Piston Thickness 6.2 VS 6.5

[6.2 turbo]

A 6.5 piston is .615 thick in the center,and the 6.2 piston is only .425. They are both original GM pistons.

 

[Slim Shady]

Look how much closer to the top the ring land is on the 6.5 versus the 6.2 . Interesting. I think the 6.2 ring land would survive the higher temps better under the naturally aspirated mode, and less reciprocating weight by how much ?

 

[Missy Good Wench]

The weight is the same.

GM used the very same crank in the later 6.2 when the one piece cranks came into production.

 

[6.2 turbo]

This 6.2 piston is from a military 660 block. The counter weights on the crank are a lot smaller than a 6.5 crank.

 

[buddy]

Look how much closer to the top the ring land is on the 6.5 versus the 6.2 . Interesting. I think the 6.2 ring land would survive the higher temps better under the naturally aspirated mode, and less reciprocating weight by how much ?

That is why I recommend not shaving pistons, but dishing them if you want to lower CR, so you do not reduce the ring height.

 

[6.2 turbo]

How much can a 6.2 piston be shaved? I'm worried about the thickness in center.

 

[Slim Shady]

I think the 6.2 can take a flat top shaving, where as the 6.5 should be dished to maintain the ring land thickness. I don't think what you would remove on the 6.2 piston to drop compression ratio would be of any concern. I made a special fixture to turn down6.2, 6.5 pistons in a lathe just for kicks. Did a couple of pistons for testing. The lathe worked well but the CNC machine makes a way nicer setup.