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What does a burned exhaust valve look like?

Discussion in 'The Hokey Ass Message Board' started by Kevin Lee, Jan 22, 2006.

  1. Kevin Lee
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    Kevin Lee Super Moderator Staff Member

    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.
  2. squirrel
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    squirrel Member

    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.
  3. Tman
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    Tman Member

    Any degradation or pitting of the seat area?
  4. squirrel
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    squirrel Member

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

    [​IMG]
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  5. Steve Ray
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    Steve Ray Member

    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.
  6. squirrel
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    squirrel Member

    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.
  7. 51 MERC-CT
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    51 MERC-CT Member

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

    [​IMG]
  8. Kevin Lee
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    Kevin Lee Super Moderator Staff Member

    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.
  9. Bruce Lancaster
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    Bruce Lancaster
    ALLIANCE MEMBER

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

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