This is what I found before I dropped it off. I shined LED flashlight on combustion chamber and took this picture through valve port on intake manifold side (60% leak from leak down test).

 

Right, I saw that before, but the head overall looks normal to me. Valve seat wear seems about normal for a hard driven 4G63, been there done that.

 

Check out the buildup. Is there a way to keep this clean?

 

do i need to plan on pulling head every so often?

 

How are there stains on my exhaust valves on the part that is inside the bowl right above the seat?

 

Not aware of the background on your EvO. Youve owned it for 6 years? and have been running E85 for less than a year.
This build up is obviously all 91 build up coupled w/leaky valve seals. Maybe the previous owner ran 87 through it?

Ive been on E85 for 10 years & was never out of service & always in a good state of tune. Now my spark plug issue may have been E85 related, but will always use anti-seize going fwd

Dont think youre going to see this level of deposits running mostly E85 w/your 91 cycles, as required

 

I got it brand new in 2006. I actually bought it 3 weeks before it was offloaded from port. It was stock for 2000 miles and then I got Vishnu V400. It stayed that way until last year where I started building it before 1st timing belt work at 56k miles. I'm at about 61k miles now. I guess 91 could have done all this over the years.

 

Forgot about this thread. Here's my head now.

 

 

 

Late to the party on this one but next time you've got a bunch of gunk on valves the quickest and easiest way to clean them is with a brass wire wheel on a pedestal grinder.