bent valve. any suggestions on causes?

[mikeykey]

My 99 v8 vortex tahoe started running rough and making a noise consistant with bad lifters.

I tested #4 cylinder and found zero compression. (yes, believe it or not ZERO).

I torn into it and found that the intake valve was bent and not seating fully. This caused the fuel injector's plastic body to slightly burn back due to the gases escaping back up into the intake in that specific cylinder.

I replaced the bent valve and conducted a full inspection of the area. Thankfully the top of the piston head was only slighty touch by the bent valve and if your not looking for it, you probably wouldn't ever notice the scar on the piston.

Other than a forgien object somehow working its way down to the cylinder, can anyone think of how this happened.

All of the other valves and in great shape. When I replaced the vavle with the new one, it seated nicely.

 

[TnTahoe]

timing out maybe

 

[mikeykey]

Thought about that but figured the rest of them would also be bent too....maybe not.

Thanks

 

[SunlitComet]

Perhaps it got bound up was hit and bent while fully open and was knocked loose again?

 

[mikeykey]

Thats what i'm hoping. I have the heads back on and ready to start the torque seq.

Give me a day or so and I'll tell you if that was all that was wrong. Hopefully nothing is going on with the cam

 

[Jim_Rockford]

I hope you at least lapped the new valve ....

 

[foreverfalcon40]

My truck had a misfire, everyone thought I had a cam in it.

My bent valve was caused by the previous owner...why I got the truck cheap.

He had a misfire and never took care of it, still beat the piss out of...valve got bent.

I just ended up getting new heads...