[bigdaddykane]

is this wear pattern normal? if u measure on the darker part on the skirt, its about .001 -.0015 smaller in diameter and didnt make contact w/the bore. all 8 look similar. could the skirt have been improperly machined?

 

[Pmotion]

This article explains piston shaping, it should answer your question

http://blog.jepistons.com/maximizing-horsepower-with-piston-skirt-shaping

 

[Ryanjoseph1994]

I’ve never seen that before but it’s possible it was improperly machined. Are those aftermarket pistons or gm

is this wear pattern normal? if u measure on the darker part on the skirt, its about .001 -.0015 smaller in diameter and didnt make contact w/the bore. all 8 look similar. could the skirt have been improperly machined?

 

[Rick_L]

It's pretty common for a piston to "collapse" in the skirt area after hard or long use. But that means it was once in contact and should have some wear marks.

 

[66II]

The skirt is basically the “bearing” of the piston. It’s normal to see wear as it will rock back and forth going from bdc to tdc.

 

[sbc1320]

Someone(machine shop) knurled the pistons in my old 23 T Bucket. I tore it down, bored it .030" and put it back together with new parts.

 

[bigdaddykane]

I’ve never seen that before but it’s possible it was improperly machined. Are those aftermarket pistons or gm

original GM