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  #1  
Old 4th July 2009
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Default Cleaning exhaust valves

So I took the exhaust valves off my 2.1L head (apologies for the crappy pictures but I am using the crappy (read Olympus) camera):

The green liquid is Carbon-X, which I used to clean turbo shafts. This time it did not do much. What is this thick gray stuff wrapped around the bottom of the valve? Can it be safely cleaned or I will have to get new valves?
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  #2  
Old 4th July 2009
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Neither.
Intake Ports, Valves, and Manifolds need to flow well. It's pretty unimportant on the Exhaust side because of the huge pressures involved.
When the Intake Valve opens, there might be as much as 18 psi pressure behind it, when the Exhaust Valve opens it's closer to 2000 psi.
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Old 5th July 2009
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Don't you have to at least face the valve as the seats on the head will be recut?
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Old 5th July 2009
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Are you sure you aren't looking at a stellite facing surface on the valve? Stellite is a very hard facing material primarily used for valve seats and faces, and on some valves, requires replacement rather than facing due to the thickness. Was this a leaded engine originally? It may be a residue from tetraethyl lead used for higher octane fuels of the day. This is where the phrase "Ethyl" came from for gasoline. When aviation fuels used it they also added ethyline bromide to form lead bromide which would flake and exhaust out of the cylinder, rather than building up on the valves. May have to scape, but be aware lead dust is toxic, IF that's what the buildup is. Talk to an older high performance guy and see what he remembers about cleaning valves. ANY make.
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Last edited by crwchf01; 5th July 2009 at 12:36 PM. Reason: Additional comments
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Old 5th July 2009
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I honestly do not know, that is why I tried taking those lousy pictures. Here was I hoping they would be clear enough someone would say, "Oh, this is a deposit of whatever and the best way to remove it is this." But, my stupid Olympus camera (never buy one) was in a ghey mood. I will try again today, I promise!

The owner of the machine shop I go to wanted to clean it the same way he would do a Chevy valve. But, I do remember reading here those valves are coated with something so grinding them may not be the smartest thing to do.
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Old 6th July 2009
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New and prettier pictures:
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Old 6th July 2009
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I used a wire brush and Easy OFF oven cleaner. Got my valves to be original metal. Then I use both coarse and fine grit and GENTLY lapped my valves whilst in the head.

pierre
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