can't get it back off.   That's tomorrow or the day after. I might need to do this. 

I've  had troubles boring the cylinder that deep.  It's like my 8-12x20 lathe  isn't rigid enough and something keeps moving.  The tailstock has slid  and the QCTP has rotated around its mount on the cross slide.


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## Cogsy (May 15, 2018)

CFLBob said:


> Can you tap graphite?


 
I have a tapped graphite piston in my Ridders internal valve flamelicker and it holds just fine, but it's a fairly slow revving engine and I don't know if it would at high RPM like I've seen some Duclos engines run.


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## el gringo (May 15, 2018)

"I've  had troubles boring the cylinder that deep.  It's like my 8-12x20  lathe  isn't rigid enough and something keeps moving.  The tailstock has  slid  and the QCTP has rotated around its mount on the cross slide."

what are you using for a boring bar?


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## CFLBob (May 15, 2018)

el gringo said:


> "I've  had troubles boring the cylinder that deep.  It's like my 8-12x20  lathe  isn't rigid enough and something keeps moving.  The tailstock has  slid  and the QCTP has rotated around its mount on the cross slide."
> 
> what are you using for a boring bar?



Nothing special.  Something like this Little Machine Shop set.  

It has made me want to get something more like a larger diameter bar with a replaceable carbide insert.  The small shaft to the end with the brazed carbide head on what I have seems more likely to allow flex.


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## el gringo (May 15, 2018)

I would use the larger 5/8 shank....works for me.
A little nose radius on that type helps also.


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## CFLBob (May 16, 2018)

Agreed.  This is the first time I've bored something this size, it's both larger diameter and deeper than anything I've done before.  I'm using the tools on hand rather than buy new ones, and I got the boring bars back when I got the lathe from Little Machine Shop.  The biggest QCTP holder I have is for a 1/2" boring bar. 

I don't really know how to measure to see if it's tapered with anything I have on hand, other than to try to turn a cylinder of a close diameter and see if it wants to get stuck.  Seems risky.


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## el gringo (May 16, 2018)

jchevy said:


> When I built this engine I found the best material for the piston was graphite.




I don't really know how to measure to see if it's tapered with anything I have on hand, other than to try to turn a cylinder of a close diameter and see if it wants to get stuck.  Seems risky.[/QUOTE]

Inside calipers?


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## CFLBob (May 16, 2018)

el gringo said:


> Inside calipers?



Don't have any with 2.5in inside jaws.  A search for calipers with long jaws only showed long outside jaws.


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## fcheslop (May 16, 2018)

As a rough check, turn a bit of bar stock down for a similar length and measure it each end .It should show up any problems. Dont use tailstock support
For a boring bar make one as from personal experience I get a better finish than a tipped tool gives
cheers


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## el gringo (May 16, 2018)

https://www.google.com/imgres?imgur...ved=0ahUKEwjH7-T01IvbAhWT-lQKHcfUCJ4Q9QEILDAA


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## CFLBob (May 17, 2018)

Thanks, El Gringo.  

I've seen those before.  Not sure if I have anything that can be made to work, but maybe I could get some.


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## CFLBob (May 25, 2018)

And... it's ruined.  

This has been a busy 10 days.  I first finished the cylinder and then put it on the vise, only to find my vise is a bit too small.  I could just barely open the jaws enough to grab the thing, then when I tried to close the jaws, it was hitting the cylinder below the centerline, which would push the cylinder vertically out of the vise, or press a notch into it.  

I don't know how big a posting I can make, but I'll add images until it tells me I can't.  

This is the original test fit.  The vise jaws are less than an inch tall, about 7/8 if I recall.  







I could pick up a bit more room across the jaws if I could make the jaws thinner.  Then it occurred to me that if I made the jaws taller, by about a quarter inch, it would grab above the centerline.  I found some lower profile button cap screws than the SHCS that came in the vise, and figured I could thin the jaws by about an eighth inch on both sides, giving me a quarter inch more opening.  I had to order the button head screws, but that was just a couple of days delay.  Oh, yeah, I ended up leaving the soft jaws 1-1/2" tall.  I might lower that a little.  






 I machined the soft jaws out of some quarter inch aluminum plate I had while waiting for the bolts.  Time for a test fit. 






Seemed like it was all good.  The gap between the bottom of the cylinder and the vise jaw figured to be 1" and I had a piece left over from 1" bar stock.   It felt very secure.  It took me a while to figure out how deep to cut the fins and the 1-1/2" diameter part of the cylinder over on the right end because it's never really specified on the print.  The print does show that the flat should be 1" wide, so a little geometry (and online calculator) showed me I ought to cut it about 3/16" deep - 0.190.   

A friend convinced me to put an extra clamp across the top - I guess he was afraid of aluminum jaws replacing 3/8" steel - so I added that.  I cut the flat over the base of the cylinder in a few cuts, .025 deep at at time (3/8 end mill)  and it went very well.  Which led me to decide to take off the 3/32 wide fins in a couple of passes.  First pass at 0.100 depth followed by a second pass at 0.190.   At the end of the cut, I thought I'd move the end mill toward the base as a spring cut, just to level out any cutting marks.  Instead it dug in and ripped the cylinder open.  Look at the shelf on the end where I stopped the cut.  That's a deep cut at that end.  






You can see how bad it is.  The Z axis on the mill never went below -0.190", so as I moved right to left along the cylinder cutting the fins off, the cylinder must have pivoted and lifted the right end.  I sure couldn't see it happen.  You can measure the diameter to the flat by putting the calipers on the fin and the flat at both ends.  The end closest to the camera is 1/16" smaller than the end by the pedestal.  The flat spot on the cylinder that was supposed to measure 1.000 measures exactly that.  Like I say, the entire piece was cut with the EM never going deeper than -.190".

My guess is that the cylinder pivoted because even with the taller jaws and the 1" bar stock spacer, the contact area is still pretty small.  There wasn't enough holding force to keep the cylinder from rotating.  Maybe really light cuts?   

Do you guys think there's a way to fix this?  (I don't have any welding ability or tools).  If not what do I change to keep from ruining another piece?


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## el gringo (May 26, 2018)

CFLBob said:


> And... it's ruined.
> 
> This has been a busy 10 days.  I first finished the cylinder and then put it on the vise, only to find my vise is a bit too small.  I could just barely open the jaws enough to grab the thing, then when I tried to close the jaws, it was hitting the cylinder below the centerline, which would push the cylinder vertically out of the vise, or press a notch into it.
> 
> ...


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## el gringo (May 26, 2018)

If  the part was properly  held, it wouldn't have moved.

usually the endmill is the one that burrows into the part... make sure it isn't somehow able to move.

Also, why such an aggressive (100 thou) on a tenuous situation?


Ray M


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## deverett (May 26, 2018)

Another aid to stop bits moving in the vice is to put a piece of card (cereal packets are good) between the jaw and the work.

Dave
The Emerald Isle


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## CFLBob (May 26, 2018)

el gringo said:


> If the part was properly held, it wouldn't have moved.
> 
> usually the endmill is the one that burrows into the part... make sure it isn't somehow able to move.
> 
> Also, why such an aggressive (100 thou) on a tenuous situation?



It didn't seem very aggressive.  It was a cutting back a fin that's 3/32 wide, so tall in DOC but small in Width.  My cutter was 3/8 or 12/32, so I was cutting 1/4 of the cutter width.  I only cut one fin at a time. 

Of course, I've been giving myself a hard time over that ever since.


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## CFLBob (May 26, 2018)

deverett said:


> Another aid to stop bits moving in the vice is to put a piece of card (cereal packets are good) between the jaw and the work.
> 
> Dave
> The Emerald Isle



Thanks for that tip!  I have some thin cardboard around but didn't think of that.


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## CFLBob (May 27, 2018)

Should I make my soft jaws narrower?  Closer to the width of the vise body?  That should help the clamping forces out near the left end.  

How about shorter?  I could take them down from 1-1/2 to somewhat lower.  

I noticed this problem while looking at the pictures:





So I started wondering if my mill's head was actually going too far (this is a CNC mill, all driven by keyboard commands or hand controller, so getting it to go between depths repetitively is just the up arrow key - I don't have to type the number every time).  

I ruled that out by putting a dial indicator (1" by .001) where the spindle going up and down would compress it.  Then raised and lowered the cutter back and forth between -0.100 and -0.200 about 40 times.  The indicator never showed a change in position, which means the cutter wasn't getting lower every time I raised and lowered the mill's headstock.  I did find my backlash had gotten a little worse, but that would have caused it to end up short of -.190 instead of too deep.  So it looks like the only explanation is moving in the vise.


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## Cogsy (May 29, 2018)

Are you sure the cutter wasn't pulling itself out of its holder? That would account for the deeper cut and not being able to see the part move.


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## CFLBob (May 30, 2018)

Not to be a wise ***, but I'm not sure of anything.  At least not much.  I think I'm sure that the mill was working properly.  When I removed the cutter, it felt as tight as always.   

I cut the replacement cylinder over the last couple of days.  I should be able to put it in the mill today or tomorrow.  I'll spend some time with an indicator and make sure it's level.  A friend recommended I cut a shallow pass with an end mill along the soft jaw's face.  It could give me two lines of contact on each side instead of just one.  

I sketched it in my 3D CAD to get an idea what the slot needs to look like.  Something like this:





The o.538 was found by moving the model of the cylinder into the jaw until it got "too close" to the counterbore for the screw.  I think if I use a 1/2" EM and cut .032 deep, that's as close as it gets.  Make sure the corners are deburred to mar the cylinder less.


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## CFLBob (Jun 8, 2018)

From the "all's well that ends well" category,  I didn't post day by day but finished the part yesterday.  






And a little different angle look showing the end fins better.  Sure needs to be de-burred.  






I'm going to do the flywheel next.  

Duclos's book goes to the flywheel support bracket next.  Mostly I'm doing the flywheel because I'm thinking of putting ball bearings in where he just lets the shaft ride on aluminum (with a little oil).  I'll have to design that and order the bearings.  I also might remake it as three pieces of sheet, either quarter inch or 3/8" thick , because turning over a cubic inch of aluminum into chips to make the thing like the book's approach doesn't seem right.   The bottom would have to be milled for clearance of the rotating flywheel if it's 3/8, but that's not bad.  I'd just hold the base and side together with screws on the side.


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## deverett (Jun 9, 2018)

You can use ball bearings from a discarded hard drive.  High quality items and Free!

Dave
The Emerald Isle


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## CFLBob (Jun 9, 2018)

Never thought of that.  I'll have to see if I have any old drives lying around.


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## Tim Wescott (Jun 10, 2018)

CFLBob said:


> I don't envision this as a build thread, because I have so little to contribute, but I could use some help with questions as I muddle through my build of this engine, from "The Shop Wisdom of Philip Duclos".



I post build threads on model airplane fora (Stunthanger, mostly) so that other forum members can tell me how I'm screwing up.  It makes my builds better.  Whether that will be welcome here is a question for the group -- I'm new.



CFLBob said:


> ... I'll lose more than .001 just turning it in the lathe.  I don't know what my 3-jaw chuck's runout is, but .001 is way too good for a 3-jaw ...



You can lose a little less if you're willing to put an indicator on it (or just make test cuts) and shim the short (long?) jaws in a bit.  It'll make you wish you had a 4-jaw, but it'll work.  You'll still need to go undersize, but the advise you're getting about just making the bore undersize sounds right to me -- there's certainly plenty of commercial engine manufacturers that change displacement by changing bore and little else.


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## CFLBob (Jun 10, 2018)

Tim Wescott said:


> It'll make you wish you had a 4-jaw, but it'll work.



I have a four jaw, but I still cut the cylinder a bit undersized.  It has been long enough that I don't remember exactly what I cut it to. I think it was 0.980.  It will give me enough to work with to cut the piston.   

I've since seen a video listed on YouTube that shows putting a grinder in a tool post and closing the jaws onto it to make them even and reduce runout.  I don't know if that's a good idea.  Maybe with something covering the ways to keep abrasive dust from landing on them.


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## Blogwitch (Jun 10, 2018)

Bob,
Don't even think about grinding the jaws in a 3 jaw, I have done it a few times when people didn't believe me, and it soon proved to them that grinding isn't a good solution unless you can throw large amounts of cash and valuale time into it.
Even then, you will be lucky to get an very accurate 3 jaw lathe chuck.
From my own findings, I have found that 4 jaw self centering chucks, straight out of the box  (I have four of them at last count) do give better runout figures, plus if you buy a set of soft jaws at the same time, and use them correctly, your precision goes up in leaps and bounds, to zero or very little runout (well under 0.001"),

John


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## CFLBob (Jun 17, 2018)

Making the flywheel on the lathe went as smoothly as expected.  It's tedious and requires I change cutters every couple of cuts, but it came out fine.   This is halfway cut, but the other side looked just like this. 






Once it was cut, it was onto the rotary table on the mill to cut 3/4" diameter holes in it, which I did with a 3/4 EM, the biggest I have.   It seems I didn't stop to take any pictures of this, but took a picture when it was finished, next to my first little engine.  The big flywheel is 3-3/8 OD with 3/4" holes.  The smaller one is 2-1/2" OD with 1/2" holes.   Big brother, little brother. 






Then it was on to drill and tap for the setscrews.  These are at about 10 degrees from vertical, and I had problems with the bits and drill chucks interfering with the flywheel rim.  So I had to make two custom tools for this: one to hold a #2 center drill and one to hold the bit to tap the 8-32 threads.  






Both were made from 1/4" brass rod.  On the drill bit holder, you can see where I tried an 8/32 setscrew.  Unfortunately, there was no more than 2 threads in there and as soon as I tried to tighten the setscrew it ripped out the threads.  That's when I went to soft soldering the bits in.  Back when I was working as an electronics engineer, if someone had showed me solder as ugly as that top one, I would have told them to start over.  But this isn't circuitry, and as long as the solder wicked between the brass and the steel, it'll be OK.  With those tool holders, I was able to drill, then tap the setscrew holes.  






This completed the flywheel and it's ready to use.  On to the next part, which is going to be the flywheel bracket.  Here I'm going to redesign Duclos' bracket, because I want to add ball bearings into the up rights.  I also think that instead of using a block of solid aluminum and milling away 80% of it, I'm going to use quarter inch aluminum plate and hold it together with #8 screws at the bottom.


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## deverett (Jun 19, 2018)

I notice you are using a spotting drill to support the end of the tap handle.
It may be better instead to use a home-made centre from a bit of bar.  Just put a length of 3/8" or whatever you have in the lathe chuck, turn the topslide round to 30 deg. and make your centre.  Cut off and hold this in the collet or drill chuck on the mill; doesn't need to be hardened.  It'll help to save the point of your drill.

Dave
The Emerald Isle


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## CFLBob (Jun 19, 2018)

deverett said:


> I notice you are using a spotting drill to support the end of the tap handle.
> It may be better instead to use a home-made centre from a bit of bar.  Just put a length of 3/8" or whatever you have in the lathe chuck, turn the topslide round to 30 deg. and make your centre.  Cut off and hold this in the collet or drill chuck on the mill; doesn't need to be hardened.  It'll help to save the point of your drill.
> 
> Dave
> The Emerald Isle



Good point, if you'll pardon the pun.  

