Leakdown test results, not good, head re-builder options? | FerrariChat

Leakdown test results, not good, head re-builder options?

Discussion in '348/355' started by ThomasK, Sep 28, 2017.

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  1. ThomasK

    ThomasK Karting

    Dec 8, 2009
    132
    Houston, TX
    #1 ThomasK, Sep 28, 2017
    Hi all,
    i got my whole subframe out for the major/30k service and i just completed a leak down test. If anyone remembers from older threads, but i saw lower compression numbers on 1-4 (160-175) vs 5-8 (185-195) when i did a few compression tests earlier this year. well, the leak down confirms the compression numbers:
    1: 20%
    2: 25%
    3: 20%
    4: 18%
    5: 10%
    6: 9%
    7: 10%
    8: 10%

    i pulled the header on 1-4 and i can feel a lot of air escaping through all of the exhaust valves as well as a lot of ivory coloring in the ports, from the leaking i presume. usually exhaust ports have a nice layer of black, but these have random areas of white/ivory.
    im hoping exhaust valves are the only issue. Either way, its time to pull the head. any suggestions on places to rebuild?
    i did notice on the carfax that the car had many failed emissions tests in california, maybe an O2 sensor was bad and it caused the bank to run lean? i would think Ferrari would have a default safe map it could run on in that event. car is a 99 and heads were cast in Jan 1999.
     
  2. ThomasK

    ThomasK Karting

    Dec 8, 2009
    132
    Houston, TX
    #2 ThomasK, Sep 28, 2017
    also, anyone in Utah that has the head bolt removal tools i could borrow?
     
  3. yelcab

    yelcab F1 World Champ
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    #3 yelcab, Sep 28, 2017
    Head nut removal tool is a 15mm boxed end wrench, 12 points, cut off so that you can use a cheater bar on the other end.
    The proper $500 installation tool is recommended.
     
  4. ThomasK

    ThomasK Karting

    Dec 8, 2009
    132
    Houston, TX
    #4 ThomasK, Sep 28, 2017
    thanks, i may just try to fabricate something
     
  5. Dave rocks

    Dave rocks F1 World Champ
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    #5 Dave rocks, Sep 28, 2017
    As Mitch said, just use a wrench. I sanded down the thickness of my 12 point Snap-On to be able to get into a few locations. IIRC, I had to put a pipe on the end of the wrench to break those nuts free but I did not cut off the other end.

    Image Unavailable, Please Login
     
  6. yelcab

    yelcab F1 World Champ
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    #6 yelcab, Sep 28, 2017
    If you can replicate the installation tool, post a pix and I'll buy one from you
     
  7. johnk...

    johnk... F1 World Champ
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    Jun 11, 2004
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    #7 johnk..., Sep 28, 2017
    tatry68 likes this.
  8. Dave rocks

    Dave rocks F1 World Champ
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    #8 Dave rocks, Sep 28, 2017
  9. ThomasK

    ThomasK Karting

    Dec 8, 2009
    132
    Houston, TX
    #9 ThomasK, Sep 28, 2017
    thanks for the comments, what about head work? any place that anyone recommends?
     
  10. SoCal1

    SoCal1 F1 Veteran
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    #10 SoCal1, Sep 28, 2017
    I would try some upper end cleaner and see if the numbers improve. These cars are notorious for carbon buildup on the valve seats
     
    Pangea likes this.
  11. ThomasK

    ThomasK Karting

    Dec 8, 2009
    132
    Houston, TX
    #11 ThomasK, Sep 28, 2017
    that was my first thought, but looking at the top of the valves i couldnt see much caked on carbon. ill have to scope it tonight and see if i see anything that looks like either build up or valve damage.
     
  12. Dave rocks

    Dave rocks F1 World Champ
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    #12 Dave rocks, Sep 28, 2017
    Watch this video I did. Tim is 100% correct.

     
    [email protected] likes this.
  13. yelcab

    yelcab F1 World Champ
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    #13 yelcab, Sep 28, 2017
    You know, I would be tempted to drive the piss out of that engine for a year and see where it is. But I understand if you want to tear into it right now.
     
    308 GTB and MAD828 like this.
  14. plugzit

    plugzit F1 Veteran
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    #14 plugzit, Sep 28, 2017
    Me too. Do you know the former owner? Did he drive it like a little old lady? These cars accumulate carbon like crazy if you don't run the revs up very near or to redline every time you drive it.
     
    MAD828 and Dave rocks like this.
  15. INTMD8

    INTMD8 F1 Veteran
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    #15 INTMD8, Sep 28, 2017
    Perfect reason for a track day. :D
     
    308 GTB likes this.
  16. fatbillybob

    fatbillybob Two Time F1 World Champ
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    #16 fatbillybob, Sep 28, 2017
  17. itsablurr

    itsablurr Formula 3

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    #17 itsablurr, Sep 28, 2017
    Ferrari part sex change...

    ...what does it do?
     
  18. smg2

    smg2 F1 World Champ
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    #18 smg2, Sep 28, 2017
    are you looking to send them out complete and have them repaired as needed or are you stripping them down?
     
  19. Drock28

    Drock28 Formula 3

    Jan 13, 2013
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    #19 Drock28, Sep 29, 2017
    ok.. so now this is a fresh thread on Compression/leakdown results.. I have some questions..

    obviously bank 1-4 looks like the weaker side with matching, not as ideal compression/leaddown results..

    so simply put, what is the harm, danger, risk, side effects.. to just run the car as is..?

    to the OP, was the car otherwise running, idling, driving normally before taking the engine out..?

    can there be a distinct difference driving back to back this car and then a car with the most ideal results..?

    im just trying to understand why, that as soon as the results aren't the best.. it means an automatic rebuild.?

    lastly what would be the max leak down range.. that for sure a rebuild would need to be done..?
     
  20. ducrob

    ducrob Formula Junior

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    #20 ducrob, Sep 29, 2017
    Had mine rebuilt with 18 new valves by TEM Performance in Napa Valley, Cal. Great guy, great reputation, great work.
     
  21. kenneyd

    kenneyd Formula 3

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    #21 kenneyd, Sep 29, 2017
  22. yelcab

    yelcab F1 World Champ
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    #22 yelcab, Sep 29, 2017
    15mm is the size.
     
  23. kenneyd

    kenneyd Formula 3

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    #23 kenneyd, Sep 29, 2017
    That sucks, if it was 14mm or 19mm you would be fine with a 9/16 or 3/4
     
  24. Dave rocks

    Dave rocks F1 World Champ
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    #24 Dave rocks, Sep 29, 2017
    The clearance to access those nuts is less than wonderful. A 12 point is really needed as the amount of arc you have to swing the wrench is very minimal.
     
  25. yelcab

    yelcab F1 World Champ
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    #25 yelcab, Sep 29, 2017
    Dave, how about a head install tool, 355 style, for $200. Don't need to make the end removable, just one piece. That Hill tool is sexy and all but I am not sleeping with it. $500 is steep.
     
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