How much piston scoring requires piston replacment?

[Jim662]

This is on my inline 6 1150. Some of the pistons have some scoring on them. For you guys that rebuild these, how much is acceptable before the piston needs replaced?

Thanks.

 

[fishdog4449]

Re: How much piston scoring requires piston replacment?

What are your compression numbers? If they are above 100psi and within 10% you should be ok. My inline has scoring on the number one, but with compression of 122, 135, 135, 135, 135, 135 it's not significant damage. It runs good, and I'm not worried about it for now.

 

[chrishayes]

Re: How much piston scoring requires piston replacment?

If one cyl is off by slightly more than 10%, what is going to happen? I just ask because I see this all the time and wonder.