This is the first time I've ever used this wrench in a setup like this, and I used a small spotting drill to make the divot in the wrench's head.  I just grabbed the first thing in my "bit drawer" that looked like it would fit.


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## CFLBob (Jun 27, 2018)

Well, this is turning into a build thread, although that wasn't my intent at the start.   The latest work was making the crankshaft support bracket.  

For a couple of reasons, I didn't like the Duclos' approach and this seemed like a good part to redesign.  Why didn't I like it?  Two main reasons.  First: he lets the flywheel shaft, 1/4" steel rod, just rotate on aluminum and one thing I've learned about these engines is it's worth it to remove as much friction as you can.  I wanted to use ball bearings, which causes the uprights of the part to be bigger than Duclos used.  Second: he makes this part from a solid 2-1/2x1x3/4 chuck of aluminum and turns most of it (about 65-70% by my calculations) into waste chips.  So I decided to make it out of three pieces of 1/4" aluminum (all you're left with in his design).  Two uprights and a bottom piece to hold them in place.  Some time with CAD resulted in this drawing:






My CAD model on the left and Duclos' drawing on the right.   You can see where the ball bearings sit, in the counterbored holes at the left.  I got a set 1/4" shaft and 3/8" OD overall from Boca Bearings.

I then created a drawing with two of these brackets side by side, spaced far enough apart to put a 3/8" EM between them.  A little time spent with both Rhino and Deskproto (my CAM SW) and porting it all to the mill ended up with this:






I won't bore you with the side story that popped up here, but I had to re-tram my Z-column.  The spindle was perpendicular to the table, but the Z-column wasn't.  Which made me do both.

So while these are smallish pieces, the center (deep blue in the 3D model) was 0.75 wide by 1.00" long, and a bit tedious to work on, it all went as designed and went together the way I planned it.  






Would it help if I said the back looks just like this side?  

30-some years ago, an older engineer told me that "engineering is the art of compromise".   There are rarely ever perfect choices that everyone agrees are the best way to do anything and this design is like that.  The three piece bracket does what I wanted.  All the parts worked out just as modeled.  The drawback is that it's three parts and they need to be aligned properly during assembly.  When I first put it together, the flywheel spun, but also made the characteristic scuffing sound of something rubbing.  The parts aren't perfectly aligned, but I improved that by loosening the four screws on the bottom and putting a shim between each side bracket and the flywheel hub (I used one of my old business cards - still useful after retirement!).  When I retightened the screws and pulled out the shims, the scuffing was gone.  The flywheel still wobbles which argues that the two sides aren't exactly the same height.  

I think I need to come up with an alignment fixture to hold the base and the sides while I indicate the shaft to make sure it's level and not offset side to side. 

If I give the flywheel a good flick, it spins for about 45 seconds.  Is that a good number?  I think it can be made better, but how long should it spin? 

My next project is going to be the piston, and I have a small piece of 1" diameter graphite (1.030") I was thinking of using instead of the CRS bar I bought (longish story).  Duclos' drawings call for hollowing out the piston until it's left with 1/32" thick walls.  Is graphite strong enough for that?  I can just envision it shattering as I hollow it out in the lathe chuck.


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## Cogsy (Jun 27, 2018)

It looks like you might still have the shields in those bearings? If so, pulling them out and washing out the grease, then replacing with a very small amount of light oil will likely significantly increase your flywheel spin time. On Jan Ridders internal valve design he suggests a 2 minute free spinning flywheel is what to aim for. Of course this is going to be different for this design, but less friction is always better for flamelickers so I'd remove the grease.

The build is looking good btw!


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## CFLBob (Jun 28, 2018)

Cogsy said:


> It looks like you might still have the shields in those bearings? If so, pulling them out and washing out the grease, then replacing with a very small amount of light oil will likely significantly increase your flywheel spin time. On Jan Ridders internal valve design he suggests a 2 minute free spinning flywheel is what to aim for. Of course this is going to be different for this design, but less friction is always better for flamelickers so I'd remove the grease.
> 
> The build is looking good btw!



Thanks for the advice.   The ball bearings are straight from the store and they are internally greased.  I have no idea how to open them to clean them out but maybe some reading will lead me there.


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## Cogsy (Jun 28, 2018)

Shielded bearings are reasonably easy to open. The metal shields do not contact the inner race so there is a slight gap there to put a probe in and simply pop the shield out. The smaller the bearing the more fiddly they are to do unfortunately.


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## CFLBob (Jun 29, 2018)

Cogsy said:


> he smaller the bearing the more fiddly they are to do unfortunately.



LOL.  These things are kind of in the class that it's a marvel that they can be made industrially and sold for a few bucks.  They shaft ID is 0.25 and the OD is .375, leaving about .062 on a side for the entire thing by .125 thick.  I downloaded the 3D CAD file from Boca Bearings to try to look at the shields, and they're about 1/32 across.  Fiddly is an understatement. 

Boca Bearings has an app note about this.  They basically say soak the bearings overnight in a solvent, let them dry (overnight is probably good again), then soak them in light oil for a few hours.  I have plenty of time until I need to use these, so this is an easy experiment.   A few minutes a day of actually doing something, and mostly waiting around, is easy.  

Over the years I've found I'm pretty good at doing nothing.


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## el gringo (Jun 29, 2018)

Boca Bearings has an app note about this.  They basically say soak the bearings overnight in a solvent, let them dry (overnight is probably good again), then soak them in light oil for a few hours.  I have plenty of time until I need to use these, so this is an easy experiment.   A few minutes a day of actually doing something, and mostly waiting around, is easy.

Over the years I've found I'm pretty good at doing nothing.[/QUOTE]

Hi guys,
I have  built three engines of this type including the Duclos 'fire eater'. Two have shielded bearings and the other has bushings made from bronze. All run very nicely. I have never bothered to remove shields or factory lube from the bearings. 
Thirty seconds spin time would be a record for me.
I have used bearings from Boca for years and always very satisfied with their products and support.
Ray M


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## CFLBob (Jun 29, 2018)

el gringo said:


> Boca Bearings has an app note about this.  They basically say soak the bearings overnight in a solvent, let them dry (overnight is probably good again), then soak them in light oil for a few hours.  I have plenty of time until I need to use these, so this is an easy experiment.   A few minutes a day of actually doing something, and mostly waiting around, is easy.
> 
> Over the years I've found I'm pretty good at doing nothing.



Hi guys,
I have  built three engines of this type including the Duclos 'fire eater'. Two have shielded bearings and the other has bushings made from bronze. All run very nicely. I have never bothered to remove shields or factory lube from the bearings.
Thirty seconds spin time would be a record for me.
I have used bearings from Boca for years and always very satisfied with their products and support.
Ray M[/QUOTE]

Ray, you have given me hope.  

I just finished the connecting rod.  One tiny, minor, glaringly huge error.  The small end isn't 1/4" square on a side.  I trimmed one side to the connecting bar.  I doubt it will matter.


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## Cogsy (Jun 29, 2018)

This design does run a lot better than the one I built, for that to run I needed everything as frictionless as I could get it. One day I might have a go at one of these, if I ever get any of my current projects finished...


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## CFLBob (Jun 30, 2018)

My connecting rod.  Like I say, one tiny, minor, glaringly huge mistake.  Except I don't think it matters.  






I think the wrist pin yoke is next.  Since I'm cutting the piston to the fit the cylinder, I want to be able to use the connecting rod to push the piston all the way down the cylinder, and (more importantly), get it out of there.


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## CFLBob (Jul 5, 2018)

On the topic of Graphite pistons, someone posted here that they made a graphite piston.  Since a PM didn't return an answer, I thought I'd try to ask here before going to another forum and asking everyone else.

If you made a graphite piston, did you follow the drawing dimensions exactly?  The wall thickness concerns me because I have no experience with graphite.  In the drawing, the walls are 1/32 thick and the idea of cutting away almost 15/16" from a piece of graphite scares me.  Is graphite strong enough for this? 

Having never seen one of these engines in person, I don't know if there's a lot of room between the connecting rod and the edge of the piston when it's at the back of its travel, so maybe there's not enough room to let the walls be thicker.


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## Brian Rupnow (Jul 5, 2018)

Make the walls 1/16" thick, otherwise it becomes just too fragile.--Brian rupnow


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## CFLBob (Jul 5, 2018)

Thanks, Brian.  In my mind, I could the see the graphite shattering when I hollowed out too much.


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## el gringo (Jul 5, 2018)

CFLBob said:


> Thanks, Brian.  In my mind, I could the see the graphite shattering when I hollowed out too much.


Another way to go... I have simply slotted the graphite as a regular piston with a wrist pin, you need only to remove enough material for the conrod to function .
The only part you need to worry about thinning for conrod bottom skirt clearance is at the very bottom of the skirt, probably can get away with an internal skirt champher to clear if the piston is of proper length and rod cross section is correct.
Ray M


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## Cogsy (Jul 6, 2018)

CFLBob said:


> On the topic of Graphite pistons, someone posted here that they made a graphite piston.  Since a PM didn't return an answer, I thought I'd try to ask here before going to another forum and asking everyone else.


I don't have the Jan Ridders plans in front of me so I'm not sure what thickness is called out, but I would have followed them exactly (it was my first engine build) and had no issues. Graphite, at least the stuff I used, holds up far better than I imagined is would.

About the PM - it wasn't me you sent it to was it? I had something weird happen with a PM yesterday and dismissed it as just a glitch but if others are having issues I'd like to know please. I certainly never received one from you.


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## CFLBob (Jul 6, 2018)

Cogsy said:


> I don't have the Jan Ridders plans in front of me so I'm not sure what thickness is called out, but I would have followed them exactly (it was my first engine build) and had no issues. Graphite, at least the stuff I used, holds up far better than I imagined is would.
> 
> About the PM - it wasn't me you sent it to was it? I had something weird happen with a PM yesterday and dismissed it as just a glitch but if others are having issues I'd like to know please. I certainly never received one from you.



No, it wasn't you.  

As long as I'm here, there's a side story.  I have a piece of graphite of about the right size, but I don't know anything about it.  

10 year ago, when I was just getting started, my wife and I went to NAMES.  I found out about Jerry Howell's engine plans and bought his kit for a flame eater.  All of this got put aside and moved from room to room a couple of times.  It included full drawings, two sets of ball bearings (one set would have been fine for the bracket I redesigned) and a piece of graphite pretty much perfectly sized to make the piston.   No markings, and no details on the graphite.

I stumbled across the box with these parts the day after I ordered my ball bearings.  Thankfully, I hadn't ordered a big graphite rod.


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## CFLBob (Jul 9, 2018)

It has been a slow week due to some problems threading on my Little Machine Shop LMS 3540 lathe.   The most involved part I made was the wrist pin yoke, which is a small part (5/16 OD) with a 3/16 long stud threaded 6-32 on the end.  For about three full turns. 




Briefly, I've only done a couple of threading jobs on this lathe, 1/4-28, and some practice 1/4-20 pieces.  When I went to thread the part, I changed over to the gears for 32TPI and the gears mechanically interfered.  I couldn't see how I could thread anything finer than 28 TPI on the lathe, but they say it can do 7 to 80 TPI.  LMS was of no help but staring at the setup until my eyes glazed over eventually got me an answer that worked.  Whether it's right or not, I don't know.  But maybe if it works it's right. 

I eventually found the work around, which is to reposition the swinging lever that holds the two intermediate gears (called B & C) outside the driving gear.  It makes the lathe less safe to use - there's a spinning gear about four inches from where you hold your hand, but an impromptu cover makes it less likely to grab you.  You'd have to work at getting something into the gear. 






Once that was done, I did some practice pieces to make sure I could thread them safely a few times in a row and then my work piece.  

This week's contribution to the parts pile:





The wrist pin yoke with the wrist pin (a 1/8" piece of steel with a 3/32 hole along its axis), a custom collar and washer (the washer is made from the head of a nail), the flywheel shaft, and the practice pieces I threaded three turns of 6-32 on. 

Next it's on to the piston, which will be graphite.


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## Cogsy (Jul 10, 2018)

It's been a while since I did any threading on a mini lathe but that doesn't look right to me. The gears can be 'double stacked' on each point if I remember correctly, and the bottom pivot can be moved around quite a bit on it's bracket to allow the different gear sizes to mesh correctly without going outside the gear cover. I'm guessing there's either an adjustment you've missed or your gear train should be 'staggered'.


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## CFLBob (Jul 10, 2018)

Cogsy said:


> It's been a while since I did any threading on a mini lathe but that doesn't look right to me. The gears can be 'double stacked' on each point if I remember correctly, and the bottom pivot can be moved around quite a bit on it's bracket to allow the different gear sizes to mesh correctly without going outside the gear cover. I'm guessing there's either an adjustment you've missed or your gear train should be 'staggered'.



This is a long story that I didn't want to spend lots of time covering.   I made a video of the problem where I demonstrate the interference issues to send to a friend who's much more experienced than I am for advise.

Don't mistake this as confidence that I'm sure I'm  right.   This drawing should help with the names for everything:





Gears B/C (same hub) and D are mounted along a swinging, adjustable length arm.  The hub D is mounted on is the leadscrew for the carriage and so its hub is the pivot that the arm rotates around.  

If you compare this layout to the one above, it looks like the gears on C and D have been swapped; this looks like the gearing for normal running, which is the power feed.  What was happening was that with any gear on D bigger than the size used for 28 TPI, the B/C gears get pushed farther out the lever and the C gear (being bigger) hits the bushing on the shaft of the driving gear - which is unlabeled, to the left of A.   

Gears A-C are the same for threads from 28 to 40 TPI.   Only D changes size.

I went from 32 TPI to 40 by changing gear D from 80 to 100 tooth and that larger diameter pushed B/C so far out that they hit that enclosure at upper left.  I don't think B got within two inches of A, which is supposed to drive it.  I took it all apart and put the lever to the right of that enclosure, where it would have to be, and then couldn't get the parts in there.  

I searched everywhere I could think of for help with threading on this lathe.  The thing that stood out was that the manufacturer, Sieg said it would cut 8-24 TPI.  Axminster, the big tool dealer in the UK said the same thing.  The only people who said this could do up to 80 TPI is LMS.  I asked them for help, they said something about that lever being movable (which anyone who has changed gears would know) and when I sent them the picture of the lever arm out there to the right of the enclosure asking "is this the way it's supposed to be?", they never answered. 

If I'm wrong and there's a less awkward way to put this together, I'd love to know, but I simply couldn't make it fit.


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## Cogsy (Jul 11, 2018)

Interesting - I certainly see your issue. I only have experience with the SC3 and it seems the SC4 is clearly different (though I didn't realise you had an SC4 from the pictures). My SC3 is a metric version so again it's different, but I've cut 0.5mm threads on it which is equivalent to almost 51 TPI, so I can confirm the smaller lathes can handle finer threads. Of course that doesn't help you at all, but I like your work around, way to think outside the box!


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## CFLBob (Jul 11, 2018)

Cogsy said:


> way to think outside the box!



The box came back as my safety to keep from accidentally putting a finger where it'll get hurt.







