Stuka Stunt Main Forum · 26 of 26 known posts recovered
Gil Causey
What is the reason for not being able to disassemble the engine? Are the screws seized, or is the design unfamiliar and you are not sure how to proceed?
If it is a matter of the screws being seized, remove the glow plug and immerse the entire engine. The heat and anti-freeze will loosen the screws sufficiently after an over-night to allow disassembly of the unit.
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Gil Causey
John Wright
I have two engines that seem to have a few twists on the methods recommended above, so I'm looking for more input. All assistance appreciated!
I have a K&B Greenhead .09 and a .15. They both seem to be in great condition on the outside. No corrosion, no dings, etc. The .15 may not have ever been mounted. Both have been stored for at least 20-30 years. They are both stuck with the piston covering the exhaust port. I have been dosing them both liberally with Liquid Wrench in the plug hole, in the venturi, and through the rear of the case (backplates removed) for at least 3 weeks. I tried spritzing brake cleaner into them to see if it would penetrate further without success. (The spray can brake cleaner took the baked-on caster oil right off the case of an old Fox.) I have also tried heating them with a MonoKote heat gun without success. I don't know how hot I got them, but I thought I was hitting them pretty hard. Once heated, I tried to remove the heads (wrap with rag and twist/pull) without success. I didn't want to apply tools and start mangling things. Are the heads and/or sleeves head shrunk onto the case? Is there a special puller to do this?
I guess my next attempt will be to open the windows in the kitchen, turn on the fan, and stick them in the oven at 250 or 300F?
I have not tried cooking the engines in antifreeze since they have painted heads. But it may come to that. I tried cleaning up an O.S. engine using the heated detergent method. Can you say "black and chalky?" I don't even want to think about the possible pitting inside.... If I do "crockpot" these two, does anyone know of a workable paint to redo the heads? (I'm going for nostalgia here; I KNOW that the green paint doesn't make 'em run better....) There is another thread where someone is now trying to buy a McCoy head because he couldn't successfully repaint his....
Help! At the moment, I have two nice looking paperweights. The plane is in final assembly and the engine is not ready! And the flying weather is gorgeous!!!
Dave
LA_Flyer
"Pukey Profile Pilot and Stunt Wannabe"
President, Internet Racing League
J
"It'll probably feel real good again, once it quits hurting".
I got the head off the K&B .09 last night. I heated it up and twisted; no tools, just hands and rags. The top of the piston was cruddy. The solvents had softened the castor, but not flushed it away. It looks like the steel cylinder has a fiber gasket between it and the case. Any idea how thick these are? Seems like it would affect the port timing some. Does anyone know if the cylinder is a shrink fit to the engine case? Now that I've got the head off, I'll toss it into the "cauldron of decorruptification" many are recommending.
Going to heat-cycle the .15 again tonight to see if I can pop the head off of that one too....
In a hurry here. The Rootbeard Racing Team may post a time before the MBRT! And stunt contest next weekend!!!
Dave
LA_Flyer
"Profile Puke and Stunt Newbie"
Rog aka: 66ragman aka: ROF aka: several other non endearing names per Mrs. 66ragman
oh yea,,,there is almost no odor
Jim
I have used the try it once, try it twice, try it three times... it's gotta unstick sometime. Just be patient, don't use any more force than you can use with a couple of fingers as not to elongate the con-rod.
I picked up the smallest crock pot at Walmart for $8 and the best anti-freeze used for aluminum cooling systems (cost more than the pot!) I put the parts to be cleaned and add just enough juice to cover it. The juice turns from orange kool-ade looking to brown prune juice, but the parts are almost always sparking clean.
I put a Fox 35 (completely assembled minus plug and prop drive)in two weeks ago then forgot all about it for about four days and it grew the piston (maybe that little crock is bit too hot!) but it came apart with oven mit and pot holders and a popsicle stick to GENTLY lift the cylinder and it went back together real nice and has better than before compression!
As far as losing the paint on the GH, I don't know. I cleaned a Cox Golden Bee and the gold looks as good as the day it left Cox. (one day treatment only)
***@@@ SAFTEY REMINDER @@@*** Anti freeze is highly toxic if ingested and household pets will drink it like kool-ade... to their certain death. ALWAYS keep it covered and deal with the waste immediatly...
Phil Hawkins
I used this method to loosen a stuck piston in an old O&R 60. I put a greese fitting in the plug hole and then used a greese gun and filled the cylinder, it pushed the piston free with no distortion. Dennis
Gil;
For removing castor gunk, there is little better than the anti-freeze/crock pot method. I does take off paint, but annodized surfaces seem to fare well. There are times, though, on older engines that some corrosion between the piston and the cylinder wall literally bond the two together. Crock pot or penetrating oil might loosen them, but even that does not always works. Trying to free them by using a lot of force to turn the crankshaft may damage the wrist pin or the connecting rod.
When faced with the stuck piston/cylinder situation, I have found one method that always works. First, remove the cylinder head. Next, find a dowel that is about the size of the piston and will freely fit into the cylinder. Cut the dowel so it extends about 1/4-3/8" above the top of the cylinder. If there is a ridge on the piston, relieve the dowel so that only part of the dowel touching the piston is on flat. Take a piece of 2 x 4 that is 4 inches long and relieve a channel in the middle about 1 1/4" wide and 1" deep. Set your engine on the block as if you were going to mount the engine on it to check and make sure the only part touching are the mounting lugs. Now, take all of this to a vise. Against one jaw, place the bottom of the 2 x 4. Against the other place the end of the dowel that is sticking about 1/4-3/8" out of the top of the cylinder. Close the jaws of the vise until you have all the slack out and the engine/block/dowel will not fall free. Insepct the setup again and make sure that the dowel on the top of the piston is not pushing against anything except the flat of the piston.
