Does the engine have to be pulled out? Please say no.

 

yes

the balance of the motor would be shot

 

yea

 

So I would take the repaired shortblock in to be balanced? Or does the balancing shop need to install new piston?

 

Being that the motor is gonna be out of the car just get a set of forged pistons and rods. imo

 

Pistons, rings, rods, bearings, crank, flywheel/clutch, and balancer need to be balanced.

 

Pistons,rods,and the crank will. Not the clutch of flywheel I'm in the middle of a rebuild right now and was just discussing this tonight actually.

Why do you need to replace a piston what happened?

 

If it's any consellation to you, I cracked a piston in a 454 in one of my trucks. I just made sure to buy the same piston from the manufacturer. Dropped the oil pan, pulled the head and replaced it in the truck. Sure the balance may be off by a few grams, maybe not. Will you really put enough miles on it to ever see the effects of it? Probably not. You'll get sick of the car or want a different motor first.

 

why do you need to replace a piston?

 

Yes, why does a piston need to be replaced? You're probably looking at a rehone minimum, and if more, then you'll need bigger pistons all around.

So what happened?

 

dude for the price to have just the piston replaced and it to be balanced you can buy a forged kit for about 1500 dollars and just have them put it together but why are you replaceing one piston?

 

A comp 918 broke at some point, and while idling in traffic, the valve finally fell into the cylinder locking up the engine. I haven't opened it up, but I suspect there will be a nice round stamp on the piston and the other end of the valve jammed into the head. I'm thinking since the engine immediately locked up and I was at low RPM that the piston didn't explode and the engine might be easily salvageable. I really don't want to pull it out again, but I will if it is necessary.

Was each GEN3 engine balanced after assembly the GM plant? Or were all of the OEM parts pre-balanced to work when assembled? I can get an OEM piston if that would work.

 

or just find another shortblock