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  1. #1
    SHOBiz's Avatar
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    Instant fouled plug

    Still begging....

    So, this is a rebuilt SHO motor from scratch if you haven't followed.

    Put in new plugs and run for 1-2 minutes.
    Remove plugs and #4 is oil fouled. #1-#3 are fine.

    Compression and leakdown are fine across the board. Vacuum is also low at around -5.5 psi although timing appears just fine.

    Oil ring or valve seal or guide?

    Opinions welcomed before I start into it.


  2. #2
    SHOBiz's Avatar
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    Okay, so I am guessing too much shim on one or more valve on #4 and #1.



    Also, specks form the valve?


  3. #3
    SHOBiz's Avatar
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    The silence is deafening


  4. #4
    SurfRider's Avatar
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    What is the second picture? It's very hard to tell as it's a bit blurry and I'm not familiar with that engine at all, but if that is in the combustion area, I would think that you were having detonation. Those might be little aluminum balls from the piston, etc. I did not read your thread, so I don't know if you rebuilt the head, replace the valve guides, etc. It does seem very odd that there would be that much discrepancy between the 4 cylinders though. Even with new rings, you should not have that much oil passing.

    What were your leak down percentages? I really prefer leak down testing as you can tell exactly where the leak is occurring (4-stroke). For example if you hear it out the exhaust, you know it's an exhaust valve. If you hear it in the breather hose, you know it's from the rings.

  5. #5
    SHOBiz's Avatar
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    Quote Originally Posted by SurfRider View Post
    What is the second picture? It's very hard to tell as it's a bit blurry and I'm not familiar with that engine at all, but if that is in the combustion area, I would think that you were having detonation. Those might be little aluminum balls from the piston, etc. I did not read your thread, so I don't know if you rebuilt the head, replace the valve guides, etc. It does seem very odd that there would be that much discrepancy between the 4 cylinders though. Even with new rings, you should not have that much oil passing.

    What were your leak down percentages? I really prefer leak down testing as you can tell exactly where the leak is occurring (4-stroke). For example if you hear it out the exhaust, you know it's an exhaust valve. If you hear it in the breather hose, you know it's from the rings.
    2nd is looking into the exhaust area on #4.

    Leakdown was 10% across the board. Block and head are new also with new JE Pistons and rings. I did remove the aftermarket valve seals and it appears oil was running down the valves, so those seals are history.

    Detonation could have been caused from the cams being off one tooth initially I guess.

  6. #6
    SurfRider's Avatar
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    Quote Originally Posted by SHOBiz View Post
    2nd is looking into the exhaust area on #4.
    Ok, be careful. That looks like damage from detonation. Be sure to check the surfaces of the piston and heads. Also take a good look at the spark plug electrode for the little metal balls too!

    Leakdown was 10% across the board. Block and head are new also with new JE Pistons and rings. I did remove the aftermarket valve seals and it appears oil was running down the valves, so those seals are history.

    Detonation could have been caused from the cams being off one tooth initially I guess.
    At first I was thinking 10% was A LOT until I read that you were using JE Pistons. I remember the first time my friend used them in one of his Porsche Race motors and we put them in the cylinders, without rings, we thought they sent us the wrong pistons. The were SO loose we were amazed. We called JE and they said "well they expand after the get hot". We were like holy shit. The normal Mahle pistons do not change size like that. After you break in the rings, make sure you try the leak down when the engine is really hot and see what happens.

    I hope the seals were your problem!

  7. #7
    David 1 FAST VE's Avatar
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    Did you set the valves yet?

    Could improper adjustment cause this?

    Im just guessing though?

  8. #8
    SHOBiz's Avatar
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    Quote Originally Posted by 1 FAST VE View Post
    Did you set the valves yet?

    Could improper adjustment cause this?

    Im just guessing though?
    That's what I am wondering and asking

    The valve were lapped and I literally spent 2 weeks checking and rechecking the valve clearances. I have a nice collection of shims. Of course, that does not mean the clearances are right. I am trying to find some dye right now so I wil be able to check the valve faces when closed with and without the cams in.

  9. #9
    SHOBiz's Avatar
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    Possibly a bad coil...

  10. #10
    David 1 FAST VE's Avatar
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    Quote Originally Posted by SHOBiz View Post
    Possibly a bad coil...
    Are you guessing or think thats it?

    Sucks you're not getting much traffic on this?

    Move that coil and see if the problem cylinder moves locations.

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