pantera_efi

iTrader: (1)

Hi ALL, there is little "tech" here about piston pin offset.

MOST ALL those piston manufacturing companies put the Pin "on center".

This is NOT the best case for MANY applications.

So I ASK, what would be the offset direction for a S/C engine ?

Lanec

JoeNova

Are you talking side to side offset? Won't you end up with horrible piston rock if you offset the pin?

Che70velle

iTrader: (6)

Actually Joe, all oem and most aftermarket LS pistons have offset pins. There is a performance advantage in doing this, as well as helping to quiet piston slap.
Lance is asking which direction (12oclock vs. 6oclock) to offset the pin for a s/c engine would be better.

JoeNova

Are we talking compression height?

pantera_efi

iTrader: (1)

Hi Joe, I am speaking about HOW FAST the piston moves AWAY from the cylinder head.

Lance

Dian

whats the answer?

G Atsma

We'll find out, when some one has it! lol

pantera_efi

iTrader: (1)

Hi Dain, thank you for your interest.

The question was directed to HELP those who want more/less BMEP related to crankshaft position.

The question "how much compression" is NOT VERSED well by those ask !

Examples :

The LS 4.8/5.3 engine needs a compression increase in many cases, thus the offset is opposite OEM direction.
The LS-427 is common with a 12:1 compression and Flat Top Piston, thus the offset as in the GM OEM direction.

The difference is about .5 C.R. change difference in Knock Resistance.

Lance

garygnu

would having the piston pin set toward the the outside of the piston ,put more frictional drag on the piston ,but also have less dwell time at TDC ? and quicker piston acceleration speed to and from TDC ?

pantera_efi

iTrader: (1)

Hi Gary, YOU are correct, an offset pin as is done by OEM's (LH) ALLOWS the piston to move FASTER AWAY from TDC , VERY GOOD for a Turbo Application !
ALSO much easier on the SKIRT/Cylinder Walls.

Lance

stevieturbo

Surely all pistons are offset these days ?

I know any I've used in recent years have been, Wiseco, Diamond, JE