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-   -   Combustion chamber/valve color (https://www.gtcarz.com/chevy-gmc-70/combustion-chamber-valve-color-95776/)

NoRiceInside 12-04-2004 05:30 PM

Combustion chamber/valve color
 
I just picked up some used heads today and the guy said they were in great shape, but it musta slipped his mind to tell me how many miles. they are clean and in great shape, and are perfectly straight.

recently i did a compression test on my motor and some of the plugs had black residue on them and my auto shop teacher told me that black meant somthing and so did white. well these new heads have some valves with white residue.

my guess is each color designates either rich or lean, but i dont know for sure and was wondering if anyone can help me reveal anything about the motor they removed these heads from.

archemedes 12-04-2004 10:07 PM

white residue on the heads doesn't mean a whole lot, on the plugs it indicates lean, a little white residue is normal with todays oxygenated fuels as long as they are in good shap your fine, any pitting? I would go ahead and have a valve job done and replace the seals better now than after you get them on the car especially with unknown miles (at very least change the stem seals)

NoRiceInside 12-04-2004 10:19 PM

yeah a valve job is what i'm doing for the project. ok so black is only what i need to worry about?

archemedes 12-04-2004 10:30 PM

only if really bad, alittle is nothing to worry about but ifyou get soot you have trouble

NoRiceInside 12-05-2004 07:46 PM

also are the valves supposed to be seated flush with the rest of the chamber? mine arent :(

archemedes 12-05-2004 10:43 PM

got a pic I don't understand what you mean

NoRiceInside 12-05-2004 10:47 PM

i'll have one tomorrow afternoon. basically the valves are closed yet the thickness of the valve face is protruding past the surface of the combustion chamber. just a bit though...

archemedes 12-05-2004 10:52 PM

if you lay a straight edge againt the head does it touch? if so you have issues

NoRiceInside 12-05-2004 11:26 PM

no id doesnt. i guess its just thick valves. we'll see when i take my current ones off.


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