Beat up 660 cylinder

[mkswmp]

I recently made a hell of a score at a local Stihl dealership. I got all their trashed saws they had in the back which consisted of 2 660 saws and one 046 saw doing with a ton of misc parts and odds and ends. Along with that score came 2 660 cylinders that appear to be brand new... except upon closer inspection of this on it looks like the ceiling of the cylinder has been beat to hell and back!! It looks like something fell inside the spark plug hole and was tossed around pretty violently. The weird thing is the cylinder has no carbon at all in the exhaust opening. I mean it's brand new looking. Can I still use this cylinder with the pits and divets in there? Should I attempt to clean it up some with a Dremel tool or leave it alone or is it trashed?

 

[Bob Hedgecutter]

Looks like something harder than the squish band has been sitting on top of the piston and being rammed into the squish band with each crank revolution- bet the piston was pretty looking!
Possibly the electrode strap off the sparkplug, but more likely a bearing needle?
So there are no scores in the side wall of the cylinder where the errant piece got caught in a transfer port?

 

[mkswmp]

Looks like something harder than the squish band has been sitting on top of the piston and being rammed into the squish band with each crank revolution- bet the piston was pretty looking!
Possibly the electrode strap off the sparkplug, but more likely a bearing needle?
So there are no scores in the side wall of the cylinder where the errant piece got caught in a transfer port?

Nope. The walls are nice and slick like brand new. The only thing that has any sign that this cylinder was ever on a saw is the marks on ceiling of the cylinder

 

[Maintenance supervisor]

I recently made a hell of a score at a local Stihl dealership. I got all their trashed saws they had in the back which consisted of 2 660 saws and one 046 saw doing with a ton of misc parts and odds and ends. Along with that score came 2 660 cylinders that appear to be brand new... except upon closer inspection of this on it looks like the ceiling of the cylinder has been beat to hell and back!! It looks like something fell inside the spark plug hole and was tossed around pretty violently. The weird thing is the cylinder has no carbon at all in the exhaust opening. I mean it's brand new looking. Can I still use this cylinder with the pits and divets in there? Should I attempt to clean it up some with a Dremel tool or leave it alone or is it trashed? View attachment 944726

Send it out to a reputable builder to have .020 cut out of the squish band and then do a bgd build.

 

[mkswmp]

Send it out to a reputable builder to have .020 cut out of the squish band and then do a bgd build.

Bgd build??

 

[Yukon Stihl]

I would clean it up to use on my own saw.

 

[Mad Professor]

If you were going to use that cylinder I clean up that squish band, might be stuff there that could come loose. Cutting the squish band is a good idea and a base gasket delete or take some off the base of the cylinder.

I wonder if the cylinder was on a new saw, and someone left something inside during assembly? That or a failed bearing.

I think with the latter there would some evidence it actually ran a while.

 

[Jacob J.]

Bgd build??

Base gasket delete build - i.e. building it back up without a base gasket by using liquid anaerobic sealer like Dirko or Yamabond.

 

[huskihl]

If you were going to use that cylinder I clean up that squish band, might be stuff there that could come loose. Cutting the squish band is a good idea and a base gasket delete or take some off the base of the cylinder.

I wonder if the cylinder was on a new saw, and someone left something inside during assembly? That or a failed bearing.

I think with the latter there would some evidence it actually ran a while.

Just a guess, but it looks like there was a previous failure and this was the replacement cylinder (given how clean this cylinder looks). Only problem was they didn’t rectify the original failure. The rod spit out a couple more bearings and they made it up to the band without taking out the cylinder this time.

I agree, it could easily be fixed on a lathe if there is no damage to the wall plating