So, I now know of four local evo owners that had problems with valve seats/seals. First was chukee, but we're pretty sure that was an ever-so-slightly bent valve. Next was Shawn (DoughtCom), then MattD, and now Trevor. Anyone else want to come forward that's down on power and found a cylinder or three to fail a leakdown test?
When we pulled MattD's head off, I was shocked to find about 1-2mm of carbon build-up on top of his pistons, and a nice good thick frosting of it on all of his valves. His motor had 100k miles on it, but look at this:
So my question is this: is it possible that carbon build-up is causing these leaky valve seats/seals to occur? Imagine a chunk of carbon built up and not letting the valve seat all the way. The only thing that's weird about that, is that you'd think it would get mashed/swept away over time.
Next question: is it worth (or even possible) to use some sort of cleaning product to get rid of all of this build-up?
Options include:
-seafoam
-Mopar CCC
-AMSOil QuickShot SE (Fuel injector cleaner)
-Wynn's Injector Cleaner
People have been swearing by this stuff on evoM:
http://forums.evolutionm.net/vendor-...-services.html
but, since its the exhaust valves in trevor's case, is it even going to hit them?