Carbon build up.

[nismo240sxdrifter]

Hey guys. The internet seems to be pretty vague so I thought I'd ask here. How much carbon build up is normal to see on an SR that was rebuilt 2 years ago? I am about to purchase one to use while I rebuild my current blown one. Compression is great at 158-163 across the motor, top of the pistons are dirty, but dont seem oily. Thanks for the opinions.

[5280VertDET]

I know this isn't exactly what you are looking for, but Chris Fix did a borescope test on some motors.

Check the description on this for the other ones. Should give you a visual comparison to base your pistons on...

https://www.youtube.com/watch?v=u6UeJXkzDW8