rebuilding a saw lubrication

[thompson1600]

When you put a new crankshaft in a saw, how much oil (I have been using just plain stihl mix oil) do/would you put on? Would you just soak the main bearing or do/would you put enough oil in so that there is some at the bottom of the crankcase? How much is too much and how much is not enough?

Put an 044 back together the other day and apparently didn't put enough oil on the main bearing to lubricate it until the gas mix got to it. Saw ran fine and was idling for carb adjusting for about 1 minute when the main bearing on the crank/connecting rod seized. Held vacuum and pressure test was ok. Mix was 32:1 All the parts were original/used except a new piston/rings was put in. Checked the bearing prior to reassembly and didn't see any spaces where the roller bearings were missing and the connecting rod wasn't sloppy from side to side.

Anything else that may have caused this?

Thanks

Tom

 

[Jacob J.]

Hey Tom-

Did you take the bearings out of the case and flush them out and then blow them out? If you're re-using the same bearings it is advisable to remove the bearings from the case and thoroughly clean them, and then oil them back up real good and re-install them.

As far how much to oil everything on re-assembly, all components should have a light coat of oil, but you really shouldn't have a puddle at the bottom of the mixing area.

 

[thompson1600]

The bearings in the case weren't removed but were cleaned and blown out with air while still in the case. I'm going to replace them before putting in the next crankshaft just to be sure though.

That's what I did, was just a light coat of oil.

Thanks

Tom

 

[Jacob J.]

What probably happened then was a chunk of carbon inside the bearing race broke loose and got you or a chunk of the plastic bearing cage broke away.

 

[thompson1600]

Any way to check for those things (or prevent them) before reinstalling, or just something that happens occasionally with Murphy's law?

Tom

 

[Mange]

When I put together a saw I always try and get new, It does not have to be original, just right.

Mange

 

[stihltech]

crank

it probably had a flaw under the rod where you could not see it. cranks are pretty tough. sometimes things fail despite your best inspection. you had plenty of oil.