Pistons

[Jim Hanig]

Anyone running off set pins in their pistons,and how much.?Do you feel that theirs any power in it.

[Mike Semeniuk]

Jim I didn't see any difference. Used whatever offset Patterson sent. It was a PITA when I had to replace a couple of pistons.

[Bill Diehl]

Depends upon how thick the cylinder walls are....if its friction your trying to reduce I think the coatings available take care of that.


If you have a thinwall block (like most fords) that you got carried away with, with the boring bar, you can take some pressure off the major side by offsetting the piston pin to the minor side


and, some say its easier to "rotate" the crank


as with all non standard mods...your mileage may very

[Larry Hill]

If the pin is offset, would it cause the piston rock and break ring seal due pivot point placement?

[Jim Hanig]

Well I am not sure about that Larry some pretty well known engine guys say to run them

[FED 387]

Offset pistons-----small amount of power there--- because of less power need to overcome rod load and easier crank rotation--- it makes engine RPM quicker---FED 387

[Dwight Southerland]

Originally Posted by Larry Hill

If the pin is offset, would it cause the piston rock and break ring seal due pivot point placement?

Piston rock is actually worse with centered pins.

[SSDiv6]

Originally Posted by Dwight Southerland

Piston rock is actually worse with centered pins.

Dwight is correct.

Piston offset reduces friction and cylinder wall loading; it also improves geometry.



F1 and NASCAR has been doing it and also using guided pistons.
Would not be surprised if Pro Stock is doing the same, especially with the use of short deck blocks.

[ss3011]

Depends on which way the offset is. Factory offset is to quiet piston noise.

[Larry Hill]

Is the piston balanced in the center or on the center line of the off set pin placement? Just wondering about inertia.