1QwkSport2.5r

If it's already ripped apart AND the bearings are out, why not spend $2-12 on a set of bearings and add a whole pile of peace of mind?

Sport_Pilot

Not that hard to take apart. Why spend money you don't need to spend? If it were a real airplane or even a car I would agree with you. If it has no play and no pitting it should be good to go.

Hobbsy

My Feedback: (102)

I don't try to determine whether it's castor or rust, I just go to the Boca website choose the $11.88 set, install them and forget about them.

Dealspeed

My Feedback: (17)

Well the rear bearing in my 91 is very stuck, it won't come out, I've oiled it heated it and still it's stuck, any advice?

spaceworm

Maybe try putting the engine short block in the freezer for a couple of hours, Then take it out before it has a chance to warm up and use a heat gun on the area of the crankcase that the bearing seats in. Try to time it so the case gets hot before the bearing cage does. This will allow the aluminum case to expand while the bearing is still cold and shrunken, (Yes George, we know the pool water was cold). Then whack the backcover seating surface of the case hard on a piece of wood sitting on a solid surface. The inertia loads thus imposed should drive the bearing out. Good luck. If not, Dave has made a tool that can grab the edge of the outer bearing and allow it to be driven out with a hammer.

Sincerely, Richard (neither a professional nor an expert)

Dealspeed

My Feedback: (17)

Well that did not work, not sure what else to try at this point

1QwkSport2.5r

But why do the same work twice? Especially if you have it mounted in a plane... If a guy is *that* cheap, get the bearings from AvidRC.com for $1 each. I've done that in several engines including 35,000rpm car engines. Work as well as any other "econo" set made in China.

Peace of mind is more valuable than a $2-12 set of bearings IMO. To each their own though.

Dealspeed

My Feedback: (17)

1QwkSport2.5r do have any experience getting rear bearings out that are stuck?

1QwkSport2.5r

More heat. I don't bother trying to get bearings out of the crankcase isn't heated at least to 325F for 20 minutes. I've had to heat to 400F once on an old crusty engine I bought. It smoked like mad and stunk to high hell, but the bearing came out. So... When in doubt, add heat. Forget about the freezer - it won't help. The aluminum crankcase will expand more than the bearing will.

1QwkSport2.5r

Yup. Response #84

Sport_Pilot

I have put them in the oven at about 350 degrees or more. Expands the case and softens the castor.

Sport_Pilot

I don't know, rusty bearings might be better than one dollar bearings. I have had bearings go bad after just a few runs, no rust. IMO bearings that have lasted a while might be better than new bearings.

Dealspeed

My Feedback: (17)

Ok I'll get it even hotter and see what happens.
Thank you everybody for all the help and advice, its nice to have all the different opinions on this subject, and as far as I'm concerned we're all experts on glow motors, we just don't all agree with each other's ideas and opinions

GREG DOE

Dealspeed, Try the axe handle approach. Take your case to Lowes, or Home Depot, and find a 36" dowel that is either over size, or a tight fit in the case cylinder bore. If you have to go over size, sand it down until it's a tight fit in the case. Heat the case with a torch, or in the oven (350 to 400 deg.). Insert the dowel, and "rap" the case on a block of wood (rear cover opening down). Pay attention that the end of the dowel doesn't interfere with the bearing coming out. You probably will want to use heavy gloves. Good luck.

1QwkSport2.5r

So far they have performed the same as the $12 econo sets from the popular bearing houses. Some of them even came with a plastic ball retainer. When I have one of these $1 bearings fail, I'll post about it here.

Dealspeed

My Feedback: (17)

Wow plastic ball retainer? Spinning at 10k+ rpm's and no fails? Very impressive for such cheap bearings.
I've always wondered if installing ceramic bearings in my plane motors would improve performance?
Or what if you took a OS 55ax and I nstalled ceramic bearings, and then ramp the crank like they do on high dollar car motors.
I have always thought that RC car motors are higher quality than RC plane motors, except maybe Jett engines, those are beautiful motors.

Hobbsy

My Feedback: (102)

Deal, I spent the money and bought ceramic bearings for a Fox .50 Diesel conversion, it was probably a waste of money, the bearings are in there out of sight and out of mind. The other Fox .50 has the $11.88 beairings, same story. I've never had to change those $11.88 bearings in any engine. So far I've never had to change bearings in an engine I bought new, only in used ones.

PS, I actually moved the ceramic bearings from a Fox .46 to the .50 with no problem. I busted the .46's cylinder in an accidental landing.

1QwkSport2.5r

The plastic/phenolic ball retainers are preferred for higher rpm engines. Open up any RC car engine made today and you will find plastic ball retainers. They are capable of handling higher rpm much better than the metal retainers that sometimes fly apart.

Ceramic bearings are a waste of time in sport engines and really - a waste of time in airplane engines in general. They are geared towards RC car engines because they tend to rev harder and much much quicker with the lighter weight ceramic bearings. A total waste in nearly any other engine.

Some folks consider quality in different ways. It's true some brands of airplane engines aren't made to the price point they're sold at while others are the opposite. You can't compare OS and Jett in the same context. They're worlds apart in terms of quality. I do agree Jett build's a beautiful engine and man do they rev hard! I have two of the BSE engines myself - a .35 and a .56LX. They come with regular steel bearings with plastic ball retainers and true chromed liners (I think they switched from brass to aluminum liners in all engines now. AAC used to be a $35 upgrade).

Dealspeed

My Feedback: (17)

Ok so my new bearings came today for my 91fx, I noticed the front bearing has seals on both sides, should I remove one of the seals?

Hobbsy

My Feedback: (102)

Leave both on the front, that's my choice anyway.

Dealspeed

My Feedback: (17)

Only reason I ask is the stock front bearing only had a seal on one side.
The new bearing has plastic seals not metal like the stock bearing.

the pope

That one is up to you , I dont think it makes much difference . You would probably know that the front bearings usually lasts twice as long as the rear anyway so if there was a issue with either method i reckon you would be pulling the rear time anyway so no biggie . Although with the rear bearing I take them off , whether they come from the factory like that or not . cheers

hsukaria

I had to use this improvised tool to yank the main bearing out on my old crusty/rusty Fox 45 plus lots of heat.

hsukaria

The bearing with plastic cover is a "sealed" bearing and the one with the metal cover is a shielded bearing. You want to make sure that enough oil gets to the front bearing. If those seals are going to prevent oil from soaking the front bearing, then I would take the rear side seal out. I don't have any way of telling if the seal will prevent oil from entering the bearing or not. So your call.

Dealspeed

My Feedback: (17)

well I put the crank back in the case and popped it in the oven at 350 degrees for 20 minutes, took it out and used a small block of wood so as not to damage the prop shaft, one good wack and the crank and bearing came right out.
thanks for the advise