fst100

iTrader: (5)

If a piston cracked for whatever reason in the motor, does that mean the camshaft and/or the pushrods maybe also be scored/damaged or not? Someone is selling an aftermarket cam from his LQ4 build that cracked #2 piston. He’s going to demod and upgrade to a stroker motor and has no need for the cam and PRs anymore.
He mentioned the motor was still running when the piston cracked.

Bilster

iTrader: (21)

You should be fine if it's only a crack. If the piston came apart, that's a different story. Chards of piston material could have made it's way into the oiling system clogging up vital oil passages, allowing the cam bearings to burn up and ruining the cam. Or worse if the piston pieces made locked up the valve train. The pushrods should be effected if the valve train didn't lock up. Check for straightness and insure the oil passage is clean and clear.

fst100

iTrader: (5)

thanks for the reply and info Bilster. i'll check with the seller if the piston was cracked or came apart. i'll also make certain to check the straightness of the PR. if they look straight from the seller's pics i'll make certain if i buy them to use an air can to blow anything in the holes as well as soak them in oil.

96capricemgr

iTrader: (1)

I would say depends why the piston cracked.
If the timing chain broke and a valve hung open and that cracked the piston I would expect at least the PR to be junk but if it was a too lean or too much advance issue then I would not expect any valvetrain complications.

Bilster

iTrader: (21)

Good point. Sounds like getting more information from the seller is in order.

fst100

iTrader: (5)

seller said ran too lean. ran ~8-9psi with 22* of timing with both A2W intercooler+meth on stock LQ4 CR. would of thought 22* of timing and less than 8psi is considered 'safe'....but i guess assuming AFR is not too lean correct?

Bilster

iTrader: (21)

What do the pics look like? If there is no evidence of damage on the cam and the pushrods are straight, you should be in good shape. If there is bluing on on the cam bearing surface or any lobe damage, it's junk. If he won't provide you with enough pictures to satisify you, I'd walk.

fst100

iTrader: (5)

he's planning on removing it this weekend. i already asked to take alot of pics from various angles. i'll keep you updated. he mentioned he ran 10.4AFR(wb on driver side) but again i would of thought 10.4AFR was within safe fueling as well to prevent bad things from happening?

Gunslinger09

Pull them out clean them and inspect them. If there is no visible damage you are good to go.

fst100

iTrader: (5)

i dont have the motor, the seller is pulling them this weekend to take pics for me

Gunslinger09

Okay tell him to get extreme close ups.

garygnu

take and roll the push rods on a flat surface to check for straightness .