Ferrari dealer did compression test, numbers low? | FerrariChat
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Ferrari dealer did compression test, numbers low?

Discussion in 'Technical Q&A' started by Mimmo Blue, Aug 21, 2018.

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  1. Mimmo Blue

    Mimmo Blue Formula Junior

    Apr 17, 2018
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    Stoney Creek, Ontario, Canada
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    Dom
    #1 Mimmo Blue, Aug 21, 2018
    I am looking at purchasing a 2001 Ferrari 360 from a Ferrari dealership.
    I asked them if they could run a compression test for me and received results today.
    Cyl1 143. Cyl2 145. Cyl3 144. Cyl4 145
    Cyl5 145. Cyl6 148. Cyl7 143. Cyl8 145

    I'm happy with the low variation between cylinders but extremely concerned regarding the overall low numbers.
    Could these results be due to test methods?
    So far all I know is they used a mechanical gauge. I have asked for further details and I am waiting on a response.

    I did drive the car and it seems OK but I have no prior experience in a similar car so nothing really to compare my test drive to either.
     
  2. Dave rocks

    Dave rocks F1 World Champ
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    #2 Dave rocks, Aug 21, 2018
    The lower numbers may be a result of the number of times the tech cranked the motor.
     
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  3. Qavion

    Qavion F1 World Champ
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    Ian Riddell
    #3 Qavion, Aug 21, 2018
    Are 360 compression tests normally done with a warmed up engine? If so, did they warm up the engine?
     
  4. Mimmo Blue

    Mimmo Blue Formula Junior

    Apr 17, 2018
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    #4 Mimmo Blue, Aug 21, 2018
    I just got some more info. The technician used a manual picoscope on a warm engine. The opinion of the technician was that these consistent results did not warrant the need for a leak down test.
     
  5. ago car nut

    ago car nut F1 Veteran
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    #5 ago car nut, Aug 21, 2018
    Variation between cylinders is the most important, indicates rings, pistons and valve seal. Low numbers could be type of gauge used or altitude level. Also how fast motor cranked, condition of battery etc.
     
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  6. Mimmo Blue

    Mimmo Blue Formula Junior

    Apr 17, 2018
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    Dom
    #6 Mimmo Blue, Aug 21, 2018
    Could shop temperature also be a factor, for example on a very warm day?
     
  7. taz355

    taz355 F1 Veteran
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    #7 taz355, Aug 21, 2018
    A bit
     
  8. A348W

    A348W Formula 3

    Jun 28, 2017
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    North Wiltshire, UK
    #8 A348W, Aug 22, 2018
    As you are potentially buying the car from them, its their opinion that matters most. If they say its all fine, your covered wrt warranty.

    But off course you want to understand the numbers for future info etc. Ask the Tech what is the acceptable range?
     
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  9. greyboxer

    greyboxer F1 World Champ

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    #9 greyboxer, Aug 22, 2018
    I doubt you'll get anyone to commit totally because of the issues mentioned above ie that there are so many variables in test procedure and implications from atmospheric variables which is why the spread is the valuable element (and why folk are increasingly reluctant to do the test)
     
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  10. I.T. Guy

    I.T. Guy F1 World Champ

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    #10 I.T. Guy, Aug 22, 2018
    Warm cold?
    How many times spun before gauge read?
    How fast turned over (battery / starter strength)?
    Wide open throttle? Closed?
    All spark plugs out or just cyl being tested?
    Atmospheric conditions the time of test?

    So many factors to determine final upper PSI read. Only way to know if yours is low/high is experience and consistency in test method with same model cars with similar mileage and same oil etc.




    Sent from my iPhone using FerrariChat.com mobile app
     
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  11. Ferrari Tech

    Ferrari Tech Formula 3

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    Wade Williams
    #11 Ferrari Tech, Aug 22, 2018
    I would not even blink at those numbers. Even is what you are looking for. Leak down is a diagnostic tool for issues found from bad compression test. That is not a bad compression test.
    That car has electronic throttle as well and that can keep numbers low. Cam timing has a lot to do with cranking compression as well. I have not performed a compression test on a 360. The variator may also keep the numbers low.
    In any case, I say go drive the hell out of and enjoy it.
     
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  12. taz355

    taz355 F1 Veteran
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    #12 taz355, Aug 22, 2018
    Yup what he said above
     
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  13. Motob

    Motob Formula 3
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    #13 Motob, Aug 22, 2018
    When performing a compression test with a mechanical gauge on a 360, the peak compression values are typically above 200 psi. I have never used the picoscope on a 360, so 140-150psi may be normal. Since all cylinders are very close to each other, I would say that the engine is in good condition.
     
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  14. A348W

    A348W Formula 3

    Jun 28, 2017
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    #14 A348W, Aug 24, 2018
    Agree, however if you are buying the car from the garage, you want to put the ownes of responsability on them to say "yup thats all fine"; not for you to interprite a test that your not "qualified" to interpret nor witnessed etc. which then means any subsequent issues become yours, not theirs.
     

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