911hillclimber Posted March 23 Share Posted March 23 (edited) 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 March 23 by 911hillclimber Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted March 23 Share Posted March 23 Brilliant work Jeff. What type of welding did you use on the case ? Tig or low temp ? Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted March 23 Author Share Posted March 23 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 !😄 made sure it's a nice loose fit this time I ground the needle valve by hand on a sanding belt but the suggestion to use a sowing needle is a good alternative Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted March 23 Share Posted March 23 Hi Jeff I recently fixed a OS die cast backplate with some low temp rods I bought locally . They melt at 300 deg c and seem to make a good strong joint. If interested pm me and I'll send details. They also make a 400deg rod. Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted April 7 Author Share Posted April 7 (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. Edited April 7 by jeff2wings Forgot to add pictures Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted April 7 Author Share Posted April 7 .......and I've just brought two more! Should be a lot more easier with thse than the rather poor Hemingway ones 😢 1 Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted April 7 Share Posted April 7 Castings and finished engines look fab. Envious! will you make 2 more? Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted April 7 Author Share Posted April 7 Thanks, well l'm getting the hang of it now, so................😁 Quote Link to comment Share on other sites More sharing options...
KEITH BEAUMONT 1 Posted April 9 Share Posted April 9 Jeff, Are those Sparey castings availble to buy commercialy? Keith. Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted April 9 Author Share Posted April 9 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" . Quote Link to comment Share on other sites More sharing options...
brokenenglish Posted April 9 Share Posted April 9 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. Quote Link to comment Share on other sites More sharing options...
KEITH BEAUMONT 1 Posted April 9 Share Posted April 9 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 Quote Link to comment Share on other sites More sharing options...
KEITH BEAUMONT 1 Posted April 9 Share Posted April 9 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. Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted April 9 Author Share Posted April 9 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. Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted April 10 Author Share Posted April 10 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. 1 Quote Link to comment Share on other sites More sharing options...
911hillclimber Posted April 10 Share Posted April 10 Hope to do the same next week! Just bought another 'kit' off Hemmingway, the Atom Minor Mk3........ Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted April 10 Author Share Posted April 10 Hope your set of castings are better than the ones I have.Be sure too read and take note the MEN build article on the Atom Minor. Quote Link to comment Share on other sites More sharing options...
KEITH BEAUMONT 1 Posted April 10 Share Posted April 10 Congratulations with the first run Jeff. Takes a lot to beat the sound on the first run of an engine you have made. Keith. Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted April 10 Author Share Posted April 10 Thanks, it's always a thrill with the first sustained run from an engine you have made,lessons learnt on this build will hopefully make the next three a little less problematic 😀! Quote Link to comment Share on other sites More sharing options...
KEITH BEAUMONT 1 Posted April 10 Share Posted April 10 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 Quote Link to comment Share on other sites More sharing options...
jeff2wings Posted April 10 Author Share Posted April 10 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 . Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.