My pistons have marks on them like they hit the valves, but I am looking at the valves and it doesnt look like any are bent.....So how can you tell if the valves are messed up once they are out?

Someone has gotta know....I damn sure hope I didnt take this **** apart for no reason. What should I use to smooth out the pistons with? Will sand paper work? Are the pistons aluminum?

 

there's some blue crap you put around the edge of the valves.. then you slide the valves into the head, and apply some pressure, and spin them a quarter turn.. then pop them out without touching the area you applied the crap to..

You could see a clean line going all the way around the edge.. if that's the case, then the valve is seating properly and making a good seal... and put the valve on a flat surface, like a table.. make sure it doesn't WOBBLE or anything, so you know the head is flat... and as long as the valve stem doesn't look bent or anything, it should be fine..

that's practically all i can remember about the valves from my auto tech class... hope this atleast helps a bit

 

Anyone else?

Thanks for the info.

 

I think the pistons have valve reliefs in them so if all the pistons look the same that's probably what you're seeing.

 

No valve reliefs in stock LS1 pistons. I'd take the valves to a machine shop and heve them checked. Chances are that they ARE bent. If you don't know of a local machine shop ask at your auto parts store they'll know where to send you. And check your pistons very carefully for cracks. Hypereutectic aluminum.

 

Can i still use the pistons if they have VERY small dents in them from hitting the valves? If they are not cracked that is.

 

Yep just sand off the sharp edges as they will get hot quicker thatn the rest of the piston and could cause detonation.