# B.J. Cicada build



## werowance (Sep 17, 2014)

Well, i figure i need to try building my first engine instead of watching everyone else and day dreaming about it. 

the engine i chose is the b.j. cicada, plans here: http://modelenginenews.org/plans/BJ_Cicada.pdf

i have been pondering how to go about some of the steps as well as the materials for a while, i have posted several questions reguarding all that in different sections of the forrum and have gotten great answers back. for that i want to say thank you and a warning that i have plenty more to ask. 

anyway, starting on page 2 of the plans, working on the crank case and front bearing last night and this is where i got:
first picture, the material i had ordered along with cover drawing of the engine.

second picture, sawing some blanks out of the aluminum

third picture, squaring up the sawn blanks to size in the lathe

fourth picture

third picture are the 2 blanks, one laying on its side is 1x1x1.60 for the crank case and the second pointing sraight up is the bearing support or as i will refer to it going forward as the "snout" of the engine which is 1x1x about 1.5 left extra on it to have room to get the live center to it over my cross slide


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## werowance (Sep 17, 2014)

after getting some square to size aluminum blanks done, i blued them up and used my height gauge to do some layout marks on the snout part of the engine. i chucked it up and used my test indicator to get it centered then drilled and reamed to .250 hole all the way through and cut the .875 diameter circle on the rear of the snout. once i had that i went back the the height gauge and made the rest of the layout marks once i had a reference point which was the where i faced the .875 so i could start measuring up from there for the rest of the way.


picture 1 piece with some layout marks

picture 2 getting the snout centered in the 4jaw

picture 3 after drilling/reaming and cutting the .875 diameter on the snout


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## werowance (Sep 17, 2014)

next i took the snout with the faced .875 circle face down and used my height gauge to mark the rest of the dimensions, then as per suggestions of how to hold the piece made in questions section of this forum, i took card stock around the .875 circle and put in the chuck with the jaws only holding the .875 circle and a live center with mt3 extension across my cross slide and started cutting the .400 diameter of the snout. i cant beleive that actually held and worked. thanks to those who answered on that setup question, i think it turned out well. probably wont have anything new for at least a week, garden canning and honey bee robbing the honey, mowing, etc...cant wait till all that stuff is done so i can get some good garage time.

picture 1 snout blued and face down ready for height marking

picture 2 snout after marking with height gauge

picture 3 cutting the snout

picture 4 - .400 snout cut, and form tool to make the .200 diameter at the base of the snout -note the trumpet bell at the live center, this is the excess i left on the stock to give me room to work that get parted off as last step to make over all lenght 1.0

picture 5 - completed part minus screw holes which i will drill once i have the crank case done


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## Swifty (Sep 17, 2014)

Off to a great start, keep asking questions when necessary.

Paul.


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## Brian Rupnow (Sep 17, 2014)

Werowance--You are building a very interesting engine, and I hope to follow along for the ride. I have never built a two stroke engine myself, so will be very interested in how this works out for you. If I can be of any help, just yell!!!---Brian


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## werowance (Sep 17, 2014)

Thank you Paul and Brian.  I can't seem to stop thinking about the process for each cut and the best way to do it. Up till now for most projects I have done I have had the suggested procedure for setup before the cut.  And now I am without that. Drawings only


That said my next question is on the crank case. It calls for 2 holes bored. I am replying from my phone so don't have the plans in front of me but I believe both holes are a blind bore.  I want to suggest what I think then hear how everyone else would do it.  Thus I learn from what would have been a mistake without wasting time or material


So setup question


I have a 1x1x1.60 block ready to bore 2 holes in.   Would you just drill close to close depth and to exact outside I think 7/8 without looking at plans then grind a 7/8 flat bottom drill to finish for the snout part?

Or would you drill undersized to close depth then hit with boring bar to depth and diameter then clean up the tit left in the center with either end mill slightly off center or flat bottom drill or hey even Dremel tool with stone in it?

All boring and drilling done with piece mounted in 4 jaw on lathe?

Just want to hear how you all would do it so I can put it all together and do it however works best when I get back to my machine 


Thank you all for the support to all my stupid rookie questions now and in the past.   I feel so much more confident with my equipment than I did a while back



Sent from my iPhone using Model Engines


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## Brian Rupnow (Sep 17, 2014)

The bottom of the .875" hole is just clearance, nothing real critical about it. I would be tempted to drill a 1/2" hole to exact depth, then run a 2 or 4 flute endmill down to the specified depth to remove the cone shape left by the drill. Then just use progressively larger end mills increasing by increments of 1/16" until I reached the 7/8" diameter. For the .625" hole I would center drill, then run a 3/8" drill thru to the previously bored .875" hole, then finish to depth with a 5/8" end mill. The endmills won't give you an exact size to 3 decimals, but they will be close. Since you are machining the mating parts, just make them to fit the hole size that your endmill gives. I would do it in the 4 jaw chuck in the lathe, and though I will probably be shot by the purists for suggesting it, I would hold the endmill in the tailstock chuck. I would run my lathe on its lowest speed, which is 115 RPM. ---I wouldn't advise doing that if you were machining steel, but for aluminum you can get away with it. It could also be done in the milling machine, but I find that if squareness and perpendicularity are issues, my cheap milling vice can not be totally trusted to hold things perfectly flat and true to the spindle. And no, I don't want to hear about the evils of holding an endmill in a chuck. I have heard it a hundred times. I do it. I get away with it.


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## werowance (Sep 17, 2014)

Brian, so you are saying (skipping the incremental step up in size) to use an end mill labeled to size that schematics call for to cut the diameter as well as the depth to flat bottom?  I am fine with that as I do it often for counter sunk screw holes.  and understand the incremental step ups.

 I should also say that I have at my use the following (although many not used yet) the following.

 my lathe is a combo lathe milling machine.  mt3 mill spindle,  mt3 tail stock.

 I have a crappy shop fox mill vice and agree difficult to get square and keep it square,  however my cross slide has 2 t slots running perpendicular to the lathe cuck/way and 1 t slot running parallel to chuck/way.  this also makes it difficult to reach short parts with my tailstock and have any room to machine the part between the chuck and tailstock.

 I recently purchased and have not used a mt3 boring head and tool kit. 1/2 inch carbide tipped bars included.  cheap ebay.

 I have a 3/8 boring bar with carbide tip (something French made I was told by someone else was a pretty quality tool) that I got in a batch of tools online,  it bores and faces really well on the little non critical quickies I have done with some slight chatter marks on the face cut of a blind hole.  I was making screw driver handles and boring the hollow part of the handle from the book "machine shop projects" so those chatter marks get hidden and plugged.

 but i am liking the use of an end mill as that i can handle (hopefully).

 thank you again

 Bryan.  - "werowance"


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## Jasonb (Sep 18, 2014)

As you have already made the nose piece to go into the hole and the fit in the crtankcase is quite critical I would not use endmills/slot drills to form the hole as you won't have the control over the fit.

Also on these two strokes with a crank pin that is only supported on one end the back of the crankcase acts to limit how far the conrod can move along the pin so not just a clearance you should be sloppy about

Mount the job in the 4-jaw chuck and indicate it centre. Spot or centre drill and then drill to just short of depth say 1/4, 3/8,1/2 and 5/8 if you have it.

Then take a boring bar, touch the bar against the end of the block, zero the topslide handwheel and lock the carrage. You can now bore the hole to a nice fit for the nose, start test fitting the nose in the hole as you get close to dimension incase it is a bit under/over 0.875. Then at the same settings if the boring bar is correctly on ctr height you can skim the bottom using the handwheel to get the 0.640" depth. It should be no problem to get a nice flat botton across the whole area something that plunging with a mill does not do as they tend to leave a flat cone shaped bottom.






Once thats done change position in the 4-jaw and do the same with the cylinder hole.

A word of caution with your 1" stock, make sure the stock is truely square and each face flat. you can often find the sides are slightly convex which will stop your cylinder seating on a flat surface, if so take a slight skim off the top surface to clean it up and adjust the depth of teh hole to suit, also make the cylinder longer to match.

Once the two holes are done mount on the mill, indicate the centre of each hole and drill/tap the sets of 4 holes, mounting holes and lastly mill away the waste at the sides and back.


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## Swifty (Sep 18, 2014)

If I was doing it, I would do it similar to Jasonb's way.

Paul.


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## Brian Rupnow (Sep 18, 2014)

Jason--When you drill to depth, the sides of the resulting drilled hole are a cone at the tip.  How do you remove that cone with a boring bar? Do you cut with the very end of the boring bar as opposed to the side? I have never had a lot of luck doing that. On the holes I bore, I still have to run an endmill down after drilling, at least once, to remove that coned section so I can start using a boring bar and get all the way to the bottom of the hole to leave a flat hole when I am finished.---Brian


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## Cogsy (Sep 18, 2014)

Brian Rupnow said:


> How do you remove that cone with a boring bar?


 
The 8mm boring bar that I have mostly been using uses a 4 sided insert (a rhombus shape maybe?) with the cutting edge slightly to the front and side of the bar as a result of the angle of the insert. When I bought it I was told it would both bore and face. 

With this bar I can flatten the end of a bored hole fairly easily. I drill to almost depth on the point of the drill, then face the bottom of the hole to the required depth, then keep boring to that depth until I get the required bore.

And for what it's worth Brian - I was told not to use a drill chuck to do milling because they can't handle the side forces of milling. If this is true then I would think it was perfectly acceptable to use a drill chuck on the lathe the way you described. I haven't had to yet, but I'm sure I will in the future.


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## Jasonb (Sep 18, 2014)

Here you go Brian, starting top left

1. Spot drill, I only use a centre drill when I actiually need a 60deg CSK to take a centre

2. Drill out in stages to say 1/2"

3. Now take a boring bar and open up to just below finished dia and as deep as possible until the end of the tool is cutting too wide a cut

4 (2nd row) Now that there is a bit more room the bar can be used to take the depth down in steps to remove the conical base cutting from the centre out towards you.

5. same method until the bottom is flat but just a couple of thou short of depth

6. final cuts to dia followed by facing the bottom to depth from outside towards the centre.

As Cogsy says quite easily done with a bar that can cut in both directions either ground from HSS or an indexable one.


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## Jasonb (Sep 18, 2014)

Using the bar allows you to fine tune the fit which you can't do so easily with milling cutters.

You will recognise this off a Nemett, all three parts in the second photo push together with a gentle squeeze between finger and thumb yet stay together when held upside down


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## werowance (Sep 18, 2014)

here is a picture i got off the web of a similar boring bar, mostly how the left right cut and carbide orientation on the bar is what i am comparing to mine. 

my inserts have a much rounder radious with is why i think it leaves such a good finish.

oh, and on the end mill in jacobs chuck, no worries, i have a mt3 er32 chuck that will fit my tail stock.

i think ill try both suggestions on some scrap cheaper alloy aluminum first.

i hope to get a little shop time this weekend.


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## Brian Rupnow (Sep 18, 2014)

My method seems to work great as long as you are not aiming for a specific size to 3 decimal places and you are going to make the "goes into" part after you bore the hole. You can make it to fit. If you make the "goes into" part first, then my method is totally out to lunch.---And Jason, thank you for the tutorial. My cheap brazed carbide boring bars don't have the shape required to achieve what you have shown. Next time I have a blind hole to bore I will sharpen one into the parallelogram shape you show and try that method.----Brian


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## werowance (Sep 22, 2014)

well honey bees robbed and harvested, banana peppers mostly picked and pickled, half the potatoes dug, etc.... and to the garage I went yesterday.

so first challenge locating my Jacobs chuck key. grrrrr. hate when I lose it. then finally started some test cuts. no pictures as they were all failures.

all tests done on scrap cast aluminum.

test 1, drill in increments to close depth/diameter, was facing the bottom when the carbide came lose and hung, actualy bent the retaining tab on my little insert bar. no extra inserts for it on hand so on to next trial and failure.

test 2, trying the same thing using my boring head in the tailstock, those bars are half inch mounting diameter but even the largest had a lot of visibly noticible flex. these are cheap brazed tipped bars that came with the head. not likeing this idea much. hate I messed up my good boring bar in step one.

test 3, just figured id see how close a 7/8 drill bit came, I have 2 different 7/8 bits that are different brands and different materials that I bought at separate times. both cut notacably different sizes that I didn't even have measure to notice they both cut different size holes. neither of which actually hit 7/8. so possibly scratch the 7/8 flat bottom drill bit idea.

possibly test 4, kinda sorta test.... I have a 7/8 end mill that is new from a lot of tools I bought, never used it and realized now why not. I don't have a collet or anything I can chuck it up with. guess I could make a holder 7/8 to say half inch, but not right now.

the 7/8 end mill is notacably smaller than either if the 7/8 drill holes I made but until I make a cut with it I cant really be sure of what it will actually cut. I could measure with my calipers the mill but I figure It will actually cut a bit larger than what I measure due to "give" in everything.


so at this point, I want to buy another decent boring bar like I had for at least the cylinder boring to come later, what would you all do? scrap the first nose I made and make the crank case first, then remake the nose to fit? call that a learning experience. or wait and try again with another boring bar and try to do the end mill trick again?

any way, going to eat a honey biscuit and hit the hay for the night. 

thanks much.


