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996 smoking on track after 2nd AOS

Home Forums Tech Forum 996 smoking on track after 2nd AOS

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    AvatarMike Lemmon

    Hi there:

    I’m desperately looking for any insights on why my 996 continues to smoke and continues to use oil while on track, but no smoke or oil consumption off track, after replacing the AOS for the second time.

    First lap at CTMP coming out of 5B big cloud of oil smoke, after 5 laps pulled off, oil was down 400ml.
    Next 2 startups there was clouds of oil smoke.
    The rest of the drive home, and since no issues.

    I drive the car year round, drive it aggressively and it never smokes or uses any oil while driving it on the street.

    I see other 996s on this the track with no smoke issues so I know it must be something with my car.

    Any help would be greatly appreciated. Please feel free to call, email.. drop by.

    Mike Lemmon
    289 260 8525

    Avatarandy wright

    Hi Mike,
    I am no mechanic, but a couple of observations. When you are braking for 5A and downshifting, your engine is on overrun from high revs, so any wear in your rings or valve guides will suck oil into the combustion chambers. Then when you get back on the throttle after 5B the oil is burned out causing the smoke.
    Probably on the street, you are not using such high revs and therefore the problem does not materialize. Either way, I would consult a specialist as that kind of oil usage is certainly not normal. A Compression and Leakdown test should indicate any abnormal piston ring or valve guide wear.
    Best regards

    AvatarMike Lemmon

    Hey Andy.. thanks for the feedback we will check that out.

    It was also suggested it could be a Scavage Pump problem as the oil continues to show up in the AOS.. we will be trying this next.

    Thanks again..


    Any updates here? I’m considering a 996 for dedicated track use. Would like to se if you’ve got this resolved.


    AvatarMike Lemmon

    Hey There:
    Unfortunately the 2nd AOS replacement made no change.

    4 corners into the first lap at CTMP, it was blowing smoke the same as it has for the past 4+ years.

    The next change is the two scavange pumps.

    Hopefully this will resolve my issue.

    Please do note that there are other 996s, with no work done on their motors, running them on track with no smoke.


    Oh yah, I’m well aware of this. I’ve got a friend who was seeing a lot of smoke too in his. Just interested in seeing this through to conclusion…

    Good luck, let us know how it turns out!

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