I've got a good running TT .91 four-stroke that's given me 3 years of good service, and even w/after-run oil, the bearings are getting noisy. What special tools will I need to change the bearings out? Have you found it to be cost effective to do so? We're talking four bearings and a piston ring at least, and decarboning of the head and...?

Thanks, Dennis

No replys yet, but nothing to lose, so with the help of a club member I've tackled it. Very easy. Disasemble most stuff. Take off the head, lift the liner out and ease the rod off the crank. Now I got it in the oven to loosen the bearings. Unsure of what temp to use, but we'll start with 400. Found bearings at Boca Bearings (.com)

Dennis

I just rebuilt a G45 last week. I had this sneaking feeling that my wife would hit the roof if I put one of my engines in the oven, just cuz she puts a roast in there once in a while.

I used an old electric fry pan and set the temp at about 300. After about 20 minutes, the engine was hot enough that the bearings almost literally dropped out. Never had to approach 400F. Hope this helps!

Bob

Hello; I usually use 250 and give it at lweast 15 minutes before I attempt to remove the bearing. I haven't had one beat me yet. I do find that the more expensive bearings that Boca offer do make a difference. I have a Saito 50 I have used for 6 years since putting the upgrade Boca bearings in it, with no problems whatever: It's not the kind of job I would want to do every year.

I've been up to the Boca site.. It's pretty easy to tell which size bearings that you need. But, I'm confused over all the different models that they offer. Which ones are best for R/C engines?

They have some super expensive bearings that would probably be wasted on an engine. Then there are a few other models to choose from. What does one look for in a bearing on that site? I also know that they have the engine breakdown there, but even that could be confusing sometimes.

Bob

Maybe a bit late to reply..

I use to heat the crank case on the electric stove on low heat and use a piece of brass tubing and a small hammer to knock out the bearing.

Before I put the new bearing in, I cool it down in the freezer for a hour or so. Then I heat the crank case again, I swiftly pick up the bearing from the freezer, using a glove (so my fingers won't heat it up again), then I insert it into the crank case. So far, I have always managed to do this with finger pressure only.

If the bearing has a dust-protection plate at one side, then make shure you don't put it in upside-down.

Some people just ram it in (no pre-heating), using a wrench socket and a hammer but that is too brutal in my oppinion. This might damage the bearing and/or crank case.

Check carefully that the bearing is inserted all the way down to the bottom of the seat.

Check that the crank shaft turns freely with no binds.

I use to mount a propeller, flip it over and listen to the bearings before i assemble the engine further.