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## Jasonb (Sep 23, 2014)

That bar you posted a picture of is not suitable for facing teh bottom of holes. The edge of teh triangle is at 90deg to the spindle axis so as soon as you get to the bottom of the hole the whole edge wants to take a big wide cut.

You need one that can turn and face. The type that take the rhomboid shaped cutters will do this like in my sketches. They are usually supplied with CCMT inserts but if you are doing a lot of aluminium then get a CCGT tip. About an 8mm or bar will do for these engines.

Should be able to get this type of bar in any country
http://www.glanze.co.uk/acatalog/Standard_Single_Boring_Tools.html


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## Woodster (Sep 23, 2014)

Although your boring bar is not _really_ suitable, if you just angle it in the toolpost or angle the toolpost itself to create a bit of front clearance, you can quite easily face the bottom of a bore, as long as it's not too deep so as to rub the tool shank.


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## werowance (Sep 24, 2014)

shoping for another boring bar,  what do you think for this cut,  3/8 or 5/16?  or some other size?

i plan on tooling up over time, but for now i just want something i can make this engine with.

thanks


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## Cogsy (Sep 24, 2014)

I'd go for the 5/16 (8mm) personally. The bigger the bar the bigger it's minimum bore size is. My 8mm bar needs at least a 12mm hole to start boring, so I can't bore a hole under 1/2". Having said that, the bigger the bar the deeper you can go, but my little 8mm can do 2" deep without a problem.


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## werowance (Sep 29, 2014)

Got my new boring bar in today and did another test run and I am very happy with the result. 

I bought a shares 5/16 bar with the suggested carbide shape and I produced a decent flat bottom hole. Cogsy and Jasonb thanks for the recommendations on the bar and carbide tip/technique using that tip.

Pictures of the new bar as well as my test hole in a cast aluminum ingot. The little dark marks in the hole are not swarf or dust but rather air holes in the ingot casting. The face cut was done quick and dirty just so I could get at the test bore so ignore the horrible face.  just needed it to be sort of flat. End result was a great fit with a great flat bottom (bore and bottom not the face). Just hope I can repeat it on the real part. May try a few more test cuts before the real one

Hope to have some more progress soon. And again thanks for the bar recommendations. Much better


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## werowance (Oct 1, 2014)

more progress last night.  bored the 7/8 hole and it turned out nice.  a nice tight fit with the nose cone part and a nice flat bottom hole.

picture 1 block squared up in the 4 jaw,  picture 2 the finished hole i broke the sharp edge with some emory clothe while running in lathe,  picture 3 this is me holding the block with the nose cone pointing down to demonstrate the good tight fit and it doesnt fall out.  the picture rotation is missleding, it is pointing down toward the floor.


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## Jasonb (Oct 1, 2014)

Looking good


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## werowance (Oct 1, 2014)

while its on my mind,  a few more questions.
1,  plan to bore the .625 hole for the cylinder in the crank case first, then cut the cylinder to fit.  right?
2, on the cylinder,  the cooling fin drawings call for a 7deg taper cut.  i was originaly planning on just using a parting tool and to straight plunge cuts for the fins but i sort of like the angled look.   if i were to try the angled fins,  what would you all sugguest for the cutting tool and procedure?  ground form tool sort of like a parting tool with 7deg ground on both sides and plung cut?   i may just end up doing straight fins but am curious how one would do the angled fins.
3, fuel,  i know its a diesel, but i assume it wouldnt run on diesel fuel right?  i happen to have some nitro fuel for a glow rc car i have  would that be acceptable - i know im thinking way ahead here but thought id be sourcing the chemicals if i have to mix up my own.

thanks


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## Brian Rupnow (Oct 1, 2014)

I like the blue thumbnail!!!


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## canadianhorsepower (Oct 1, 2014)

Brian Rupnow said:


> I like the blue thumbnail!!!


 

 Brian can you explain 

I didn't understand what you were referring to
When you mention Blue Finger nails!!!!!!!!!!!!!!!!!!!!!!!


It wasnt being nasty.......................was it??????????????????:fan:


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## Jasonb (Oct 2, 2014)

I think he was refering to the copious amount of blue used and the unusual method of applying it with your thumb

1. Yes hole then cylinder

2. I would do straight parting cuts first then swing the topslid eround to 7deg and using the same tool take a light cut down the side of each fin to taper it, make sure the cutter is sharp. If you use a form tool there will be so much cutter in contact with metal it will chatter and likely jam solid and there is also the risk of bending teh fins away from the cutter.

3. You need a mix of Kerosene, Oil (usually castor), ether and possibly an ignition improver but not really needed for a display engine. Some suggested mixed diesel part way down this page. Glow fuel won't do.

http://colinusher.info/Model Aircraft/fuel.html


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## canadianhorsepower (Oct 2, 2014)

Jasonb said:


> I think he was refering to the copious amount of blue used and the unusual method of applying it with your thumb
> 
> /QUOTE]
> 
> ...


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## werowance (Oct 2, 2014)

Brian Rupnow said:


> I like the blue thumbnail!!!


 
ha ha,  everyone's a comedian.....  yep i did get a bit messy with it.  was holding it in my hand and it ran over my thumb.  i do like a deep blue part as the scribe lines show up much better in my dimly lit shop.  gotta invest in some more lights.

Brian, hows the cam cutting coming along?


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## werowance (Oct 2, 2014)

more progress and a slight issue i hope will not affect running.

also note no blue fingernails in the photo's   Thm:

first picture,  the 5/8 hole bored and dead on measured with my new bore gauge

second picure,  finishied bore

third picture close up and notice i wend just a bit to deep with the half inch drill before i switched to boring bar,  on the little half moon you will notice a smaller half moon where i went to deep.  i dont think this will interfere operation

fourth picture,  this is the first hole i cut the 7/8 one,  notice where the chuck made an indention at bottom (in the photo its on the right) but the bottom if the engine were setup and running.  i used card stock in my chuck jaws but there was just to little material left thus it mared a bit.  if i had to do it over,  i would bore the 5/8 hoe first then teh 7/8 second.  the little mark on the metal doesnt seem to interfere with fit of the nose cone so i hope this wont cause a running issue.


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## Jasonb (Oct 2, 2014)

The small mark from teh 1/2" drill should not affect anything.

A smear of liquid gasget whan you finally assembel the nose piece will make sure no gasses pass teh dented area. Card is really a bit too soft, try a few bits of perspex or aluminium plate.


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## werowance (Oct 2, 2014)

Jasonb said:


> The small mark from teh 1/2" drill should not affect anything.
> 
> A smear of liquid gasget whan you finally assembel the nose piece will make sure no gasses pass teh dented area. Card is really a bit too soft, try a few bits of perspex or aluminium plate.


 

what is perspex?


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## werowance (Oct 2, 2014)

"what is perspex"

never mind,  google is my friend......i see its plastic acrylic sheeting.

thanks much.


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## werowance (Oct 11, 2014)

Tiny bit of progress.  Wanted to make my own 4/40 screws with some pieces of ss rod I have. But my slitting saw arbor was trashed so needed to make a new one out of some scrap mystery steel

That said the new one I used my new learned boring technique and bored the arbor to hold the end cap of the saw arbor.  Just a quick and dirty one but think it will do the job

Next are pics of the first screw which I have already culled as the second one I changed carbide to a sharper point so I could get a better square cut under cap to threaded shaft. 

Well.....only 9 more at least left to cut. Might do a couple more cause if I drop one I'll never find it as tiny as they are

Picture of first screw has my finger behind it just to get the camera to focus on the tiny threads.  (And for Brian not no blue on fingers.  Just grime from a brake job on wife's car lol). Just kidding.  Brian hope u are still following as well as the others. It keeps me going and wanting to finish

Any way enjoy the pics


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## werowance (Oct 17, 2014)

Started on the crank last night,  going to try a grade 5 bolt instead of the very large track hoe boom pin i was thinking of using.  the bolt cuts very easily and was much closer to the size i need so less waste of time and material.

i have been reading several of the different ways folks have done the rod journal pin on different cranks and i think im going for option 3 below but would like to know what others have to say?

1 - use .250 drill rod and silver solder in - saw Brian Runpows experience with it and understand that leaving enough clearance for the solder to flow in can also cause the pin not to be square,  but he was working on a more complex crank than i am in my opinion.

2- make an offset jig like in this post http://modelenginenews.org/techniques/crankshafts.html
and cut the journol - have had some experience with offset interupted cuts before and really didnt enjoy the cut nor did i really like the resulted part

3 - use .250 drill rod, loctite and press fit it in sort of like in this thread
http://www.model-engineer.co.uk/forums/postings.asp?th=70308&p=1
the reason i am leaning toward this option is i have the drill rod, and i have the undersized reamer for good tight press fit already.  i figure this will be the quickest, easiest, more acurate due to my limitations and will probably come out looking better.  its such a small engine i dont think i will have any durabilty issues or problem with the red loctite coming appart and the pin moving out?

id like to hear experiences from others so that when i get to the rod pin end, im a little more prepared make the decesion.

thanks


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## Cogsy (Oct 17, 2014)

If you go option 3, for added security and peace of mind, you can cross drill and pin the joints as well. I've used both loctite and soft solder on the pins (on different crankshafts) and had no problems.


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## Jasonb (Oct 17, 2014)

For some reason I would go with option 3 

You can mill away a lot of the waste to make the cutting easier on option two


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## werowance (Oct 27, 2014)

more progress this weekend, and almost a failure. i had posted earlier that i already had the .250 drill rod and undersize reamer to do the crank pin, well after i parted off the crankshaft i went back to the drawings and found i had missread the size and the .250 was actually the outside curve of the rod.:wall::wall: so i took that drill rod and cut it down to the correct size and after 4 attempts of that i finally got it right and to a press fit with lock tight.   also note the threads on the crank were left longer than plans,  i will cut it to length when i have my prop mounted.

posted below are:
1: photos from the other day that i didnt post of me slotting the ss 4-40 screws i made
2, 3 and 4 are the finished crank

5 and 6 are what i have so far assembled.


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## werowance (Oct 28, 2014)

more questions...... and thank you to all for all the help.

studying the plans further and trying to do things like locate materials and decide on a game plan for each cut and while i had some spare time today at work i have come up with these questions:

http://modelenginenews.org/plans/BJ_Cicada.pdf

on sheet 3,  can i get by with cheaper aluminum for the prop driver?

on sheet 3, on the piston, it says .437 "hone"  i have seen in one of my magazines where a guy was using a clamp looking hone to work on i believe it was vintage motorcycle push rods.  may have been wrist pins,  but is this they way the plans are calling for it to be honed?  or would you just cut a cast iron rod long enough to get both piston and contra piston out of to diameter, and start working it in and out of the cylinder untill it can go all the way through,  then part your 2 pistons out of this rod?  
- also what is that type of clamp hone called?

sheet 4, the mounting holes at the bottom of the cylinder,  how would be the best way to locate those to the crank case?  the crank case has not been drilled yet either because i was trying to decide how to get them all lined up,  the only way i can see is that i am going to just have to bite the bullett and do my very best at acurately measuring then marking both then drilling them seperately.  i was hoping to figure out a way to drill the cylinder first and transfering some center marks to the crank case but how with the cooling fins sticking out further than the bolt holes?

sheet 5,  the carb venturi section.  any problem using cheaper aluminum here?  and also what about brass?  im not concerned about the weight.


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## Jasonb (Oct 28, 2014)

1. Prop driver can be any aluminium you have

2.You don't really need an external hone. You can bore a suitable hole in a piece of brass or aluminium, slit one sid eso it can be closed up and use that with some lapping powder to refine the finish on the piston. A similar process is done with an internal lap on the cylinder liner and the final operation with a very fine 1000g powder is to lap the piston into the liner. I'll find a link to Ramon's thread which shows it.

http://www.homemodelenginemachinist.com/showthread.php?t=17674&highlight=etas&page=16

3. you can make up a simple template like a washer with a 5/8" central hole and the other 4 around it. slip it over the spigot on th ebottom of the cylinder and spot through the positions. Slip a stub of 5/8" bar into the hole in the crankcase to locate the template and again spot the hole positions.

4. Any aluminium is fine and brass should not cause a problem


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## rklopp (Oct 29, 2014)

I suggest you visit Ron Chernich's Model Engine News site for its teachings on cylinder lapping. Forget honing. I don't bother making a split lap for my "Diesel" pistons, however, opting instead to simply finish them long with incrementally finer SiC paper backed by a metal rule, then facing to length. I have done this successfully on 11 engines. It helps that my lathe cuts extremely straight and predictably with respect of diameter, and that I have collets to hold the sized piston for facing without marking it up. (It's a big heavy toolroom lathe with a DRO reading at 0.0001" on the diameter.)


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## werowance (Oct 29, 2014)

Jasonb said:


> 2.You don't really need an external hone. You can bore a suitable hole in a piece of brass or aluminium, slit one sid eso it can be closed up and use that with some lapping powder to refine the finish on the piston. A similar process is done with an internal lap on the cylinder liner and the final operation with a very fine 1000g powder is to lap the piston into the liner. I'll find a link to Ramon's thread which shows it.
> 
> http://www.homemodelenginemachinist.com/showthread.php?t=17674&highlight=etas&page=16
> 
> 3. you can make up a simple template like a washer with a 5/8" central hole and the other 4 around it. slip it over the spigot on th ebottom of the cylinder and spot through the positions. Slip a stub of 5/8" bar into the hole in the crankcase to locate the template and again spot the hole positions.


