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348 compression #s -- confusing results

Discussion in 'Technical Q&A' started by 348SStb, Oct 21, 2005.

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  1. 348SStb

    348SStb F1 Rookie
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    Apr 9, 2004
    2,991
    Palm Beach County, FL or Nassau County, NY
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    Dave
    #1 348SStb, Oct 21, 2005
    I had some work done on my 348 at a Ferrari dealer's repair facility and I have a few questions.

    I had both a compression test and a leak-down test done on the car. The leak-down numbers read about 3-5%, so all 8 cylinders look good from that perspective.

    However, the compression results read about 115 psi (7.9 bar) in each of the 8 cylinders. Is this normal? I was expecting a number between 180 and 200. Why would the numbers be so low?

    Also, a part in the air recirculation system broke and apparently the part is no longer made by Ferrari. The dealer said there is no actual part number because it is a part within the air conidtioning system. Here's how he told me to describe the part: the part is a plastic key that opens and closes the door for the air recirculation system. When the door is open, the air comes in from the outside; and, as you can guess, when it's closed, air within the cabin is recirculated. The door is an actuator door for the air recirculation motor, and the motor directs this little key to open or close the door. This little plastic key is broken, and it's the part that I need.. Does anyone know anything about this issue? Can anyone help me find the part?

    Thanks guys!
     
  2. tomoshea

    tomoshea Formula Junior

    Dec 29, 2003
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    Tom O'Shea
    #2 tomoshea, Oct 21, 2005
    Highly likley that whoever did the test did not have the throttle fully open i.e pedal to the floor so air flow meter fully open(no air going into the cylinders gives a much lower psi reading)

    Does not say much about whoever did the job!

    If this was not the case then something very strange is happening.
     
  3. BT

    BT F1 World Champ
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    #3 BT, Oct 21, 2005
    I am pretty sure you can get a brass replacement of the recirc part from either Trutlands or FerrariUK. If you do a search for 348 recirc I think you will find it. I read a thread about two-three months ago about it. Apparently the factory part breaks pretty easily.
    BT
     
  4. Miltonian

    Miltonian F1 Veteran

    Dec 11, 2002
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    Jeff B.
    #4 Miltonian, Oct 21, 2005
    Punch up the Ricambi America website, and enter RC348 in the quick search box. There's the piece in question.

    I agree that it sounds like the person who did your compression test didn't have the throttle open while cranking the engine over. Or else the battery was too weak to crank the engine over at the proper speed. Or the air filter is completely clogged. Or there are rat nests in your air intakes.
     
  5. BT

    BT F1 World Champ
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    Mar 21, 2005
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    #5 BT, Oct 21, 2005
    If Ricambi does not have the item in stock, you can order it through Hill Engineering.
    It is part number RC-348 on the page:
    http://www.customferrariparts.com/homemainferrari.htm
    Brass and more durable than stock. Price is 28 pounds plus shipping.
    Good luck!
    BT
     
  6. tbakowsky

    tbakowsky Two Time F1 World Champ
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    Sep 18, 2002
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    #6 tbakowsky, Oct 21, 2005
    ...or the timing could be out
     
  7. 348SStb

    348SStb F1 Rookie
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    #7 348SStb, Oct 21, 2005
    Wow.

    You guys are the best. That looks like the part I need.

    Thanks guys!

    As for the other thing, I tell ya, I hear different things from all different sorts of people about what the numbers should be.

    What would the numbers be if the proper methodology were used? That is, if a technician were to do it properly, what would the results of a compression test be on a healthy 348?
     
  8. tbakowsky

    tbakowsky Two Time F1 World Champ
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    #8 tbakowsky, Oct 21, 2005

    Should be in the 180 range. But when they do the test be sure to disable the fuel pumps and the ignition..easy to do by pulling fuses. Yes the throttle should be wide open aswell and all plugs out of the engine. Remeber a variance of 10% is normal for readings. So if you have one cylinder at 180 and another a 175 your still ok.
     
  9. Dave

    Dave F1 Rookie

    Apr 15, 2001
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    David Jones
    #9 Dave, Oct 21, 2005
    I concur.
     
  10. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
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    #10 Artvonne, Oct 22, 2005
    I also concur, but really, the leakdown should tell the truest story. Basically, both tests show all cylinders being equal, so no real problem to be concerned about. But now if the valve timing is off as stated earlier, well........
     
  11. brm

    brm Karting

    Apr 26, 2002
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    Tampa, FL
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    Bruce R. Morehead
    #11 brm, Oct 23, 2005
    You can make the a/c part from a 1/4 inch drive short extension. The drive fits the motor and you grind a flat on the shaft to fit the flap. Mine works fine.
     
  12. PassionIsFerrari

    PassionIsFerrari Formula 3

    Aug 15, 2004
    2,454
    #12 PassionIsFerrari, Oct 23, 2005
    How much do dealers charge for a leak down and/or a compression test?
     
  13. TomDial

    TomDial Rookie

    Aug 6, 2004
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    Chris
    #13 TomDial, Oct 23, 2005
    The leak down test is the better way of testing compression. IMO everything is great with your engine.

    Do all Ferrari dealers refuse to buy unavailable parts on the "free" market and instead quote the customers car irreparable?

    Funny…
     
  14. 348SStb

    348SStb F1 Rookie
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    #14 348SStb, Oct 23, 2005
    I don't know yet, as I haven't yet received my bill :D
     

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