348: Front cam seal leak

Discussion in 'Technical Q&A' started by Ricambi America, Jun 2, 2004.

  1. Ricambi America

    Ricambi America F1 World Champ
    Sponsor Owner

    I have a slight leak on my front cam seal in a 1990 348. By "leak", I mean a drop of oil is present, but certainly not a stream. I've noticed nothing excessive in terms of oil consumption (leak or burn!). Belts are not being contaminated.

    When the car was on the lift today (getting a track inspection), the mechanic @ Foreign Cars Italia suggested that I just drive the car and not worry about it until the next 30K service -- which is 28K miles away. That seems like a funny statement from a dealer who stands to make 45 hours of labor if I opt to pull the engine and replace the seal.

    On the other hand, replacing the seal might be a great winter-project for learning how to pull the engine. The seal itself is probably a 1 hour job, right?


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  3. tbakowsky

    tbakowsky F1 World Champ
    Professional Ferrari Technician Consultant

    Sep 18, 2002
    The Cold North
    Full Name:
    Might as well change all the seals while your in there. There are 4 of them and inbehined the seal is an o-ring that should be changed also. To change them requires removal of the camshafts. Not difficult, but you must becareful when retightening the cam down. It takes about an hour to change both seals and o-rings on one side. Obviously you need to remove the cam covers and the timing belt must be removed to do this. But you will be doing a major anyway so no big deal.

    Are you sure that it's the cam seal and not the cam cover gasket leaking? It's very common for a leak at the cam cover to be confused of a cam seal leak. I would clean the area thats dirty and then drive around a bit and re-check. Cam seal leaks on earlier 348 are common though, so he is more then likely correct.
  4. slewman

    slewman Karting

    May 4, 2004
    There are service bullitens on the early 348 oil leaks. The cam seal housings get updated will improved drain back. A new oil return hole is drilled in the 1-4 head behind the exhaust cam seal housing . Last thing when you adjust the timing belt tension you will need a Staeger Gauge. If you are 28k from a full service, then some one just finished a service 2k ago and they are responsible.
  5. brian.s

    brian.s F1 Rookie
    Professional Ferrari Technician

    Nov 3, 2003
    Full Name:
    Interesting comment on rsponsibility. I wonder what the general feeling is about that among the professional techs here? I know that I tend to eat too much under these types of circumstance, but the responsibility is not really all in the tech's hands IMO.

  6. fatbillybob

    fatbillybob F1 World Champ
    Consultant Owner

    Aug 10, 2002
    Your mechanic is right leave the small leak. Most of these cars leak infact I have seen very few which do not leak. Cam seals are not a quick 1 hr job because you have to take the engine out. You can't change the seals and do the belt with the engine in.
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  8. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    The Brickyard
    Full Name:
    The Bad Guy
    I agree with Billybob. Leave it be until the next engine out service. If it is a drop here and there you'll be okay. The engine must come out to do this job. But once it is out the seals aren't hard to change. An hour sounds about right to do them. But that is after you have the engine out, the timing belt and the cam covers off. So just wait until your next major to tackle it. But do keep an eye on the drip.
  9. parkerfe

    parkerfe F1 World Champ

    Sep 4, 2001
    Cumming, Georgia
    Full Name:
    Franklin E. Parker
    A full cam belt/seal service can be done on a 348 without removing the engine. You do have to remove the gas tanks though. That's how Shelton did the major on my ex-348 Spider.
  10. ferrarioldman

    ferrarioldman Formula 3
    Silver Subscribed Professional Ferrari Technician

    Jun 19, 2002
    Summerfield, NC
    Full Name:
    Tom Jones
    #8 ferrarioldman, Jun 7, 2004
    Last edited by a moderator: Sep 7, 2017
    These pictures verify what Slewman said about the drain holes behind the exhaust cam seals. A special jig is required for this. Wish I had taken pictures of the cam seal housings but a groove has to be cut and placed in line with the drain holes to make the oil draining process effecient.
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