i posted the other day about possibly having a warped valve stem. i pulled the heads and sure enough...its warped.the exhaust valve on the #4 cylinder. did the same thing to a 67, 390 i had in high school.

when the "incident" occured, i was about 3-4 miles from home and continued to drive the car on home. i was driving about 70 at 3000 rpms at eht time. the car idled very rough and made a pinging noise but still ran.i thought i had broken a rocker arm, which i have done before.

now for the important question -
after the incidenti know the valve made contact with the piston because the valve is "marked" and the piston had a very small "dent" in it... i cleaned the piston and it looks to be ok. anybody know how i can be sure the piston is ok before i put my new performer rpm head on?

289/306 1967.

 

Short of taking the piston out, I don't think so. I hydrolocked a motor once, the piston top was fine but the pin boss was cracked on one side. Could not see it until the piston was out of the engine.


Just wondering,,, was the head of the valve warped, or was the stem bent, or both?

 

the head of the valve is not warped - only the stem.

 

You could have a damaged piston/rod, won't know without pulling them.

 

Very unlikely. I bent ALL 24 valves in a twin-turbo 1990 300-ZX and didn't harm the first piston.

 

Yea I was going to say that I doubt that the valve reallyhurt the piston, but then I didn't want to be wrong about it and have a cracked piston destroy his engine,,, But I think you are probably right Norm.

 

The bottom end is prolly fine, but it never hurts to check, just to be on the safe side. I'd rather be safe than sorry, as the old saying goes.

 

your fine. ive seen pistons get beat to crap on the top and be completely useable

 

+1 Yea, I think I would drop the pan and pull that piston out and look at it,,,just in case, otherwise the thought of a cracked piston would haunt me everytime I turned the key for a long, long time, especially with those new heads on there.

Jroseman----
For peace of mind,, pull the piston, take a look at it, it will be just fine, you will have to put it right back in the hole, but you will feel better.

 

i wonder what would happen to the CR of the pistions after they got all bent up