pic of cylinder, advise please

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Farmerboy

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Here's a pic of a cylinder and piston off a Stihl TS510. There's some transfer that can be cleaned off, however there's an offset at the very end of the piston stroke, at the very top of the cylinder. It doesn't seem to be equally around the whole of the cylinder. Would that happen to be wear? It's a noticeable offset, so hard to believe there would be this much wear. Could it be Aluminum that's accumulated there. I'm hoping I don't have to junk this.

The saw tested at 150 lbs compression right before I pulled it apart.

image1.jpg image2.jpg
 
The piston measurement is about 51.88mm, while the cylinder is 52.05mm where I can measure it at the bottom. So somewhat able to jiggle around.

How sure are we that that’s carbon? There’s almost a lip there. I’d hate to spend $ on parts if the cylinder that’s not worth it
 
Replace the piston and cylinder, looks like it has worn through the plating. New air filters and check the bearings for wear. If the cylinder has been dusted so has everything else.
 
Here’s a better pic. Notice the offset around the outside? Or is that normal?

28F3DF4D-D530-4948-BED7-ACB7464E20DF.jpeg
 
It looks like the piston has been hitting the top of the cylinder at some stage. Is it possible that it has been rebuilt before? It might have had a piston in it that could rock enough so that it could hit the top of the cylinder or a bearing might have failed at one stage
 
Where did you measure piston diameter? Need to slide piston in jug with a feeler gauge. If you can fit better than a .003 feeler between the end of the skirt and the base flange, the piston is done.

My math, which can be off, puts you at .20mm difference. That’s around .008 which is no bueno.

The chamber is either carbon or factory casting issue. It’s not a problem, they are nearly always off a bit, even OEM.

Not enough information or pics to tell you if jug is salvageable. More pics needed.
 
It’s the offset I’m worried about, about 1/8 inch down from where the walls meet the dome. I can see it clearly on the pic.
 
Just put new oem on the saw, so you can sleep at night. If it's going to be sold use new, if it's mine to keep I rebuild with used, then worry about it too much and rebuild with new oem. OCD or something. :)
 
There's some slop in the crankshaft bearing, so would need a total teardown.

My plan was to put a bar and auxiliary oiler on there and use is as a dedicated chainsaw milling saw. Not sure if it's worth it now. Will need crankshaft, seals, bearings, cylinder, piston.

Or can the bearings in the crankshaft be replaced easily.
 
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