Help needed for persistent distributor shaft oil leak - 308 QV | FerrariChat

Help needed for persistent distributor shaft oil leak - 308 QV

Discussion in 'Technical Q&A' started by ztarum, Apr 18, 2015.

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  1. ztarum

    ztarum Formula 3

    Mar 30, 2008
    1,302
    South Jersey, USA
    #1 ztarum, Apr 18, 2015
    Last edited: Apr 18, 2015
    The seal on the front cylinder bank distributor drive end of the camshaft has had on ongoing leak that I can't seem to stop. It is minor, not getting better or worse, but it is still a nuisance. The oil never makes it to the floor, but makes a mess of the engine and bell housing.

    Over that past 5 years I have changed the seal at least three times with the same results. I'm doing a cam belt change now, so I thought it might be a good time to try again. The prior seals I have removed all looked fine, and were not damaged or rolled. The only thing I can think of is that the seal is running in the exact same spot on the shaft which has now taken too much of a polish to seal effectively.

    Has anyone ever altered the seal installation depth by not pressing it in all the way, or made a spacer so the it seats in a slightly different location? Any other ideas?
     
  2. Beetle

    Beetle Formula Junior

    Apr 10, 2013
    776
    I have had a similar problem though not on a ferrari what did help for me was before installing the new seal was to pack it so to speak with a high temperature grease. It seems to attach itself to the shaft and seals areas prevent oil weeping. Only a suggestion for something that worked for me. Good luck
     
  3. waymar

    waymar Formula 3

    Sep 2, 2008
    1,321
    Northeast, PA - USA
    Full Name:
    Wayne Martin
    On my 308i I found the leak was not between the lip and the shaft but seeping between the metal to metal outer seal to housing. I put some sealant on the outer metal seal before pressing into the housing.
     
  4. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    33,736
    Austin TX
    Full Name:
    Brian Crall
    A Ferrari fix on later cars was to change seal depth, so yes it has been done. There is no such thing as too polished to seal well but that can help if there is damage to the sealing area on the shaft.
     
  5. ztarum

    ztarum Formula 3

    Mar 30, 2008
    1,302
    South Jersey, USA
    #5 ztarum, Apr 19, 2015
    Last edited: Apr 19, 2015
    Thanks. The shaft doesn't appear damaged (no detectable wear ring or ridges that you can feel where the prior seals ran), but I can visually see that it is shiner where the seal was than the original ground finish of the shaft surface. This may not be an issue, but I'm pretty well out of ideas.

    I also considered that maybe it it the o-ring that seals the distributor drive into the end of the cam, but have no way of knowing. Would this be worth changing just to be sure?
     
  6. ztarum

    ztarum Formula 3

    Mar 30, 2008
    1,302
    South Jersey, USA
    Good tip, I will look more closely at that interface. Thanks.
     
  7. ztarum

    ztarum Formula 3

    Mar 30, 2008
    1,302
    South Jersey, USA
    #7 ztarum, Apr 19, 2015
    Last edited by a moderator: Sep 7, 2017
  8. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,574
    The Brickyard
    Full Name:
    The Bad Guy
    #8 ernie, Apr 19, 2015
    Last edited: Apr 19, 2015
    It looks as though you have grooves worn into it.

    Have you thought about sending the cam out and having the end polished to get the grooves removed? It may be a good idea.

    If you go that route, and after it has been micro-polished, you may also want to send your cams to WPC in California to have them apply their treatment process to them. I had WPC treat my cams, shims and cam caps last year when I did my major service. Everything cost me $600ish bucks, and I had my stuff back in a few days. The benefit of the WPC treatment is it puts a microscopic "shot peen" finish on the surface which helps prevent wear, friction, and improve sealing. Here is their site. WPC - Metal Surface Treatment / Micro Shot Peening
     
  9. Turbopanzer

    Turbopanzer F1 World Champ

    Oct 2, 2011
    11,120
    Under a bonnet
    Full Name:
    Panzer
    Ever consider changing o-ring size to create a little more tightness?
     
  10. ztarum

    ztarum Formula 3

    Mar 30, 2008
    1,302
    South Jersey, USA
    It looks that way, but there is no detectable groove. Nothing that can be felt with a finger tip or by running a fingernail along the surface.

    I definitely don't want to pull the cams. I did all the valve adjustments at the last major, so am not planning to do it again this time.
     
  11. Santino1

    Santino1 Karting

    Jun 4, 2014
    101
    Sacramento, CA
    Full Name:
    Daniel
    Take some 1000 grit wet and dry sandpaper, dip the paper in a bit of oil, and give the surface a micro polish. Same situation on my TR major, worked perfect.
     
  12. jlc308

    jlc308 Karting

    Jul 11, 2009
    120
    Irvine CA
    I had the same problem on my 85 308QV and you need to replace the o ring on the distributor drive on the end of the cam. Carefully drive the pin out and pull off the distributor drive and replace o ring. The o ring is clearly shown on the parts diagram.
    I chased this problem like you and change the distributor housing seal three times and did all the suggestions as posted and still leaked. Finally it was the o ring that solved the problem and now totally dry.
     
  13. Prugna

    Prugna Formula 3

    Nov 13, 2014
    2,005
    Unites States
    Our company does this all the time. The problem usually can be traced back (via China) that the new o-ring is not the same as 30 years ago......

