i did something really stupid this weekend, i turned the engine by hand through the top of the pistons travel with a piston stop in the spark plug hole. there was was a lot of resistance, but i pushed through until until the rotation was smooth again. is there a way i can check for piston damage without taking it apart?

http://www.summitracing.com/parts/PRO-67581/

this is what i had in there.

 

it can jack the rings, and score the piston skirt if you managed to crank thru it, and if any of it broke off in there your cylinder wall could be screwed as well, open it up and take a look, youll probably have to re ring that piston at the very least

 

next step is to pull the piston then, no other way to diagnose?

i havent attempted to start it but i didnt feel any type of crunch or grinding, just added resistance until i pushed through it.

 

I'm sure there's other ways but that's gonna be your best bet for making sure nothings wrong, you don't wanna grenade your build do you?

 

I doubt you did any damage if the stop was installed correctly there is no way you could have ran past the stop. The crank bolt would break before you got it past the piston unless the piston was so weak you pop'd a hole in the top of it which is doubtful. Bring her back up to TDC and use a flash light in the spark plug hole to see if you can see damage if not call it good.

 

Id seriously doubt he would mess all that stuff up. The rings and skirt dont even come out of the cylinder wall. If anything he would nick the piston, but if turned it over by hand he is fine, id even bet money on it.

 

Did you have the rockers off for that cylinder when you turned the engine over? If so then the valves opened and hit the piston stop.

I doubt the piston stop did any sort of damage to the piston itself. If you were able to turn the engine over past the resistance, you probably didn't have the stop in far enough. There may be a small indent in the top of the piston. It's more likely that you'll cause damage to the piston stop before the piston.

Now if the rockers were on, there's a possibility that you may have bent a valve. Do a leak down or compression test on that cylinder to make sure it still has a good seal.

 

Is it possible that the resistance was just the compression of that cylinder? I dont know if he was at TDC on that cyl or not, or whether all the other plugs were removed. If the rest were removed it'd probably turn over real nice and smooth until the intake valve closed and compression built up in that one cylinder... I wouldn't call that a "lot of resistance" though.

I've never used that sort of piston stop, not sure if it's in the way of the valves as they open/close, but it seems plausible that it could be.

I dont see why not having the rockers installed and lashed down for that cylinder could cause that though. seems like that would just make the valves not open at all... which is what you'd want, yes? But if you had the rockers on and lash set, then tehy could have opened during the rotation and bent aruond the stop, but like I said, I have no idea if the stop would interfere with the valve movements or not.