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jeff2wings
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Jeff:

Did you weld that up yourself?

My back cover disc 'welded' itself too, but I quickly just about got it out before it gauled (?) tight. Crippled a lot of the cast thread.

Great repair and rescue of the case, that casting is still a 1000% better looking than mine. The surface on mine is dog rough, a new pattern is needed at Hemmingway.

 

How did you make the taper on the N/V please?

A friend has suggested the piano wire in the 3 jaw and to grind the taper/point with a stone in a dremmel.

Graham.

Edited by 911hillclimber
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Repairing a crankcase is always a bit difficult particularly if it's diecast due to having things like zinc,tin,nickel etc low temperature brazing being equally as difficult as  tig,the castings tend to be thin and it's  easy to melt the hole lot! With tig welding you get blow holes from the zinc gassing off giving a poor weld/finish.That being said these are sand castings with LM4 and will take tig welding quite well and that's how I got out of jail this time !😄

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made sure it's a nice loose fit this time 

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I ground the needle valve by hand on a sanding belt but the suggestion to use a sowing needle is a good alternative 

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  • 2 weeks later...
Posted (edited)

Thanks ED,I have tried those rods ,found them OK for manifolds and silencer but again a bit hit & miss on castings. 

 Finished off making the second Sparey, actually got to reuse the piston/cp so quite pleased with that.

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Edited by jeff2wings
Forgot to add pictures
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I brought them from Hodakov Tolik who is in Odesa Ukraine you can find him on Facebook $40+postage.

So I gave the engine a thorough clean in the u-son strapped a 16x6 wood on it and had a go at getting it to run, got a few short burst from the prime but it kicked back a few times and  loosened the prop, so on the fourth time gave it a bit extra on the spanner, and the end of the crank snapped off!! Point of failure being where the centre drill hole finished. 'Oh bother ' I said (para phrasing here) so stripped it down again ,cut a bit more thread,took 20 thou off the shoulder to reduce end float and made a new prop driver in keeping with the original. I think the  next time I will use a MA or APC probably 14 or 15" .

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Jeff, I thought your propeller choice seemed a bit big, so I checked the original article. Laurie Sparey obtained best results with a 13x6, but his 13x6 must have been wood, i.e. far lighter than your MA & APC stuff (and easier on the fingers!).

I'm lucky to have a huge collection of old propellers, and I would never use a modern composite prop on an old engine. Wood is best, or old soft plastic in the smaller sizes.

Maybe a little more ether and a little less compression would be a good idea.

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Thanks for the info on the Castings,   You will always get a few thrown props at this stage in finding the starting point.  Although I usually make a "pretty" spinner, usually anodised, I do not fit it untill engine has run successfully, due to the probability of it getting damaged when it hits the floor, Until I am happy with it running, I use 2 ordinary nuts,locked against each other.  Ref not continuing to run, You have remembered to cut out of the gasket, the small piece over the fuel transfer duct. I hope?  I did not and am still red faced over missing it!

Keith

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In Ron Chernic's notes with the Hemmingway kit,he uses a 16" wood prop and that is what I use on this engine without problems,with a 4 inch pitch.

It is worth noting also that he had backfire problems and found the contra piston was too deep and reduced it by 3/32".

Keith.

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Ron's notes actually state the backfire was due to excess fuel from the course taper on the needle valve which gave a 1/2 turn from fuel shut off to running and shortening of the cp due not being able too back off sufficiently for slow running, both issues having been dealt with when I first built this engine. 

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Run four tanks through the the engine this morning after changing the prop to a14x6 MAS and the fuel for some D2000 (had been using D1000) the 14" proving more suitable than the 16' wood that I used for one run.

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I am new to posting on this Forum,as I am normaly on the ME Forum, but the recent changes made by Mortons to both, allow us to see both at one visit. Hence I am curious regarding you making several Sparey 5cc Diesels. Are you going into production of them?🙂

I have tended to stay away from castings, as when several are involved, they give problems trying to make them fit together neatly.  I am more inclined to make those engines that can be made from bar stock.

Keith

 

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Yes,I know, I have followed a number of your builds such as the boll-aero glow &diesel engines and the Jones 10cc (that I have a set of castings) along with Ramons's

And Jason's builds that are both inspiring and intimidating at the same time! I suppose I should really take this over to ME but as a life long aeromodeller I naturally posted here,this is a relatively new side of the hobby for me that started out just fixing up/restoring old engines and escalated from there LOL !

Anyway the castings for the Sparey and Atoms were a job  lot from eBay,  part of an estate sale that I got for a very good price, but as you have noted they leave a bit to be desired both in dimensions and with porosity within the castings, the new castings I have arriving will be a lot better .

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  • 2 weeks later...

So got her fired up this morning with 6 flips of the MK 13x6 prop D2000 fuel with a bit extra either, actually much better than the other one that needs the electric starter too start probably due to leaking past the cp so will have to address that and hopefully get it running like this one. 

 

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now I need to decide on what  model build for it ??

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Well that was interesting if a little unexpected, finally stopped raining long enough to test run these engines back to back and get some rpm readings, the dc wildcat on a14x6 MAS and D2000 made 4,150,the first Sparey on the same made..............4,750 ! This was after some fettling that consisted of making a new cp,conrod, resized piston by 'cherry bombing and grinding a much finer taper on the needle valve, the other Sparey made only 4,200 rpm although the fits are a bit tighter so may need a bit more running in,so l think I will call these finished and a success and handedly enough, these arrived the other day....

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