Philip Duclos Fire Eater

[Gedeon Spilett]

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.

 

[CFLBob]

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?

 

[CFLBob]

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.

 

[fcheslop]

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

 

[fcheslop]

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

 

[minh-thanh]

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 )

 

[CFLBob]

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?

 

[minh-thanh]

It's like this video

 

[fcheslop]

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

 

[CFLBob]

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.

 

[fcheslop]

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

 

[CFLBob]

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.

 

[fcheslop]

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

 

[CFLBob]

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.

 

[minh-thanh]

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.

 

[minh-thanh]

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.

 

[CFLBob]

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.

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.

 

[werowance]

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.

 

[CFLBob]

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.

 

[werowance]

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