    Use the next size UP in O.D.

    Any o-ring from 1985 will likely have originated from Parker, and now any replacement o-ring will have passed through so many hands that the original translalation will have been lost to the mfg in China and back again.
     
  14. Brian Harper

    Brian Harper F1 Rookie
    Owner Silver Subscribed

    Feb 17, 2006
    4,078
    San Jose area
    Full Name:
    Brian Harper
    Bearing and seal suppliers sell shims to go under seals exactly to move the sealing surface to a new spot. If the seal interface is genuinely your problem then this might be an easy answer.

    Easier might be to run two gaskets between the carrier and the head. I don't think this messes with the distributor mounting enough to matter but look and see.

    I have had o-ring issues on my smog pump drive cam. Fitting a slightly larger o-ring seems like a good idea, but the issue I had is that a larger o-ring seems to get damaged/nicked on the way in and leaks. The original size is supposed to be a tight fit as is. I think I might have it solved (so far, maybe?) by using an official Ferrari o-ring lightly lubricated with RTV to help it go in and keep it sealed.
     
  15. jlc308

    jlc308 Karting

    Jul 11, 2009
    120
    Irvine CA
    #15 jlc308, Apr 25, 2015
    Last edited by a moderator: Sep 7, 2017
    Attached is a pdf diagram showing the o ring and part number that needs to be replaced. It is item number 8 and part number 109478. I have done this without removing the cam.
    Image Unavailable, Please Login
     
  16. ztarum

    ztarum Formula 3

    Mar 30, 2008
    1,302
    South Jersey, USA
    Thanks. I was aware of the o-ring and have a couple on hand that I had ordered previously. I am not sure how easy the distributor drive will be to remove with the cam in place, but I will try tomorrow.
     
  17. theunissenguido

    theunissenguido Formula 3
    Owner Silver Subscribed

    Jan 21, 2004
    2,371
    Argent/Brasil
    Full Name:
    Guido
    Let that seal sit 1 mm more inside or outside...so that seal lip will not fall in the old groove.
    You have some play to do this...

    Guido
     
  18. ztarum

    ztarum Formula 3

    Mar 30, 2008
    1,302
    South Jersey, USA
    I changed the o-ring today. The old one looked fine, and I doubt it was the source of the problem although there is no way of knowing for sure. I also installed the new seal at a slightly different depth with a dab of light grease on the seal rubber and a thin film of Hylomar sealant on the seal OD and housing bore prior to installation.

    Thank you all for the suggestions. I'll post the results when I get the car back on the road in a few weeks.
     
  19. theunissenguido

    theunissenguido Formula 3
    Owner Silver Subscribed

    Jan 21, 2004
    2,371
    Argent/Brasil
    Full Name:
    Guido
    What you can do also : spring inside the seal can be reduced so it put more pressure on the cam. Remove that spring, and when looking closely, you will see that there are 2 ends on that spring. One is entering the other side and can be split by turning one side counter clockwise for some turns. After this you cut 1 or 2 mm from the bigger side and put the smaller side back by first turning counter clockwise (the same turns as before),let it sit in that bigger hole and turn clockwise. Seal will be with a smaller diameter.

    Guido
     
  20. ztarum

    ztarum Formula 3

    Mar 30, 2008
    1,302
    South Jersey, USA
    Well, I've had the car out twice after completing the major service and so far so good. No oil drips yet, so it appears that the problem is solved. I can't be sure if it was the o-ring or repositioning the seal that did it, but I'm happy regardless. Thank you to all who offered suggestions.
     
  21. Turbopanzer

    Turbopanzer F1 World Champ

    Oct 2, 2011
    11,120
    Under a bonnet
    Full Name:
    Panzer
    No Problem. Now....when do we get our turn at the wheel for offering all this "expert" advice? :D
     
  22. jlc308

    jlc308 Karting

    Jul 11, 2009
    120
    Irvine CA
    Great, believe me it was the o ring. I chased this problem for months using all the different housing seals and nothing worked because it was not the housing seal. Replacing the o ring on the end of the camshaft solved the problem.

    Happy motoring
     
  23. HielToh

    HielToh Karting

    Oct 6, 2015
    70
    Redondo Beach, CA
    Full Name:
    Beau LeBlanc
    Hi, all. I'm facing a similar seeming issue with quite a bit of oil leaking around my front bank distributor. What concerns me is that the sleeve for the blow-by system is saturated. Is that expected? In pics from other people who have repaired distributor leaks, I haven't seen that sleeve saturated. Image Unavailable, Please Login

    Beau
    via Tapatalk

    ig: @beauschmo
     
  24. waymar

    waymar Formula 3

    Sep 2, 2008
    1,321
    Northeast, PA - USA
    Full Name:
    Wayne Martin
    Check you oil vapor can - clean it out - check the drain line and flow from the oil can to the sump....
     
    Milkshaker0007 likes this.
  25. waymar

    waymar Formula 3

    Sep 2, 2008
    1,321
    Northeast, PA - USA
    Full Name:
    Wayne Martin
    Ferrari made an oil screen 119237. Two of these are used one on each nipple coming from each cam cover. Reduced blow by oil. There is a service bulletin on this. Just saying.....
     

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