Plain old cardboard box.  I'd like to take credit, but it's my wife's idea.  One flap is folded into it and the two pieces of cardboard make it thick enough that it wedges behind the lever with B and C on it.  Yeah, I can push the box out of the way, but not the kind of brush against it that I might do by accident.  

I'm hoping that if I'm wrong someone searching the web for "SC4 threading" or "LMS3540 threading" comes along and tells me how to do it better.   

The graphite piston is cut slightly oversized, hollowed, drilled through and slightly oversized.  Now comes the meticulous part of putting it on the push rod, trying to fit, taking it off the push rod, turning a little more and so on.


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## CFLBob (Jul 12, 2018)

The piston is done and the size tweaked in.  I can feel it pull a vacuum when I pull it or push it in the cylinder.  

Since the advise here wasn't unanimous, I decided to leave the piston walls 1/8" thick.  No particular real reasons.  The only portion of the piston made exactly to the plans for a metal piston say is the middle of the cap where making it too thick would keep the three threads on the yoke from sticking through. 











I'm really not sure what percentage done this makes me, but there's a handful of very intricate little parts that have to be done.  The cam, cam roller, roller shaft, roller fork, valve and a few others.   

I'll say somewhere around half done.


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## werowance (Jul 12, 2018)

Hi bob,  was just reading your build.  concerning the graphite piston,  I just wanted to throw this out there:
I just finished a flame eater and like to have never got it to run,  the final solution was this:

my cylinder was 303 stainless,  the piston and valve were graphite.  the 303 would expand so much when up to operating temp that it wouldn't run. 
solution was to make the piston and valve so tight that when cold the engine was completely seized up.  but once warm it spun freely.  I think the stainless expands so much more than graphite does that it was leaking to much vacume.

but your build is coming along nicely. and looking good


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## werowance (Jul 12, 2018)

and on the piston yoke,  that was the hardest part on mine to make as well.  looks almost identical


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## deverett (Jul 12, 2018)

CFLBob said:


> I'm really not sure what percentage done this makes me, but there's a handful of very intricate little parts that have to be done. The cam, cam roller, roller shaft, roller fork, valve and a few others.
> 
> I'll say somewhere around half done.


If you are anything like me, with 50% done that leaves only about 90% to go with all the forgotten bits to make and remake!

Dave
The Emerald Isle


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## CFLBob (Jul 13, 2018)

werowance said:


> Hi bob,  was just reading your build.  concerning the graphite piston,  I just wanted to throw this out there:
> I just finished a flame eater and like to have never got it to run,  the final solution was this:
> 
> my cylinder was 303 stainless,  the piston and valve were graphite.  the 303 would expand so much when up to operating temp that it wouldn't run.
> ...



Interesting...  My cylinder is aluminum, so expansion will be different.  Probably worse, because I think aluminum has a higher CTE than 303.  The piston pulls a vacuum.  If I put my thumb over the slot on the cylinder I can definitely feel the pressure both pushing into and pulling out of the cylinder.  There's a slight rough spot about halfway down the cylinder, but I'm not going to do anything about it, yet. 



deverett said:


> If you are anything like me, with 50% done that leaves only about 90% to go with all the forgotten bits to make and remake!



I always thought the last 10% of the work took 90% of the time.   That's how it was when I was working.  I hope to finish by December.


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## CFLBob (Jul 22, 2018)

I need to ask for help of the members that have built one of these Duclos engines.  

The week was a bit slow, as I had to wait on a tool I needed to order, and the only part I finished was the valve.  For this, I moved over to my Sherline CNC system.   (Disclaimer: none of those scars in the vise have been made in the last couple of years)





I'm starting on the cam and some of the small, fiddly bits.  I come across this screw: 






I'm stumbling over this.  Notice over the left where it points out the thread as 4-40 and then shows lines extending over the threads and dimensioned .156.  

Those don't go together.  A 4-40 screw has a major diameter of .112 by my tables.   .156 is between #6 and #8.  The lines aren't extending from it, but is that supposed to be the OD of the shoulder?  There's nothing else that seems to indicate the diameter of that section.  

How would you make such a thing?  I'm tempted to get a flat headed 4-40 screw and put a .188 long clearance sleeve on it.  If I have to flatten the head of the screw in the lathe, or on a belt sander to make it .032 high, that's probably easier than threading that 1/8" long section.   

One of the parts I cut a few weeks ago was a piece that's like the sleeve I'd need to make if I did this but larger in diameter - if that .156 applies there.  A #34 drill bit is 0.111, which would clear most #4 screws.  Looking at the book, I don't see where this sleeve goes.  






Looking through the chapter on this engine, I don't really see any mention of where these parts go, or how to put it together.  

Looking for any advice on these parts I can get.


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## fcheslop (Jul 22, 2018)

You can make the major diameter to what ever you like within reason and then bore/ream the roller to match.Again the thread canbe what ever is available my engine is a BA size.
The pin screws into the forked L shaped part that carries the valve spindle and carries the cam follower
Not sure about the bushing and would have to check just cannot remember
I can do a wee pic if needed of my old banger


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## CFLBob (Jul 22, 2018)

This screw goes into the cam roller, right?  It says to ream the center to 5/32 which is .156, so I can see where that number comes from.  

I'm still trying to figure out how to make that piece, given what I've got to work with.  I get what you're saying about it can be anything as long as the parts match.  What I'm concerned about is that the thread is drawn all the way up to the .156 portion, and I don't think I can work right up to it.  I have a small 60 degree thread cutter, 1/4" shank, but I think that still takes a corner off that .156 shoulder.   Or else I stop one or two turns away from it.  

Pics would be cool, but maybe I can just ask how much of that thread extends out of the nut when it's put together.   On the wrist pin yoke, there were only three threads sticking through the piston and the nut took up all three of them.  If this is the same way, I'm less concerned about my cutter taking a bit off that .156 shoulder.


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## Cogsy (Jul 22, 2018)

I could be/probably am, completely wrong, but looking at it the shoulder is given as 5/16" isn't it ("5/16 under the head")? I would then assume the 4-40 is a female thread into the .156 projection. I have no idea if this makes sense as a part but it makes sense (to me) based on the drawing.


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## fcheslop (Jul 23, 2018)

On my engine from memory I counter bored the part it screws into  or under cut at the threads shoulder
I simply turned the pin to what ever I decided on at the time (20 plus years ago) then reversed in the chuck to face the head and cut the slot by hand now I would set it up and use a slitting saw
The threaded portion has no nut as its for the tapped hole and on my engine one thread protrudes
The head of the screw is ony 1/4 dia but it canbe bigger


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## fcheslop (Jul 23, 2018)

Just checked and I did counter bore for the cam followers pin and also undercut the thread on the pin by around 1/32 wide.Just enough to allow it to seat properly


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## CFLBob (Jul 23, 2018)

Thanks for taking it apart and grabbing those pictures.  Like they say, a picture is worth a thousand words.  

I'm less concerned about cutting that thread, now.  I usually leave some slop at the end of the threaded part, so that I don't have to stop it exactly at the same point every time.  Like in my picture of the parts in post 57.  That cutoff tool I used was too wide, but that's the general idea.


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## fcheslop (Jul 23, 2018)

Glad thats cleared up and good luck with the rest of the build
It is a great design and my engine has done many hours running at shows and still fires up easily despite a few rough edges. It was the first of many flame gulper engines I built
I keep promising to to tidy it up but never get round to it
Just grind up a short thin parting tool for those jobs it will last for ages or make one from a wee bit of old slitting saw blade 
I have a bit of square key steel drilled and tapped with a simple shouldered bolt and often use this with a slitting saw mounted to it for cutting grooves.A wee bit rough ar++d but it works even for cutting fins and the small slitting saws are cheap enough and you can stack them together .
cheers


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## CFLBob (Jul 26, 2018)

Done except for parting off.   






The metal scale was to prove to myself that it was cut through properly.

Either the cam roller or the cam roller shaft (screw) is next.


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## CFLBob (Jul 28, 2018)

fcheslop said:


> Just checked and I did counter bore for the cam followers pin and also undercut the thread on the pin by around 1/32 wide.Just enough to allow it to seat properly



Back to this little screw again.  I just made the Cam Roller, and since I didn't have a 5/32 reamer in my set, I just drilled it to 5/32.  The drawing for the screw says to make that shoulder 0.156 and the calculator says 5/32 is 0.15625.  I figured I'd machine the screw to match the roller.  

Does the Cam roller spin on this shoulder or is it press fit on?


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## fcheslop (Jul 28, 2018)

It spins
If you dont have a reamer a slot drill will do the job or better still make a D bit much cheapness and very usefull bits of tooling


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## CFLBob (Jul 28, 2018)

fcheslop said:


> It spins
> If you dont have a reamer a slot drill will do the job or better still make a D bit much cheapness and very usefull bits of tooling



Thanks.  I'll turn it to a loose fit in the cam roller. 

The cam roller came out pretty cool looking in the rotary table.  I was trying to figure out how to cut that relief between the hub and the outer rim, and a friend said "you're going to put it on the rotary table to drill those holes, can you just mill a ring there?"  I used a 1/8" HSS end mill and it worked fine.






*Edit* for writing error. 1628 EDT


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## CFLBob (Aug 2, 2018)

This took longer to do than it should, but I did everything on my micro lathe (Sherline) and had to spend an extra couple of days trying to remember how to set up the threading attachment and then make a couple of practice pieces.


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## CFLBob (Aug 6, 2018)

Next part; the roller fork alongside that screw.  Relatively enormous by comparison.   It could use lapping on some sandpaper.


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## CFLBob (Aug 13, 2018)

The crank arm. 







The brass press fit was a minor adventure, but not in bad way.  I have a 4-jaw scrolling chuck for my Sherline micro lathe that I hardly ever used.  Just the thing for holding a cube.   So getting to justify tools you have is always a good thing.  

Now the shocking part:  this is the last part that requires machining.  I'm having minor issues with the springs, and then drill the holes for the mounting plate, but it's getting to be time to build this up and try to get it to run.


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## CFLBob (Aug 25, 2018)

Close, but no cigar.  It's built but isn't spinning smoothly enough for me to think it's worth trying to get it to run off my alcohol lamp.






The push rod for the sliding valve, visible in the middle  with a spring around it, doesn't slide smoothly.  It doesn't return to starting position like it should.  The spring isn't wound from wire, the way Duclos wrote.  I found a pen spring and abused by stretching it out.  It has the same wire diameter.

At best, I just tweak the positions of some parts, maybe replace that spring with another that I have.  At worst, the flywheel and it's mounting brackets might have to be moved slightly away from your point of view in this picture and that will require a bit of effort.

If anyone's reading this, wish me luck!


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## Cogsy (Aug 26, 2018)

Good luck, you'll get there eventually I'm sure.


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## Shipdisturber (Aug 26, 2018)

I know this question isn't part of your build thread CFLBob but I'll ask it anyway. Are you a B.C. Lions fan?


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## CFLBob (Aug 26, 2018)

Shipdisturber said:


> I know this question isn't part of your build thread CFLBob but I'll ask it anyway. Are you a B.C. Lions fan?



Since I don't know who they are, I'm sure that means I'm not.


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## CFLBob (Aug 26, 2018)

No joy.  Can't get it run on its own.   Sometimes it sounds like it wants to run but never goes more than about four piston strokes. 

It spins fairly freely.  I can feel resistance from compression and lower pressure in the cylinder.  

Anyone have pointers of things to look for?


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## CFLBob (Aug 26, 2018)

This is a craptastic video (my camera changed focus on me), but it shows the general situation.


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## minh-thanh (Aug 26, 2018)

CFLBob!
I think you should reduce spring tension. I never use a pen spring for my flame eater


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## CFLBob (Aug 26, 2018)

Thanks minh-thanh.   I've been working primarily on that spring.  I didn't make the spring as Duclos says.  The first spring was taken from ball point pen.  It was the right wire diameter, but too short, so I stretched it to fit.  Second spring was too long, but a thicker wire.  I cut that to length.  Then cut it another turn shorter.  

I guess I need to break down and buy some music wire to make the spring.


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## minh-thanh (Aug 26, 2018)

CFLBob !
In your video, I saw the engine move quite ok, but in about 24 seconds of video from the start, I saw the force of the springs too much.


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## rlukens (Aug 26, 2018)

Bob, I've not yet finished designing my flame eater so I'm not a qualified expert. But... I think your timing is off, or the duration, or lift, of the cam is wrong. You shouldn't have compression blowing the flame away (as in the video).  These fickle engines can't stand compression working against them. 
I'm struggling with my design for that very reason. I'm thinking of a check valve in the cylinder head.


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## Shipdisturber (Aug 26, 2018)

CFLBob said:


> Since I don't know who they are, I'm sure that means I'm not.


Just asking because with CFL at the start of your name reminds me of the Canadian Football League "CFL", the Lions are in the CFL.


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## Shipdisturber (Aug 26, 2018)

I think the timing is key to make this run better. I would be inclined to have the valve shut a little before the bottom of the stroke that would add some vacumn to the power stroke and assist with that stroke.


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## CFLBob (Aug 26, 2018)

Shipdisturber said:


> Just asking because with CFL at the start of your name reminds me of the Canadian Football League "CFL", the Lions are in the CFL.



OK, I get it.  CFL is the usual local abbreviation for Central Florida.   I looked up the name BC Lions, and I'm about as far from British Columbia as you can get while still being on the same continent.


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## CFLBob (Aug 26, 2018)

Shipdisturber said:


> I think the timing is key to make this run better. I would be inclined to have the valve shut a little before the bottom of the stroke that would add some vacumn to the power stroke and assist with that stroke.



One of the features of the Duclos design is that the cam is adjustable, so I can vary the timing.  I'm not sure which way to move it, but it's pretty much centered right now, as he recommends in the book.   Post #78 shows the cam and the roller that rides on it and pushes the push rod.


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## Cogsy (Aug 26, 2018)

Bear in mind I've only built the Jan Ridders flamelicker so I'm no expert. The thing I notice is your flame looks quite yellow/orange in the video, what fuel are you using? I use ~95% alcohol and the flame has more blue in it, so is likely a bit hotter than yours.

As for the timing, some air has to be expelled from the port at the top of the stroke to get rid of exhaust gases so I wouldn't be concerned about that. If you  close the valve before BDC to get 'extra' vacuum, that power has to come from somewhere and you'll be robbing your engine of full power.

How much preheating did you before the video? If the cylinder is stainless it might take a minute or two to heat up enough for the engine to run. It's certainly making all the right noises. Check your fuel, preheat the cylinder and have another go maybe? Good luck!


