# Carbon on piston tops



## Red74Goat (Jul 31, 2015)

I had to remove both heads from my 1974 350 to have broken exhaust bolts removed. While I have the heads off, any suggestions for a good way to remove carbon deposits from piston tops without removing the pistons or further engine tear down? Only 28,000 miles on the engine. 

Thanks.


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## PontiacJim (Dec 29, 2012)

Red74Goat said:


> I had to remove both heads from my 1974 350 to have broken exhaust bolts removed. While I have the heads off, any suggestions for a good way to remove carbon deposits from piston tops without removing the pistons or further engine tear down? Only 28,000 miles on the engine.
> 
> Thanks.



I don't think I would mess with it. You really don't want to be breaking loose carbon deposits that may fall between the sides of the piston and the cylinder walls and score them up upon start-up or worse, get lodged in the ring lands.

If you gotta do it, I would have a vacuum running as I scraped to draw up the loose stuff so it got sucked up immediately.


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## Rukee (Feb 8, 2007)

Just use some sea foam in the gas tank after you get it together, that will clean it up.


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## Red74Goat (Jul 31, 2015)

Jim and Rukee, thanks for the recommendations. I'm not set on cleaning the piston tops up right now, just thought it might be worthwhile with the heads already off. 

I always worry about any initial project getting farther and farther from the original intent ... next thing you know a 2-3 week project turns into 2-3 years and a "project car" for sale on craiglist. :smile3:

At this point, I'm likely to just paint the heads, intake manifold, valley pan, etc. put on new gaskets all around, do an oil change and get her started and going.

Have either of you pulled the coolant drain plugs from the engine block and then done anything when reinstalling the plugs, like using any kind of non-hardening sealant, wd-40, or teflon tape on the plug threads before reinstalling? My plugs came out pretty easily, but had some surface rust on them. 

Thanks.


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## Rukee (Feb 8, 2007)

Teflon tape, be sure to wrap it clockwise when looking at the bottom of the plug so the tape doesn't unwrap as you put it in.


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## ALKYGTO (Mar 29, 2010)

I prefer Teflon paste.


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## geeteeohguy (Feb 2, 2008)

X3 on not scraping the carbon. Use Seafoam or run ATF through the carb at about 2500 rpm in neutral. I use gasgasinch on freeze plugs, or nothing at all. I also use brass plugs, so they never rust out. I would not use teflon tape, personally....too slick. Thread sealer? Perhaps.


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