 
2.  thank you ill check that out.
3. using a washer,  genious pure genious.  i like that idea very well.  thank you so much for that one.


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## werowance (Oct 29, 2014)

rklopp said:


> I suggest you visit Ron Chernich's Model Engine News site for its teachings on cylinder lapping. Forget honing. I don't bother making a split lap for my "Diesel" pistons, however, opting instead to simply finish them long with incrementally finer SiC paper backed by a metal rule, then facing to length. I have done this successfully on 11 engines. It helps that my lathe cuts extremely straight and predictably with respect of diameter, and that I have collets to hold the sized piston for facing without marking it up. (It's a big heavy toolroom lathe with a DRO reading at 0.0001" on the diameter.)


 
so you are sanding them to size?  start a little over size and sand them down with a flat object like using a lapping plate with the lathe spinning it?.  ill have to look up SiC paper thats a new one to me.  is it like emory cloth or more like wet and dry sand paper?


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## rklopp (Oct 29, 2014)

Yes, I start about 0.0003-0.0007" oversize and polish to size with silicon carbide (SiC) wet-dry paper strips lubricated with oil and backed by a beater flexible steel rule. The part is spinning in the lathe at ~1000 RPM when I do this. I polish with 320, 400, 600, and 1200 grit. To get the size at which to start polishing, I use plug gauges (can be home made)  to check the cylinder, mic the one that is about right, then turn the piston to the estimated proper size based on the micrometer measurement of the plug gauge +0.0003 to +0.0007". I clean the piston scrupulously before testing the cylinder fit. I bring the cylinder to the work, rather than the other way around. I sometimes mess up and go undersize on the pistons, but they're small and quick enough to make, it's no big deal. I polish with the pistons 1/8" to 3/16" long so the unavoidable rounded ends get cut off.


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## werowance (Nov 12, 2014)

got just a little while in the shop yesterday and managed to get the collet and taper D-bit made to cut the matching taper in the prop spinner.

started by using my angle blocks and set my compound to 6 deg to the face of my chuck, then took some brass rod and faced/ center drilled it to size  then cut the outside of the collet to .300 then using my compound i cut the taper on the outside of the collet.

for cutting the slot in the collet i kept looking for a way to cut that .016 slit in it,  finally i came up with a slotting saw that was dead on .016 and decided to try it in my tool holder and it worked great!.  i set the tool height with the blade in it to center of my tail stock point then swung it arround and pulling the teeth from left to right for each cut i made a reall nice clean slot for me.  cant believe that worked so easily.  the idea came from watching manual key way broaching using the cross slide.

next while the compound was still set at 6 degrees i made the D bit.  actually i made 2 as i dropped the first one after heat treating it and it broke.  i think 2 things are at fault on that - asside from me being clumsy and dropping it.  1. its O-1 and i used watter to quench it and 2 i didnt temper it after that so it was really brittle.  on the second one i quenched in oil and then off to the toaster oven at 400 for 45 mins.  
i do not yet own any V blocks so i used one of my tool holders from my quick change tool post and sinched it down.  then to my height gage to mark the center line on both sides.   while still in the tool holder i put it in my qctp and adjusted height and started milling it using my lathe chuck with an end mill in it and cut it to the center line.   test cuts in scrap made a smothe clean tapered hole for me.  i am happy.

pictures:
1. brass in chuck almost finished with taper cut
2. slitting saw to make the slit in collet
3. finished collet
4. finished collet
5. start of d-bit to make internal taper on prop spinner
6. scribing center line using qctp holder as improv vblock
7. milling the dbit
8. finished d bit after heating.


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## werowance (Nov 12, 2014)

now thinking about the prop driver and the knurles on it.  since i dont own a straigt cut knurl, i was considering taking a piece of square stock, milling a grove in it and cross drilling it to hold a single knurle in it.  then taking a torch and heating it in the middle and twisting it to a close match to the angle of the knurl,  sort of like how a black smith twists ornamental rods for things like iron fence or handles in iron.  has anyone ever done this?  im wondering if having the knurl rotating at an angle will cause to much stress as it sort of would be pushing sideways of the rotating axis and sort of down on the rotating axis if that makes sense.

also i have seen some swirl pattern prop drivers done but not how they did it.  is it likely that was done using a rotary table or something and milled instead of knurling?  or is their a technique using a knurl to do that?  just curious.


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## Jasonb (Nov 12, 2014)

You can do it using one of the wheels on a diamond knurling tool. I was able to mount the tool very high in the tool post but you may have to take a wheel out of yours and make a simple holder.


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## werowance (Nov 13, 2014)

Thanks, and that looks like the swirl patern i was thinking of.  what engine is that prop driver and collet for?

how did you hold the driver after knurling it to ream the rear?


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## Jasonb (Nov 13, 2014)

Its for a Nemett Oscelot/Bobcat/Jaguar

The taper was bored at the same setting (small to large)then parted off so only needed a light skim to clean up the face no reaming required


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## werowance (Nov 17, 2014)

got a few more hours in the garage this weekend and got the prop driver, washer and nut finished,  then started squaring up some stock for the rod but didnt get that finished.

faced, center drilled and cut to size some scrap aluminum rod,  then cut the angle on the face for the prop washer then parted it off.   with the same stock in the chuck i faced it again,  Thanks to Jasonb i managed to get that swirl pattern in the knurl on the prop driver.  it did take a few tries with re-facing the stock before i got something i liked by adjusting the knurl height,  but it worked well once i found the sweet spot.   Thanks Jasonb for that info.   once finished, i parted the driver off, turned it around and used the d bit reamer and reamed the taper in it.  that worked well for me to.  then last some scrap hex bar i drilled and tapped 10-32 then parted off for the nut

pictures:
1. stock ready to part washer off
2. finished parted washer
3. prop driver ready to part off
4. finished prop driver, washer and nut
5. loose test fit of it all


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## werowance (Nov 21, 2014)

rod finished and some pictures.

1. blank layed out with marks
2. in vice with drill and rod to hold it square
3. sides milled
4. finsihed rod after rounding in the mill.  didnt take any picutres of doing that.


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## werowance (Nov 21, 2014)

now for the cylinder, i have really been dreading this part and have questions.

on sheet 4 of the drawings  http://modelenginenews.org/plans/BJ_Cicada.pdf

it shows a .250 offset cut inside the cylinder going .750 deep.  am i going to have to mount this in the mill and use a .250 end mill to cut this after i bore the main hole?  or should i offset the stock before i bore it,  bore the .250 first then move it back and bore the main cyinder hole second?

i might get done by sumer time.....


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## Jasonb (Nov 21, 2014)

I would be inclined to bore the main hole and then cut the other as you say by plunging with a milling cutter. The interupted cut doing it the other way round may affect the main bore.

Other bits are looking good


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## werowance (Nov 21, 2014)

Jasonb said:


> I would be inclined to bore the main hole and then cut the other as you say by plunging with a milling cutter. The interupted cut doing it the other way round may affect the main bore.
> 
> Other bits are looking good


 

so use a .250 end mill and when you say plunging do you mean use the tip and cut downward to vertical depth like a drill bit or cut with the side untill i hit horizontal depth?  not sure there would be a speed or finish difference with either way but this is one part i feel is critical to get a good square finish on and dont know which way to cut with the end mill

thanks again for your help.  i couldnt have gotten this far without you and the others help.


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## Jasonb (Nov 21, 2014)

Yes use the end of the cutter and plunge it down like a drill. I would do a littel, move the work over 0.005" take another cut etc until you reach the 0.142" offset.

J


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## werowance (Nov 28, 2014)

got a large portion of the cylinder done over the last few days,  but looking at the drawings http://modelenginenews.org/plans/BJ_Cicada.pdf  sheet 4 and looking at the .750 tall cut witht he .250 bit as mentioned above and i thought that the intake or exahst hole would drill into that little slot.  but the plans dont show that.  so what is that slot for?  why would it need to bypass into the crank case?  just trying to understand the mechanics of how this one works.


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## werowance (Nov 28, 2014)

i think i understand it now,  when the bottom of the piston passes the intake port it sucks fuel in beneath the piston.  then on down stroke the fuel is pushed through the crank case and up the .250 slot in the side of the cylendar to the top of the piston where it is then compressed and ignighted.  right?

reallly only used to working on reed valve 2 strokes,  so if this is how this one works,  thats pretty cool.


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## hussien95 (Nov 28, 2014)

Hello all
Very nice work,thank you.
Some time ago and I want to ask about this type
Is this type of engine only works on diesel or are there other additions ????


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## werowance (Nov 28, 2014)

Hessien95,  thanks for the compliment.

are you asking if this engine will only run with diesel fuel? or if the engine only works on the dieslel priciple of compressing the fuel until it ignites?  

i am told this engine should be run on kerosein and castor oil,  id say this engine could probably be made to be glow plug ran by removing the contra pistion,  adjusting the height of the regular piston and adding a glow plug.  i dont know for sure though.


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## werowance (Nov 28, 2014)

another question, after finding out my scrap cast iron i planned on using for the piston and contra piston isnt going to work out for me (pitted to bad, horrible casting) and not wanting to buy more dura bar and wait for delivery. i was wondering if i could substitute 12L14 for the piston/contra piston. the cylinder is cast iron dura bar. would the mis match in material be so much that expansion rate would be to far off between the 2 and cause a poor running engine once it heats up?

and the scrap i had isnt dura bar, it was window sache.  the dura bar i used for the cylinder was nice as cast iron goes.  certainly not 12L14 but it cuts decent


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## hussien95 (Nov 28, 2014)

Thank you for your answer, my friend.
I see a lot of these models on the internet and I want to know that they only need to diesel or materials that they need help to complete the ignition process.
Such an engine, for example,





I honestly new in the world of engine industry did I make any engine yet, for this I am looking for information to help me in the first engine industry
Sorry for my bad English


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## werowance (Nov 28, 2014)

if i understand your question correctly,  that engine in your picture should only need the correct fuel to run.  no external ignition source required.  i.e. no glow plug or spark plug.  the compression in the engine is so high that it causes the fuel to ignight under preasure.  the diesel principle.  

there are different fuel mix recomendations out there.  i plan to try the kerosein / castor oil mix when or if i complete my engine.


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## jj-smith (Nov 28, 2014)

Hello werowance,

I just read the thread.., pretty cool build, I already learned a few things just browsing through the posts.

I'm rooting for your engine to run fist try, and when it does I'd like to ask you what fuel and aditives you'll be using.

I have an old russian diesel engine and could never get it go run at all.

I like your calm persistence to get it done, I can learn from that too lol.

Cheers, J.


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## werowance (Dec 1, 2014)

jj-smith,  thank you for the compliment.  i am going to try the kerosein castor oil mix first and see where that gets me.  i have read taking a small plumbers propane torch to pre heat the cylinder helps fire it up sort of like a glow plug pre heats a diesel truck or tractor.  i am a complete newb to this hobby.  i am enjoying it but some of the procedures scare the crap out of me.  not litteral of course but i am just not that confident in what i am doing is correct so i have asked for alot of hand holding and have had great results with questions and answers here.  everyone has been so helpful and i appreciate it.


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## werowance (Dec 1, 2014)

i have started jumping around a bit on what i am working on due to needing material and just getting tired of working on the same part,  so not to get burned out i switched things up a little.  got some starts and finished a fiew of the small bits this weekend.   the weather here compared to a week ago this weekend was great.  even grilled some burgers outside.  so i didnt spend alot of time in the garage but here are my results.

1. cylender sitting on the crank case - fins, bore and hone finished but thats all.  the fins were horrible to cut,  so much chatter out of that little thin parting blade.  i found that cutting with fast feed force really helped with the chatter.  go figure,  i would have thought slower feed force would have been better
2. the cylendar mounted on the arbor i made to cut the screw holes and mill the flats
3. the arbor and washer for holding it.
4. skipping around a little - the aluminum blank to cut the carb body from.  didnt have any 3/8 stock so cut this out of 1.0 stock
5. using a cross drill jig as seen in one of "tubal canes" youtube videos and a 5/8 end mill in the lathe chuck i cut the radius on the end of the carb mount lug that solders to the cylendar
6. finished lug
7. just an example of what the lug will look like when soldered to the cylendar.



7.


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## werowance (Dec 8, 2014)

this weekend I completely ruined my cylinder I worked on for weeks:wall:
 I was silver soldering the caruburator bung to the side of the cylinder and I ruined it.

 i have experience silver soldering brass to cast iron and brass to brass, brass to copper etc. but never cast iron to drill rod.  for the life of me i could not get it to stick to the drill rod.  i ended up melting one of the ears on the cylinder.  the pictures i am posting are after several attempts and after i had already ruined the ear and i cranked the heat up real high just to see if i could ever get it to stick.  after each attempt i would re-clean the metal and reflux it but i just wouldn't go.  it would stick to the cast iron but not that drill rod.  

 it took me at least 2 weeks to do the cylinder and just minutes to ruin it.  after that i havnt touched my lathe and probably wont for a few days until i get over it


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## Brian Rupnow (Dec 8, 2014)

Werowance--You have my deepest sympathy. I know how it feels, because I have experienced similar failures myself. I can not offer any advice about silver soldering to drill rod, but perhaps someone with more experience than myself can offer some helpful advice.----Brian


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## Jasonb (Dec 8, 2014)

Got to ask the question why did you use drill rod? and for that matter why Iron for the cylinder??

