Small Crack on bearing housing

[singinwoodwackr]

That, or something like a chunk of bearing cage getting jammed up in there

Possible the crank ground up part of the bearing. Need pics of everything

 

[jiggsawjimduncan]

Well, the crank sure as hell wasn’t centered
The bearing seat looks fine. All that gouging is from the crank…got pics of that?
The little chip was most likely cause by the not centered crank and can be ground down easily

It's never been opened until I opened it up and the cracked came removing the bearing the saw was gave too me by my boss man he has all kinds of 372xp laying around he usually jus buys more once they start acting up he said he thought it was sucking air

 

[jiggsawjimduncan]

Possible the crank ground up part of the bearing. Need pics of everything

Ill lay it all out and take pictures but the chip happened removing the bearing everything looks great except the scratches on the side where the chip is

 

[jiggsawjimduncan]

Ill lay it all out and take pictures but the chip happened removing the bearing everything looks great except the scratches on the side where the chip is

 

[jiggsawjimduncan]

Ill lay it all out and take pictures but the chip happened removing the bearing everything looks great except the scratches on the side where the chip is

Yes appears the crank was spinning up against something I'm having a hard time finding the bearing i took out from that side

 

[singinwoodwackr]

Yup. Crank not centered and ground into the bearing. Or...bearing wasn't fully seated.

 

[Vintage Engine Repairs]

Just to correct the notion of crank centring. It’s a myth that is perpetuated by misinformation from person to person online. There’s no need to centre the crank in a saw. In fact, the center of the four bolt holes for the cylinder is rarely, if ever, perfectly aligned with the center of the crankcase opening. If you try to center the crank, the connecting rod won’t be centered in the cylinder. Manuals typically recommend pulling the crankshaft down onto one bearing first, then into the other, without mentioning anything about centring. There’s ample lateral play at both the big and small ends of the connecting rod, so this damage isn’t related to centring. It looks more like an issue with the crankshaft being out of square - damaged bearings failing to keep it properly aligned is my
guess. Bearings sit slightly proud of the case and the web of the counterweight has a step, all to keep the clearance. If it was an issue of being too close from not centring, the entire counterweight would be marred, rather than a portion, hinting at it being off square rather than any off centre issue.

Edit: this is an example of the damage from a shot pto bearing on a 660 I was doing. Like on your counterweight, uneven contact, until it’s left long enough and damages the whole surface.

 

[Tobystihl]

Just to correct the notion of crank centring. It’s a myth that is perpetuated by misinformation from person to person online. There’s no need to centre the crank in a saw. In fact, the center of the four bolt holes for the cylinder is rarely, if ever, perfectly aligned with the center of the crankcase opening. If you try to center the crank, the connecting rod won’t be centered in the cylinder. Manuals typically recommend pulling the crankshaft down onto one bearing first, then into the other, without mentioning anything about centring. There’s ample lateral play at both the big and small ends of the connecting rod, so this damage isn’t related to centring. It looks more like an issue with the crankshaft being out of square - damaged bearings failing to keep it properly aligned is my
guess. Bearings sit slightly proud of the case and the web of the counterweight has a step, all to keep the clearance. If it was an issue of being too close from not centring, the entire counterweight would be marred, rather than a portion, hinting at it being off square rather than any off centre issue.

Edit: this is an example of the damage from a shot pto bearing on a 660 I was doing. Like on your counterweight, uneven contact, until it’s left long enough and damages the whole surface. View attachment 1223403

Well, speaking from my own experience, pretty much all of the saws that I have rebuilt the crank will only run free in the crankcase after a gentle tap on each end of the crankshaft to relieve any side pressure on the bearings, thus therfore centring the crankshaft.

 

[Vintage Engine Repairs]

Well, speaking from my own experience, pretty much all of the saws that I have rebuilt the crank will only run free in the crankcase after a gentle tap on each end of the crankshaft to relieve any side pressure on the bearings, thus therfore centring the crankshaft.

That’s not centring the crankshaft as referred to here, that’s removing preload on the bearings.

 

[jiggsawjimduncan]

Yup. Crank not centered and ground into the bearing. Or...bearing wasn't fully seated.

Well idk it had to be a factory issue then because this was the first time it's ever been opened up is the case still good enough to use in the rebuild?

 

[J D]

Well idk it had to be a factory issue then because this was the first time it's ever been opened up is the case still good enough to use in the rebuild?

It'll be fine to use, although I'd be paying close attention to where the crank is wanting to sit when it all comes together