Red exhaust valves?
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Junior User
Joined: May 2010
Posts: 99
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From: Hibbing, MN
Red exhaust valves?
Alright, so i bought a 390 engine a couple weeks ago and i am finally starting to dig into it and take it all apart for a little rebuild.
I had taken off the headers a week ago or so and noticed the the gasket for the headers was kind of red looking, but i figured what ever and went on.
Today I took off the heads and 6 of the 8 exhaust valves have a red coating on them? One side has all 4 exhaust valves red with no red on the intake valves and the other head only has 2 red and again no red on the intake valves.
I wire wheeled on of the exhaust valves and it is normal color under it so why, or what would cause this to happen?
Heres some pictures.
I had taken off the headers a week ago or so and noticed the the gasket for the headers was kind of red looking, but i figured what ever and went on.
Today I took off the heads and 6 of the 8 exhaust valves have a red coating on them? One side has all 4 exhaust valves red with no red on the intake valves and the other head only has 2 red and again no red on the intake valves.
I wire wheeled on of the exhaust valves and it is normal color under it so why, or what would cause this to happen?
Heres some pictures.
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
The exhaust valves operate at a much higher temperature than the intakes. The carbon that builds up on them will have a lighter color. It can be anywhere from dark brown all the way to nearly white. I don't know if different brands of fuel have any effect on the color.
You can also tell which cylinders have lower compression, their valves will be darker compared to healthy cylinders.
You can also tell which cylinders have lower compression, their valves will be darker compared to healthy cylinders.
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