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Cleaning exhaust valves

4K views 6 replies 4 participants last post by  idiot_saabvant 
#1 ·
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 ·
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.
 
#4 · (Edited)
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.
 
#5 ·
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! :cheesy:

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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