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Cleaning sludge off pistons

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Old 12-18-2003, 01:10 AM
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Default Cleaning sludge off pistons

I just took off my lower intake and when I looked into my intake ports... yikes! There is quite a bit of sludge deposited on the top of the pistons. Maybe 1/4" in some places. My car doesn't have a performance problem but I would guess all that sludge can't be good. Is there a good way to get it out without removing the heads? I've read about marinating it in decarbonizer and then running it out the tailpipe but I'm not too excited about that idea.

-Jeremy
Old 12-18-2003, 01:40 AM
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1/4" ON the pistons?! Holy powerloss bigJ!! haha But really, you're probably meaning your valves and yeah they'll get pretty dirty but they shouldn't be THAT bad. I've seen the intake valves on a '79 400cid from a trans am, THOSE were nasty. Uhmm but I had 109k on my '93 SSEi and still only had fairly minor amounts of carbon buildup. Might wanna take a look at how rich you're running and why. On a fuel injected computer controlled car I don't think you should have that much. It'd be time consuming but maybe you can insure the valve is closed and spray *** loads of carb cleaner right on top of the valve and let it soak for a while. Then maybe use a shopvac to suck the remainder out so it doesn't fall into your cylinder and find itself a new home. Once you're done with the closed valves bump the car or turn it over using a socket to ensure the next valve is closed and repeat. You'll never get it all off, I pulled mine and let them sit in industrial cleaner for almost a week and still couldn't get about 1/8" or less off but it'll make a difference. Think about it, people spend sizeable amounts of time and money getting 0.02" larger valves (Jeff haha ) for that "performance gain", imagine what that sludge is doing.
Old 12-18-2003, 02:20 AM
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2 words. Water injection.

But with your buildup, it would have to be a permanent system.
Old 12-18-2003, 10:50 AM
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Have you run water injection? I've seen articles on this, and would like to try it, but the cost of an engine is a little too high for me. Let me know if you've run it and how it worked!
Old 12-18-2003, 12:35 PM
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I've run it, same with Jeffrey10x2. It won't cost you an engine if it'* set up right, it will PROLONG the engine life by keeping everything cleaner and cooler. But it will cost you to have it done right.

I built my own, but it was very involved. I'll probably modify an off-the-shelf setup for my replacement system. Do a search on "water injection" (search for all terms). The earliest topics by me were when I was beginning my own research.

Water injection has been used effectively since the early 1900'*, and was used on our WWII planes. That'* one of the reasons we had higher service ceilings than the Axis powers.
Old 12-19-2003, 05:01 PM
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Sorry my bad, those are indeed the valves not the pistons. I was able to loosten some of the buildup with a thin wooden dowel. I have some intake cleaner so I'll try spraying it in there and then shop-vaccing it out.

Water injection sounds exciting but I think it'* a little much... I'll just be happy to get my car running again after having it sit in my garage for 3 weeks!
Old 12-20-2003, 01:13 AM
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Water injection technique WILL NOT remove deposits from valve tops. Water hammering the piston tops, cyclinder ceiling, and valve faces will work though. It is easy with carbs. Not so easy with fuel injection.

Be VERY careful if you are trying to remove carbon from the top of the valves. You may end up trapping carbon in the seats. That will not be a particularly pretty if you do.

Actually, I'm wondering how you can see much of the top of the valves.
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