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## minh-thanh (Aug 27, 2018)

I'm not an expert too 
but in the video i saw the force of the springs too much. I think should reduce spring tension I think it will run. if not and with some check : temperature, adjust a little of time valve


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## fcheslop (Aug 27, 2018)

Set the cam full advanced. My engine runs retarded just to slow it down.
Set the valve so the leading edge only cover the port by 1/64 
Is the valve seating Try turning the engine the wrong way and you should feel the suction it is fairly strong
The valve spring only needs to just keep the follower on the cam
Make a proper burner it may save you wobbling about like a one handed fan dancer
When starting make sure any condensation has burned off from the port face These engine some times need a wee bit of pre heating although the Duclos one doesnt suffer badly from the problem
If you need any pic from my old klunker just shout or a rough video
cheers


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## CFLBob (Aug 27, 2018)

Cogsy said:


> Bear in mind I've only built the Jan Ridders flamelicker so I'm no expert. The thing I notice is your flame looks quite yellow/orange in the video, what fuel are you using? I use ~95% alcohol and the flame has more blue in it, so is likely a bit hotter than yours.
> 
> As for the timing, some air has to be expelled from the port at the top of the stroke to get rid of exhaust gases so I wouldn't be concerned about that. If you close the valve before BDC to get 'extra' vacuum, that power has to come from somewhere and you'll be robbing your engine of full power.
> 
> How much preheating did you before the video? If the cylinder is stainless it might take a minute or two to heat up enough for the engine to run. It's certainly making all the right noises. Check your fuel, preheat the cylinder and have another go maybe? Good luck!



Fuel is from a can of Klean Strip denatured alcohol from the hardware store.  The company website says about 50/50 ethanol and methanol mix.  Should be about the same as yours.   As for the color of the flame, possibly something dripped on the wick from another project a while ago.  Or the wick burning itself.  The wick is black, like it has been burning.

In that video, I didn't preheat the cylinder, but for most of the time I was working, I heated it 30 seconds or so in the flame, enough to get it too hot to touch.  I had been messing with the engine for a long time and then had to break for an hour to recharge my camera's battery.  Since I was just there to take the video, I just sat down to spin it.  I mostly wanted folks to hear the sounds of the air compressing or escaping

The alcohol lamp was always supposed to be temporary.  Virtually every video has a custom alcohol lamp and every video has the guy fooling with the placement to get it exactly in the right spot.  Since the Duclos plans have a lamp made from a door knob that's permanently mounted, I thought I'd try something I already had and not mount make a mount for it until I found where it needs to go.  The problem was I never pulled the lamp up to the cylinder until yesterday.  That's when I saw it's much too big.  

Looks like another week or so.  I started cutting metal around the end of February, and didn't start this thread until May, another few weeks doesn't matter.

Meanwhile, I need to find some .015 spring wire to wind a spring.  I think I mess with the spring before I mess with the timing.   I said I started with a spring from around the house with .015 wire and stretched it out, then went to a bigger wire spring and cut it off.  After the second time I cut it back it looks like this:





That gap isn't that big.  Rough guess is 1/16".   But it doesn't press the cam roller onto the cam.   The slightly too long spring is less bad than this, but it needs to be replaced.  






Somewhere in there, I make an alcohol lamp.


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## CFLBob (Aug 27, 2018)

post deleted


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## minh-thanh (Aug 27, 2018)

With large diameter steel wire,I think you should make the diameter of the spring larger in the middle and only smaller at the two ends, when the diameter is larger, its tension will decrease.


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## minh-thanh (Aug 27, 2018)

Edit post


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## fcheslop (Aug 27, 2018)

For burners I like to use copper pipe reducers as they are cheap and available
The original burner canbe adjusted by pivoting it around.The flame needs to be as close as possible but not touching the valve
The spring on my engine is as rough as a badgers backside but looks a lot finer wire than you have used I think it was wound from a guitar string
I found on my first few runs as it bedded in the timing needed retarding  or else it rattled along the bench
I v attached a link just to show the fittings as I dont know what they are known as in youre neck of the woods
https://www.google.co.uk/aclk?sa=l&...hUKEwipoKKIlY7dAhWSLFAKHfGPDcwQ9aACCDo&adurl=


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## CFLBob (Aug 27, 2018)

fcheslop said:


> For burners I like to use copper pipe reducers as they are cheap and available
> The original burner canbe adjusted by pivoting it around.The flame needs to be as close as possible but not touching the valve
> The spring on my engine is as rough as a badgers backside but looks a lot finer wire than you have used I think it was wound from a guitar string
> I found on my first few runs as it bedded in the timing needed retarding  or else it rattled along the bench
> ...



Thanks.  I was actually thinking of trying a string off one of my guitars.  I'm due to change strings on a few of them.  The third string be around the .015" that Duclos calls out.  I just don't know if a wire guitar string is "music wire" or if it's too weak, too strong, too something.

For an alcohol lamp, I was thinking of buying one.  Making one is almost in the realm of "why bother?"  There's a handful of cheap options on eBay, like this one.  It's a bit too tall, but there are lots of options.


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## fcheslop (Aug 28, 2018)

Not sure if youve seen this but it maybe of some use
http://www.deansphotographica.com/machining/projects/springs/springs.html


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## CFLBob (Aug 28, 2018)

fcheslop said:


> Not sure if youve seen this but it maybe of some use
> http://www.deansphotographica.com/machining/projects/springs/springs.html



Yes, I've been there before.  Good site.  Thanks for the reminder.


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## fcheslop (Aug 28, 2018)

Dean was / is a member although he has not posted for sometime
Good luck with the rest of the build


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## CFLBob (Sep 4, 2018)

Still won't run.  

I changed the spring over from the one on the bottom (wire too thick, spring too short) to one more like the one on  the top, only a little longer.  







Still not quite the way Duclos describes it, but this is my first experiment winding a spring on the lathe as Dean shows.  Made from a guitar string (.013) and the one I used is better seen here:






It's 20 turns and Duclos said to make 32 turns.  I need to work on that.  Here's today's video.  I preheated the cylinder with a butane torch for 30 seconds, then kept the new alcohol lamp where it's visible here.  



Last week, there was some talk about changing the cam timing.  I do see the compression in the cylinder blowing the flame aside for just a fraction of a second.  You can see in the second picture that the piston is about as far in the cylinder as the crank allows it.  The valve is all the way open and that spring pushing the cam roller onto the straight side of the cam.  Can someone tell me if that's right?  Which way should I move it?  

Thanks.


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## minh-thanh (Sep 4, 2018)

Now , 
I think :
Did you check that the valve and the piston are airtight? In the video, I feel it does not seem to make a vacuum (- the flywheel turns back only when the spring is compressed, and it is not vacuum)

  Like Cogsy said, "The thing I notice is your flame looks pretty yellow / orange in the video, what fuel are you using? I use ~ 95% alcohol and the flame has more blue in it, so is likely a bit hotter coal yours.

As for the timing, some air has been expelled from the port at the top of the stroke to get rid of exhaust gases so I would not be concerned about that.  "


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## CFLBob (Sep 5, 2018)

minh-thanh said:


> Now ,
> I think :
> Did you check that the valve and the piston are airtight? In the video, I feel it does not seem to make a vacuum (- the flywheel turns back only when the spring is compressed, and it is not vacuum)
> 
> ...



The alcohol I'm using is  "Klean Strip denatured alcohol", and tab 5 on that page says, "Klean-Strip® Denatured Alcohol has between 40 – 50% ethanol and 50 – 55% methanol."   It might be possible to get something better from the drug store, but it's what the hardware stores around here sell.  

If I take the steel valve off and just put my thumb over the valve opening, I can feel the pressure while trying to pull the piston down the cylinder.  The difference in force it takes to move the piston is noticeable.  The piston was too tight when I first put the engine together and would bind in one spot along the cylinder, so I ran the engine with my electric drill for about a minute to loosen it up just little.  

I'm not quite sure what I could do to test how tightly the valve seals.  It doesn't seal as tightly as my thumb does, but I can feel air being ejected as the piston comes to the "top" of the cylinder.


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## minh-thanh (Sep 5, 2018)

Can help you understand more ...airtight
1 / No springs



Video :


2 / springs :



Video :


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## CFLBob (Sep 5, 2018)

Thanks, Minh!  

Just so I'm sure I understand, in video 1, you disconnect the rod to the valve, and the seal is so tight the piston hardly moves.  Right?


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## fcheslop (Sep 5, 2018)

Thats correct Bob and on the Duclos you should find it is the same
Also check the valve can swivel on the shim spring as it may come off the port if theres the slightest misalignment .Hence the D shaped cut in the valve and the D shape on the end of the shim bit.
With the port blanked when you pull the piston to bottom dead center it should snap back up the bore . 
The flame you use looks very yellow I prefer to use shellac thinners that French polishers use not sure what its known as over youre neck of the woods
What are you using to lubricate the cylinder as these engines hate any oil


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## CFLBob (Sep 5, 2018)

OK, I ran a test by disconnecting the push rod and flicking the wheel to see if it spun.  Nope.  The valve pulls shut. 



Fcheslop - I though they were the same thing: denatured alcohol.  Like I said a few posts ago, the manufacturer says about 50/50 ethanol and methanol (the poisonous stuff).  This web page makes it sound like it should be good for thinning shellac.  

What percentage ethanol should I look for?  I have no idea what else is out there.   I have a vague memory that pharmacists had really high percentage ethanol, the kind you drink, but could put in a little something to make it sellable (poisonous).  I'll call around and see if anyone has more pure ethanol available.


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## fcheslop (Sep 5, 2018)

This is whats I use when I cannot get the French Polishing thiners
https://darrantchemicals.co.uk/methylated-spirits
cheers Frazer


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## CFLBob (Sep 5, 2018)

Thanks!  The difference is that web page says you methylated spirits are 10% methanol, 90% ethanol, instead of the 50/50 blend I have,

I just checked the four closest hardware chains and none of them carry any brand that gives any better than that.  

However, it looks like Amazon carries 95% ethanol.   Unless a call to the pharmacist shows I can get some from them, it will have to be Amazon.


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## minh-thanh (Sep 5, 2018)

CFLBob !
You check the close valve before BDC, piston + cylinder + valve : is it airtight?
Because it is very important to create a vacuum.. If it's airtight - BUT move gently.


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## CFLBob (Sep 7, 2018)

Could someone look at this picture and tell me if my cam is on the right way?  The piston is at the top of its travel, just off Top Dead Center (as I understand it) with the large radius of the cam on the left side.  I don't see how It could go any other way, but it could rotate with the top more to the right (closes valve sooner) or left (closes it later).


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## minh-thanh (Sep 7, 2018)

I adjusted the slide valve for my engine (and I think it's the same as your engine )
"" 4. The adjustment of the flame-eater.
The correct movement pattern of the slide valve in the 360° cycle is crucial.
The valve must open the flame hole in the cylinder about 30° before the piston is in its position closest to the cylinder head. The reason for that is that the cooled flame gases also are compressed again to atmospheric pressure during the working stroke of the piston already before the piston has reached its end position. If the flame hole is opened too late a counter-acting pressure will occur in the cylinder; the engine slows down or even stops running than. This opening of the cylinder hole through the slide should preferably be as abrupt as possible. During this 30º the cooled gasses with atmospheric pressure escape trough the flame hole to the outside. The valve must close the flame hole again at the time the piston is arrived again at 20 to 30 º from the other end side of the cylinder.
The overlap of the valve over the flame hole at the time that this is closed needs to be close to zero. I even have the experience that the motors run better if there is a very small gap left with the thickness of a human hair! For this phenomenon I still don't have a good explanation yet, presumably this also has to do with the occurrence of any counter-acting pressure in the cylinder.
The pressure of the spring(s) that holds the slide valve against the cylinder surface need to be adjusted so that the valve moves very well parallel along the cylinder surface but with a minimum pressure to minimize frictions. In fact, the valve only needs to be kept in place because the partial vacuum in the cylinder will pull the valve to the cylinder surface making a good leak free contact.""

For more :
Link  

http://ridders.nu/Webpaginas/pagina_ervaringen_tips_happers/ervaringenhappers_frameset.htm

And one more thing, in your video I feel like the engine does not move as smoothly as my video


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## CFLBob (Sep 7, 2018)

minh-thanh said:


> I adjusted the slide valve for my engine (and I think it's the same as your engine )
> "" 4. The adjustment of the flame-eater.
> The correct movement pattern of the slide valve in the 360° cycle is crucial.
> The valve must open the flame hole in the cylinder about 30° before the piston is in its position closest to the cylinder head. The reason for that is that the cooled flame gases also are compressed again to atmospheric pressure during the working stroke of the piston already before the piston has reached its end position. If the flame hole is opened too late a counter-acting pressure will occur in the cylinder; the engine slows down or even stops running than. This opening of the cylinder hole through the slide should preferably be as abrupt as possible. During this 30º the cooled gasses with atmospheric pressure escape trough the flame hole to the outside. The valve must close the flame hole again at the time the piston is arrived again at 20 to 30 º from the other end side of the cylinder.
> ...



Thanks again, Minh-Thanh.  That piece from Jan Ridders gives me some numbers and things I can measure.  



minh-thanh said:


> And one more thing, in your video I feel like the engine does not move as smoothly as my video.



That's the part I feel least comfortable about, but the least sure about what to do.

I ordered a liter of 90% ethyl alcohol fuel from Amazon to be here Sunday.  I made two more springs (different lengths) from the music wire that got here Wednesday.  I'll try a few things while waiting for the fuel.


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## fcheslop (Sep 7, 2018)

Hi Bob, the cam can only go on one way as you correctly say. The engine will run or at least my engine will run at any position on the adjustment slot it just goes faster oneway and a wee bit slower the other
One problem I remember was that I adjusted the valve to come to far forward it only needs to fully cover the port by about 1/64 thats the leading edge of the valve I set it wrong and it wouldnt run or ran erratically. I think I had a problem with the shim bit that holds the valve I bent it up slightly wrong but maybe Im wrong as its 20 years ago
It must be lubricated with graphite anything else kills it .I just use a 4B pencil and scribble around the piston again to much graphite chokes it up hence just using a pencil. I also lubricate the valve face the same way
It needs to spin freely any binds will stop it running even the slightest
If you need a pic I can to one or two Sunday
cheers
frazer


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## CFLBob (Sep 7, 2018)

fcheslop said:


> Hi Bob, the cam can only go on one way as you correctly say. The engine will run or at least my engine will run at any position on the adjustment slot it just goes faster oneway and a wee bit slower the other
> One problem I remember was that I adjusted the valve to come to far forward it only needs to fully cover the port by about 1/64 thats the leading edge of the valve I set it wrong and it wouldnt run or ran erratically. I think I had a problem with the shim bit that holds the valve I bent it up slightly wrong but maybe Im wrong as its 20 years ago
> It must be lubricated with graphite anything else kills it .I just use a 4B pencil and scribble around the piston again to much graphite chokes it up hence just using a pencil. I also lubricate the valve face the same way
> It needs to spin freely any binds will stop it running even the slightest
> ...



Thanks, frazer.  I ordered a liter of 90% ethyl alcohol from Amazon, so I won't be able to do anything until Sunday.   I'm not sure what picture would help me, but your description of the cam adjustment helps tremendously.

My piston is graphite, and when I turned it to its final size, I collected the dust to sprinkle or rub on things as the lubricant.  There's no oil in the cylinder at all, but I have put some light machine oil on the moving pieces on the flywheel, and on the cam roller.  The original Duclos engine had the steel flywheel shaft running on the aluminum bracket and had little oil ports bored into the tops of the brackets to lubricate the flywheel shaft.  I used ball bearings for those.  

I really like the idea of a soft lead pencil to scribble on the sides, though!


