Oil burned on plugs fouling issue.

Discussion in 'Troubleshooting & Diagnosis' started by Beaber89, Mar 6, 2018.

  1. Beaber89

    Beaber89 New Member

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    Feb 3, 2017
    So I have a small block 350. Rebuild on the motor has been maybe 1000 miles ago. I've been having issues with cylinder 6 and 8 fouling the plugs put and when I pull them it looks to have burned/seared oil on them. I'm trying to get most likely ideas from the people as to what the problem could be. This is cylinder 8 plug. My carb is tuned well, idle at 14 afr, cruise at 13 afr, wot at 12.5 or so. This plug was put in yesterday. The car was run street and highway for maybe 45 minutes so that's how long this plug has operated. Hit me with some knowledge please so I can get it sorted out.
     

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  2. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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    Several things can be the culprit; bad valve seals or guides, intake manifold not seated, aligned, or torn, and piston rings not seated in bore. Bad valve guides and/or seals will usually puff smoke on startup or after you coast for a while the mash back down on the gas. Intake gasket, you'll have to pull the intake off unless someone knows a magic trick. You can do a compression check for rings. Good luck.
     
  3. budro6968

    budro6968 Veteran Member

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    X2 on compression check, The easiest is the compression check.
     
  4. COPO

    COPO Veteran Member Lifetime Gold Member

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    Last edited: Mar 7, 2018
  5. budro6968

    budro6968 Veteran Member

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    Nifty. The H/F type got a lot of bad reviews. How much did it cost to make yours?
     
  6. COPO

    COPO Veteran Member Lifetime Gold Member

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    Last edited: Mar 7, 2018
  7. tom3

    tom3 Veteran Member

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    That's real quick for a valve guide or seal. I'm guessing a broken ring on assembly being a new build. Hope not!
     
  8. Beaber89

    Beaber89 New Member

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    Feb 3, 2017
    So let me ask this . With the problem occurring on cylinder 6 and 8 could the cause be head gasket allowing compression and such traveling between the two .
     
  9. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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    Yes it could, but with a blown head gasket, you likely see other issues like steam coming out the exhaust pipe or coolant bubbling in the radiator. What you're describing doesn't point to blow head gasket at this time.

    As mentioned above, easiest to check will be a compression or bleed down. If all is good, then pull the intake to check for bad gasket.

    You can check with parts stores in your area, many have loaner tool programs. You might be able to get a compression or leak down tester that way. They generally come with instructions or we can help here.

    Where are you located, might be another NastyZ guy nearby.
     
  10. Beaber89

    Beaber89 New Member

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    Feb 3, 2017
    Oklahoma city is where I'm at.
     

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