J


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## werowance (Dec 8, 2014)

Jasonb said:


> Got to ask the question why did you use drill rod? and for that matter why Iron for the cylinder??
> 
> J



 Jason, I used iron for the cylinder because I could never come up with L24 steel as the drawing called for,  and looking at other builds the liners are mostly cast iron.  Looking back today at this post I did http://www.homemodelenginemachinist.com/showthread.php?t=23342
 you suggested 12L14 for the cylinder.  I think that's what ill go for this time and a cast iron piston.  
 also figured, cast iron piston - then cast iron cylinder for even expansion rates between the 2.
 but hey, if you all say 12L14 is the way to go, I love working with it just about as much as Aluminum or Brass.



 as for the drill rod on the bung,  my plans just say steel with no mention of type, I had a piece of scrap drill rod almost already the right size and was reall handy at the time (laying right beside the lathe) so that's what I grabbed.   would you suggest 12L14 for that to?

 I do have a concern on the 12L14,  that's when heating it up to solder it,  wont the Lead in it sweat a little and possibly cause pitting in the honed bore?  I guess I could hone after the soldering but still what about pitting?

 I have heated 12L14 to red hot before and when it cooled the lead had sweated out a little bit but this was on a solid bar,  just wondering what a hollow tube would do?


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## Jasonb (Dec 8, 2014)

I think when i said that I had not notoiced the stub that needs to be soldered on, so may be better to go with the unleaded 1214 rather than 12L14


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## werowance (Dec 8, 2014)

Brian Rupnow said:


> Werowance--You have my deepest sympathy. I know how it feels, because I have experienced similar failures myself. I can not offer any advice about silver soldering to drill rod, but perhaps someone with more experience than myself can offer some helpful advice.----Brian



 Thanks for the sympathy Brian.  its such a disappointment, I was all smiles when I went out to the garage because I knew I was almost there,  then I ruin it.   it just ruined my whole weekend.  hard to believe something this small that most would consider trivial (but not me) in the world and in life could bring me down so much this weekend.

 oh well,  guess ill lick my wounds and clean up the shop (pout as my wife calls it) for a few days and then get back at it.


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## werowance (Dec 8, 2014)

Jasonb said:


> I think when i said that I had not notoiced the stub that needs to be soldered on, so may be better to go with the unleaded 1214 rather than 12L14



1214 - had never heard of it until now.  does it cut at easily as 12L14 or close to it?

 ill take a look on ebay and a few metal suppliers and see what I can get


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## werowance (Dec 8, 2014)

looking at a few spots like onlinemetals and ebay and a few others but not seeing 1214 for sale on them.  I am finding plenty of deffinitions for it but not where to easily buy it.  anyone got a metal supplier they like that would have it?


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## Swifty (Dec 8, 2014)

It's a real bummer about the cylinder, I can only suggest that you got it too hot and the drill rod started to have scale come off it, that would certainly cause problems with soldering.

Paul.


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## werowance (Dec 10, 2014)

Jasonb said:


> I think when i said that I had not notoiced the stub that needs to be soldered on, so may be better to go with the unleaded 1214 rather than 12L14




 Jason, how about 1117 steel as a free machining steel substitute for the cylindar?  that alloy I can locate.


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## Jasonb (Dec 10, 2014)

Sorry I'm not tottally up with the american codes. The 12L14 was the equivalent to our EN1Apb and the unleaded version 1214 would be the same as our unleaded ENIA


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## werowance (Dec 17, 2014)

well after some pouting and some major shop clean up and shelf building I started cutting some metal again.  I made a test cylinder and carb bung from 12L14 just for testing purposes to see if the lead would sweat out.  I am pleased to announce it did not.  the silver solder flowed nicely for me and no lead sweat or pits left from the heat.  this makes me very happy as I love to work with 12L14 as the finish is better and I can make quicker cuts without as much effort.  now just waiting on a piece of 12L14 big enough to make a real cylinder with fins out of.

 once question,  will the lemon juice and water solution work to clean up the part after heating like it does with copper?  or will I just end up with a rusty piece of steel?  guess I can test that but just wondering.

 here are some pictures of the cylinder.  outside diameter and inside bore are the same as the real one would be minus the fins and such.

 1. part all fluxed up, clamped and ready for heat
 2. finished solder
 3. finished solder different angle


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## Brian Rupnow (Dec 17, 2014)

Thank you.--that is good information to file away.---Brian


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## Swifty (Dec 17, 2014)

Glad that you fixed the problem, just a thought though, keep the flux just to the local area as the solder will run where the flux is, and way too much solder on the part. This will help make a neater part and it's easier to clean up. Not critisism, just helping.

Paul.


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## werowance (Dec 17, 2014)

Swifty said:


> keep the flux just to the local area as the solder will run where the flux is


, 

 Thanks Paul,  yeah I know it was thick and spread out,  I normally use a  q-tip to apply it but as it was just a test piece I didn't bother running back in the house to get some,  I just used the large brush that came in the can of flux.  started to wipe some off with a paper towel,  but again,  just to lazy for a test piece. I will also probably use a small diameter piece of solder on the next one to.I will though be careful on the real piece when I get it ready.  had heard that white out correction fluid was handy in that you could paint a ring around the part to keep the solder from flowing so far,  have you ever heard of this or tried it?


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## Swifty (Dec 17, 2014)

werowance said:


> ,
> had heard that white out correction fluid was handy in that you could paint a ring around the part to keep the solder from flowing so far,  have you ever heard of this or tried it?



I haven't tried the White out, but I know that Brian Rupnow is a great fan of using it, so it must work well.

Paul.


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## werowance (Dec 17, 2014)

maybe that's where I saw or heard about it in one of his posts.  will have to go back and see if I can find it.


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## Brian Rupnow (Dec 17, 2014)

It shows it in my very recent carburetor build thread.


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## werowance (Dec 23, 2014)

finally got some 12L14 large enough to cut the cylinder from. I love working with this stuff. while making the new one I found I had made a mistake on the old one and had the fins to close to the intake and exhaust holes:hDe:. I had forgot to subtract the diameter of the base flange from my measurements. this should make soldering the bung even easier on the new one. you can see in my picture of the old melted one compared to the new one the difference.
I also used a larger radius tip carbide insert and that gave a nice radius to the larger section between the base fin and the first cooling fin. I found those tips on ebay and they do seem to leave a much nicer finish than the sharper tipped ones.
didn't have time to put the cylinder in the rotary table to do the flats and drill the holes but did have time for a quick part, so I decided to make the jam nut for the carburetor. ended up taking longer on that because I ruined the threads on the first one. I used tap fluid on the first one and galled the threads up:wall:. the second one I remembered that brass should be cut dry so I tried tapping it dry and it turned out just fine. lesson learned I guess I should tap brass dry all the time?

pic 1:cylinder all blued up and on its arbor for the rotary table
pic 2: same just different angle
pic 3: old and new cylinder side by side to show my measurement mistake on the first one
pic 4: brass jam nut
pic 5 brass jam nut other side
pic 6 the new large nose radius carbide inserts
pic 7 large radius carbide next to normal sharp tip carbide. the black one is the new one


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## werowance (Dec 26, 2014)

not able to be in the shop right now so I thought I'd do a little shopping for a prop.  what size would you all recommend for it?  is there a rule of thumb for the prop size?  would you measure from center of crank to top of head or longer?  when ordering,  are props listed for example a 6 inch prop,  would that be 3 inches from center of prop which makes a 6 inch over all length prop?  

 would you go for plastic or wood or does it matter?

 would like to make my own but I think Ill start with a store bought one at first.

 Bryan


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## goldstar31 (Dec 26, 2014)

Swifty said:


> I haven't tried the White out, but I know that Brian Rupnow is a great fan of using it, so it must work well.
> 
> Paul.


 
An HB or a B Pencil works well. All that happens is that it makes the part that doesn't want solder to be 'dirty' . Also works on soft solder but oddly, if you are gas welding with oxy/acetylene the carbon in the acetylene acts as a flux. If you are Mig/Mag weldingie Metal Inert Gas using Metal Active Gas system, carbon as CO2 becomes a shielding gas.:hDe:


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## Swifty (Dec 27, 2014)

As far as I understand, props are always sized by their overall length and the pitch, ie, a 6 x 1 prop is 6 inches overall length with a 1" pitch per revolution of the prop. I have used plastic props as well as wooden props, but for display purposes only. I prefer the wooden props for display as they look a lot better.

Paul.


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## goldstar31 (Dec 27, 2014)

Paul is right about diameter and pitch and from what I recall, the jury is still out on which to make or buy.
Really, it depends on how capable your engine is and the task for which it is intended. 

If my ancient memory is holding out for a while longer, you actually need a set of props and a home made rig as a dynanometer. If you are merely wanting to see the 'wheels go around' or to 'run in' your engine from new, I'd choose a large prop to get more leverage for flicking it over.

Others WILL be just as right-- and wrong. 

Norman


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## werowance (Dec 29, 2014)

goldstar31 said:


> If you are merely wanting to see the 'wheels go around' or to 'run in' your engine from new, I'd choose a large prop to get more leverage for flicking it over.



Yeah, that's pretty much it,  just something to make the engine run and look good.  ill not be putting it in anything other than a display case if it will run for me. 

 considering the engine from center line of crank shaft to top of cylinder is right at 2.1 inches high,  would you go for about a 6 inch prop?  or longer / shorter?


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## werowance (Dec 29, 2014)

made some headway this weekend.  almost finished the cylinder.  made the head. started on compression screw and tommy bar.  all I lack on the cylinder and head is to drill and tap the  two 4-40 head screws.

 On sheet 4 of these drawings :http://modelenginenews.org/plans/BJ_Cicada.pdf
 i believe there is a mistake.  the head shows to drill and tap for 10-24 compression screw.  but when you look at the compression screw it shows 10-32.  i went with 10-32 for both.  this is a mistake in the drawings right?

 the silver solder was almost a disaster again however I think I figured out my problem.  in my test piece I did not use the arbor that I have been holding my real cylinders in.  this arbor is a good slide fit to the bore of the cylinder.  I believe this arbor has been leaching heat or taking much longer to heat up and thus the carb bung is over heating.  i did manage to get it soldered and sort of made a mess of it but after some cleanup with file and sand paper it looks fine.  may do a little more filing later.

 i did not have any piano wire for the tommy bar on the compression screw so i chucked up my pencil grinder (diy tool post grinder) which fits my 3/4 boring bar holder perfectly.  i ground down some drill rod i had to make the 3/32 tommy bar out of

 here are some pics

 1 - 3 are of the cylinder and head.  just different angles
 4 - 5 are the tommy bar being ground.


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## werowance (Jan 7, 2015)

well, I have finished the contra piston and almost the piston, waiting on a reamer for the cross drill wrist pin.

been working on the carburetor parts and man, some of those drills are tiny. bought a set of pin chucks and they are not at all accurate, what do you guys hold those little tiny drills in?

here are some pics I have of what I have assembled so far.


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## werowance (Jan 13, 2015)

my reamer arrived this weekend so I finished up the piston,  this completes the main portion of the engine - I do still lack trimming the crank case on the sides for the mounting flanges however that can be done after I get a chance to see if it even runs which will be after I get the carb finished.

I also got a small Shars brand chuck last night and its wonderful for those little tiny drill bits.

I also learned a new trick (new to me) for center drilling brass.  for some reason brass always wants to make even center drill bits walk off center a little whereas steel or aluminum doesn't seem to do that to me.  but the trick I learned was to take my sharpest dead center and put it in the tail stock and push it in the end of the brass just to make a small center punch mark,  then the center drill doesn't walk any more and where my dead centers are centered just as the drill would be it makes a perfectly centered dimple in the brass

so that trick combined with the new chuck has really helped me with the little itty bitty carb parts and drilling those little holes with pin drills

only picture I have today is of the completed piston.


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## werowance (Jan 13, 2015)

Jasonb said:


> 3. You need a mix of Kerosene, Oil (usually castor), ether and possibly an ignition improver but not really needed for a display engine. Some suggested mixed diesel part way down this page. Glow fuel won't do.
> 
> http://colinusher.info/Model Aircraft/fuel.html


 
Jason,  getting close enough to where I need to start ordering fuel mixing supplies,  Kerosiene is no problem to source,  but what about castor oil and ether?   on ether can I just buy a can of starting fluid and spray it into a container and then put a lid on it so it doesn't evaporate?  castor oil- you mean the stuff that they used to show on old television shows where the kid who was acting up would get a spoon full of castor oil as punishment?  would I find that at a drug store?   

Thanks
bryan


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## goldstar31 (Jan 13, 2015)

Castor oil? Medicinal stuff is too dear. I always used 'cow castor oil' which farmers used on beast as it was cheap(er) However, the paints and plastics industry used literally tons of it. 


