BlownAP

I have a problem with a bent exhaust valve, or valves.... I have narrowed the problem down to the #3 cylinder, compression is leaking out the exhaust valves causing a Rich misfire at Idle...

what kind of repair work am I looking at? at most 2 valves replaced, I know that, but what kind of head damage can a bent valve cause? head machining work?

I am assuming that I am pretty lucky as I caught this problem before the valve dropped, and that my car is still running surprisingly strong...... must mean the valve is bent just a tad.......?


thanks

negcamber

Heresnowhy's head was not damaged by his 2 bent valves. He was able to get back on the road with new guides, valves and retainers.

Sideways

Bent or burnt. It will have to come off to see if there is piston damage.

BlownAP

possible piston damage huh? I did the leakdown and it was something like 15% leakage, but we could hear air escaping from the exhaust valves into the header. the compression test showed that it was still in spec. 210 across the board with #3 at 195. Surprisingly..... how the hell does that work?

Teknik_EJ8

How would u check to see if the pistons were bad?

BlownAP

I am pulling the head myself in a couple days, is there any way i can check for this myself? I would assume a professional would have to use a vacuum gauge with the new valves installed to see if they are sealing?

negcamber

You would want to go ahead with new guides anyway. I doubt the machine shop would allow it to come back to you without them anyway. It's just common sense to replace what normally wears as long as you have the head apart.

I would bet any piston damage will be minor. After seeing Heresnowhy's head off the car when 2 valves bent (one snapped a stem), there was very very minor damage to the piston top. The carbon build up was worse than the piston damage.

jyeung528

i had bent exhaust valves in cylinder #3 as well.

i had all my exhaust valve guides replaced as they were all warped, dunno how or why.

i suspect the valve damage was due to a mis-shift from 3rd to 2nd, although i didn't notice symptoms until 2 years later (compression and leakdown performed immediately after the mis-shift checked out fine).

how did you bend your valves, was it a missed downshift?

anyway, to answer your question, i didn't even have to replace the valves, just relapped the face. replaced all the exhaust valve guides, and that was it, and my leakdown showed 66% leakage in cylinder #3

BlownAP

thats really good to hear, I don't know what the problem was. I am in the same boat as you. I misshifted the money shot about a year ago, I have my retainers checked atleast 4 times since then.

so hopefully my head can be salvaged and all I would need is 2 new valves, all new valve guide and I would be good to go...... portflow is telling me 250 for labor on the valve job, and surface...?


how much do you think the valves and guides would run me?

jyeung528

i forgot the price breakdown...but alaniz was cheaper than portflow...

not to mention portflow refused to fix my head because they said it was driver error...and it would be a headache for them to deal with me cuz i would blame them for future problems...and they quoted me a ridiculous price even though they wouldn't work on my car.

so i took it to alaniz.

i don't like portflow.