What caused this piston scoring?

[ncvarmint]

can i see the crank bearings good when i take the seals out, so i can look at them good without taking the crankcase apart?
Would like to not have the crankcase pulled apart if i dont have to. Do i need to worry about the spots where the crank rod hit the case if all the bearings check out?
thanks

 

[blsnelling]

You'll be able to see the PTO side bearing, but not the flywheel side.

 

[greg409]

Is the rod discoloration normal?

Or a product of unnatural "heat treating" ?

I'm ASSUMING the surface in the pics IS the outer race of the small end.

IMO, there's no way THAT rod hammered out the case like that - I don't see how it could have that much fore/aft play with an intact piston - and spinning it by hand wouldn't produce that kind of force.

I'm nervous opcorn:

luck,greg

 

[ncvarmint]

starting to think about selling it for what i have in it and sell the other stuff i bought for it and just get a 562 and get the 372 ported for the big wood
trevor

 

[ncvarmint]

BTW how do you tell if the crank is oem or aftermarket without taking it out? Is there a way?

 

[srcarr52]

BTW how do you tell if the crank is oem or aftermarket without taking it out? Is there a way?

Hard to say, usually the markings are on the outside of the crank throws and you can see them till you have it out.

 

[Mastermind]

Wanna do some trading on that saw for some port work?

 

[ncvarmint]

Wanna do some trading on that saw for some port work?

Randy, send me a pm, did you want the saw the way i got it, everything with the scored jug. Anyone interested in buying the new oem piston/cylinder assembly.

 

[Mastermind]

Randy, send me a pm, did you want the saw the way i got it, everything with the scored jug. Anyone interested in buying the new oem piston/cylinder assembly.

PM sent

I'd do two saws for the carcass and the new top end.....

 

[Justsaws]

If the P/C were pulled before the clutch and flywheel were removed a crafty impact wrench owning "mechanic" could make those marks. Does not take much time or effort just special skills.

 

[ncvarmint]

Just looked at the crank agian and saw the numbers 1121 on the side, so it must be oem.
randy, did you get my 2nd pm sent to you?
trevor

 

[Justsaws]

1122 is the Stihl prefix for 064-660s.

1121 is the prefix for 024-260s.

It should have 1122 on it, if it has 1121 that would be odd.

 

[ncvarmint]

1122 is the Stihl prefix for 064-660s.

1121 is the prefix for 024-260s.

It should have 1122 on it, if it has 1121 that would be odd.

your right, my bad, should have been 1122, was way past my bedtime when i typed that