Hey guys what would be symptoms of a bent intake or exhaust valve? Got a buddy who just got stationed here and he has an 02 wrx that he just did a VF34 swap, with all the supporting mods. He claims it wont make any boost and it runs like buttocks, so took it to the dealership they told him it was a bent valve. Any input on this? Thanks..

 

Hmm, I would do a leakdown test, it's probably best way to see what is wrong and which valve is bent. It would missfire alot and probably not hold compression if a valve was bent... Also it would be noisy.

 

Yea I listened to it the other day and it sounded as if it had alot of "lifter noise" if u know what I mean, the dealership told him it was on cylinder #3 which is the left bank if im not mistaken. You have any Idea how this could of happen? Could the timing belt jumped a tooth and caused this? If so then what about cylinder #1 arent they both on a buddy throw?

 

Lifter type noise would be it... Do you know how they determined it was a bent valve? did the do a compression or a leakdown?

I think heavily over revving the engine can do it, or the timing belt skipping. However if it is just 1 valve that is bent then maybe there is just a sticking valve guide for that valve?

This is a diagram of a flat-4: http://auto.howstuffworks.com/engine-flat.htm

 

U know I dont think they did a compression test. I am going to recommend this to him.