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General control line discussion => Open Forum => Topic started by: Jerry Leuty on September 22, 2011, 04:26:54 PM
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OK all you, or at least one of you, engine gurus out there; how do you get the back plate off the crankshaft? I see what looks like a 'o' type ring lock wire on the shaft. I am putting a new block on my Brodak .40 and I have it all apart except for the crankshaft. But the prop back plate will not come off. I am thinking that I will have to get something to dig that little snap ring out of there. Any help is appreciated.
Jerry
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No snap ring, just should come right off. Try heating it up a little and use a puller.
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I use pliers....that's why Hampshire grabs 'em from me if I even hint that I am going to look inside an engine...
Eandy says it's okay if I change glow plugs, but that's it.
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Ok, now to answer my own question and for other's information. These engines are made in Russia of all places. It seems they use very close tolerances.The prop back plate has a bevel cut into it. There is a corresponding beveled shim that tightens down on the crank shaft when the prop is installed the first time. I put a block of wood under the plate and used a dowel rod cut to about an inch long and taped it to the threaded part of the shaft. While holding the whole thing with one hand I used a small hammer to tap the end of the dowel rod with. It all popped loose after that. Next came reassembly of the new block. The NVA was a tight fit, the piston and liner was a tight fit and the crank case back plate was a real tight fit. But it is all togther now and is turning feely. Now to go mount it on the test stand and give it a short fun. This engine assembly is going in a scratch built Road Runner. I have taken many engines apart in my life but this engine was by far the tightest fitting engine ever.
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Got a good bench run out of it. Very happy with this virtually new engine. I originally had this engine mounted on a Doodle Bug profile that the controls gave loose on. My weak build on this particular wing. I have a sure fire way of mounting the bell crank now that the stud bolt holding the B-crank is the weakest part now. Anyway when the plane went in from about 10 ft. high the muffler broke off the block leaving one of the mounting holes for the muffler sheared off. This engine had not had any run time on it since. I got encouraged and ordered a block from Brodak. They did not have one in stock but someone else had ordered the internal parts for a .40 so they sent me the block. Now I am happy.
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I finally figured out that you couldn't get the "prop driver" off the "crankshaft" thingy. I don't have any B.40's, but I would expect they'd use a split collet like the Super Tigres. Not that tough to remove, just a sharp whack with a block of wood or plastic hammer.
The "big" Brodak engines are made in Moldova, not Russia, by the same shop that builds Double Stars (which I call "2Stars", for what I think are obvious reasons). Not sure about the 1/2a's family trees... H^^ Steve
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Not sure about the 1/2a's family trees... H^^ Steve
CS=China
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Phil...You saying that Brodak 1/2a's are made by CS? Are AP's made by the same factory? I know what CS means, and where it's made. LL~ Steve
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I'm not positive, but I think they are made in Russia.
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Several years ago I also had an "incident" with my B40 and broke out the muffler mounting hole- tried to order a new crankcase and found out it wasn't available- sounds like situation hasn't changed- no parts available. I sent the engine to Scott Dinger and he made a great weld repair w/o disassembly of the engine- he drilled and retapped a new hole and have had no issues since- its my best running B40. Cost was same as if I had to buy a new case. Not sure if Scott still doing these repairs- hope I don't need another.
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I use pliers....that's why Hampshire grabs 'em from me if I even hint that I am going to look inside an engine...
Eandy says it's okay if I change glow plugs, but that's it.
Oh, so your the guy...I've seen my share of engines with plier marks on the drive washer.
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My Brodak 40 has been welded twice by Scott. It didn't survive the second time.
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On my Brodak .40 after the one ear was broke off, I just J-B Welded the tongue muffler on permenantly.