Frozen Engines - RC Groups
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Jan 16, 2007, 10:14 AM
Registered User

Frozen Engines

My planes have been sitting up foer about 5 years and a few of the engines have froze up. I read the post about using antifreeze and plan to try. My question is will it clean up the bearing type engines or do I need to replace the bearings in the engine
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Jan 16, 2007, 11:28 AM
Registered User

frozen engines

The engines are probably just gummed up, take the engine off the airplane, either use a hair dryer or I used a propane torch, carful not to heat it to much. Once the engine is warmed up you can turn it over. If you want to use the antifreeze, just don't cook them to long, they will turn black (that won't come off)
Jan 16, 2007, 12:37 PM
Registered User
pilotpete2's Avatar
Anti-freeze is more for getting the baked on gunk off the exterior of the engine, as the prior poster suggested, heating the engine will help, but if you have any self-respect as an R/C guy, please use your heat gun, not a hairdryer ,sorry, not enough left to need one of those
Another sure fire way to free up an engine that has sat too long, is to squirt some fresh glow fuel down the carb, in the exhaust manifold, then pull the plug and squirt a little in on top the piston, should free right up
Good luck,
Jan 16, 2007, 03:14 PM
jimi hendrix
is there ice inside inside this "frozen engine"?

has it been stored in the freezer for 5 years?



Jan 16, 2007, 04:29 PM
Bill Mohrbacher, MECA Fox Guy
G WILLIE's Avatar

unsticking an engine

A good rule of thumb is don't take an engine apart unless you really have to! The piston to cylinder or ring to cylinder fits are really critical and if you take the piston out, you basically have to breakin in the engine again, almost guaranteed to reduce compression.

That said, most eninges freeze up due to congealed oil. Put an old prop on the engine (after taking it out of the plane), then heat the engine with a heat gun, a hair dryer isn't hot enough. You are on yoour own with an open flame and a torch! Use gloves and once the engine is nice and hot Lean on the prop until it starts to move. Don't force it, just heat and lean, heat and lean. Once the engine turns, put some kind of air tool oil in it and turn it over. MARVEL MYSTERY OIL is NOT the same as MARVEL Air Tool Oil. The air tool oil will mix with the fuel and burn out when you run the engine the first ime, other solutions usually will foul the plug.

You can use heat to free up the carb also. Once the engine is COOL, you can put in some fuel and turn the engine over. If the bearings aren't rusted, you probably don't have to replace them. Once the engine is free, you can remove the rear cover so see how things look inside; you'll be able to see rust on at least the rear bearing. Be aware that you may destroy the rear cover gasket, so be prepared to replace it if you remove the rear cover.

Besides the obvious bearings, two other places for concern are the ring-piston and the wrist pin-conrod. If the ring doesn't expand it won't seal, but it will usually free up. The wristpin sometimes sticks to the rod and then it rocks in the piston, instead of the rod rocking on it.

Without total disassembly, there is not much you can do aboout these last two conditions. Just run the engine nice and rich for a couple of tanks after you have it cleaned up. Oh yes, and make sure you blow out all the little orifices in the carb!
Jan 16, 2007, 05:28 PM
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BTerry's Avatar
I bought a nice plane at a garage sale a few months back, and the engine (OS 46SF) would NOT turn over. For the price it was a bargain even if it needed a new engine.

I pulled out the heat gun and worked on it for a while. After it heated up a bit, it started to turn over slowly at first, then a bit more smoothly. It still felt like the bearings were dragging. I also heated the carb and cleaned it with a shot of brake cleaner.

I took it to the field the next day, and it started on the third flip! I let it run up for a few minutes before going to full throttle, then killed it. After this it felt completely smooth, was easy to turn over, and had decent compression. Then I refueled it and flew, and flew, and flew... It is easy to start and runs great! I thought I was going to junk it and now it works just fine.

I used fuel with a synthetic oil and it the bearings are still smooth a couple of months later.

My bearings were just gummed up with castor. They are smooth and tight (can't pull or push the crank) now. If they were rough or the crank felt loose, I would have replaced them.

Good luck,
Jan 17, 2007, 04:59 PM
Registered User
Thanks for the idea I will try them this weekend and let you know how I make out I have aprox 6 engines to clean up

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