A little bit more is Castrol R oil which was the unmistakeable smell of old motor bikes and this was the Wakefield's trade name.

Norman

As this is a total loss oil, why not use sunflower oil?


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## werowance (Jan 14, 2015)

Castrol r - like 2 stroke oil for dirt bikes and chain saws?  if so then I can source that at the auto parts store no problem.  sun flower oil?  if that will work then I should be able to find that at the grocery store.

I don't plan on running this engine much.  just to prove it works and then every now and then to show off (assuming it works)  it will spend the rest of its life on the shelf as my first engine. (also assuming it runs).

now for the ether part.  man I wish I still had access to the lab at school.  they had quart bottles of the stuff.  but cant seem to source a small amount anywhere on the internet.  at least not without buying in quantities that a large business would use.

Bryan


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## Jasonb (Jan 14, 2015)

Yes Castrol R as in performance 2-stroke oil which should be available from Bike, snowmobile, etc stores.

Ether is the hard one to get here now and sound like it is where you are too, its used in the manufacture of illigal drugs so they make it hard to get.

May be worth checking some of the RC aircraft stores to see if they can supply ready mixed for the small amount of running you will be doing.


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## werowance (Jan 14, 2015)

Jason,  I checked around on line and seems the way to get it now days and was actually suggested by fhs hobby fuels for ether was to buy John Deer starting fluid and get it out of the can that way.  reading on other forums about it they are saying pretty much the same thing,  John Deer or a quality starting fluid as it contains more ether and less aditives.  take a mason jar, poke a hole in the lid,  use a wd-40 straw in the aresol spray tip.  spray the whole can out in the mason jar.  replace lid with one that doesn't have a hole.  

so I think ill do this formula - what do you all think

kerosein - about 40%
ether from john deer cans - about 35 % - read anything over 30 percent is a waste but considering john deer ether wont be pure I was going to up it to 35%
Castrol r - about 25 %   

but if I keep messing up on cutting the venturi nipple ill never get this carb built to even need fuel.
tonight ill start the third attempt at the nipple.  each one looks better than the first, almost had it last night and on the last drill I went to deep and ruined it. - again:wall:  oh well 1/4 inch bras hex isn't terribly expensive and its itty bitty size so I guess I can afford to mess up a few more if I have to.

on the plus side,  the needle valve, jam nut and gland nut all went very well.  so only 4 more parts to make or re-make before I can test it.  we get a long weekend this week from work so hopefully ill have lots of garage time this weekend.


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## werowance (Jan 19, 2015)

Well only lack the main carb body.  Wanted a change of pace something more fun without major attention to tolerance so I decided to make a fuel tank.  Mostly scrap, the main body is from a scrap oxygen concentrator for people with breathing problems a friend brought me, the fuel nipple is from a piano that I'm not sure went through a flood or fire or both but a friend who did the cleanup brought me the wire and brass and scrapped the rest, the fuel filler was a very short piece of scrap 360 brass I had saved that was very hard to chuck up and last the end caps are from a scrap door kick plate that goes at the bottom of a fancy door that I cut out to fit.  Then soldered it all together and lightly polishedView attachment ImageUploadedByModel Engines1421706630.450256.jpg
View attachment ImageUploadedByModel Engines1421706642.648585.jpg
View attachment ImageUploadedByModel Engines1421706734.382016.jpg
View attachment ImageUploadedByModel Engines1421706743.944513.jpg


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## Brian Rupnow (Jan 19, 2015)

Super nice work on the gas tank. Be proud!!!


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## werowance (Jan 22, 2015)

Brian Rupnow said:


> Super nice work on the gas tank. Be proud!!!


 
Thanks Brian,  the tank was a fun diversion.  

got started on the carb body last night and things were going very well and quick to.  got the whole body cut out and was threading the back of it and was to the point that I only needed about 1 and a half turns left when snap it rung in to.  CRAP!:fan:.  the D bit cut the inside taper very very well and the whole thing was going really great. a few things I think will help the next time.

1. use 2024 instead of the scrap unknown alloy I had
2. make the area that will be threaded a little smaller diameter.  I used my cheap plastic thread gauge that also has bolt hole size's in it to but I could have gone down a little bit more and still had full threads.
3. possibly thread it first before I drill the full bore of the carburetor thus I am not threading a tube.

oh well,  just glad this doesn't seem to be such a difficult piece to make.  however this time im just going to source some 3/8 square stock so I don't have to cut it down to size just to get started.

also finished up the fuel tank by adding a cap.  also wanted to experiment a little and come up with a paper gasket like you would fine in an older briggs and Stratton lawn mower engine gas cap.  the metal syle gas caps.  they are sort of yellowish/redish/brownish and are flakey brittle.  yeah I know that's a lot of colors for a description and yes I am green brown color blind.
anyway  for my testing I started with some card stock I get free from work.  its a tad thicker than a Tide soap box and is plain card board with no printing on either side.  I found some indian head gasket shellac at the car parts store and rubbed a little on it.  when it dried it looked and felt almost exactly like the old brigs gas cap gaskets.  will test it with a little gas to see if it will hold up.

anyway here are some pictures of the failed carb body and gas tank with cap.


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## werowance (Jan 25, 2015)

Almost ready to attempt a start.  Gotta go get some fuel and have company coming over in a few.   Man I hope I can start this thing tonightView attachment ImageUploadedByModel Engines1422204069.416489.jpg
View attachment ImageUploadedByModel Engines1422204097.456545.jpg


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## werowance (Jan 25, 2015)

A few kick backs with a pop and some smoke coming from around a leak between head and cylinder and also have a leak around block and prop snout flange.    

Well gotta stop and clean up for family 

Hope to try again tonight


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## werowance (Jan 25, 2015)

View attachment ImageUploadedByModel Engines1422212175.180336.jpg
View attachment ImageUploadedByModel Engines1422212228.760867.jpg


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## werowance (Jan 26, 2015)

Well, no luck getting it fired last night. got the leaks sealed up with some gasket shellac on the head and prop snout but still no fire. so last night I started shaving the head down a little as well as deck the cylinder top a tad bit to increase compression. didn't get finished with that though.

a friend also came over last night, he thinks I am using to much oil in my fuel mix. here is my recipe, what do you all think? is their any fuel that ignites at a lower compression ratio?

3 tablespoons of catrol 2 stroke racing oil
3 tablespoons of ether obtained by poking a hole in a mason jar lid and spraying the contents of a can of starting fluid through the hole with a wd-40 straw and allowed to sit for a while 
4 tablespoons of kerosein.


also  a note on the ether,  after I emptied the can of starting fluid in the mason jar,  about 5 mins later it started bubling like a can of soda after shaking it or like water boiling.  it was about 40degrees in my shop at the time.  was that the propane propellent separating from the either?

I left the lid on loose so it could vent that out some.


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## goldstar31 (Jan 26, 2015)

Me? I'd make a flywheel with a groove for a pull cord instead of a propellor. Not quite the question asked but a damned sight easier than flicking a prop.

Mind you, I doubt whether your so called ether was 100% ether.

Just a thought or three?

Norman


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## werowance (Jan 26, 2015)

started using a battery drill to spin the prop last night just to see if I could even get any pops or smoke. im slinging fuel out the exhaust but no ignition.

yeah im positive its not 100% either. but its pretty much impossible to source either in the USA for home use. im sure if I was a commercial account or a doctor or something I could get the real stuff but all the meth/crack heads ruinded getting etiher for everyone.

but I may whip up a fly wheel to test with.

just found this on tower hobbies,  pre mixed model diesel fuel,  im going to buy a can of that to try as well.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXANCP&P=0


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## goldstar31 (Jan 26, 2015)

Meantime, has squirting a bit of 'neat' ether in the exhaust port been tried?  Sounds obvious but well?

Norman


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## werowance (Jan 26, 2015)

Neat ether?  do you mean just starting fluid?  yes I did try that.


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## goldstar31 (Jan 26, 2015)

Yes, I did mean that. You've got to watch that you don't 'bog' the engine with too much liquid but lubrication is not a concern because if it does fire , your next cycle should be what is in the carb.

From a long distance away, I suspect fuel first, then wrong metering on the needle valve. Here, I can be wrong as it is a long, long time since I had my knuckles wrapped on a prop.

Just knocked a chunk out of my ancient fingers removing chipped cutter blades on a wood branch shredder. I DO sympathise- been there.

Norman


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## werowance (Jan 27, 2015)

still no luck last night trying to start it after shaving the head and decking the cylinder a little. I do have more compression but I don't think enough.

a few thoughts / questions
1. the piston going up - the bottom just clears the intake hole to allow fuel to be taken in from the bottom of the piston - is this correct?
2. the piston going down - it almost completely clears the exhaust hole just a little bit of the top of the piston can be seen - is this correct or close enough?
im worried I have intake and exhaust positions reversed.

3 as a test if I fill the compression screw hole with fuel, It will lock the piston and takes a good while to leak by. not sure how else to do a compression test.
4. tried pure ether sprayed in the carb with fuel turned off. no fire
5. the carb seems to work well, can adjust to just barely any fuel to fuel running out like crazy. from experience with other store bought airplane engines this is doing just like it should.

so if the intake and exhaust ports are correct then im probably left with just not enough compression right? thinking of putting some jb weld in the top of the contra piston where its counter sunk so that if there is blow by on the contra piston it will not have as much volume for air to compress hopefully increasing compression. what do you think?

I cant even get any more pops or kick back like I did on the first attempt. although I was pre-heating the cylinder with a plumbers torch. but don't want to do that with all the ether being sprayed around it and possibly not evaporated off yet when I re-heat it over and over during attempts. good way to burn down the garage and all. (already had a small fire yesterday is how I know.  a towel put it out quickly didn't have to use extinquisher)

I am using a cordless drill for attempting to start, I should at least get smoke or pops using that shouldn't I?


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## Jasonb (Jan 27, 2015)

Obvious questing do you have the drill in reverse as these engines run anticlockwise when looking at the prop end.

You should be able to adjust the compression enough by screwing down the contra piston screw


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## canadianhorsepower (Jan 27, 2015)

werowance said:


> 1. the piston going up - the bottom just clears the intake hole to allow fuel to be taken in from the bottom of the piston - is this correct?
> 2. the piston going down - it almost completely clears the exhaust hole just a little bit of the top of the piston can be seen - is this correct or close enough?
> im worried I have intake and exhaust positions reversed.
> 
> ...


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## werowance (Jan 27, 2015)

canadianhorsepower said:


> this sound totaly wrong
> when the piston is completely up the complete intake port must be open
> and when the piston is down the complete port should be open also:hDe:
> 
> good luck


 
CanadianHorsepower,  thanks for the quick reply.  looking at sheet 4 of these plans http://modelenginenews.org/plans/BJ_Cicada.pdf  there is a .250 semi circle milled up the side inside the cylinder.  it reaches almost center line to the exhaust hole.  or at least what I call the exhaust hole.  I thought that was for when the piston was on the down stroke it pulled gas in the intake and pushed it into the crank case,  then on the upstroke it was pushed up that .250 semi circle to make to to the top of the piston then once past the exhaust hole it started compressing it.  

so looking at the drawings the .125 hole is intake and the .157 hole is the exhaust right?


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## Jasonb (Jan 27, 2015)

.125 intake. .157 exhaust.

As the piston rises it creates a vacuum in the crankcase so as it continues to rise past in the intake hole the vacuum will draw fuel/air into the crankcase.

As the piston drops it will compress the fuel air in the crancase until the piston is below the transfer groove so the fuel/air mix gets pushed into the cylinder at the same time as the spent fuel exits the exhaust.

As it goes up it compresses the mix in the cylinder while drawing in the next lot of fuel. Fires and goes down allowing that mix into cylinder and exhausting spent fuel and so on.


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## werowance (Jan 27, 2015)

Jasonb said:


> .125 intake. .157 exhaust.
> 
> As the piston rises it creates a vacuum in the crankcase so as it continues to rise past in the intake hole the vacuum will draw fuel/air into the crankcase.
> 
> ...


 
Thank you Jasonb,  that means I have that correct so pretty much leaves compression right?  I should fire on just raw starting fluid at worse case for at least a pop or 2 right if compression was good enough?


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## canadianhorsepower (Jan 27, 2015)

werowance said:


> Thank you Jasonb, that means I have that correct so pretty much leaves compression right? I should fire on just raw starting fluid at worse case for at least a pop or 2 right if compression was good enough?


 
just try spaying wd 40 in the intake track


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## werowance (Feb 10, 2015)

had a little time to work in the shop this weekend and I am sad to say that the cylinder is tapered at both ends is why I believe I cannot get it started.

so I will likely make another cylinder.  im going to try and see if I cant just get the taper out of this one but not going to waste a whole lot of time trying before I just make a new one.  the next one im just going to ream it and then polish it


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## canadianhorsepower (Feb 10, 2015)

werowance said:


> I am sad to say that the cylinder is tapered at both ends is why I believe I cannot get it started.


 
thats sad, 
I personaly don't like the fack that you are soldering that port:fan:
If you would to build another cylinder maybe considering a billet pieace
instead of soldering.

you can also try reaming it and make a piston to fit the new bore

good luck


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## werowance (Feb 11, 2015)

on soldering that port,  that's what the plans call for but I wonder if I shouldn't do the soldering before I bore it.  wish the plans had procedures along with it.  sort of like the kits from Hemmingway,  they are great with full drawings and setup procedures that I learn so much from.  oh well guess I need to learn to set things up on my own some time or other.

anyway,  did a little lapping and the new piston I had cut that I found out my cylinder was tapered and smaller in the center of the cylinder now goes all the way through and has much more compression with my thumb over the top now.  

sealed all the mating surfaces and left for the sealant to cure over night.  will hopefully give it another shot at starting tonight.

if it doesn't start then im going to do anther cylinder.  but after my new DRO kit comes in.  could only afford 2 pieces right now,  mill and cross slide dro.  should be helpful cutting the fuel passage inside the cylinder though.


