Evo 8 Rust on tops of pistons

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Jul 7, 2018 | 06:04 PM

BbotVIII

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From: Central NJ

Evo 8 Rust on tops of pistons

Hello, I am in the middle of changing the spark plugs on my 2004 Evo, which has 85k miles. I pulled the sparkplugs out and decided to look down the spark plug holes. I see a coating of surface rust on the top of cylinders 1, 2 and 4 I believe, It could be all of them I just simply can’t see. The car ran perfect and turns over by hand with zero effort and never used any oil or anything of that sort(which I am thinking may have lead to this problem). I live in NJ and there is a large amount of humidity in the summer and road salt in the winter, which do not help either. There was no oil in the coolant I drained and no coolant in the oil. Should I be overly concerned by this? Is there any solution to removing this besides pulling the head off and potentially the engine apart? Thanks, Brian

Jul 7, 2018 | 08:21 PM

drive955i

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From: NE Indiana

Do you use E85, and/or the car sits for long periods? Curious as to how enough moisture is present in the combustion chamber to develope rust.
You sure it’s not residue from poor fuel quality, or carbon deposits? Maybe you could take a long pick and try to scrape a little off of the top of a piston. Just don’t gouge the piston!

Jul 7, 2018 | 08:32 PM

BbotVIII

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From: Central NJ

Quote:

Originally Posted by drive955i

I bought the car in 2013 with 39k miles on it, so in the past 5 years i’ve been daily driving it about 10k miles a year up until recently when i got another daily driver. So the car definitely has sat earlier in its life and a bit recently. My friend was thinking it may be some type of residue also, but to me it really looks like surface rust. I could try getting a sample of it out somehow. I don’t have e85 by me or I probably would use it, but i usually always use sunoco or raceway/hess 93. It is absolutely possible I could have gotten a bad batch recently. I would guess whatever did this happened very recently, because carbon would have probably covered it? I really would rather not pull the head, but maybe i can do that as I am doing my timing belt also and just make it a full service. To me, It doesn’t seem that rust on the tops of the pistons would effect the car at all(within reason). I can’t see the walls, but the engine turns over perfect and I know my rings are in great shape because the car uses zero oil. Which I think is what really matters? Correct me if I am wrong

Jul 8, 2018 | 11:12 AM

drive955i

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From: NE Indiana

Sounds right to me. If you’re not burning oil, if you’re not losing coolant, if you’re not getting misfires, if you’re not getting odd smells or smoke from the exhaust, don’t make a mountain out of a molehill. Fuel contamination and deposits typically have a brownish rust color to it, and is normally evidenced on the spark plugs. It could be coating the top of your pistons and the cylinder head combustion chamber if the deposits build up enough.
If that’s the case, a good fuel injection system cleaner can help control the buildup. You may like to try a new station to fill up and monitor your plugs to see if it makes a change.
I personally wouldn’t go through the hassle of pulling the head unless a driveability issue develops that calls for it, or its upgrade time.
I’ve heard that steam/water in the intake can really clean combustion chambers, but I have never tried it, so I will not attempt to talk you through the process. You may want to research it t if you feel its necessary.

Jul 8, 2018 | 12:43 PM

kaj

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From: Fresno, CA

Aluminum doesn't rust so are you sure it's actually rust you are seeing and not carbon deposits?

Jul 8, 2018 | 05:11 PM

hutch959

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From: Chattanooga, TN

sometimes the burned additives in fuel leave a brown color.
you sure its not some carbon build up with that brown color?

stick a magnet down in there and see if it will pick up any of the "rust".
bet it doesnt.

Jul 8, 2018 | 07:03 PM

kaj

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From: Fresno, CA

Octane booster also turns plugs and other things orange. Could be that, if you've ever used any.

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Jul 8, 2018 | 07:57 PM

barneyb

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From: Grand Island, NE

Unless the engine has sat idle for a long long time, its not rust.

Jul 8, 2018 | 08:43 PM

BbotVIII

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From: Central NJ

Really appreciate all the feedback, before reading this I was about to pull the head. The car was running just fine before I took it off the road, so I will carry on what I was doing with it. Thanks again guys!