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## fcheslop (Sep 7, 2018)

Hi Bob, my bad for not reading the thread fully although I struggle due to dyslexia so tend to miss things
My engine is as per the original design and the crank shaft runs direct in the alloy and is still good although Little Blazer has a lot of wear no idea why as its half the age and made from the same grade of alloy.If I was building another I would also use ball bearings
I did have a few problems getting it to run due to my errors mainly piston fit and the valve adjustment and its seating but once these things were sorted its ran for 20 years plus with no new parts what ever . Be sparing with the oil as it gets thrown about a bit a gets into the cylinder then you end up with black crud
On later engines I used graphite but have gone back to bronze or leaded mild steel as I just didnt get on with the stuff for some reason
Im a fan of this engine as its just so reliable and not to fussy about flame position although you need to make sure the flame covers the port but does not touch  the valve 
One other area for leaks is the small end fitting that screw into the piston I sealed it with a bit of gasket glue
cheers
frazer


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## CFLBob (Sep 7, 2018)

No sweat on not reading everything.  Heck, I _wrote_ a lot of it and I'm not sure I remember everything.   

One of the reasons I picked this one to build is reading (here, I think) that it was a reliable runner.  I'm hoping the hotter burning fuel will help, but either way I'm kinda dead in the water until the alcohol gets here.  


Bob


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## Cogsy (Sep 7, 2018)

If you're using ball bearings, have you removed the grease from them? The drag on a shielded ball bearing with grease lubrication is quite large, and with full contact rubber seals it's even worse. Ball bearings in an engine like this will work fine with a tiny bit of graphite in them and no other lube.


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## fcheslop (Sep 8, 2018)

Another thought that Cogsys post brought to mind. For these and Stirling engine dont make the bearings a press fit bore/ream to size and use a wee dab of loctite or super glue to hold them in place. Probably telling my granny how to suck eggs
Good luck they are frustrating little beggars to build but great fun when they run


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## CFLBob (Sep 8, 2018)

Cogsy said:


> If you're using ball bearings, have you removed the grease from them? The drag on a shielded ball bearing with grease lubrication is quite large, and with full contact rubber seals it's even worse. Ball bearings in an engine like this will work fine with a tiny bit of graphite in them and no other lube.



No, I haven't.  This is one of those subjects that didn't seem clear to me while reading about things.  I've read both ways on it, and it seemed just as many guys were saying it never bothered them as saying flush them.  That makes me guess it depends on who manufactured the ball bearings you bought and exactly what they used in them.  

These are not rubber sealed, they have metal seals, and I'm honestly amazed they can make ball bearings that have a 1/4" shaft and fit in a 3/8" hole.   (These bearings)  Boca Bearings has a whole page on how to remove the lube and they basically say to soak them overnight in mineral spirits.  I can do that, I just never made it a priority.  As I run out of options, I probably will.


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## CFLBob (Sep 8, 2018)

fcheslop said:


> ...Probably telling my granny how to suck eggs...



Nope.  In my case, I'm a retired engineer, but an electrical engineer.  That means I'm more like the students than the teacher in this far side cartoon:






I need, will take, and am grateful for all the help I can get.


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## Cogsy (Sep 9, 2018)

Those are indeed very low profile bearings and because of that, they will have many very small balls in them, rather than a few larger ones (like you'd see in a 'normal' profile bearing), so there is the potential for a lot of grease 'pumping' inside the bearing and drag. It's an interesting thing to do, just for your own curiosity, to grab a couple of brand new ball bearings and test for yourself the difference with and without grease. For ease and cost, a couple of 608 skate bearings would be perfect. At a guess, with the inner race pinched between your finger and thumb and spinning the outer race by whacking it with your hand, the shielded 608 full of grease will spin for only a second or two at the most after you stop hitting it. The washed out one, without any lube at all, will likely spin for 60+ seconds. Even saying that though, just turning them slowly by hand will demonstrate the amount of drag the grease is causing.
I'm not sure the bearings are causing all the running problems, but the extra drag is certainly not helping you.


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## CFLBob (Sep 9, 2018)

Just an update.  

The alcohol arrived as scheduled, but it isn't enough to get the engine to run.  It's still binding and not moving smoothly.  I need to go after that first.  BTW, the new stuff, which says 90.5% ethyl,  also has yellow in the flame.


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## Cogsy (Sep 9, 2018)

Here is a video of my Jan Ridders design running so you can see the flame colour. It still has yellow/orange but the 'heart' of the flame is blue and that's the bit you want to draw in to the engine. The fuel I use is sold as 'methylated spirits' here in Australia and is about 95% alcohol, mostly ethanol with a dash of methanol to make it undrinkable.


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## minh-thanh (Sep 10, 2018)

CFLBob ! 
--- Mechanical friction: It is an extremely important issue
unfix it and check each section
     Flywheel + crankshaft + bearings + bore of bearings: You rotate strong the flywheel   it should rotate for about 60 seconds - or more,  it rotates as long as possible ! With the friction of the bearing, bore of bearings   : You should follow the way Cogsy and fcheslop  said
     Friction between piston and cylinder: The piston must be virtually airtight fit in its cylinder but also with the lowest possible friction. This can be as follows with a completely dry and clean piston and cylinder:
     - With the cylinder in the vertical position and closed on top with your thumb the piston must stuck in the cylinder; airtight
      - When the thumbs off the piston should spontaneously fall out of the cylinder; friction is low enough. 
   The friction between the valve and the cylinder surface: The valve just needs to be kept in place,it should not create pressure on the cylinder surface, because the vacuum part in the cylinder will pull the valve into the cylinder surface  ,  it will create airtight.


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## goldstar31 (Sep 10, 2018)

CFLBob said:


> Don't have any with 2.5in inside jaws.  A search for calipers with long jaws only showed long outside jaws.



I've got a micrometer with adjustable jaws going up to more than 6". So I can measure a Myford lathe on a good day!
However, if the barrel of a 0-1" mike is put in a 6" or whatever metal clamp, it should be possible.

It's not new merely re-hashing what Professor Dennis Chaddock used as an addition  on his Quorn tool and cutter grinder.  Reminds me to add this to my machine, too

Norm


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## fcheslop (Sep 10, 2018)

Hi Bob, cannot add to the advice already given. 
You probably have already seen this
http://ridders.nu/Webpaginas/pagina_ervaringen_tips_happers/ervaringenhappers_frameset.htm


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## Gedeon Spilett (Sep 10, 2018)

a very interesting thread ! very nice build.
Well, you almost got it, a little too much drag maybe, and some leaks in the valve
you have to feel the vacuum or compression easily for an immediate start of the engine.


this is the link for one of my album on googlephoto, where you can see some of my flame gulper engines...with some comments that may help you...
https://goo.gl/photos/zpJYqxgR4XHuv6hv5


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## CFLBob (Sep 10, 2018)

Thank you so much to: Gedeon Spilett, fcheslop, minh-thanh, Cogsy and Goldstar31.  There's much to go over here.  

I sort of said last night that I think my issue is the engine doesn't spin smoothly enough on its own.  When the crank arm is vertical (push rod at the top OR bottom), I can feel a little extra drag on the piston, a little catch.  That's with both the piston going in and out.  I've known about this since I made the piston, and I know I've said I ran the engine using my battery powered drill for a couple of minutes to smooth it out.  I told myself "graphite on aluminum, graphite is softer and will grind away first".  It seems it didn't smooth out.   

I think I need to put some 400 grit  sandpaper on a wooden mandrel and try to smooth that out until there's no drag.  Of course, I'm afraid of taking away too much material and making it too loose.  I do have some CRS bar to make a replacement piston, but would rather not (of course).    I've never done the test Minh Thanh describes and Gedeon Spilett shows, where you hold a finger over the flame port and can't pull the piston out.  Perhaps I should do that first and see if my piston is worth saving.  

I noticed for the first time yesterday that the cylinder has a little wobble in the pedestal it mounts in.  I can pull the pedestal and add a couple of setscrews to immobilize it.  

Another thing is that I changed Duclos' flywheel support bracket, as I showed in post #42.  I see wobble in the flywheel and that's the only place I can think to look that's different.  I can always go back to the original design and make another bracket (able to accept my ball bearings, of course).  

All I can think to do is make each part smoother, one at a time.  Start with the cylinder and work backwards.  Remove every little loss and inefficiency I can find.


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## CFLBob (Sep 10, 2018)

I'd really appreciate comments on this video.  It's hard to convey just how much force was involved, but it was hard to pull it or push it in with the port sealed.


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## CFLBob (Sep 10, 2018)

Video #2.  This is spinning the flywheel with nothing attached.   



As always, comments, suggestions or old jokes appreciated.


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## fcheslop (Sep 10, 2018)

Looks good to me apart from the flywheel wobble but thats more cosmetic
I would try it bolted together no valve fitted and see how it spins as the cylinder assy might not be square to the crank or the crank pin not square to the crank both these will give tight spots at top and bottom centre
Fit the valve in the closed position and you should get nearly the same amount of suction you show in the video
Just my two bobs worth from another retired member of the magic smoke club


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## CFLBob (Sep 10, 2018)

fcheslop said:


> I would try it bolted together no valve fitted and see how it spins as the cylinder assy might not be square to the crank or the crank pin not square to the crank both these will give tight spots at top and bottom centre
> Fit the valve in the closed position and you should get nearly the same amount of suction you show in the video



In this case, we're trying to put the magic smoke in, not keep it from getting out.  

I was surprised how tightly the suction pulled the valve closed and wouldn't let the flywheel do a rotation.   

The part that gives me the most stickiness seems to be the valve push rod and cam roller fork on it.  That hole in the pedestal says "Drill or Ream 1/8", and the rod is 1/8" dowel rod, but it seems tight.  I'm all but sure I used a .001 over sized reamer (.126).  I might enlarge that a little just so it doesn't bind in there.  If the threads (#5-40) on the valve push rod get to that hole, they won't go through it.  I didn't think a tap would raise the threads so much.


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## Cogsy (Sep 10, 2018)

Flywheel spin test looks good to me too - not much drag in those bearings even with the grease.


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## CFLBob (Sep 10, 2018)

Cogsy said:


> Flywheel spin test looks good to me too - not much drag in those bearings even with the grease.



Thanks for looking and your help.  In the big picture, soaking my spare set of bearings really is an easy thing to do.  I just think the drag is coming from somewhere else, though.


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## minh-thanh (Sep 11, 2018)

If the piston and cylinder are dry and clean: it's very good
Flywheel spin test : good
Reassemble the partial, and test it step by step.
Between valves and cylinder surfaces, the valve should not put pressure on the cylinder surface, The valve just slides along the surface of the cylinder, ensuring it is close enough ,you can put little oil between them


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## minh-thanh (Sep 11, 2018)

One more thing, in the video I see the surface of the hole air intake seems not good. If the surface of the hole air intake and slide valve is not straight , it is difficult to seal , and will not create vacuum.



You should place the sandpaper on a flat surface ( glass ) and grind it to the straight (first with sandpaper 100, then sandpaper 600).


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## CFLBob (Sep 11, 2018)

minh-thanh said:


> One more thing, in the video I see the surface of the hole air intake seems not good. If the surface of the hole air intake and slide valve is not straight , it is difficult to seal , and will not create vacuum.
> View attachment 103992
> 
> You should place the sandpaper on a flat surface ( glass ) and grind it to the straight (first with sandpaper 100, then sandpaper 600).



Thank you.  

The valve seems to seal well, but the bent shim stock spring seems to be a weak spot in the design.   I keep messing with it, moving it left or right, but nothing has made a difference.


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## fcheslop (Sep 11, 2018)

Hi Bob, the valve rods needs to be a slide but shake free fit. The wee carrier thingy ma bob  the bit that has the cam follower on I thinned it down a bit as Im sure from memory it was causing a bind .It has not caused any probs
The shim bit that holds the valve onto the port face doesnt need to push the valve tightly onto the face it just needs to touch the face as the vacuum will pull it onto the face but if its to hard onto the face the engine cannot exhaust . As Minh Thanh mentions the port face and the valve face need to be flat and its the only area after years of running Iv had to re flattenThe valve needs to be able to swivel on the shim bit thats why it has a rad and the valve has a rad groove cut into it.This allows for any out alignment  that may lift the valve from the port face. What thickness material did you use for the valve shim thing as again to thick and the engine wont be able to exhaust
Dont use oil as it wont like it simply scribble over the valve with a pencil .
One step at a time and you will get there as the rest seems good to go,


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## minh-thanh (Sep 11, 2018)

CFLBob said:


> Thanks.  I'll turn it to a loose fit in the cam roller.
> 
> The cam roller came out pretty cool looking in the rotary table.  I was trying to figure out how to cut that relief between the hub and the outer rim, and a friend said "you're going to put it on the rotary table to drill those holes, can you just mill a ring there?"  I used a 1/8" HSS end mill and it worked fine.
> 
> ...


 
Picture of part opening and closing the valve  my engine


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## CFLBob (Sep 11, 2018)

fcheslop said:


> What thickness material did you use for the valve shim thing as again to thick and the engine wont be able to exhaust



I used .010" stainless shim stock.  Couldn't find .007, without buying a lot of it, so I got a two pieces of .010 from a guy on eBay.  

It seems to pull shut and seal just fine.  In this post, I show a video where I disconnect the push rod and try to flick the flywheel.  The valve pulls shut and won't allow the piston to go far back in the cylinder.   

Oil has never touched that area.  The only place I've put thin (fishing reel) oil have been the cam roller and that fork you say you thinned out.  I was thinking of doing exactly the same thing to that: thin it out, then sand it to more of a polish.


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## fcheslop (Sep 11, 2018)

Hi Bob, I think at the moment finding /eliminating any sticky points would be the way to go and than have a look at the valve gear.
I cannot remember what my shim thing was made from probably a bit of shim or an old tin can as its gone rusty
Iv had a look at my old banger and the reason I thinned the follower carrier seems to have been a slight out of square on the cams working face as I can see it rotates the carrier very slightly when you turn the engine by hand.
The shim part only needs to very gently hold the valve onto the face just enough to stop it falling of. I know I keep muttering on about this part but if not right it will stop it from running or at least thats my experiance
I need to rework my engine its still a good runner but it could do with a freshen up 
cheers


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## CFLBob (Sep 11, 2018)

Thanks, Frazer,

So far, no joy, but everything moves pretty easily until I put that pushrod in place.  I took about .010 off the thickness of that roller fork and then found I got more room by putting the crank a little farther out on the shaft.  Now there's plenty of room in that area, but something still just isn't right.


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## minh-thanh (Sep 11, 2018)

Until now, everything I see and hear you say is perfect fit with the way I do flame eater engine
I really only have one
You adjust the valve a little bit forward ( or backwards ) and run it, bit by bit.
You will find a position that seems like it wants to run, continue to adjust the valve .. and position the flame. BUT: make sure everything is smooth, and air tight. It will run
Flame eater is a difficult engine, Just think in your mind: it has very little power, reduce the friction and air tight as much as possible !
 as fcheslop has said: "Good luck they are frustrating little beggars to build but great fun when they run"


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## CFLBob (Sep 12, 2018)

minh-thanh said:


> Until now, everything I see and hear you say is perfect fit with the way I do flame eater engine
> I really only have one
> You adjust the valve a little bit forward ( or backwards ) and run it, bit by bit.
> You will find a position that seems like it wants to run, continue to adjust the valve .. and position the flame. BUT: make sure everything is smooth, and air tight. It will run
> ...



