Willis1983

Anybody know why this would happen?..3 out of 4 pistons have chunks missing in exact same spots basicly..It's a ls vtec with other mods aswell

PyroProblem

What were your ring gaps? Was it boosted?

Willis1983

I have no idea the answer to both questions...I bought the car running poorly and this is what I discovered..I'm just wanting to try to figure out why so when I put a new bottom end in this won't repeat itself

TomCat39

You bought the car running (good bad no matter) and you don't know if the car has a turbo or super charger (boosted)?

Willis1983

yes I got it running poorly...and I believe he asked "was it boosted" so that I don't know but I do know that it does not currently have turbo or supercharger

eh2_Trav

iTrader: (1)

TomCat39

So the answer is, no it is not boosted. If it was boosted previously, you would probably know if it had a turbo they pulled out before selling the car as there would be mods to the car for the inter-cooler etc.

Also bolts and nuts would likely be fresh from a fast header swap, plumbing changes etc etc.

Willis1983

Any Ideas why?...its not boosted...iit's a b18b1 with I believe a sir head..has skunk 2 intake manifold and throttle body, golden eagle fuel rail, injectors are blue I believe from a talon or eclipse turbo (not 100% on the injectors), VMS cam gears..
These are things I know, it was apparently tuned at some point...I bought the car running half *** as I figured it was something simple I'm an idiot and neglected a compression test..I just wanna know that if I redo or replace bottom end with b20, am I gonna run into this same problem

eh2_Trav

iTrader: (1)

Those pistons look like some aftermarket high comp pistons that the previous owner must have put in. If you replaced them with stock b18 pistons the tune will be off and will be off as well with a b20 bottom end. Either option will require a re-tune which would be a good idea anyways.

TomCat39

Yeah, well, based on the blown pistons, the tune might be out anyway.

Could be they were learning to tune and didn't follow whatever you are suppose to follow to keep the motor safe.

I know that is something in the marketing of tuning schools. How to tune "safely".

motoxxxman

I see a LOT of pitting from detonation, and all the crusty black is from either running way too rich or oil burning. The chunks missing are broken ringlands, which is typical when there is detonation as well. So I would have to say that either it was never tuned before and was running on a stock ecu of some sort, or the tune was absolute crap. a new bottom end and a professional tune should be all that's needed.

Willis1983

Thankyou everyone for your help!!!!..much appreciated