The goal here is to move the piston. To do this, we will gradually increase pressure via the vise jaws. This calls for a light touch. I usually heat the engine with a hot air gun, tighten 1/8 turn, and then tap around the cylinder best I can with a hammer handle (not the hammer). Usually within a half a turn or so the piston will break free of the cylinder wall. Once that happens, remove from the vise and lubricate immediately. If necessary, continue the stripping process.
My only caution with this process is if you are trying to free up an engine that has a scintered iron main bushing, e.g. most of the Testors/McCoy 35s (except the lightning bolts series). These will sometimes have the corrosion bond between crank and the bushing. This must be free first, or you run the risk of damaging the conrod and wrist pin.
Best of luck in getting your engine(s) freed up.
Bob Kruger
Hi Ron,
Unless the engine was worn out before tearing it down, there should be no problem when you put it back together. If it was a "low time" engine, it may need to be further broken in.
It is always a good idea to bench run any engine that has been taken down and re-assembled. You will never get the sleeve/piston set "Exactly" like it was before.
Bill <><
When the character of a man is not clear to you, look at his friends.
Japanese Proverb
I did not even get a chance to vote!!!
Whats up with dat?
Paul
I am a retread, - I did C/L in my youth and did not know what I was doing then other then having fun. And not much has changed.
You're mixed up with some fast company, my friend!
Dave
LA_Flyer
"Profile Puke and Wannabe Stunter"
PS-The positions of Vice President of Operations, Safety, Engineering Standards, Pilot Training, Treasurer, Secretary, and Newsletter Editor are still vacant. I'm hoping Josh will head up Pilot Training. Now that he has soloed the Flight Streak Trainer, it seems like a natural fit.
Usually they are reusable. If there was a "rust bond" holding the two pieces together, you might find a little light etching or pitting. As long as the compression was pretty good prior to the engine "setting" up, you have a good chance at restoring compression.
There is one other issue, though, that you should consider. All of the engines I have ever handled are supposed to have wrist pins that can turn. Every old McCoy, OS, K&B, Veco, and Fox that I have stripped down all have wrist pins that are stuck and must be freed up. I am sure someone out there can tell me of an engine they found that although it was gunked up, the wrist pin rotated freely. The majority of the time, the wrist pin is stuck. Now, here is the rub. When you pull down a lapped fit piston/sleeve and then reassemble, it is almost impossible to get the piston and sleeve back exactly the same alignment as they had before. This means a new, albeit shorter, "breakin" period. This also means the possibility of shorter engine life. Don't pull it down and free up the wrist pin, and the engine runs erratcally. So, you will probably need to pull it down all the way make sure it will run right.
Also, you may find that your engine relied on castor buildup to hold compression. Pull it down and clean the castor off, and compression seems shot. You can get it back by running the engine on fuel with all castor for a while. However, getting one with bad compression started by hand can be an interesting proposition. Sometimes it takes a shot of straight castor into the exhaust port. Straight castor is viscous enough to give compression long enough to get the engine running.
Dealing with old iron is fun. Just understand there are some unique quirks and limitations. Expect a few things to go wrong. Its fun to take an old engine that sat in a cellar and "stiffened up" for 30 or 40 years, get it cleaned up, and bring it back to life.
V/r
Bob Kruger
Hello Bootlegger,
When I got back in the sport after about 35 years I had 6 old engines which were frozen solid as a rock. I tried gasoline, kerosene, antifreeze (not in a crock pot or heated), glo fuel, penetrating oil, etc., etc. In a hobby store, primarily RC products, I found Perfect Brand Engine Cleaner made by the people who make Perfect brand model paints.
If I could get the head and backplate screws removed I removed these parts before soaking as per instructions. In the cases where the screws wouldn't come loose prior to soaking they would come out after the first soaking. Then I removed the head and backplate and soaked a second time. In all cases I was able to move the piston in the cylinder and completely free the engine.
I had two McCoy Redheads and one K&B Greenhead. These I blocked upright and filled the containter not quite up to the head since the instructions said the solution would remove paint. I was able to free up these engines without loosing any paint from the head.
Later I bought a lot of 14 used engines to get 4 that I wanted. Ten of these engines were frozen solid. I used the Perfect Engine Cleaner on these and all of them freed up OK. One was a Fugi .25S which I had to soak and work on 4 times before it became completely unstuck.
I have since learned about the crock pot method and intend to try it in the future. I have already gotten a crock pot and it is just sitting waiting.
However, although I am going to the crock pot method in the future, I recommend the Perfect Brand Engine Cleaner if you only intend to clean and unstick one or a few engines. It is cheaper than buying a crock pot and the antifreeze (if you don't already have some), it is clean and easy to work with, you only need to wash good with soap if you get it on you and I don't see how you could expect better results. I have been completely satisfied with it.
Mel Peeples
ps: I don't work for the Perfect company. I'm a retired Texas state employee.
Mike in Atwater,
'When I fly, the plane gets nervous'