Background info: 76k miles stock block. Arp head studs, oem head gasket.


Car was recently tuned and made 575hp/440tq. Everything has been running great up until recently.

First thing that happened was the dip stick blew out under boost and that made a hell of a mess. My fix to that was 2 -10 an lines in the Valve cover and a vented catch can.

After that the car seemed to run fine. I checked my plugs today after the car was running a little weird. This is what I found.



All 4 spark plugs were in this same condition. I cleaned them up, threw them back in and fired her up. Car starts just fine and afr are perfect.

What do you guys think it is? Piston rings? Head gasket?

 

Valve cover gasket and Spark plug valve cover seals.Easy fix buddy.

 

Both recently changed out

 

Spark plug seals, make sure they are on correctly or didn't move around when you installed them. Did you check the valve cover bolts too? I had two (spark plug seals) shift on me once I turned it upside down to bolt back up....I simply used a little silicone so that it stuck to the valve cover and didn't move once flipped for install.

Check the piston tops for oil as well. Borescope all the cylinders while you are changing/cleaning the plugs.

 

Is there blue smoke coming out of the exhaust? If not the the valve cover spark plug seals are leaking. Did you wipe off the mating surface when you bolted the VC back on? Do that and don't forget the proper torque sequence.

 

but do it right this time.

 

Spark plug gaskets or rings are shot. Doubt that though, but do a compression test anyway.

 

I just bought an Evo 9 MR about two months ago and once I finished replacing all of the fluids, timing belt, water pump and plugs, I replaced the VC gasket due to the exact same issue you have.

Compression and leak down test were fine, it was just the VC Gasket and spark plug seals that needed replacing. About a month has gone by and the problem is gone, definitely do it again, they didn't seal right.

 

tip of the plug is dry the problem is oil leaking from the gasket.

 

lmao