Is it okay to run used forged pistons even if the skirts are scratched?

What to check for buying used forged pistons? How do i know if they sre good to run?

 

how much are they? compared to a new set? i am always leary of used pistons.
post up pics of the srcatches.

 

Dont buy them if the sidewalls are messed up.

 

I'm debating this same thing from a local on on the Jax forums for some 84.5mm...his block was overbored which gave some play...machine shop said I could add that coating stuff to it
pic of worst one..these scratches you can't feel though

 

i skirt coated a set of used pistons and they worked out great. i was the guy that used them previously though.

if they dont have detonation marks, etc, and are in decent shape, i'd say skirt coating is a great option for you. worked great for me...running great in the engine thousands of miles later. they were in my engine for 30k before also

 

When buying used pistons, I am more concerned about the history of those pistons rather than physically inspecting it.

I'd only buy used pistons on motors with low mileage, and minor mishaps, like washed out cylinders, etc... Any heat-related damage, detonation, etc.. I stay away just in case of internal stress cracks, etc.. stuff you can't see with a naked eye.

 

i wouldnt buy used pistons. think about what forged pistons go through. parts fatigue quick, remember that.

 

the guy said one of the pistons got some heat.
but they look like low miles

 

How cheap are they, new one can be had for like 300$ with searching depending on build. I'd rather a lower brand new piston i.e. probe or srp or something like that don't see it worth the savings for the risk.

 

75 bucks for used srp
i just need rings

couldnt pass up on the deal

 

well they are cheap pistons at a cheap price

refer to my sig

 

I bought some used CP 84mm pistons for my b20/vtec for $150. If i had a larger budget i wouldn't even consider buying used pistons but i had no choice at that moment. They had some scratches on the skirts but cleaned them up by hand and they've been working flawlessly for over 10k miles.

 

nice that relieving

 

SRP are cheap pistons to begin with. Don't compare to the above post mentioning CP's. If you have to learn your lesson the hard way, so be it.

 

Its really on u ...Ive seen guys reuse pistons that were worse than them ..And motor ran great ..

 

Forged pistons can usually take a lot of abuse. If they are only visible scratches and do not catch your fingernail, they can be reused - as long as they are w/in spec. The skirts are supposed to flair out slightly; if not they are worn away. Rings are almost universally $100 for forged pistons, so that eats up some of your savings.

I don't know of a whole lot of people with 20k+ on their forged build, since its common to upgrade or sell it for some reason - blow a sleeve or get a sleeved block, etc. SRP's aren't that bad, you just need to run them a little looser than normal.

 

 

what kind of clerance should i run them at?

 

what compression do these look like?

also where can i buy rings for these pistons

 

look for who made them on the bottom of the piston, then do some research to find some good prices.

look like 9:1 but im not sure. they are dished so its gonna be low.

 

I would like to hear your experience and explanation why you think this way. I have ran them in 2 blocks and my current block has made just shy of 400 whp with SRPs in them for over 5000kms.

 

so what do you think bout the pics guys

 

nothing wrong with srp's. they just arent the best choice for high power is all. there just a cheaper knock-off je slug. only je's will take more, thats why they cost more. and cp is one of the best choice for pistons out there. they can take some serious abuse, not to mention they have a good variety for c/r's too.

 

they arent a "KNOCK OFF" JE slug, they are made by the same parent company of JE and use a different silicon content forging.

they can take a ton of power , but slightly less than some other, if the piston is your "limiting factor" .

99.9% of the time the piston is not the limiting factor, the tuning is. you can probably make more power with SRPs than most ever will.

 

def buy new, its worth the extra money