Crankcase Bearing Question

[GAJ]

I purchased an R/C chassis for parts, attached was an Axial motor (number on bottom of engine is 8G07793A, if anyone can decipher what this engine is for me). The engine was totally seized, so I decided nothing to loose, I will take it apart. It was all gummed up. Lubed it, got it moving, stripped it down.

This is my first total strip down, pulled the crank out, exposed the back of the crank bearing. There are 14 small balls in the bearing, but they are not evenly spaced. I can see what looks like some type of bearing spacer behind the balls, but is not keeping the bearings spaced. Is this normal, or is the bearing bad? If it is bad, how do I get it out?

When I slide the shaft back in and rotate it slowly, the movement feels a bit clunky, is this normal at low speed?

Thank you.

 

[Jam Racing 1]

That bearing cage is bad allowing the balls to fall out of place, you can heat the case and use a small punch to get it out, do the same heating when you install the new bearing, do not do it cold because the fit is rather tight and you could damage the case if not done right....
I believe fast eddy among others have the bearings you will need... use a good caliper to get the sizes id and od

 

[GAJ]

Thanks Jam, I assume that I will have to remove the front bearing to be able to tap out the rear bearing, is this correct? Do I remove the front bearing by heating and tapping it out from the rear?

 

[Jam Racing 1]

Yes you have to pull the front one first and while you are getting bearings may as well just replace the front one also.....
when I am heating the engine I use a small metal pan and heat to about 250 in the oven, use your oven glove and knock them out on a small block of hardwood....

 

[olds97_lss]

Usually, once you heat the crankcase up (only the crank case and bearings, everything else removed), you can hold the engine in an oven mitt, then whack the back of the engine down on a board and the rear bearing will fall out. The front one is a little more annoying. I usually whack the front of where the sleeve is similarly straight down on a board a few times while it's hot and it comes out too. Or I tap on it from the back after getting the rear one out.

This vid at 1:58 is what I'm talking about:

To put the bearings back in, heat the case up to 250F after putting the bearings in the freezer. Between the heat/cold, it will give you a little more tolerance to get the bearings back in without getting them cockeyed.

 

[N713TL]

that's the best vid for that out there

 

[GAJ]

Great information.
Thank you all.

 

[GAJ]

Any risk in putting it back together as is to fire up? As mentioned above, I do not know if this motor runs.

 

[Jam Racing 1]

I wouldn't run it, that bearing is already falling apart and you don't want to damage the crankshaft...

 

[GAJ]

Ok Jam, thanks again.

 

[GAJ]

So, I followed the instructions in the video..... Worked GREAT. Heated the crankcase on a hotplate to about 225F, tapped the crankcase on a block of wood a couple of times, bearing dropped right out. Poked at the front bearing a few times from the back with a dowel, came out easily.

Thank you again for the advice.