StorminMatt

It looks like I have some pitting in one cylinder on my swapped LS2. So I will probably need to bore. It looks like GM sells TWO different .5mm oversized pistons for the LS2 - the 89017479 and the 19178568. The 19175868 costs about DOUBLE what the 89017479 costs. What is the difference between the two? Is there any reason NOT to go with the 89017479?

brandon6.0

iTrader: (32)

Are u just boring over one cylinder? I would just bore it over .30 to a 370ci. And run some forged pistons like wiseco or something. I looked up those part# u listed and thts for a single piston. U would be at the same cost as a set of name brands with better forging.

StorminMatt

brandon6.0

iTrader: (32)

Im just saying u can get a set of better pistons for around 6-700. At the price $100x8 equals 800. So u would come out better

StorminMatt

ColeGTO

iTrader: (3)

The material the piston is made from determines the "running clearance" needed.

I just finished my LS3 and used JE SRP Pistons because they are a 4032 alloy vs. the 2618 alloy found in most "race" forged pistons and I wanted a tighter clearance for longevity and "street" use.

The difference is my piston to wall clearance as suggested by JE is .0020"-.0025" vs. .0035"-.0045" clearance of a 2618 alloy piston.

https://www.jepistons.com/PDFs/TechC...instrc4032.pdf

http://www.jepistons.com/PDFs/TechCo...instrc2618.pdf

Efi69cam

The lq9 used a 4.0" bore piston with a 1.5mm top ring vs. the LS2 with a 1.2mm maybe that's the difference in the part #s?

heykw

lstvr

I'm now using the new JE pistons, with a tight clearance. Really quiet on start up and zero oil consumption. This is my third incarnation 383/416 and now 419 and this is the only one i've not had oil consumption with.