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replacing synthetic oil w/petroleum based

Discussion in 'Technical Q&A' started by groovzilla, Feb 2, 2004.

  1. groovzilla

    groovzilla Karting

    Nov 28, 2003
    117
    seattle, wa.
    Full Name:
    william
    hello all,

    when i purchased my 79 308GTS, the previous owner had been using synthetic oil...the car developed an oil leak at 2 of the motor mounts...

    ron at camissa motors, who did my pre-buyers inspection, reccomended i go back to petroleum oil...he explained that the seals in these engines were not designed for the synthetic oil and most of them leak when synthetic is used..

    is there a flushing procedure when changing over to petroleum based oil??...or do you just drain synthetic oil/replace filter and ready to go??

    regards,
    william ceriale seattle, wa.
     
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  3. tifosi

    tifosi F1 Veteran
    Lifetime Rossa

    Sep 5, 2001
    5,382
    texas
    Full Name:
    Tom D
    no need to flush, but I am not sure changing will solve your problem, synthetics are much diff today then years ago.
     
  4. pma1010

    pma1010 F1 Rookie

    Jul 21, 2002
    2,559
    Chicago
    Full Name:
    Philip
    When I took a set of cams to Dema Elgin, we got into this issue. First, synthetics are usually thought "better" from a variety of perspectives, summed into "protection". In this case, Dema explained he used to "fix" a lot of 246 cams where the cars sat for long periods and then experienced short trips (oil drained off the cams, short trips = max wear per mile). He strongly advocated synthetics due to their ability to "cling" to the metal.

    Second, not all synthetics are equal. Outside the performance envelope (and there are others that know much more than me on this - where's Ali Haas?). I raised with Dema the question of the oil leaks from synthetic. He indicated some formulations were changed so that the element in the catalytic converters didn't degrade. Unfortunately, these were the same additives that caused the butyls to swell and hence the seals to do their intended job. What you've got to look for is a fairly "wide range" synthetic (sorry, don't know the technical term), I run 5w-50 Castrol Syntec, and avoid the flavors with the circular washer emblem carrying the legend, "Specially formulated for gasoline engines". Then you are fine.

    Third, the engine mount studs are notorious. Ferrari drilled them too deeply. Others have described the repair. I've just done mine. It is dirty work, but not hard and quite satisfying when done. You've got to drain the fluids, remove the mounts, pull the studs, let it dry out a bit, clean the threads and then apply Permatex #2 to the studs when you wind them back in.
    HTH
    Philip
     
  5. 4re gt4

    4re gt4 Formula 3

    Apr 23, 2002
    2,279
    Roseburg, OR
    Full Name:
    Hans E. Hansen
    FWIW, I'd say the majority (but most certainly not all) of those of us here are using a synthetic. Leaks are from seals that are old. My car doesn't leak a drip. Well, not any more. I've replaced some seals.
     

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