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## Jasonb (Feb 11, 2015)

If you do end up making a new cylinder then bore it undersize by say 1mm or 0.50" so there is less bulk to heat up, solder and then once its all settled down bore and lap to fianl size. Thay way you won't distort anything with the heat, pit the bore or have to clean up the bore.


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## modelmotor (Feb 23, 2015)

Hallo Werowance,,
I have seen a great lot of high tec skills you have.You can really build a very beautifull B.J.Cicada engine.
You might be proud on yourself because all the parts you made are 
very proffesional and well made.
My Cicada can n't even stand in the shadow from yours as it comes to craftmanship and beauty.I even went through the maincrankcase with my metal sizel because of having left  not enough material at the bottem of the crankcase.
I had a nice nylon hammer and pushed back the very thin(like silver paper) aloy what was left after that mistake.I even have n't glue it to close and lucky i was the engine ran for 90 minutes which made my neighbours left their home in angryness.
I saw your cilinder troubles .The problem is that the cilinder must not be getting it to warm/heat on a sudden spot otherwise the roundness will
be ruined.I will write you a personal message how to do this welding or soldering from the intake tube.
Your B.J.Cicada diserves many likes in my opinion so congratulations with the results.At this moment i am busy with a new project a 8,02 cc model glow engine designed by my engine friend from England Mr.Chris Boll yes the man from the B.J.Cicada,the Boll Aero 1,8 and the Boll Major 4,4 cc.

                            many greetings from modelmotor


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## Billitmotors (Mar 18, 2015)

G'day Werowance
Jasonb is closer to the money.  I would have made the crankcase first and then the front bearing (or as you have called it the snout piece) as it is easier to make the OD fit a bore than the other way round.
You said that you have a boring bar is it a carbide tipped bar or a ground piece of high speed steel ground to a boring tool shape?
The better the fit of the of the boss in the crankcase the less chance that the four screws that hold the two parts together will work loose while running. Also I would definitly  take a a skim across the front face of the crankcase adjacent to the 7/8 bore.
I would then mount an angle plate on your faceplate with a 7/8" alignment disc screwed to the faceplate.   You then mount the crankcase over thie disc using a finger clamp from the angle plate. You can then move the face plate around until your previously marked out  .625" bore is set up on center ready to be bored out.  I would also again take a skim across the face adjacent to the .625" diameter.This will give you two square faces to mount the front bearing and the cylinder on.
Boring tools are supposed to be mounted slightly above centre which will always leave a small conical tit as you go past centre, but there is nothing wrong with lowering the tool for a final pass to remove the central tit. High speed steel tools are easy to grind to shape and you can make them to suit any job.


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## GeorgeGreek (Mar 18, 2015)

Hi wero,
There is one point left i.e the developer....
Any idea
Thanks in advance 

George


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## werowance (Mar 18, 2015)

GeorgeGreek said:


> Hi wero,
> There is one point left i.e the developer....
> Any idea
> Thanks in advance
> ...


 
by the developer,  do you mean the person who designed the engine?
from what I gather it was Chris Boll and Rob Jenkins


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## modelmotor (Mar 18, 2015)

Hallo Werowance,

The B.J.Cicada has been developed by Chris Boll from the U.K.,but the story goes a little bit further.Rob Jenkins from Australia a man with lots of experience in building high quality home made model engines did some modifications and refinements at the porting system.Now after all the engine is based on the knowledge from both persons.So Chris decide to give the engine a much more realistic name based on B(Boll).J(Jenkins).Cicada 1.4 model diesel engine.The picture aompagnied with this reply shows all the engines Chris designed ,but still without the big brother which i showed a message ago.That 
8,02 cc glow engine is more or a less a kind of test case for me to see if it all works as intended.

                                 many greetings from Gerard-modelmotor-Europe.


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## Billitmotors (Mar 23, 2015)

G'day Werowance
Sorry i haven't seen your posts until the other night, as i haven't been on the site for a while.

I have a couple of questions:- 
What sort of lap are you using to lap the bore of your cylinder?
Are you using a split brass  lap with a screw in the end to expand the end and add a bit of taper to the bottom end?

What sort of torch are you using to carry out your silver soldering?
You only really need a propane torch to carry out this job as you only have to get the parts to a dull red colour. If you get it much hotter you get scaleing and burning of the parts.  When you are silver soldering add your flux and start heating, watch the flux, at first it will dry out, but as you keep heating it will go clear and turn liquid, at this point it is time to touch your silver solder to the job, just brush it against the job and and if it is at the right temperature the silver solder will melt and adhere to the joint. (While doing the heating keep your torch moving the whole time) Once your solder starts to melt if you move the flame in the direction you want the solder to run the silver solder will actually run around the joint, just keep adding a little more solder sparingly and you should get a neat joint.
I should add that the better the fit of the joint the better the solder will run.

 Also what sort of silversolder are you using? The best one I have found is easyflow 50% silver, it is more expensive but if every thing is clean ( wipe over all the parts with metholated spirits to remove any oil)  and the joint is good, when you reach the right temperature the solder will run very well. 

Why did you machine off the top of the crank case and the head to vary the compression,  that is what the contra piston is for.

When you make your new cylinder you will need  to add the corresponding amount to the bottom of the flange to make up the difference, other wise you will have changed the timing from the original design. 
When you make the new cylinder, bore it out to within a couple of thou of the required size, don't ream it, as you can sometimes get an out of round bore which then makes it very time consuming to lap straight and round, also you should aim to end up with a very slight taper at the bottom end of about .001" to .002".
You should also machine everything and carry out all your silver soldering before you start your lapping

When you make your piston and are fitting it to the cylinder, just break the top corner of the piston with a small radius(.002" to .005")  aim for it to be just starting to tighten in the bore as it goes past the top of the exhaust port.

I also noticed that your wrist pin looks to be a sawn cut and then polished finish. You really need to machine a large radius on both ends to help stop it from picking up in the cylinder. unfortunately the drawings don't really show this very well.

You were right about the 10X32 UNF thread on the compression screw and head.

 Your contra piston needs to be a tight push fit in the cylinder which can be moved down by the compression screw and then when you release the compression screw, the compression of the running engine will then  move the contra piston back up.( there should be no blow bye at all past the contra piston)
 If you have a look at Model Engine News, look at the   DCO contra piston method,it works brilliantly.  Ron's site has so much invalueable information on it for motor building it should be read by anyone intending on having a go at engine building.
I hope this helps.
Rob Jenkins


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## Billitmotors (Mar 23, 2015)

G'day Werowance
 your fuel mix should be 20% castor oil 30% ether and 50% kerosene.
I noticed your remark about the decanted ether boiling.
Ether has a very low flash point and will boil in sunlight or at 34.6 degrees C It is also dangerous because it is a heavy gas and will move across the floor and doesn't take a lot to find an ignition scource.  So it is not a good idea to leave the lid loose as you will loose all thee volatile s from the bottle.
I also noticed that in the photo with the tank set up to run the engine, the tank looks to be quite high which makes it hard to regulate the fuel supply it really needs to be level with the venturi.
Rob.


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## werowance (Mar 23, 2015)

Billitmotors, thanks for your reply, 

EDIT - Billitmotors,  just spoted the part about not reaming the cylinder in your post  i might just make a bigger boring bar so i don't have the deflection.  and on the wrist pin, it does have a decent radius on it that i did with a file in the lathe before i polished it so it wouldn't gouge the cylinder wall

1. for the lap I was trying the sand paper on wood dowel, I plan on the next cylinder to ream it then us a real lap made from copper pipe.
2. for the silver soldering, I usually don't have an issue using silver solder, it was just the cast iron piece would not take it. sometimes I use my jewlers torch and sometimes I use my homemade propane burner. the 12l14 takes the solder just fine and i really don't know what was up on the cast iron, but shouldn't have been using castiron for the cylinder in the first place
3. I machined the top of the cylinder just as a last ditch effort incase there was just to much blow by on the contra piston or something, this does not change the timing on this engine. machining the bottom will change its timing. 
4. on fuel, thanks for the heads up on the ether and mix ratio, I ended up buying a bottle of pre mixed for diesels from tower hobbies.
5. on fuel tank, i have it so that gravity brings fuel to about .250 inches from the bottom of the carb, in other words there is about .250 inches of air bubble in the fuel line right as it attaches to the carb, if i raise the tank up, then fuel will flow in and keep running in the engine.
6. ill take a look at the dco contra piston thanks for that.

and I know where a good deal of my problem is with the engine, I have a tapered cylinder either caused by my boring or by my lapping method or both. so my next one when I get a chance will be reamed instead of just bored, then laped with a copper lap like the ones on model engine news. I have never made a lap before so i shyed away from it on the other cylinder.
also i just learned from some other posts last week or so ago that my contra piston is not tight enough i machined it from the same stock that the piston was made from exactly the same size diameter as the piston so on the next one i plan to make it just a little tighter as the recommendations from the other posts.

i just have to find the time to get back in the shop. and finish up my dro install which i think will help


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## Billitmotors (Mar 24, 2015)

G&#8217;day Werowance
If you are intending on your engine being a runner, sandpaper on a dowel will neither get a round or a straight bore.

Laps are the easiest things to make. Just get a piece of brass that is bigger than the final size required and machine it down till it is .001&#8221; to .002&#8221;smaller than the bore of your cylinder,  your cylinder is approximately 1.6&#8221; long so make the  machined length of the brass 2&#8221; long plus your chucking length.
Once you have machined the parallel 2&#8221; length centre drill using a No 2 or No3 centre drill then drill with a 5.1 drill or 13/64&#8221; drill around 1.5&#8221; deep.  Then using a ¼&#8221; BSW or 1/4&#8221; UNC   TAPER  tap, only let the tap enter for 16mm or 5/8&#8221; of an inch. Next get your hacksaw and cut down the axis of the lap for about 1".  Run your tap in again to the same depth remove it and screw in a 1/4" allen headed cap screw until it just starts nipping up.
You can either use diamond past or aluminium oxide lapping paste, I prefer the diamond paste which you can buy cheaply on Ebay.
To load the diamond paste onto the lap put a small amount (it goes a long way) on a flat piece of steel preferably high speed steel and while pressing the lap hard against the flat steel roll the lap over the paste.
Cover your lathe bed with plastic and put the lap back in the chuck leaving a small amount of the chucking piece protruding from the chuck jaws so that the cylinder can touch on it without marking the it.
Set your lathe to run slowly and slide the cylinder, head first onto the lap, use kerosene as your lubricant and turn the lathe on. It can be worth making a shroud that the cylinder is attached to so it protects your hands. Grasp the cylinder and slide it back and forth along the lap. Your aim is to get a cross hatched surface finish over the entire length of the bore.  You will need to keep incrementally  tightening the screw as the lap wears and the bore size increases and becomes round and straight.
When you first start use coarser grit paste and once the bore gets an even matt finish over the entire length go to a finer grit.  It is worth having a second lap prepared to use with the finer grit.  Once you are happy with the finish of the bore wash and scrub it clean of any grit before you try and fit your piston and contrapiston.
When you make your contrapiston use the DCO method  it really works well.  Also what sort of cast iron are you making your piston and contrapiston from. I've been using P4 centrifically cast cast iron,  it is really fine grained and machines easily.
I hope that this helps.
Rob.


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## werowance (Mar 24, 2015)

i did see that technique for making a lap on model engine news.  the taper of the tap is like making a tapered thread which expands the brass,  i am considering it,  

but while i was looking around on ebay i saw this :http://www.ebay.com/itm/ACRO-USA-7-...410?pt=LH_DefaultDomain_0&hash=item35e6be471a

at 50.00 its a bit pricey but its got me wondering that if i can find a cheaper one,   would 7/16 laping tool work for this engine,  it calls for .437 as final size,  so would a 7/16 .4375 be correct for a commercial made lap?
do commercial laps start a tad under size and 7/16 is its maximum expanding size or is 7/16 its minimum size and expands out further?


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## werowance (Mar 24, 2015)

and while i am on the subject of possibly buying some tools,  i was also looking at an external hone.  to me the word hone = scratchy finish and not polished,  but also reading on model engine news as well as one of my magazines home shop machinist i saw the use of external hones like the one listed here http://www.modelenginenews.org/~modeng74/faq/hone_art.jpg which i can purchase fairly cheaply.  the 2 examples i have seen it used in produced a very smoothe finish from the looks of the pictures.  what do you all think.


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## werowance (Mar 24, 2015)

Billitmotors said:


> Also what sort of cast iron are you making your piston and contrapiston from. I've been using P4 centrifically cast cast iron, it is really fine grained and machines easily.
> I hope that this helps.
> Rob.