In that article on Jan Ridders site that I think you sent me to, he says it might take as many hours getting it to run as it took to make the engine, and I'm not there yet.  It took me a lot of time to make the parts.  Some of them I had to make more than once.  

There's still something not right with the valve push rod.  Until I hook that up, it spins pretty well.  Once I hook that up, it doesn't.  That's what I'll try to figure out today.


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## fcheslop (Sep 12, 2018)

Does the valve rod slide in the hole thats machined into the cylinders upright? 
Is the valve rod parallel to the flat machined on the cylinder
Just wondering is something is out of square and jamming a bit
cheers
frazer


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## CFLBob (Sep 12, 2018)

fcheslop said:


> Does the valve rod slide in the hole thats machined into the cylinders upright?
> Is the valve rod parallel to the flat machined on the cylinder
> Just wondering is something is out of square and jamming a bit
> cheers
> frazer



I just took it apart in an effort to find that.  Nothing definite yet.  The hole is marked "Drill or Ream 1/8" on the drawings.  Those are different classes of fit.  I only have .001 over or under reamers, so it's probably reamed .126.  The 1/8" drill rod is tight fit in it.  I opened the hole to 9/64, now it's a bit sloppy.  

If need be, I can drill it out larger and turn a bushing for it that's 1/8 ID and whatever OD I get away with. 

Bob


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## Cogsy (Sep 13, 2018)

Bear it in mind that when the valve rod is hooked up the valve should be operating and the engine will be resisting being turned over without a flame if it is sealing correctly. Only you will be able to tell if it's mechanically binding or not, of course, but spin tests with it all hooked up should probably be done with the flame lit. You may even get lucky and it will just start up and run for you. When I built my Jan Ridders one, it took many hours over many days to get it to go, even when I was certain it was all correct. The flame position on mine is extremely touchy and if it's a bit off it just won't run.


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## CFLBob (Sep 13, 2018)

Cogsy said:


> When I built my Jan Ridders one, it took many hours over many days to get it to go, even when I was certain it was all correct. The flame position on mine is extremely touchy and if it's a bit off it just won't run.


Thanks, Al.  

I've spent a lot of time watching YouTube videos of flame eaters running, and the one thing that stood out was everyone playing with the flame.  I also noticed that when people turn the engine on a turntable, the speed will change.  Don't know if that's from a fan or something in the room, but they seem really sensitive.


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## fcheslop (Sep 13, 2018)

Hi Bob, The Duclos engines dont suffer as badly as the Ridders engines about flame position. The flame needs to cover the port so you are not pulling cold air in with the hot. On the Utube vids its probably the flame wandering a little as they turn the engine as they dont like it.
The Duclos engines are the best runners in my humble opinion once set up they usually just run and run without the the faff that the Ridders engines seem to need thats the internal and external valved ones. I think Iv build about 8 of these beggars now and every one of them has had a few problems mostly of my making
Once the binds are sorted when you spin the motor over you should hear a definite and sharp quacking farting noise this is the engine exhausting
Funny youre build has made me look over my old banger and the hole for the valve rod has a bit shake rattle n roll in it now and it could do with bushing
Im a tight wads of Scottish parents so for reamers I tend to make D bits from the Drill rod Im going to be using sometimes they are a little tight but more often good to go .
Just a wee tip from clock it n flog motor engineers


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## CFLBob (Sep 13, 2018)

fcheslop said:


> Once the binds are sorted when you spin the motor over you should hear a definite and sharp quacking farting noise this is the engine exhausting



I must be close, because I'm getting that noise, but I got that from the start.  It has gone away and come back.  I get some binding over half the cycle, when the piston push rod is pulling the piston out, and the crank arm is pointing more or less up.


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## fcheslop (Sep 13, 2018)

Maybe worth trying to make sure the cylinder is square to the crank or does this not happen with the valve gear removed
You may have enough clearance on the cylinder mount and main bearing mount bolt holes to wiggle it about
If you look on the piston for rub marks it may give you some indication as to whats going on
As in say scuffing top right and bottom left on the piston would point to it been out of square
cheers


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## minh-thanh (Sep 13, 2018)

Just remind you of how the valve is sliding and air tight, as well as when fully assembled it works smoothly :


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## Gedeon Spilett (Sep 14, 2018)

Flame positions is not that crucial,  as they run with an hot air gun... and concentrate your efforts on the mechanics, no binding at all, no tight spot, it is mandatory ! you will feel easily when you have got it IMO, up to the point where, as in above video, you fell free bouncing and compression.


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## CFLBob (Sep 14, 2018)

Gedeon Spilett said:


> Flame positions is not that crucial, as they run with an hot air gun... and concentrate your efforts on the mechanics, no binding at all, no tight spot, it is mandatory !



I've tried to run mine with my little butane torch, but not my hot air gun.  Mine has adjustable temperatures and air speeds, so I guess it would be hard to set up.  Do you know what temperature your gun puts out?


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## CFLBob (Sep 15, 2018)

More work, still won't turn over and run.  It runs more freely by playing with the position of everything on the flywheel's shaft, but still won't run.


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## fcheslop (Sep 15, 2018)

Hi Bob, close but no cigar . Need to have a think about this one and have a look at my engine
What position is the cam it may help starting from the middle of the slot
How close can the flame get to the port its not clear on the video
It looks free enough are there any tight spots? left.
cheers


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## fcheslop (Sep 15, 2018)

Found these old pics maybe not much use but you can see the piston position at TDC and BDC and also a mark that shows how the valve just covers the port


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## minh-thanh (Sep 15, 2018)

There is no vacuum.
You adjust the valve and check its airtightness: when you turn  flywheel  reverse rotation of the engine, it will create a suction (on my engine is about 45 degrees - reverse rotation of the engine, *your engine may be different* . That's just the way I check )


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## CFLBob (Sep 16, 2018)

fcheslop said:


> Hi Bob, close but no cigar . Need to have a think about this one and have a look at my engine
> What position is the cam it may help starting from the middle of the slot
> How close can the flame get to the port its not clear on the video
> It looks free enough are there any tight spots? left.
> cheers



What I did between last time and now was loosen up the setscrew holding the crank and the setscrews holding the flywheel onto the shaft, then tried to let each piece find it's "natural" position.  By that I mean let them drift right/left until the resistance was minimal.  I think I got there.  I could try it again to see if I get closer.  

I'm not sure it's sealing well enough, because I don't think I get the fart sound often enough/well enough.  Minh Thanh, I think that's what you mean, right?


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## minh-thanh (Sep 16, 2018)

It's like this video


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## fcheslop (Sep 16, 2018)

I will also do a wee video so you have a direct comparison as its the same engine
I think Minh Thanh is on the right track
cheers


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## CFLBob (Sep 16, 2018)

fcheslop said:


> Found these old pics maybe not much use but you can see the piston position at TDC and BDC and also a mark that shows how the valve just covers the port
> View attachment 104110
> View attachment 104111
> View attachment 104112
> View attachment 104113



Fraser, am I right in thinking your pic of the back of the valve is showing that it covers the slot with a fairly wide margin?  Mine is just barely closing.  Someone said to try that farther back in the thread.  It closes by less than a full turn of the 5-40 screw, so no more than .025.  That's fairly easy to adjust with the two nuts, so I could try closing it more.


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## fcheslop (Sep 16, 2018)

Bob, if you look at the pic of the cylinder with the rusty shim bit at the left hand edge of the port you can see a bright spot and this is the leading edge position of the valve.The pic of the valve was an old thread to show that bronze canbe scratched by an alloy cylinder
The valve covers the port by 1/32 max and Im sure I did this to slow the engine down as it runs like crazy
I will do a couple of vids to let you hear how it quacks and the flame position Monday
Hope thats of some help.I do think you are very close to having a runner


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## CFLBob (Sep 16, 2018)

I moved the valve cover almost another .050" to the left and it didn't matter.

I forgot who asked where the cam was positioned, so I grabbed this picture.   Pretty much in the center.






Finally, I tried Minh Thanh's test and flicked the flywheel both right and left (CW and CCW).  It goes a few revs to the right, but won't go one to the left.



No matter where I put the alcohol lamp, it won't run, which is another way of saying the position doesn't matter yet.  When I move the lamp a little past the left edge of the opening in the cylinder, the engine will blow out the flame.


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## fcheslop (Sep 16, 2018)

Hi Bob, just try turning the flywheel anti clock when viewed from the valve side of the engine and you should be able to feel a spot when it becomes hard to turn if not it maybe the valve not sealing well enough.The engine runs clockwise as you probably know. The shim part literally only just holds the valve onto the port face really very little pressure if its to much the engine doesnt exhaust properly. The quack doesnt sound right to my ears who would have though engines quaking and farting :}
The cam position you show on my engine it flys so I think that maybe correct
The flame needs to be to the left of the port around the max foreward position of the valve but the wick must not come into contact with the valve
If you watch it as you try starting you should see the flame sucked into the engine and you will get a flicker on the flame when it exhausts and my engine at onetime did blow the flame out but cannot remember what I did to stop it but seem to think it was the valve not seating correctly


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## CFLBob (Sep 16, 2018)

fcheslop said:


> Hi Bob, just try turning the flywheel anti clock when viewed from the valve side of the engine and you should be able to feel a spot when it becomes hard to turn if not it maybe the valve not sealing well enough.



Yes, I can feel that.  When I look from that position (as in the video) and turn the flywheel CCW, it stops moving freely from about the 7 o'clock position up to about 2 o'clock.   

If I turn the flywheel CW, when I go through the same interval and let go, it won't spin on its own.  

When I flick the flywheel CW it spins a few times.  When I flick it CCW it stops when the piston starts to go back out of the cylinder, which means the flywheel goes around halfway.


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## minh-thanh (Sep 16, 2018)

CFLBob said:


> When I move the lamp a little past the left edge of the opening in the cylinder, the engine will blow out the flame.


 I was also like that.

You need to check the valve gear (height..), rod (length) and valve: it should be exactly follow the drawing , and total length when assembling them, because *opening and closing position of valve is very very Important, it decided to create a vacuum at the BDC.*


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## minh-thanh (Sep 16, 2018)

One more thing . You need to make sure that the valve is airtight when the piston is somewhere in front of the BDC. This only ensures when the surface of the hole air intake and the valve face is straight.


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## CFLBob (Sep 17, 2018)

minh-thanh said:


> You need to check the valve gear (height..), rod (length) and valve: it should be exactly follow the drawing , and total length when assembling them, because *opening and closing position of valve is very very Important, it decided to create a vacuum at the BDC.*





minh-thanh said:


> One more thing . You need to make sure that the valve is airtight when the piston is somewhere in front of the BDC. This only ensures when the surface of the hole air intake and the valve face is straight.



I think I've verified both of the these.  The position of the valve is adjustable on the Duclos engine because the spring holding the valve against the cylinder isn't machined, it's just bent steel.  It's adjusted by moving the two nuts over on the push rod left or right.  The threaded portion of the push rod is 7/16 long, which is longer than the opening is wide (1/4).  Since it's a 5-40 screw, I can adjust it 1/6 of one turn at a time (about .005") by turning one nut by one flat and then locking it with the other nut.   






My problem is that everything I can measure or test tells me it should be working, but it's not.  

I will measure and test more.


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## werowance (Sep 17, 2018)

Bob, are you still using graphite as the piston?  if so try making the piston so tight in the cylinder that it will not budge when cylinder is cold.  in other words seized up.  then apply the flame and allow cylinder to pre heat,  once heated the piston should free up and hopefully start.  my experience was that expansion rate between materials were so different that I could not get enough vacume (although it felt good by hand and had plenty of pull back but not enough to run)  once I did this mine ran just fine.  but once it cools down it is completely seized up and wont budge.

I did not attempt to lap in the piston because even a film of 5w30 oil while lapping to a cold cylinder would have been to much.

hope this helps.


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## CFLBob (Sep 17, 2018)

werowance said:


> Bob, are you still using graphite as the piston?  if so try making the piston so tight in the cylinder that it will not budge when cylinder is cold.  in other words seized up.  then apply the flame and allow cylinder to pre heat,  once heated the piston should free up and hopefully start.  my experience was that expansion rate between materials were so different that I could not get enough vacume (although it felt good by hand and had plenty of pull back but not enough to run)  once I did this mine ran just fine.  but once it cools down it is completely seized up and wont budge.
> 
> I did not attempt to lap in the piston because even a film of 5w30 oil while lapping to a cold cylinder would have been to much.
> 
> hope this helps.



I have to say that's an interesting idea.  I don't have any more graphite, but I originally bought a bar of CRS to make the piston from and it's untouched..   I should get another graphite rod.


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## werowance (Sep 17, 2018)

on the graphite, I got mine from becker graphite,  6.69 U.S. for jc4 rod 1"x12"  pretty cheap,  and they were very nice to deal with over the phone.  they were recommended to me by another member here during my flame eater build.  I would recommend them as well.  I didn't know there were different heat grades etc of machiniable graphite, and the jc4 is what they recommended for that engine.  worked good for me. and they shipped pretty quickly to.  evidently they have a lot of model engine customers as they were somewhat familiar with the ridders engine.
beckergraphite.com


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## werowance (Sep 17, 2018)

and I should say my first graphite rod from ebay was just a stir rod and it was aweful and pourus full of voids.  and not to mention cost me just as much as the real deal machinable graphite.  so id stay away from the stir rods on ebay.


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## fcheslop (Sep 17, 2018)

Hi Bob, the  videos as promised
You can see how worn the valve gears has become
She is running a bit slow as its gummed up after a couple of years collecting dust
You can see they are not to fussy about flame position unlike the Ridders engines


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## CFLBob (Sep 17, 2018)

Thanks, Fraser.  Yours runs fantastic.  

What I'm going to focus on now is the sound.  I don't know what to troubleshoot because I have no idea what makes that sound, but yours sounds different.   Comparing it to the sound of my video in post 172 shows a different sound.  It's both shorter duration and higher frequency.  


Bob


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## Tim1974 (Sep 18, 2018)

CFLBob said:


> Thanks, Fraser.  Yours runs fantastic.
> 
> What I'm going to focus on now is the sound.  I don't know what to troubleshoot because I have no idea what makes that sound, but yours sounds different.   Comparing it to the sound of my video in post 172 shows a different sound.  It's both shorter duration and higher frequency.
> 
> ...


Where talking Stirling I take it ? I hope to find out haw to make for speed and power any hints ?


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## CFLBob (Sep 18, 2018)

Tim1974 said:


> Where talking Stirling I take it ? I hope to find out haw to make for speed and power any hints ?



These aren't considered technically Stirling engines.  They're atmospheric engines because the atmospheric pressure works over half the cycle.  

I think.  I'm really not expert at this sort of stuff, and I've never built a Stirling engine.


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## CFLBob (Sep 18, 2018)

fcheslop said:


> Found these old pics maybe not much use but you can see the piston position at TDC and BDC and also a mark that shows how the valve just covers the port
> View attachment 104110
> View attachment 104111
> View attachment 104112
> View attachment 104113



Fraser,  this might be a personal record for me being dense, but in the third picture, that's the top of the piston visible in the cylinder opening?  

