Not sure if my leak was from me overrevving my engine to 8200 rpm on oem valvetrain when my clutch gave out in 4th gear, but my #3 cylinder intake valves don't seat. This was last November in Fontana when I made 430 hp. I was running 115-118 mph, but when I saw 8200 rpm, I let off the gas and bogged 4th and still managed 12.1 1/4 mile.

 

I started to think about how my intake valve seats are gone and wonder if this is E85 related. I'll drive around town and shut off engine for weeks at a time. The last injector spraying may not fully get completely sucked into combustion chamber. It could stick to intake ports in head/bowl/valve area and collect moisture from air in intake pipes. What if E85 on my intake valves collect moisture and sits over the next 2-4 weeks (especially when I simply move my car in driveway). Over a year, I wonder if this is what chewed up my valve seats. Thoughts anyone?
After fixing my head, I think I'm going to stick with 91 octane and use E85 for times when I will know I can empty the tank.

 

Yeah, remember my issue w/all 4 spark plugs corroded in the alum hole. I did not use anti-seize originally & those plugs saw mostly E85 (15K miles) w/a few stints of 91. Wonder why the orig spark plug plating did not survive in the alum hole?

Anyway, sorry to digress. I know you will, but we look fwd to seeing how this rework goes. Keep us posted w/pics

 

Thinking about your plug corrosion, I wonder if you've not fully warmed up your engine often. E85 will have a lot of moisture and if not fully hot, it will condense on everything inside your engine and exhaust pipes. Your spark plug body is a steel material (I can't find the exact materials) so water moisture over time will rust in the thread at the tips of your spark plugs.
Do you have pictures of your old plugs?

I wonder how your cylinder walls are since it is iron. On mine, I see dots of discoloration (from cheap borescope). I'll take a closer look once my head comes off.

 

Also, I just read that if you used anti-seizing grease, it can act as a lubricant and lower your actual torque (how much extra torque will you need to compensate?).

 

I'm so tempted to build bottom end at same time, but the thought of removing transmission and pulling off my freshly broken-in exedy twin disk and adding in the cost to buy parts and machine the block, it is a huge jump in cost. I could get cheaper parts, but I don't like the feeling of settling for cheap materials to save money, especially if the cheap parts fail.
I think the ideal time to build bottom end is with my next clutch job.

 

I think the engine probably rotates enough after key off to take care of that. If you are worried about it though you could always pull the Crank sensor, or a fuse etc. and crank it over a little bit before you let it sit for long periods. We have alot of long time e-85 users around here though and I haven't seen anything like what your worried about here. Usually its the black goo everyone is worried about.

 

I recently pulled my fuel pump to do some work on the hanger. Every metal part of the hanger assembly had white spots of deposit/corrosion. I let the car sit for a few mos with e85 in it, so I guess that's why. Since then, my fuel level sensor is kinda whacky. It'll say I'm out of gas, but as I drive around the level will go up LOL.
Currently searching for a new assembly.
Just another reason I'm not a fan of storing/letting a car sit with e-85 in the fuel system. I suppose it could be possible for some to be on the valves.. but I have to think it would burn off once the engine runs for a few mins?

 

Since I don't drive my evo much, I'll probably leave 91 in the tank until I know I'll empty a full tank of E85. I've let my car sit for 2-3 months last year after Fontana in July.

Also, I'm sure my PCV has been recycling all my blowby gases, which is mostly water vapor (~95% from emptying my catch can, which I just installed last month).

 

And now that my intake valves don't seat, there is plenty of moisture in exhaust gas to be absorbed by E85 as it is sprayed.

 

My car started sounding like WRX right after I finished with my fuel pump rewire where I was driving it to check my AFRs. WRX sound was from intake valve leaking so it was a weak exhaust pulse from that cylinder so it was like a missing sound for that cylinder.
Does anyone else's evo sound like a WRX?

 

 

Actually, with the newer WRX/STIs, I think the turbo was relocated to front near pulleys and Subaru made equal length headers to turbo. So the boxer sound is gone.

 

What sucks is I didn't get to run my car with new clutch and S2 cams at Fontana. I was certain I'd see 11s passes with an extra 30 hp and 25 tq. Oh well, hopefully with rebuilt head, I'll come close to 500 hp after next retune. I should be around 470-475 with rewired fuel pump. Also, I have a TurboSmart 22 psi WGA to install and should be able to hold 27 psi at redline to squeeze a little more power out of HTA71 (currently falls to 24 psi).

 

Look what I found in a search!! I hope my cylinder walls are not as bad since I drove about 5000 miles on E85.
https://www.evolutionm.net/forums/ev...ce-needed.html