 
Rob, i have both dura bar and 2kun5 cl40 gray cast iron.
last piston and contra were made from the dura bar. 

but i know for a fact now that my contra pistons have all been way to loose, and i like the idea of tapering the contra as described on the other web site.  will have to give that a try.  i also liked the idea of a Viton oring since i wont run it very long and have no problem replacing an o ring.  even though the oring way was not recommended on that other site. 

and thank you for all your help.


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## Billitmotors (Mar 25, 2015)

G'day Werowance
    I haven't used one of those commercial laps so I couldn't say how small they go,but you can buy a whole lot brass for $50 and the split lap can also be used to add a little taper at the bottom end.You can also make a whole lot of laps out of it ,it shouldn't take more than 10 or 15 minutes to make a couple of laps.

Your outside lap is good but you still have to be careful nut to turn your piston into a barrel.
Are these external laps for sale over there and if so how much are they?

I am not a fan of Orings in the contrapiston, besides the fit of the contrapiston still has to be done properly and then you still have to machine the groove for the   O ring. Sounds like a make work program to me.

Using David Owen's method, tapering the outside of the contrapiston also relies on the fact that the wall section of the contrapiston is thinner than normal which gives it a little bit of springiness and makes for a better seal. I haven't had one failure since I started using this method.

 I have just finished a Thaller T39  which is a 2.5cc long stroke diesel I used the DCO method and it worked perfectly. I have attached a few photo's.
Rob.


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## werowance (Mar 25, 2015)

that's a nice looking engine,  on the outside lap,  the only place I have found it for sale is in the uk.  and I was thinking of ordering the kit (tool envy)
here is the website http://www.pollymodelengineering.co.uk/  its in their pdf download


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## werowance (Mar 25, 2015)

I also like the compression screw on your engine there.  I might have to steal that idea and replace my tommy bar with a knurled screw like that one.

thanks again.


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## Billitmotors (Mar 29, 2015)

G'day Werowance
The compression screw isn't my design it was from the drawing of the T39. I prefer the tommy bar as you have better control over the compression adjustment. If your contrapiston is a bit tight you can't get a good grip on round headed screw.
Rob.


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## werowance (Apr 13, 2015)

well, got back at it for a little while yesterday afternoon.  cylinder 3.0.   and I found yet another mistake I had made on 1.0 and 2.0 (aside from the bad bore and lap job)  the diameter of the cooling fins,  I had left them on both of the previous ones at 1.250,  but the plans call for the fins to be 1.100 .  no wonder it was so hard to get the screw in at the base as well as get the carb bung soldered on.

anyway I got the cylinder bored and took extreme care and time just barely skimming with each pass until I hit .4365 as best I could measure.  I guess + / - .002 isn't going to affect running as long as I match both pistons to it.

It was getting late and I stopped at cutting the cooling fin groves.  for the life of me I cant recall do I take .607 and divide by 4 to get the cut points for each groove?  I mean really I should know this as this is cylinder 3.0 but I just blanked out last night, and now im at work so I cant realy just make some test marks in blue dye just to tell until tonight.


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## werowance (Apr 15, 2015)

got back at it last night,  for the fins its divide .607 by 5 to get the 4 fins.  which I managed to mess up during cutting,  but it'll do.  my parting tool I had used to do the others had so much chatter that it walked on me a little.  oh well hopefully if it runs no one will notice.

on the plus side of things,  my new dro was awesome fro cutting to depth on the fins.  no more making a gauge to judge the depth by.   just run it up on the smallest diameter part of the cylinder (in the area where intake and exhaust ports go) with a piece of paper between it and the blade,  zero out the dro back it off and go to first fin to cut and go till I hit 0 again then repeat.  that's nice.

and while I type this,  makes me realize what the chatter was probably caused by.   I had set my parting tool to center with my tailstock center thinking I needed to be on center so that the dro would be correct.  I realize that it wouldn't have mattered as long as I was touching the cylinder when I zeroed it even if I was just a tad below center line like normal when parting.  oh well.....that's another lesson learned.



cant wait to get the final dro for my way.  right now all I have it on is the cross slide and milling head.


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## Billitmotors (Apr 17, 2015)

G'day Werowance
I have been away with work for a week without a computer.
Sounds like you have been having fun.

Your right about the final size of the bore so long as you match the piston to it.

I purchased a DRO for my lathe but have only fitted the long slide scale as there isn't enough room to fit the cross slide scale. Having said that the easy way to set your depth of cut is as you said touch the tool against the job with a piece of paper between, zero your dial and at the same time using a marking pen draw a line on the cross slide dovetail casting and also draw a "O" adjacent to it. Then after determining how far you have the wind the cross slide dial in, cut the first groove and stop the machine.  Then use your marking pen to place a mark on the cross slide casting and add the reading of the dial so that you don't forget your final depth of cut. Then reposition the tool to cut the next groove and so on.

What sort of parting tool are you using? Is it a piece of HSS that you have ground to size and shape or is it one you purchased already made?

Usually the reason that parting tools walk is either it is being run at too high an RPM, the tool is not on centre or or the cutting angle geometry is incorrect, usually the clearance angles are too great.

 Another thing to watch is that during the normal use of your lathe the compound slide with the toolpost on top can end up overhanging the dovetailed slide, which when you start using a tool like a parting tool can can cause vibration, if so reposition the compound slide so that it is fully supported. Also check the adjustment of the gibb strip on the compound slide and cross slide and adjust it for minimal play then take a cut. 

When you are parting, being on centre is probably the most important thing, also try to make sure your tool is set square to the axis of the job.

If you are using a two or four way turrret style toolpost have all your tools matched with the correct size packing and keep said packing and tool as individual sets so that you can swap tools at any time and know that each tool is on centre every time. If you are going to set each tool up this way do it with a piece of material in the chuck and take a cut across the face if you are below centre you will end up up with a parallel nib in the centre of the job, if you are above centre you will get a conical tit and if you are on centre it will cut the centre off cleanly.
                            Rob.


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## werowance (Apr 17, 2015)

Billitmotors said:


> What sort of parting tool are you using? Is it a piece of HSS that you have ground to size and shape or is it one you purchased already made?
> 
> Usually the reason that parting tools walk is either it is being run at too high an RPM, the tool is not on centre or or the cutting angle geometry is incorrect, usually the clearance angles are too great.
> 
> ...


 
it was a parting tool I bought in a "lot" of used bits on ebay.  it was I believe a half inch piece of hss but looked factory ground to a parting tool.  I took that and ground it narrower.  the first 2 cylinders It cut really good with minimal chatter as compared to this one.  

I believe my problem with vibration and chatter is on the first 2,  I usually put my parting tool just a tad under center.  but on this one I actually centered it to the point of my tailstock live center then swung it around and started cutting.  I didn't lock the gib on my cross slide to way.  and frankly my gib adjustment screws really needed a little snugging as well at the time.

so I think the vibration from cutter being to high along with gibs not tight caused the issue.

oh well,  part doesn't look that bad hopefully it wont be noticed by my friends if/when they see it run.


also I am using a qctp axa size from phase ii.  I need to get some more tool holders,  just havnt gotten around to it.  I have enough for my most common tools.  but as this parting tool was ground just for these fins I had to swap out a tool in the holder and didn't think about going lower that dead center when adjusting it.

thanks for your help.  hope to get some more shop time this weekend.


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## werowance (Apr 19, 2015)

Little more progress.   Cylinder 3.0 ready for lapping.  Will take time to re read and study the lapping suggestions in this post before I go there.  

Need a little cleanup on the brazing job but it's decent and will do
View attachment ImageUploadedByModel Engines1429484270.809156.jpg
View attachment ImageUploadedByModel Engines1429484291.502526.jpg


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## Billitmotors (Apr 21, 2015)

G'day Werowance
Your getting there, are you going to taper the fins?
You can remove the the excess silver solder with a Dremel and some of their rubberized abrasive points.
Also I don't know if it is just the photograph but that transfer port looks a bit shallow.
Rob.


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## werowance (Apr 22, 2015)

I am probably not going to taper the fins,  if my tool hadn't walked I could have gotten 1 more fin in like my others and that looks so much better but in this case if I can just get it to run ill probably call it quits on this engine.
on the transfer port, I agree it does look shallow but I centered my .250 mill in the center of the bore and then moved it .125 over like the plans call for.  but honestly the original 2 cylindars were not properly measured the first go rounds so they were deeper.
ill give the rubberized grinding tips a try,  would be easier that filing and sanding.  thanks for that tip.


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## werowance (May 2, 2015)

Wow billitmotors.  A lap seems to work extremely well.  I can feel the taper in the cylinder and can feel it leaving

Started with 7 micron lapping paste.  I assume the smaller the number = larger grit size.  My fingers just can't feel the difference.   But looking at the pics. The fist one is after about 5 mins.  Can't believe the pitting.  Next pics are after about 30 mins off and on with a break in between.  
The brass lap is working great. I can feel the taper leaving


So after about 30 mins I have a very small pit left at the top.  Should I keep on with current grit till pit is gone or go ahead and stat working my way up in grit sizes?View attachment ImageUploadedByModel Engines1430602800.419095.jpg
View attachment ImageUploadedByModel Engines1430602819.360273.jpg


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## Swifty (May 2, 2015)

You will find that the smaller the number, the finer the paste. A micron is 1000 of a millimetre, so 7 micron lapping paste is finer than say, 14 micron paste.

I can see the confusion, as wet and dry paper goes the opposite way.

Paul.


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## Billitmotors (May 3, 2015)

Gday Werowance
Your looking good I would continue a bit longer with the same grit and then make a new brass lap and change to your fine paste.
Looking at your photo's I think you need to traverse your cylinder a bit faster along your lap as I like to be able to see more of a crosshatch pattern in the bore.
 Also try and leave a bit of taper in the bottom of the bore below the exhaust port, preferably at least .001 and try to keep the top section adjacent to the contrapiston as parallel as you can.
Rob. 






'


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## werowance (May 15, 2015)

after about 5 or 6 more contra pistons (ive lost count) I finally have one that is nice and tight,  no blow by.  its tight enough that at first I was a little concerned that the force needed to push it back out if pushed down to far might be to much for the little aluminum rod to handle.  but after some testing I can push the contra back up if I over compress it with the screw without breaking anything.

tried to start it last night.  only had about 15 mins to spare,  but after about 30 to 45 seconds of spinning with a cordless drill the cylinder fins were getting good and hot just from the compression.  I could put my hand on it but it never got hot enough to ignight.  and of course murphys law when your in a hurry,  the battery on your drill is never charged up good so I didn't get to spin it very long.

wonder how hot it should get before I start getting smoke or fire?  maybe I should pre heat with a little plumbers torch before I try again tonight?

I hope this heat is a good sign.


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## Billitmotors (May 17, 2015)

G'day Werowance
You shouldn't need to use the electric drill to start the engine. You are not trying to heat up the cylinder to make it start.
You should be able to get it to fire by flicking the propeller over even if cold.
It sounds like your fuel mix is incorrect or your compression needs to be increased.
Don't use your blow torch to preheat the cylinder especially if you have already put fuel in the engine, as it is very flamible and you could very well end up with smoke and fire.
The fuel mix that I use is 20% castor oil 30% ether and 50% kerosene.
If your piston and contrapiston are a good fit, your fuel mix is correct, and you have set your compression correctly, it should fire when cold or hot, even just turning the engine over by hand you should feel a kick.
Good luck 
Rob.


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## Jasonb (May 17, 2015)

And if you are using a cordless drill make sure you have it in reverse!


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## werowance (Oct 18, 2017)

Morning all,  last night I decided to give the little cicada another try after sitting in a box for almost a year with a broken rod.
so I made another rod and made a fake propeller out of a strip of wood that was a little bigger than the bough prop I was trying.

so I got to the point that I had some kick backs, a loud "ping" noise a few times like dropping a thin piece of steel on the concrete floor and some smoke / oil out the exhaust.  lots of black/brown residue oil coating the case and some smoke out of the exhaust.  but still would not fire up.

that ping scared me to death the first time then I realized it was just trying to fire.

I found that loosening the compression screw actually helped where I thought I didn't have enough compression at first I found that it would ping and smoke whith less compression.

I ended up after several hours and frustration breaking the rod again.  totally my fault and stupidity.  

but was wondering,  those of you who have made this engine,  how many screws out on the carburetor seems to work for you?  example on a brigs and Stratton mower engine I usually screw all the way in and then back it out 2 and a half turns.

then on the compression screw lets say we screw it down just until you can feel the piston hit the contrapiston.  then how many turns backward are you backing it off for starting?

Brian Runpow,  I read that you made a venture sleeve or something on your carburetor?  I never fully understood what you did there and was wondering if you had pictures.