Mine isn't that far forward.  

A quick check shows the crank and the push rod are the right lengths.   I don't see what I got wrong, but if the system doesn't compress enough, this is never going to play.


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## minh-thanh (Sep 18, 2018)

CFLBob said:


> Fraser,  this might be a personal record for me being dense, but in the third picture, that's the top of the piston visible in the cylinder opening?
> .


The piston visible in the cylinder opening !
The pistons must move near the cylinder head - but do not touch.
It must push the gas out of the cylinder and draw hot air from the flame


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## CFLBob (Sep 18, 2018)

minh-thanh said:


> The piston visible in the cylinder opening !
> The pistons must move near the cylinder head - but do not touch.
> It must push the gas out of the cylinder and draw hot air from the flame



I'm really confused about this.  I just measured every dimension that affects the position of the piston and every one is right.  My piston seems to be 1/8" too far down the cylinder possibly a little more than that.  It's hard to measure.   

I can understand how to make the piston move farther up the cylinder.  I could move the flywheel and the cylinder closer to each other by moving those holes in the base plate.  I just don't understand how everything can be built properly but the position be so wrong.


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## fcheslop (Sep 18, 2018)

Hi Bob, youre assuming youre engine is wrong I simply dont know if my engine is correct, Although now you pointed it out I think I didnt set the engine up as per the drawings but its such a long time ago I have trouble remembering what I did yesterday let alone 20 odd years ago.
I would try a simple test for the valve and port face
Disconnect the conrod from the crank then turn the engine until the port is full covered
Pull the piston down the bore reasonably quickly and let go.It should snap back up the bore and may even hit the head with a bump. If thats ok then start looking at the timing
The piston on my engine also comes out of the bore by about 1/16 to 3/32 and as you say half covers the port at TDC
Tim these are vacuum engines and as far as I know have no connection to the Stirling engine .If you want to start a thread I would gladly help in anyway I can and have built far to many of these engines for my own good with and without speed control
cheers


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## CFLBob (Sep 18, 2018)

fcheslop said:


> Hi Bob, youre assuming youre engine is wrong I simply dont know if my engine is correct, Although now you pointed it out I think I didnt set the engine up as per the drawings but its such a long time ago I have trouble remembering what I did yesterday let alone 20 odd years ago.
> I would try a simple test for the valve and port face



There's one big difference between yours and mine: yours works.  It's possible the problem with mine is something else, but this is relatively easy to test.



fcheslop said:


> Disconnect the conrod from the crank then turn the engine until the port is full covered
> Pull the piston down the bore reasonably quickly and let go.It should snap back up the bore and may even hit the head with a bump. If thats ok then start looking at the timing
> The piston on my engine also comes out of the bore by about 1/16 to 3/32 and as you say half covers the port at TDC
> Tim these are vacuum engines and as far as I know have no connection to the Stirling engine .If you want to start a thread I would gladly help in anyway I can and have built far to many of these engines for my own good with and without speed control
> cheers



I can't measure it right now, but mine comes out farther than that.  Still the extra 3/16, I think.  

The easy test is to slot the screw holes in my base so that I can slide the flywheel and crank 3/16 closer to the cylinder.  A perfect example of the kind of job that takes as long to set up for - or longer - as to machine.  Unfortunately, I have some commitments tonight so I'll have to reassemble it tomorrow.


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## Engine maker (Sep 18, 2018)

I built one years ago, set the cam in the middle of the slot and it fired right up, runs faster than most too! I did notice that it likes a very WIDE  tall flame. You might try spreading the wick out some. I had a friend that had one that would not run and all it needed was more fire! Give it a try.


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## CFLBob (Sep 18, 2018)

Engine maker said:


> I built one years ago, set the cam in the middle of the slot and it fired right up, runs faster than most too! I did notice that it likes a very WIDE  tall flame. You might try spreading the wick out some. I had a friend that had one that would not run and all it needed was more fire! Give it a try.



Thanks!  That goes on the list to try.


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## fcheslop (Sep 19, 2018)

Hi Bob, Iv just checked the other Duclos design Little Blazer and the piston come about a third into the port hole
cheers


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## Gedeon Spilett (Sep 19, 2018)

Looking at the video on post #172, I feel that movements are not free enough, we also hear the friction noise ( the valve and the spring?) that you have to fix...hidding the popping and farting noises, you must have !


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## tim (Sep 19, 2018)

hmm really love your work i hope you get it running i will consider this as my next project i like the look


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## CFLBob (Sep 19, 2018)

Just an update after moving the flywheel and everything mounted on its shaft closer to the cylinder.   The top of the piston is now about 1/16" past the back of the opening, so I moved it about 1/8" inch farther into the cylinder.  I cut slots for the SHCS mounting screws in the bottom of my mounting plate.  







This splits the difference between how far the piston is in front of that edge of the valve opening and how far it hangs out the back of the cylinder.   It hangs out of the back about the same amount, 1/8".   

I've tentatively concluded that the piston is too small, and ordered a graphite bar from Becker graphite (thanks, werowance) to make a new piston.  I've tried to run it after preheating the cylinder but not without doing that.  If it's true that these engines either run hot or cold due to critical clearances, it might make a difference.  

Here's a short video I shot that shows if I move the flywheel fast, as if trying to start it, I get some sound, but if I move it slowly I don't.  Fraser's  video shows sound when moved slowly.   Since pressing the valve against the cylinder didn't affect this, but if I try to move the flywheel CCW quickly it seals and prevents the flywheel from moving, I'm thinking the piston is most likely the problem.



Comments appreciated, of course.


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## minh-thanh (Sep 19, 2018)

CFLBob said:


> Just an update after moving the flywheel and everything mounted on its shaft closer to the cylinder.   The top of the piston is now about 1/16" past the back of the opening, so I moved it about 1/8" inch farther into the cylinder.  I cut slots for the SHCS mounting screws in the bottom of my mounting plate.


I do not know why there are piston position differences at TDC between how you do and fcheslop said!
But the piston needs to push all cold air out of the cylinder



CFLBob said:


> Here's a short video I shot that shows if I move the flywheel fast, as if trying to start it, I get some sound, but if I move it slowly I don't.  Fraser's  video shows sound when moved slowly.   Since pressing the valve against the cylinder didn't affect this, but if I try to move the flywheel CCW quickly it seals and prevents the flywheel from moving, I'm thinking the piston is most likely the problem.
> Comments appreciated, of course.




-- the piston is most likely the problem : maybe
--- or maybe :
valve is not seal (valve surface and surface of hole air intake  are not straight)
or  valve does not completely cover  hole air intake .
or all three of them


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## CFLBob (Sep 20, 2018)

minh-thanh said:


> -- the piston is most likely the problem : maybe
> --- or maybe :
> valve is not seal (valve surface and surface of hole air intake are not straight)
> or valve does not completely cover hole air intake .
> or all three of them



Ran another test.  I let the engine cool off for about three or four hours and then tried it again.  It actually turned over and ran for about a second.  Couldn't get it to run after that.  

The reason I tried that without preheating the cylinder is thinking that if the problem is the piston being slightly too small, I should test it when the cylinder is as small as it can be.  Preheating the cylinder makes the fit worse, so it has the best chance of working when the cylinder is cold.  

Well, I probably won't have my graphite rod for another week, so I have time to repeat this and look at other things.


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## werowance (Sep 20, 2018)

might try icing the cylinder to just for grins and giggles while you wait on the graphite.  what you are describing is exactly what my flame eater was doing,  a little oil in the cylinder helped but would of course gum up as soon as it got to the smoke point of hot which happens pretty darn fast.  also on the fuel, I use denature alcohol which I get at the hardware store.  it actually even says "fuel" on the can below the denatured alchohol part


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## werowance (Sep 20, 2018)

also on my flame eater, adjusting the piston to just barely past the port opening like you have it now vs it coming to the edge but not past didn't make a difference on mine once I got it running.  but while trouble shooting and fighting with it,  it did seem to maybe turn over a couple more times with it just past the intake port than without,  just enough to give me false hope that it was going to run.  the design of yours and mine are not that much different, key thing is your valve operating and covering the outside of the intake port whereas mine is covering the inside of the port, the cylinders look very similar so I'm hoping for you that its just expansion rate.  sure would make me happy if that's all it is.


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## CFLBob (Sep 21, 2018)

Much to my surprise, the graphite rod just arrived in the morning's mail.  I was expecting no earlier than Monday.  

Time to remake the piston with a tighter fit.


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## werowance (Sep 21, 2018)

good luck,  cant wait to see if this fixs it.


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## CFLBob (Sep 21, 2018)

werowance said:


> good luck,  cant wait to see if this fixs it.



You'll find this interesting: before taking the engine apart, I sprayed the cylinder with one of those compressed air in a can dusters.  If you turn those upside down, you get out the propellant, which is a refrigerant and it will chill what you're working on down below zero (F).   Did that for a while, and then put the lamp next to the valve opening.  It ran for over 10 seconds.  Long enough for me to grab my phone and start fumbling with it to take a video. 

And then it slowed down and stopped.  It must have seen the camera.


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## fcheslop (Sep 22, 2018)

Thats good news glad you are on the way to a runner
cheers


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## Cogsy (Sep 23, 2018)

Seems like you've found the problem. Not long now and the trouble you've had will make the first run even sweeter!


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## CFLBob (Sep 23, 2018)

Unfortunately, as they say at NASA, I screwed the pooch on this and my replacement was barely better than the original.  Still wouldn't run, but I could tell it was too loose before I tried.  

I had already started on the third attempt at a graphite piston before this occurred to me, but if this doesn't work I think I'm going to use the CRS bar I bought to make the piston in the first place.  If the CTE is so different that I need to make the piston virtually stuck in the cylinder until the cylinder is heated up, I think maybe the original material is a better choice the graphite.


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## minh-thanh (Sep 23, 2018)

Pistons can be made of cast iron or brass with steel cylinder  (I also tried aluminum pistons, it was ok with little oil )


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## minh-thanh (Sep 23, 2018)

CFLBob said:


> I need to make the piston virtually stuck in the cylinder until the cylinder is heated up,  .


I do not know if it's okay or not, I just try to make the piston sealed but move in the cylinder as smooth as possible.


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## CFLBob (Sep 23, 2018)

After a lot of delicate sanding, my third graphite piston just wouldn't get into the cylinder.  I tried heating the cylinder with my butane torch to get the piston into the cylinder before I assembled it and still couldn't get the piston to fit.  

Back to the lathe, a strip of 400 grit sandpaper and then a few seconds of sanding and now it's too small.  I don't think I took off more than .0005.   

This is way too sensitive for me.   Before I take it outside and drive my car over it to turn it into a bunch of misshapen scrap, I'll try making a piston out of CRS or something.  

The bar of CRS I bought is marked that it's 4130 steel.  Is that a reasonable alloy, or should I try to find a bar of cast iron or what?  The drawing in Duclos' book says, bronze, cast iron or CRS.  Since those aren't materials so much as families of materials, I got whatever CRS that Online Metals had in stock.  

Oh, BTW, before I put everything back together, I lapped the area around the valve opening on sand paper on a block. 400, 1000, 2000.  It looks pretty nice and the wear pattern was very flat.  No high or low spots.


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## fcheslop (Sep 23, 2018)

Hi Bob, a bit late .To polish a graphite piston use brown paper bag or the rough side of cardboard
Iv used graphite in the past but gave up on the mucky stuff it has its advantages but for this engine Im not convinced
The alloy cylinder may expand a wee bit while the graphite wont expand much
My engine and Little Blazer has pistons from Bronze Alloy horrible stuff to machine and tough as the hobs of hell but has ran many hours and the material was free from an old stop valve spindle
Try CRS as you have it 
Keep plodding on the grin will be from ear to ear when it eventually runs well


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## CFLBob (Sep 23, 2018)

Test of my third graphite piston.  This is about as good as it gets, and that's after chilling the cylinder with "freeze mist" until it's frosty (which doesn't last long in the 80 degree garage). 

 

After I stopped the video, I played with it a little more and got another 3 or 4 seconds out of it.


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## Gedeon Spilett (Sep 23, 2018)

wow, you have got it, nice ! congratulations !
the engine stops when starting from cold as water from the combustion condenses inside, and increases drag, this is usual...
once the temperature of the engine reaches its running temp, in 2-3 min, the engine runs indefinitely....


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## CFLBob (Sep 23, 2018)

Gedeon Spilett said:


> the engine stops when starting from cold as water from the combustion condenses inside, and increases drag, this is usual...
> once the temperature of the engine reaches its running temp, in 2-3 min, the engine runs indefinitely....



I've never heard that!  

Does it help to warm the cylinder first?  Is there something that can be done to reduce or eliminate that 2-3 minutes, so that it starts and keeps running?    

A friend asked me if chilling the cylinder before starting the engine worked by shrinking it or changing the temperature difference across the engine.  I had never thought of that, and don't have an answer for him.


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## Gedeon Spilett (Sep 24, 2018)

Yes, it helps a lot to preheat the engine with the hot air gun...
this problem with condensation is something well known and often discussed...
you're not far from a good runner !


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## werowance (Sep 24, 2018)

hi bob,  what I did (and I know its against the rules) is I hand sanded the last bit off my piston with a piece of emory and then I used scotch bright pad in my hand - scotch bright actually removes a lot of material when using it against graphite,  using the piston rod as a handle I spun it in my hand and had to force it in the cylinder.  yes I know that doesn't generate a perfectly round or square edged piston but it worked for me.  here is a video showing how tight my piston is when cold  it wont budge,  any movement you see is just slack in the wrist pin and crank journal to rod fit.  that graphite isn't budging



next video shows it starting up after a little preheat,  then you will notice after it gets warmer it speeds up,  then it passes that perfect fit and gets a little to big and slows down a bit but still tight enough to keep it running


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## CFLBob (Sep 24, 2018)

Can't thank you enough for those videos.  I was just about where the first one is, except that I couldn't push the piston into the cylinder.  I had visions of breaking the top out of the piston by pushing on the rod.  That's when I put it back on the lathe and took a few turns against sandpaper (400 grit).  It's still loose enough to move in the cylinder and not as tight as yours shows, so it may be that mine is stopping because it's losing compression and not condensation in the cylinder.

I'll experiment with it some more,  try my hot air gun to warm the cylinder up a few degrees above room temp and see if it runs any better.


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## CFLBob (Sep 24, 2018)

Heating in advance doesn't seem to work, based on a few tries.


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## werowance (Sep 24, 2018)

when fitting the new piston,  might heat the cylinder a little bit to get a measurement from.  just a thought that it might make it easier to get that tight fit,  but then again holding that hot metal might not be fun to hold....


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## werowance (Sep 24, 2018)

and on the heating in advance to reduce condensation - on mine I don't have to wait for it to get that hot,  I will often start mine up with a little condensation still showing.  I run it a lot,  practicly anyone who comes by to visit and will stand still long enough for me to get it out lol and I have not gummed it up yet.  now yes when trying to first get it running I gummed it up often but it seems that with mine now if I run a tank of fuel out any gum or buildup is either burned out or something because I did disassemble it after many many runs and a paper towel soaked in alcohol came out clean when wiping it out.


