Is the race supposed to loose?

[IHCub1450]

In the process of removing crankshaft and crank bearings on my Kohler K321 for my Cub 1450 I noticed that the race for the roller bearings on the left side, (that's with the starter down towards the work bench) is loose and not tight to the crankshaft, is it supposed to be this way?

[athomas]

on the one end the bearing plate comes off and the bearing slides off the crank with it. then you can slide the crank out of the block and the other brg will stay in the block but to answer the question yes the crank will slide off the brgs it's a close tolerance but not an interference fit as would be if you needed to heat the races to get them on . if that answers your question ?

[IHCub1450]

Originally Posted by athomas

on the one end the bearing plate comes off and the bearing slides off the crank with it. then you can slide the crank out of the block and the other brg will stay in the block but to answer the question yes the crank will slide off the brgs it's a close tolerance but not an interference fit as would be if you needed to heat the races to get them on . if that answers your question ?

This doesn't exactly answer my question, really what I'm asking is: is the race on the on the PTO end supposed to loose, as in not fixed to the crank, like the one on the drive shaft end of the crank.

On the PTO end I can take a small screw driver and turn the race either way, on the drive shaft end it is fixed to the crank, and if I try to turn it it turns the whole crankshaft.

So the real question is, is the PTO end crank bearing race supposed to be able to turn freely and not be fixed to the crank like the drive shaft end?

[ol'George]

Bearings usually have anywhere from to a press fit to a to a light slip fit achievable using ones hands during assembly.
An example would be a wheel bearing on a vehicle, pre front wheel drive,
a truck or a light trailer.
--- an easy slip fit.
Now we don't know if the inner race or the crank is slightly worn?
a precision measurement with a micrometer of the crank will tell you that.
Also after you remove the tighter fit bearing on the other end of the crank, try that bearing on the end that seems loose to you.
(if it is the same number bearing)
that would tell you if it is the bearing that is worn or the crank is slightly undersize.
It is difficult without experience for one to determine what is acceptable.
But the fact that the crank is captive in the block would suggest it can be a loose fit and not a press fit.
Now if the bearing is obviously "loose" on the crank or shows an area on the crank where it has been pounding it into a smaller diameter, of course that is not acceptable.
but just being a light slip fit is not cause for concern.
Sorry for the long explanation.

[IHCub1450]

Originally Posted by ol'George

Bearings usually have anywhere from to a press fit to a to a light slip fit achievable using ones hands during assembly.
An example would be a wheel bearing on a vehicle, pre front wheel drive,
a truck or a light trailer.
--- an easy slip fit.
Now we don't know if the inner race or the crank is slightly worn?
a precision measurement with a micrometer of the crank will tell you that.
Also after you remove the tighter fit bearing on the other end of the crank, try that bearing on the end that seems loose to you.
(if it is the same number bearing)
that would tell you if it is the bearing that is worn or the crank is slightly undersize.
It is difficult without experience for one to determine what is acceptable.
But the fact that the crank is captive in the block would suggest it can be a loose fit and not a press fit.
Now if the bearing is obviously "loose" on the crank or shows an area on the crank where it has been pounding it into a smaller diameter, of course that is not acceptable.
but just being a light slip fit is not cause for concern.
Sorry for the long explanation.

No, the bearing isn't loose on the crank, just the race. I talked to my uncle and he didn't know for sure, but he said his gut tells him it is supposed to be a loose slip fit race.

[Ambush]

The bearing you’re talking about has two races, inner and outer, and balls, plus a ball cage. That whole assembly is called “the bearing”.


The inner race should be a slip fit, but not loose. Basically size to size fit.

Pull the bearing back 1/2” and see if there is any difference in fit.

[ironman]

According to the Kohler Service Manual for K Series Engines,
it vaguely insinuates that when dis-assembling the engine,
BOTH bearings could remain attached to either the bearing plate, the block, OR the crankshaft,
and if they must be removed from the crankshaft, use a puller.

So if both your bearings would have stayed on the crankshaft, likely neither inner race would spin.

[IHCub1450]

Originally Posted by Ambush

The bearing you’re talking about has two races, inner and outer, and balls, plus a ball cage. That whole assembly is called “the bearing”.


The inner race should be a slip fit, but not loose. Basically size to size fit.

Pull the bearing back 1/2” and see if there is any difference in fit.

I still have the crank in the engine.
So, do I need to pull it to see if there is wear and it needs to be replaced?

The race that I'm talking about, that spins, is most likely the outer race, since the crank is still in the engine.

That would mean I need to pull the crank and get new races and bearings?

[IHCub1450]

Originally Posted by ironman

According to the Kohler Service Manual for K Series Engines,
it vaguely insinuates that when dis-assembling the engine,
BOTH bearings could remain attached to either the bearing plate, the block, OR the crankshaft,
and if they must be removed from the crankshaft, use a puller.

So if both your bearings would have stayed on the crankshaft, likely neither inner race would spin.

I'm not sure if it's the inner or outer race that is loose, I'm guessing it is the outer since the crank is still in the engine, but I wouldn't know for sure. But if it is I need to pull the crank and replace the bearings and races?

[ol'George]

Wow some confusion here apparently.
A ball bearing is an assembly consisting of an inner race,------- the part that slides on the on the crankshaft, ----- and an outer race that slides in the engine block or bearing plate that bolts to the block.

Also the balls between the inner race and the outer race are kept in place by a race retainer, it all is manufactured as an assembly, inner and outer race, balls and ball retainer.
End of story.

Ball bearings are not like a Timken style, tapered roller bearing, that consists of a cup and a cone with the rollers attached to the cone.
A ball bearing comes as an assembly.
Now there are some exceptions that I'll not go into as its irrelevant in this case.
Hope this clears up any confusion.