I am using store bough tower hobbies diesel aero fuel.  when I got close to it wanting to start I could smell the rich fuel smell sort of like trying to start an old diesel tractor in the middle of winter using lots of either.  when that tractor starts it smells like either and rich diesel.  so that was encouraging me to think I'm close.

and last but not least,  if my next starting attempt fails, would any one volunteer to let me ship you my engine for a look over and tell me what all I did wrong on it?  along with maybe a gift card for your favorite lunch restaurant


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## Brian Rupnow (Oct 18, 2017)

Werowance--I have never built a compression type engine as you show here, but I have dicked around a lot with small carburetors. Sometimes, if a carburetor intake is too large for the engine the carburetor is on, the air flowing through the carb will not be fast enough to create sufficient venturi  effect to lift fuel up from the gas tank. The answer to this is to build "sleeves" of varying diameters that are simply a "push fit" into the carburetor air intake. (This is not an exact science, so you have to try sleeves with different bores until you find one that works.) This makes the inrushing air to move at a higher velocity, creating more venturi effect to be able to suck fuel up from the tank.


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## werowance (Oct 18, 2017)

ok, that makes sense,  and should be easy enough to try,  ive got some teflon rod that should make that job easy to test with.

thanks
Bryan


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## fishy-steve (Oct 19, 2017)

Hi werowance, 
I came across some great videos a couple of days ago of the correct starting procedure for ci engines.  I really wish I'd  seen these before spending hours trying to start my Cicada. 
Having now built a couple of these types of engines I have a better feel for them and there is a definite knack to it that you can't  really convey in words.
Search "Brian Cox engines" on YouTube.  Make sure to add "engines" to the end or you will be watching Videos of Brian Cox the Physicists until the sun fizzles out. 
Good luck .
Steve.


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## Billitmotors (Oct 24, 2017)

G'day Werowance
I found your story again.
Firstly, don't let someone else have the pleasure of starting your new engine for the first time, I would encourage you to persevere.
From the sound of things there could be a number of things going against you.
I would suspect that the fuel you are using isn't up to scratch if you are not even getting a pop out of your engine when flicking the prop.
The fuel mixture that I use is 20% caster Oil, 30% Ether, 50% Kerosene. Although the last time I bought kerosene from the local hardware it was poor quality and it was suggested to me that the suppliers had added something to it which retarded firing of the engine. 
I would suggest that you try to find one of your local model flying clubs usually one of the other members can get Ether and they are usually happy to sell you some for a good cause like running a home built engine.
If you have made the venturi to the drawing sizes you do not need to restrict the air intake the engine will run fine as it is drawn.
As I remember it you said that you shaved off the top of the crankcase where the cylinder mounts to the crankcase have you made a packing piece to repair this because  by doing this you will have changed the timing.
Also try and poor some fuel around the cylinder crankcase joint and then turn the prop over and see if there is any leakage around this joint. If there is you are loosing crankcase compression and the fuel air mixture won't be transferring to the cylinder properly even so you should still be getting a small bit of firing when you flick it over.
Try and put a very small squirt of fuel inside the exhaust port and then flick it over it should fire after the second or third flick if your contra piston is somewhere close to it's running position.
It could also be the fit of your piston, liner, contra piston. Invert the engine, and again put a small squirt of fuel into the exhaust and turn the prop to close off the port and continue to turn the prop gently, all the time looking in the exhaust port to see if there is any blow bye past the piston.
If all your fits are good there should be no leaks and provided the contra piston isn't backed off to far the propeller should come to a hydraulic lock, don't force it past this position. Also if it hasn't leaked so far remove the compression screw completely put your finger over the compression screw hole and flick the prop over. If you feel any pressure change from the hole then your contra piston is leaking.
When trying to start the engine, install an 8"X4"prop, set your tank up so that the centre line of the fuel feed pipe is in line with the centre line of your needle valve, make sure that your compression is backed off. Try to start with no fuel in the engine, open the needle valve about 3 to 4 turns. put your finger over the venturi and turn the prop over 2 times making sure that the fuel was already drawn up to the needle valve. At this point remove your finger from the venturi and give the prop a good flick. If it fires you are getting close to the running position. If not increase the compression by about an eighth of a turn and flick the prop again continuing until the engine fires, about every third try you will need to put your finger over the venturi and draw a little more fuel into the crankcase.
Once the engine fires increase the compression a little more and the engine should run.
at this point you will probably need to increase the compression slightly more and the engine should run steadily at this point you can wind the needle valve in and your engine should increase the rev's.
At this point don't run your engine to hard at first as everything will be bedding in and there will probably be a few tight spots, just let it run and settle down. Let it run for about 2 to 3 minutes at a time slowly increasing it's speed as well as slowing it down until it has had about 20 minutes running.
Remember if you force it and something breaks all spares will need to be remade by you.
I hope this helps please let me know how you go.
Rob Jenkins.


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## werowance (Oct 27, 2017)

Thank you Rob Ill give it another go.  honestly I never got back to remaking the connecting rod from the other night.  to much honey do work... and its my anniversary this weekend so probably wont get to this weekend.  but the rod is a quick part to make and I think I still have stock the right thickness left over (fingers crossed)

on the fuel, its store bought aero Diesel fuel from tower hobbies specifically for diesel engines,  I had also tried the homemade mix which is pretty much the same as your mixture some time way back.  but since I am getting a few kicks now, I may try mixing my own again to see.

on the head and shaving it down etc,  that was some time back and I had already gone back to the standard drawing dimensions (remade parts) so we are good there.  I'm actually on about the 6th cylinder and pistons remake lol.  but the contra piston has that slight taper and is good and tight  no fuel blow by on that getting into the head.

on crank case leakage.  that just might be one of the issues ill double check on that.

on 8x4  really don't know much about props dimension but the one I am using was a 2 blade 7 inches long prop.  but on this last test I used a biger piece of wood that was about 9 inches long and thicker.   but I assume 8x4 means 8 inches long and 4 blades?  ill ebay for one if so while I'm remaking the rod


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## Cogsy (Oct 27, 2017)

8x4 is an 8 inch prop with a 4 inch pitch - it's still 2 bladed. The higher the pitch number the more force required to spin it, but the longer the prop the more 'flywheel effect' it has.


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## Billitmotors (Oct 29, 2017)

G'day Werowance
from past experience, store bought diesel fuel is often low on the volatile component of the mix, so the home mix fuel is always a better bet, provided you can get the ether. Also only mix enough fuel for running on the day.
On the crankcase leakage also check around the front housing and the crankcase by pouring fuel around the joint and then turning the propeller over and checking for air bubbles.You might need to cut a paper gasket to suit.
As for the propeller size Cogsy is spot on. I only use the 8"x 4" prop to get the run settings and for initial running after the engine is starting consistently then swap to a 2 bladed 7"diameter 6" pitch prop.
I have been running a 7X6 on my Cicada to fly a control line Veron Viper for some time.
I'm currently working on a pair of Naylon Vipers but I haven't had a lot of time in my workshop lately. 
Rob Jenkins.


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## 777engman (Nov 20, 2017)

Hi there Werowance, just wondering how you goton with the littlediesel? any luck yet with starting it?
cheers
Dean


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## werowance (Nov 21, 2017)

havnt had a chance to do much yet. I started a major shop cleanup and strip cleanup on the lathe/mill combo. just finished that up this weekend and started cutting down a pice of 2024 aluminum to make the new rod.

if I'm lucky ill have a new rod by this weekend.


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## werowance (Aug 20, 2018)

this weekend I had lots of garage play time so I decided to see if I could get anything to work on the little cicada.  and I had some luck.  not much but I did manage to get it to run for about 10 seconds multiple times. 

so at the lowest compression possible on the compression screw it will fire. 

I replaced my propeller which I believe is to small with a piece of wood transition strip like you use to separate carpet from tile on your house floors.  made it about 7 or 8 inches long drilled in the center and used that.  has lots more flywheel effect.

I remade the rod for the umpteenth time and fueled up the tank,  primed the engine, and gave it a flick or 3 and it took off.  sprayed fuel all over the side of my truck bed like an aerosol spray can.

now if I had to describe it,  it didn't take of like a cox 049 that I used to play with as a kid but more like my little steam wobbler engine that just about has enough steam preasure to take off but not good steam preasure.  kind of slow.  but the fuel spray is just like I remember the 049's do on the string controlled planes I had as a kid.

I tried upping the compression and it will not fire at all on hire compression.  and once it uses up the prime fuel it dies.  (about 10 seconds or less)

when I hold my finger over the carb it will suck some fuel up then push it back in the tube with air.  so it seems to me its not really sucking the fuel?  but if I put the tank higher than the carb it will run through the engine and flood it.

maybe an inline check valve would help?

any suggestions on the carb?  I believe it to be to spec as per the plans.  I did a pretty decent job on grinding the needle valve and what not.


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## Chris Murphy (Aug 21, 2018)

Ok-I may be a newby on this forum-and a tyro at _* making*_ engines but I have 50 years experience operating these engines-and there are several points of information you could benefit from: first the fuel recommendations are fine-though in this particular situation you could do a lot worse than go the old 1/3-1/3-1/3 route for the three components-this mix has stood the test of time (for about 70 years!)-most of us consider it has a lot more oil than necessary (true!)-but that has the advantage of compensating (to a degree) for less than perfect fits in a homebuilt engine. Secondly-without seeing your mount, it is not clear what the tank level is in relation to the engine-you do NOT want gravity feed under any circumstances-that is a recipe for flooding and ongoing grief.  Ideally you want the fuel level just below the carb level...reading between the lines your engine may be a bit lacking in suction....this is surprising as most sideports (ie piston ported intake) diesels have a lot of suction...sometimes embarrassingly so...which leads me to the next point-the needle setting. On a typical sideport diesel you generally only have the needle unscrewed about 1-2 turns from fully closed (this obviously is heavily influenced by the actual thread used on the needle)-if too far open you'll flood the engine and they then (especially sideports) get sulky and won't do much at all-not even fire...! Furthermore you run a good chance of hydraulicing them-ie getting so much liquid fuel in the cylinder that the engine cannot physically turn over-and if forced...something will bend or break...usually the rod as it is the weakest point....if you're really unlucky...the gudgeon pin and crankpin as well!

Now another problem/issue for you will be that you have no idea where the contra piston setting should be for starting-especially on a brand new homebuilt engine. An old trick used in this situation-and also on a commercial model diesel that has been 'fiddled' with and the setting completely lost, is to carefully screw the compression down until the piston and contra just touch-you have to proceed carefully of course-but you can feel the contact when it occurs-and of course at that point you can no longer turn the engine over-THEN back off the compression screw by ONE FULL TURN, and flick till the contra piston snaps back up to this position. That position should get you in the ballpark for starting. If your contra is too tight to return upwards to this new position -then you would have to remove the cylinder, and gently tap it up the bore again till it reaches the correct position.

Props-if anything I would regard an 8x4 as too small for this engine-and certainly so for initial starting from new-I would suggest a 9x4-the larger diameter will give you more flywheel effect-and keep the revs down to a reasonable level whilst you are running in. Bear in mind that these type of engines usually run at about 6-8000rpm-or about half the revs you get from a Cox reed valve. On a 9x4-assuming you've made it correctly to the published design-and the timings are as per the drawings I would expect a 9x4 to turn about 5-6000 rpm or so ....as the engine runs in (which could take anything up to about an hour of accumulated running) it would not be unusual for the revs on the same prop to gradually rise up to 1000rpm  more than the first initial run.

One other method of learning to start these engines is simply to keep the needle shut, and squirt a couple of drops of raw fuel mix into the exhaust port, and flick the engine over-I cannot recommend using a drill as you have been doing-firstly because you lack any 'feel' on the engine-and secondly because a drill does not turn fast enough. Once you can successfully flick start the engine and get it running on a prime (it will only run for 1-2 seconds) consistently-then you can be sure you have found the correct compression setting.....and you can then proceed to gradually opening the needle. The difficulty with diesels is that with two controls-the compression and the needle-both of which interact to a degree-for a beginner to the type, there is potentially a lot to go wrong...the compression ultimately controls the ignition timing-which in turn is dictated by the load on the engine (ie the prop size)-the normal mode of operation is you generally have a needle setting adequate for starting (ie a rich mixture)-start the engine-(which may require you to reduce the compression by  up to half a turn from the running setting)-adjust the compression for smooth running (ie increase it until the misfiring stops and the engine runs with a steady exhaust note) and finally screw in the needle to lean out the mixture for optimum running. If you go too far on the compression-the engine will start to labour-likewise too lean on the needle and the engine will starve and slow to a stop over several seconds-and overheat in the process.

Finally-someone has recommended you watch Brian Cox's Youtube videos on starting diesels-I fully endorse this suggestion-here's a couple to start you off:     

He has plenty more-and you can learn a lot on model diesel starting and handling by watching them....listen to both his commentary-and also to the sound the engine makes as the compression is altered


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## werowance (Aug 22, 2018)

ok, well that explains some of it.  if I squirt some 5w-30 in the exhaust port and work the prop back and fourth (its hydraulic locked at this point from the oil) and work it until the lock is gone,  then give it a good flick it will take off.  the fuel is just a smidge below the engine so as not to gravity feed, maybe an inch lower than the carb.  I was thinking about adding a lot more oil to the mix to see if that will do the trick,  restricting the venturi a little bit  like taking a piece of wire insulation that was stripped off that just fits the hole seems to give it the suction effect it needs. 

was thinking that since the oil makes it fire up that maybe I need to cut a new piston thats tighter,  thinking the oil was giving the seal it needed to boost compression.

oh and I have way since quit using the drill as I did break to many rods trying that.


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