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Why did my valve burn again?

Discussion in 'General Tech and Maintenance' started by runderwo, Aug 27, 2007.

  1. runderwo

    runderwo New Member

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    I have a F22A, it had a burned #1 exhaust valve when I got it, I had a valve job done at a machine shop, put it back together with correct valve lash and drove 10,000 miles. I was driving on the highway yesterday and lost power, now #1 is dead again.

    I'm not so sure the valve job was the best in the world because I was burning 1 qt / 500 miles. Also, I was never able to get the ECU to run in closed loop, because of some electrical issue in the O2 circuit. Anyway, the motor ran very smooth with good power and no missing at all, and got about 28 miles to the gallon.

    Can anyone tell me where I screwed up? All I can think of is that the oil burning and/or rich mixture did it.
     
  2. TurboMirage

    TurboMirage YEEAAAHHH VIP

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    fix that o2 sensor...
     
  3. runderwo

    runderwo New Member

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    I pulled the plug. 0 compression (180 across the others), and the plug had coke spots around the white insulator while the others were clean. I guess all the oil was being burned in that cylinder and the deposits are what burned the valve. There is a new valve stem seal on it and there was no coke on the #1 piston before the valve job. Where did all the oil come from? It would be hard to believe the rings were that bad if the piston was clean to begin with... ugh.
     
    Last edited: Aug 27, 2007
  4. runderwo

    runderwo New Member

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    Hmm, I took the head to the closest place I could find, which also seemed pretty cheap ($175). I thought a valve job was a valve job unless you are going for performance

    By coke I mean there is just ash all around the white insulator, it looks like a moldy piece of bread.
     
  5. runderwo

    runderwo New Member

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    It's black ash, looks like burned marshmallow.

    What do you think they screwed up on the valve job?
     
  6. runderwo

    runderwo New Member

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    What was inaccurate about my description? :confused:

    If it was the O2, why only ash in #1? If it fouled the plug from running that rich I should have ash on all the plugs, I would think? I know 28mpg isn't that great for a honda, but it wasn't exactly dumping gas either.

    I will call the shop that did the valve job tomorrow. At the moment I'm looking at replacement motors.
     
  7. runderwo

    runderwo New Member

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    coke 1 (kk)
    n.
    The solid residue of impure carbon obtained from bituminous coal and other carbonaceous materials after removal of volatile material by destructive distillation. It is used as a fuel and in making steel.
    tr. & intr.v. coked, cok·ing, cokes

    ;)

    Compression was good after the rebuild. I didn't test it with an oil squirt though, probably should have because it would have relieved some questions now.
     
  8. runderwo

    runderwo New Member

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    I guess I disagree that coke means cocaine when you're inside an engine or anything else that burns fuel. Though if my car was doing lines, I guess it would explain why the valve burned up...

    The reason I wish I did a wet test was that I seem to remember the number being slightly different on the #1 as opposed to the other 3 that were uniform, but I was so excited to get it running that I didn't really put much thought into it.
     
  9. runderwo

    runderwo New Member

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    Except your two definitions are slang and have nothing at all to do with cars.

    As I originally posted, the motor lasted about 10K miles. I just wasn't careful about checking how well it was working right after reassembling it... which is too bad since it would remove some questions now.
     
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