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## CFLBob (Sep 25, 2018)

Started on the CRS piston yesterday and got called out of the shop.  I'll get that fitted later.  

Last night I found that if I just let it sit at room temp, it will start up on its own, run a few seconds until it warms up and then stop.  It's _so_ close ...  Not even sure I need the new piston, but I haven't cracked the code that lets it run for a few minutes.


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## fcheslop (Sep 25, 2018)

Hi Bob, Iv found on a few flame gulpers they need a bit pre heat but on the Duclos unless its a bit humid they dont suffer and will start straight from cold as was the case for that wee video I showed
It maybe a case of the alloy cylinder expanding so you loose vacuum Iv not built an engine with an alloy cylinder /graphite piston but do know graphite is more stable hence on the Ridders engine the materials have been chosen to try and keep the expansion prob to a min.When I built my Duclos engines I simply used what the designer recommended and not had this sort of prob
The CRS piston may cure the prob.
Good luck its nearly there


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## CFLBob (Sep 26, 2018)

Well, the new piston didn't make the difference.  Still won't run properly.  Actually, it won't run at all at the moment.  There was some sticking at the very end of TDC, and I moved things to try to fix it.  Now nothing works, not even the piston that worked two days ago.  

I'm about out of ideas here.   Maybe I need to take some time off and not think about it.


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## minh-thanh (Sep 26, 2018)

Hi CFLBob 
I've seen the way you try with the cylinder-piston, flywheel ... it's ok with the way I do (It's hard to say exactly when  i only see   videos ) , have you checked the dimension and location of the hole air intake is correct  ? (It also determines the valve opening and closing time )


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## CFLBob (Sep 26, 2018)

minh-thanh said:


> Hi CFLBob
> I've seen the way you try with the cylinder-piston, flywheel ... it's ok with the way I do (It's hard to say exactly when  i only see   videos ) , have you checked the dimension and location of the hole air intake is correct  ? (It also determines the valve opening and closing time )



Yes, it's centered where it's supposed to be and the right width.  The exact position of the valve is very adjustable.


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## minh-thanh (Sep 26, 2018)

If everything is correct to plan, you should check the cylinder - piston,* you should check them with the light, with each position of the piston in the cylinder you do not see the light passing through- But they have to move smoothly*, that is how I checked.


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## CFLBob (Sep 27, 2018)

Post mortem.  I can measure the pistons with a digital micrometer.  I can only measure the cylinder with calipers as far in as they stick, which doesn't mean much.  My cylinder measured between 1.001 and 1.002. 

The CRS piston is too small.  0.9989"  That's the diameter of the 1" bar I made it from.  All I did other than cut to length and bore the inside to size was de-bur it.

My "too small graphite pistons" are 1.0000 and .9996".  Pretty obvious the problem is the pistons, and I recall thinking about that steel bar being too small when I decided to go with graphite.  

Clearly I can't bore it out smaller so I see two possibilities.  The one I've heard of would be to sleeve the cylinder.  I've heard of doing that but have no idea what to use or how to do it.    The second possibility is a friend said I could electroplate some copper onto the graphite.  I have no idea how.  

The thing that drives me nuts is that it literally seems like the piston goes from too tight to too loose within about .0002" diameter - it's really, really critical.  That just doesn't seem reasonable.  The steel piston would jam at the end of its travel at TDC.  I loosened the two SHCS holding the flywheel to the base and moved the holder to the right so that the piston doesn't go as far into the cylinder as it did.  Wait.  Why should it jam?  The cylinder could be tapered; smaller at the end.  Could the cylinder wall have a bur?  Didn't feel anything by finger.  The graphite didn't jam either because it's softer material or because the top rim is more rounded than the steel from me holding sandpaper against it.  The rounded edge didn't get affected by the narrower spot.  All this is guesswork.  

If there's something wrong with the cylinder, it seems unfixable, except for putting in a sleeve.  

Suggestions appreciated!


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## fcheslop (Sep 27, 2018)

Hi Bob, if the cylinder is wrong just bore it out slightly over size the engine wont know the difference. I dont know with any degree of accuracy what my engines is.It just dont matter
You cannot measure a bore accurately  with calipers as you are measuring a chord and not the dia
CRS with not be truly round.
Has the graphite piston worn tapered
Do a simple test on the lathe Grip a bit of bar the length of the cylinder with no tailstock support and give it a couple of light cuts then measure it at each end or nearest to the chuck and the other end if its got a taper youre engines bore probably has as well..
If the taper is slight you could make a simple lap to make it true
These engines do need good fits and are infuriating at times although you are getting near
Just some thoughts


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## CFLBob (Sep 28, 2018)

This is about as good as it gets.  I find that if I let it get to room temperature it starts pretty reliably and continues to run.  Room temp is about 80 in the air conditioned shop, with a ceiling fan blowing nearby.  As it warms, the position it wants the flame to be in seems to change, but that might be the vibration from the engine running is moving the lamp, and if I held the flame in one spot, it would keep running!  



This is with the third graphite piston, the biggest.  

I'm trying to convince myself whether it's "done" or not.  Do I turn another graphite piston, maybe .001 bigger than this?


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## Brian Rupnow (Sep 28, 2018)

You're done. You've built an engine--it runs. Give yourself a break. Go on to other things. You may want to come back and revisit this one sometime in the future, but I'd say to consider yourself finished.---Brian


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## fcheslop (Sep 28, 2018)

Congratulations on a runner
Glad you persevered with it
Whats nest 
cheers


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## werowance (Sep 28, 2018)

congratulations on a runner.

on mine,  flame likes to be just forward of the intake hole not centered on it and with the wick actually touching the cylinder.  seems to keep it from sucking cold air in or something.  but I definitely think you can call it a success.


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## rlukens (Sep 28, 2018)

https://www.amazon.com/dp/B00R5E5PI6/?tag=skimlinks_replacement-20
20 bucks and you're covered. 
Btw, I built my first steam engine on my dads's little Atlas, at 13. I didn't know how to read mics so I made the cylinder first.


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## CFLBob (Sep 28, 2018)

rlukens said:


> https://www.amazon.com/dp/B00R5E5PI6/?tag=skimlinks_replacement-20
> 20 bucks and you're covered.
> Btw, I built my first steam engine on my dads's little Atlas, at 13. I didn't know how to read mics so I made the cylinder first.



Well, there's a story there, but thanks for the link.  I need a set like that.   

I made my cylinder first, too, so that I could fit the piston to it.  My concern about the cylinder having a taper was because of the boring bar moving my QCTP while I was boring the cylinder to size.  I was pretty sure that I fixed that and it came out straight but when you spend weeks trying to get it to run, every little concern comes back.  Making the piston to fit the cylinder still requires you to know what a good fitting piston feels like.  I didn't know.  I'm not 100% sure I know how it's supposed to feel now.  

As for what's next, I was going to ask for recommendations.  I'd like to build some sort of internal combustion engine, but I have no idea of what's a good project for a relative beginner.  I'd assume something with castings instead of bar stock, but I'm ignorant.  It's probably too early in my engine building "career" to try a 1/4 scale automotive engine.  

This is only my second engine, and the first one I made from bar stock and drawings, with nothing else to go by.  My first engine was the Little Machine Shop wobbling steam engine.  The kit came with DVD showing how to build every part, which was a good thing for a rank beginner.  

I have some improvements to my shop I want to do, so some of those are probably the immediately next thing.


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## minh-thanh (Sep 28, 2018)

Congratulations !
  Good news  of the day
  Good  luck with  new projects !


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## CFLBob (Sep 28, 2018)

minh-thanh said:


> Congratulations !
> Good news  of the day
> Good  luck with  new projects !



Thanks for all your help!


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## CFLBob (Sep 28, 2018)

fcheslop said:


> Congratulations on a runner
> Glad you persevered with it
> Whats nest
> cheers



Thanks for all your help, Fraser.  

I haven't picked out the next project.


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## Cogsy (Sep 28, 2018)

Congrats on getting it to run - lots of frustration but you got there in the end! I agree with Brian, you can always revisit it down the road a bit if you like, but I'd call it done and start something else for now.

For a first I.C. engine, the Webster is what a lot of people start with. It runs great and is relatively easy to build, while you learn all the skills to build a more complex engine. Castings are more difficult to work with than bar-stock so you want to work your way up to them.


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## Tim1974 (Sep 29, 2018)

I’m so happy mate that’s a runner


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## CFLBob (Sep 29, 2018)

Cogsy said:


> Congrats on getting it to run - lots of frustration but you got there in the end! I agree with Brian, you can always revisit it down the road a bit if you like, but I'd call it done and start something else for now.
> 
> For a first I.C. engine, the Webster is what a lot of people start with. It runs great and is relatively easy to build, while you learn all the skills to build a more complex engine. Castings are more difficult to work with than bar-stock so you want to work your way up to them.



I looked up the Webster engine on YouTube to get an idea what they look like.  It looks very much like this engine, with the important differences and (famous last words) doesn't look that bad to do.

I like the idea of something that could produce some power.  I imagine it's producing a fraction of a HP, but more than the flame eaters. 

Last night I was telling my wife I thought it would be cool to build something along the lines of a one cylinder lawn mower engine.  Maybe a whole 1 HP.  Four stroke would be cooler than two stroke with oil mixed in. 

On the topic of the Duclos fire eater, I've been thinking that since it runs better cool, maybe I could add cooling to it.  I noticed the engine minh-thanh was showing had a little fan pointed at the cylinder fins.  Coming from the electronics world, I thought about the CPU coolers you can get to actively drop the temperature of your PC's processor.   It gave me a lot of thoughts along this line.


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## Brian Rupnow (Sep 29, 2018)

Build a Webster. They are the perfect beginners i.c. engine. It was my first engine and I have videos of it running various things.   ----Brian Rupnow
https://www.homemodelenginemachinist.com/threads/anybody-want-to-guess.7687/


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## minh-thanh (Sep 29, 2018)

More information for a  I.C. engine :

http://ridders.nu/Webpaginas/pagina_blokker_vonkcircuit/blokker_circuit_frametekst_engels.htm


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## CFLBob (Sep 29, 2018)

Brian Rupnow said:


> Build a Webster. They are the perfect beginners i.c. engine. It was my first engine and I have videos of it running various things.   ----Brian Rupnow
> https://www.homemodelenginemachinist.com/threads/anybody-want-to-guess.7687/



I went looking for Webster's website a while ago and it appears to be gone.  Where would I get plans?


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## CFLBob (Sep 29, 2018)

minh-thanh said:


> More information for a  I.C. engine :
> 
> http://ridders.nu/Webpaginas/pagina_blokker_vonkcircuit/blokker_circuit_frametekst_engels.htm



I was just watching a video of a Ridders four stroke with the cylinder made of a glass tube.   The builder puts one battery (looks like AA size) into a holder in the engine.  Must be that ignition system.


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## Cogsy (Sep 30, 2018)

CFLBob said:


> I went looking for Webster's website a while ago and it appears to be gone.  Where would I get plans?


They're in the downloads section of this forum if you want them - LINK. If that's not the right version just search 'Webster' in the search box from within the downloads forum.


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## CFLBob (Sep 30, 2018)

Cogsy said:


> They're in the downloads section of this forum if you want them - LINK. If that's not the right version just search 'Webster' in the search box from within the downloads forum.



Thanks.   

Right now, the list I'm thinking of is kind of odd:
The Webster, 
A Stirling engine, 
A friend said I should build "some sort of diesel", but I know nothing about those.  
A glow plug or model airplane engine is a possibility, too.  
Maybe a multi-cylinder, radial, wobbler type steam engine (which are just entertaining to watch).


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## Brian Rupnow (Sep 30, 2018)

A stirling engine is very much like a flame licker (like you just finished). They run, but they make virtually no power, and can be very ticklish to get and keep running. Build a Webster. Then, if you are feeling really good about yourself, build a Kerzel hit and miss.


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## Cogsy (Oct 1, 2018)

For a second I.C. engine, I really enjoyed building the Rupnow Vertical so that's something to consider as well.


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## CFLBob (Oct 1, 2018)

Cogsy said:


> For a second I.C. engine, I really enjoyed building the Rupnow Vertical so that's something to consider as well.




Very nice looking and sounding engine.


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## Brian Rupnow (Oct 1, 2018)

That is a nice uncomplicated engine, but you have to be aware that any i.c. engine you build is going to have two gears in it. If you have the set-up to cut gears, then yes, my vertical is a great engine to build. The gears on my engine are custom cut. If you build the Webster, the gears can be purchased for a very reasonable amount. The Websters gears are commercially available.--Brian Rupnow


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## fcheslop (Oct 1, 2018)

The Webster is a nice engine to build
Just to play devils advocate a Stirling although lower powered can still do a bit of work

cheers and good luck with what ever you decide to build next


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## CFLBob (Oct 1, 2018)

Brian Rupnow said:


> That is a nice uncomplicated engine, but you have to be aware that any i.c. engine you build is going to have two gears in it. If you have the set-up to cut gears, then yes, my vertical is a great engine to build. The gears on my engine are custom cut. If you build the Webster, the gears can be purchased for a very reasonable amount. The Websters gears are commercially available.--Brian Rupnow



Ah ...   I haven't tried cutting gears.  I don't have any of those tools (hobs?) for cutting tooth profiles.   If that's the only new thing to learn in making the engine, though, I'd hope that's not that bad.  There were several new things to learn in making this Duclos engine.  

Fraser, I went to the NAMES show once, in '08.  There was a guy there with a really cool model of a crane that was about 2 or 3' tall extended, moved around and the winch would pick up things.  It was all powered by a Stirling motor.  No video, but I have some still pictures to give a rough idea.  Note the guy behind it and its scale compared to him - that's the builder.


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## fcheslop (Oct 1, 2018)

Hi Bob, Is there is any secret to Stirling engined models its gearing them down
I held off cutting gears for years then bit the bullet made the cutters and cut the gears and it wasnt a bad experience and thought what was all the fuss about.Guess its a case of suck it and see. Although I did manage to make a few 1/2 tooth gears oops
What ever you decide to build I wish you good luck and enjoy building it
Back to the model boat builds as its Autumn and I need to build some boilers
Keep well
kind regards


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## doc1955 (Oct 1, 2018)

CFLBob said:


> Ah ...   I haven't tried cutting gears.  I don't have any of those tools (hobs?) for cutting tooth profiles.   If that's the only new thing to learn in making the engine, though, I'd hope that's not that bad.  There were several new things to learn in making this Duclos engine.
> 
> Fraser, I went to the NAMES show once, in '08.  There was a guy there with a really cool model of a crane that was about 2 or 3' tall extended, moved around and the winch would pick up things.  It was all powered by a Stirling motor.  No video, but I have some still pictures to give a rough idea.  Note the guy behind it and its scale compared to him - that's the builder.
> 
> View attachment 104488





Don't let making gears scare you they are not that hard t do. ANd you really don't need much to make them just make a gear hob and if you have a -V- block your set. Here is a link to a simple way to make gears with minimum equipment needed.

Making a gear hob




Cutting gear with no indexer


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