Carbon deposits

Ckn087

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Hey guys. I'm working on a cylinder head off of a generator and had a stuck exhaust valve which I got fixed but there are tons of carbon deposits on piston and inside exhaust valve chamber and around spark plug. I've got most of it off but there is still quite a bit. What is the best thing I can use to clean this junk off? And do I need to get every bit of it out? Thought about brake or carb cleaner but will that damage the oil seal on the intake valve guide if it gets on it as it doesn't seem to be removable? I've also got small wire brushes that are copper and brass but I dont want to damage anything in the cleaning process such as the mating surface for head gasket. Any help would be greatly appreciated!
 

Scrubcadet10

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i use a handheld wire brush on the piston with some brake parts cleaner.
i always use a drill and wire brush inside the cylinder head combustion chamber with WD-40, if the valves are out, don't hit the valve seats with the brush just to be on the safe side.
 

Ckn087

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Ok thanks! Tell me if I'm doing this right. I put rags inside pushrod chamber and put grease around them and piston at tdc hoping to keep stuff from falling down into it. My fear is some of those deposits got on top of compression ring between piston and wall. Should I try to vacuum around piston before I move it or put it back together?
 

Scrubcadet10

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Generally what I do is put it at TDC, wire brush it a bit, spray it off,brush some more, then when done I rotate the piston through several cycles by hand making sure the cylinder is clear.
Done it this way and never had a problem. But vacuuming it out would not hurt a thing at all.
 

bertsmobile1

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I use a Dremel tool with brass brushes, scrapers made from old piston rings and in extreme cases the oxy torch with a very lean flame to burn the carbon off.
As for around the piston, never worried about it when you have finished put the piston at bottom toss a lot of your favourier solvent on top of the piston then give the engine some nice fast pulls.
If the pull start is off hook up a drill to the flywheel nut and do the same .
If there is a lot of gunk you might need to do this a couple of times.
when finished , wipe the bore with some engine oil and crank the engine slowly a few times to get some oil on the bore.
Do not try to remove the carbon ring that is around the top of the bore, leave it there is is beneficial .
You really need to work out why there is so much carbon.
I rather feel that the inlet oil seal has already been destroyed if the there is a lot of coke in the combustion chamber.
There is no need to make the surfaces mirror bright either.
 

7394

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I use Seafoam, it makes the carbon soft & gummy.. But would need to soak or stay wet overnight anyhow.
 
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