Burnt valve (and head)
#1
Burnt valve (and head)
So after 13 years of turbo ownership, I have joined the ranks of those with catastrophic engine failure. Luckily this failure is not so bad. I had been running the engine lean for at least 3 track days due to over boost (~14psi peaks), before I corrected the problem. I ran two more track days and then toasted the #3 exhaust valve (see photo). This car is running stock chips and at the time of the failure stock boost controlled by the cycling valve. I did discover the small plastic vacuum line from the TB to the thermo valve was melted closed in the middle.
Before the tare down the compressions were 145 - 120 - 0 - 145. So there is also an issue on #2, but I have not removed the valves to inspect. The event also damaged the #3 valve guide cast boss that protrudes through the port liner (see 2nd photo)
The big question is can this head be saved or should I be looking for a new/used one?
Thanks for any help.
J
Before the tare down the compressions were 145 - 120 - 0 - 145. So there is also an issue on #2, but I have not removed the valves to inspect. The event also damaged the #3 valve guide cast boss that protrudes through the port liner (see 2nd photo)
The big question is can this head be saved or should I be looking for a new/used one?
Thanks for any help.
J
Last edited by redrow951; 06-17-2009 at 01:35 PM.
#3
Racer
I just went through the exact same scenerio. #3 at zero and #2 low. My exhaust valve was brurned it two seperate areas however.
It's tough to see the extent of the damage to your guide area in that photo. I ended up getting an exchage head from Markus Blaszak for mine. Perhaps a local shop in your area can do the same and then they can repair the guide area before they rebuild it for someone else. Also, I believe VOoDOoGTX had at least one, if not two used turbo heads available. Food for thought. It's not a fast or easy fix, but the engine runs great now and I am very happy with it.
I will be posting a few pics of my repair soon. Good luck!
It's tough to see the extent of the damage to your guide area in that photo. I ended up getting an exchage head from Markus Blaszak for mine. Perhaps a local shop in your area can do the same and then they can repair the guide area before they rebuild it for someone else. Also, I believe VOoDOoGTX had at least one, if not two used turbo heads available. Food for thought. It's not a fast or easy fix, but the engine runs great now and I am very happy with it.
I will be posting a few pics of my repair soon. Good luck!
Last edited by OntarioTurbo; 06-17-2009 at 12:56 PM. Reason: Added text.
#4
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#5
Not so happy to be in the club, but thanks for the company
J
#6
Racer
I agree with Chris. In fact, the exchange head I put on had a little chunk of aluminum missing by one of the guides in #4. The guide is still firmly in place and I'm sure wont cause any heartache. If your other exhaust valves are ok then you can re-use them. Up here one sodium filled exhaust valve goes for $192.00. So re-use them if you can. A proper three angle valve job with hand lapping should be fine.
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#8
Drifting
Be sure to have the head checked for warpage before you decide what to do. When I burnt my #4 valve, the head warped too much to be machined flat (it had already been machined previously) so it became a boat anchor.