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Why does #4 exhaust valve burn?

Posted: Fri Jan 06, 2006 9:02 am
by 93Leg-c
It seems like several of us on the Board have burnt exhaust valves in cylinder #4 (the one closest to the driver). A burnt exhaust valve in cylinder #3 may largely be due to insufficient fuel feed, but what causes the burnt valve in cylinder #4?

Posted: Fri Jan 06, 2006 4:02 pm
by vrg3

Posted: Fri Jan 06, 2006 4:52 pm
by 93Leg-c
Wow! Thanks for that link, vrg! I searched but that thread never came up. In fact, I tried it again with different key words but that thread still never came up. I seem to not know how to use the search mode properly.

Based on the thoughts from the above-posted thread, has anyone been successful in remedying this situation?

The v8 intake will not fit our engines, correct, unless we get v8 heads? Are fuel rails made for our cars--from other threads it seems only the NA rails will fit but if douglas vincent's NA engine burnt exhaust valve #4 then that's not a solution either, is it? What kind of mod can be made to restrict air flow to cylinder #4 by the proper amount? Can anything be done to increase cooling to cylinder #4 (I think the answer to this question is "no," right?)

Should we run a colder plug in cylinder #4? It might help detonation but it still wouldn't solve the underlying issue, would it? But if it will help some, I'll do it because I've already burnt #4 exhaust valve pretty badly in my previous engine and I think I'm developing the same problem with the current engine I've had installed.

Posted: Fri Jan 06, 2006 4:59 pm
by vrg3
Yeah, it took me several tries to find it too. I tried searching for "more air" but for some reason the word "more" got thrown out.

It might be better to add to the existing discussion there rather than starting it again here...

Posted: Fri Jan 06, 2006 5:02 pm
by 93Leg-c
Thanks, vrg. I was thinking about continuing the discussion there, too. So, I'll try to copy my previous post over. Never tried it before but if it doesn't work, I'll just retype everything. Thanks!

Posted: Fri Jan 06, 2006 5:05 pm
by vrg3
Cool. =)

Posted: Fri Jan 06, 2006 5:09 pm
by 93Leg-c
Okay, I was successful in copying over my inquiry. And I modified it some so that it made sense.

So, if anyone reads this thread, the discussion should be continued on this thread: http://bbs.legacycentral.org/viewtopic.php?p=87616