Unusual marking on cylinder wall
 

Anybody know what caused this? Is it serious?
I'm hoping it's not a crack!
Engine is a Chevy 250, cylinder #6

Re: Unusual marking on cylinder wall
 

The Piston From that same cylinder.

Re: Unusual marking on cylinder wall
 

It looks like it rusted. The engine might have sat in a barn for 20 years at some time in its life.

Re: Unusual marking on cylinder wall
 

I agree. Water sitting in the cylinder for a long time.

Re: Unusual marking on cylinder wall
 

Thanks guys, I think that did cross my mind.
The engine had been running not long before I purchased it but no clue what has happened earlier in it's life.

Re: Unusual marking on cylinder wall
 

I would say they got it running with the damaged cylinder wall and the scoring on the piston skirt is a result of the rough surface of the cylinder wall.

Re: Unusual marking on cylinder wall
 

All of the above, time for a cylinder sleeve

Re: Unusual marking on cylinder wall
 

Agree with the water sitting in cylinder thoughts. The piston scoring probably happened on the initial start when the rust was being scraped off the walls in both directions.

Might want to flush all the oil passages in case some of the rust escaped past the filter.

Fix might range from something as simple as a good honing and new rings for something that will see only occasional use to boring out all the cylinders and installing new oversized pistons.

Re: Unusual marking on cylinder wall
 

Would suggest new pistons....plus 030 or 060...and a rebore....

New pistons are around $100 a set....

:chevy::chevy::chevy:

Re: Unusual marking on cylinder wall
 

Rebuild. Bore 30 over. Rods and crank may be reusable. Look into a cam upgrade.
No worries. Lasts a long time.

Re: Unusual marking on cylinder wall
 

New rings, polish the piston and you're good to go, for a while. Or splurge on a new piston and it will go even farther. For the few miles I drive a year it would outlast me.