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Old 01-22-2006, 08:22 PM   #1
Kevin Lee
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Default What does a burned exhaust valve look like?

I know you can read spark plugs. Wondering if there's a similar technique for valves?

Popped the heads on my flathead and noticed the exhaust valve in #1 looked grey. Basically a sort of "fogged" greyish white around the outside of the valve. I've heard before how the no. 1 cylinder sometimes runs lean and in turn gets hot, causes problems with soft header bolts, etc.

It doesn't really look like it's in bad shape - but definitiely looks different than the other fifteen.
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Old 01-22-2006, 08:25 PM   #2
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Default Re: What does a burned exhaust valve look like?

A burned valve has a notch or flat spot at the face (the part that contacts the seat), so it does not contact the seat at the burned part.
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Old 01-22-2006, 08:25 PM   #3
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Default Re: What does a burned exhaust valve look like?

Quote:
Originally Posted by Grimlok
I know you can read spark plugs. Wondering if there's a similar technique for valves?

Popped the heads on my flathead and noticed the exhaust valve in #1 looked grey. Basically a sort of "fogged" greyish white around the outside of the valve. I've heard before how the no. 1 cylinder sometimes runs lean and in turn gets hot, causes problems with soft header bolts, etc.

It doesn't really look like it's in bad shape - but definitiely looks different than the other fifteen.
Any degradation or pitting of the seat area?
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Old 01-22-2006, 08:26 PM   #4
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Default Re: What does a burned exhaust valve look like?

heres one I found with google image search....

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Old 01-22-2006, 08:31 PM   #5
Steve Ray
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Default Re: What does a burned exhaust valve look like?

Quote:
Originally Posted by Grimlok
I know you can read spark plugs. Wondering if there's a similar technique for valves?

Popped the heads on my flathead and noticed the exhaust valve in #1 looked grey. Basically a sort of "fogged" greyish white around the outside of the valve. I've heard before how the no. 1 cylinder sometimes runs lean and in turn gets hot, causes problems with soft header bolts, etc.

It doesn't really look like it's in bad shape - but definitiely looks different than the other fifteen.
The valves in my Alfa Romeo motor actually turned black-they had a charred appearance and one was cracked with a chunk missing. Yeah they looked like the picture.

I did see a set of burnt flathead valves once-similar appearance and the edges were crumbled away. A burned valve will eventually lose big chunks so if you have any doubt replace it.
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Old 01-22-2006, 09:07 PM   #6
squirrel
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Default Re: What does a burned exhaust valve look like?

Quote:
Originally Posted by Grimlok
Popped the heads on my flathead and noticed the exhaust valve in #1 looked grey. Basically a sort of "fogged" greyish white around the outside of the valve. I've heard before how the no. 1 cylinder sometimes runs lean and in turn gets hot, causes problems with soft header bolts, etc.

It doesn't really look like it's in bad shape - but definitiely looks different than the other fifteen.
Sounds like no 1 is running properly, and the other 7 cylinders are running a tad rich.

Normally the exhaust valves will be white, grey, or tan, if the fuel mixture is right and the engine isn't burning a lot of oil.
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Old 01-22-2006, 09:07 PM   #7
51 MERC-CT
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Default Re: What does a burned exhaust valve look like?

Here's a really bad one out of a flathead.

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Old 01-22-2006, 09:16 PM   #8
Kevin Lee
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Default Re: What does a burned exhaust valve look like?

Quote:
Originally Posted by squirrel
Sounds like no 1 is running properly, and the other 7 cylinders are running a tad rich.

Normally the exhaust valves will be white, grey, or tan, if the fuel mixture is right and the engine isn't burning a lot of oil.
I can live with this explanation. The rest of the cylinders did have a pretty heavy carbon buildup. I'll try to get pictures later.
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Old 01-23-2006, 11:54 AM   #9
Bruce Lancaster
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Default Re: What does a burned exhaust valve look like?

Also might just have lots of pitting on seat without any big area gone.
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