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308 Compression Test Results

Discussion in '308/328' started by pete308, Feb 3, 2005.

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  1. pete308

    pete308 Rookie

    Dec 31, 2004
    17
    Atlanta, GA
    Full Name:
    Pete Haughton
    #1 pete308, Feb 3, 2005
    I need advice regarding the results of a compression test on a 308 QV. In my on-going search for my first Ferrari I have had a PPI including compression test done on a 308 QV with about 70K miles. The compression test showed measurements of 160-165 psi on 6 of the 8 cylinders. The remaining two cylinders measured 146 and 148 psi. Both of these cylinders were on the same bank. How should I interpret these results? Whatever I buy I plan on keeping for a long time and am worried about having to face a 10-15K rebuild in a couple of years for a car that is not valuable enough to justify this. I do not have the results of the rest of the PPI yet but the car is in general in good condition cosmetically.

    Thanks,
    Pete
     
  2. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    37,100
    Cowboy Capitol of the World
    Full Name:
    Brian Crall
    #2 Rifledriver, Feb 3, 2005
    Those motors are very tough. I just had the heads off one with 105k miles for gaskets and looked new inside. First thing I would do is to repeat the test and see if it comes up the same. It may have just been some junk from the plugs that got on some valve face's. Keep your fingers crossed.
     
  3. pma1010

    pma1010 F1 Rookie

    Jul 21, 2002
    2,559
    Chicago
    Full Name:
    Philip
    #3 pma1010, Feb 3, 2005
    Have a leakdown performed.
     
  4. TOM B

    TOM B Formula 3

    Jul 24, 2003
    1,038
    Orange County, NY
    Full Name:
    Thomas Buckley
    #4 TOM B, Feb 4, 2005
    It's really not what the actual compression readings are, but whether they are within 10% of each other. All should be taken within the shortest time possible as temperature dramatically affects the readings.

    Yours are within 10% of each other so i'd say your good.

    Tom
     
  5. thecarreaper

    thecarreaper F1 World Champ
    Silver Subscribed

    Sep 30, 2003
    18,067
    Savannah
    #5 thecarreaper, Feb 4, 2005
    carbon build up may be affecting the reading on those 2 discrepant cylinders.
    if you do purchase the car, re test it after some good driving and miles are put on it ( say 1500 ) . give it the italian tune up when its fully warmwed up and see how the numbers run.
     
  6. pete308

    pete308 Rookie

    Dec 31, 2004
    17
    Atlanta, GA
    Full Name:
    Pete Haughton
    #6 pete308, Feb 4, 2005
    I have added some info to this thread and moved it to the Technical forum. I would appreciate all the advice I can get. The leakdown test revealed 16% leakage in cylinder 5 from the rings and 18% leakage in cylinder 7 from the valves (which I am very worried about). The other post is linked below:

    http://ferrarichat.com/forum/showthread.php?t=47627

    Thanks,
    Pete
     

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