308 Cam Belt Lower Sprocket Seals | FerrariChat

308 Cam Belt Lower Sprocket Seals

Discussion in '308/328' started by AndrewE, Nov 8, 2014.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. AndrewE

    AndrewE Karting

    Aug 29, 2008
    123
    Sevenoaks, England
    #1 AndrewE, Nov 8, 2014
    Last edited by a moderator: Sep 7, 2017
    Hi - After having new upper cam seals and belts fitted we have now found a biggish leak on the lower belt sprockets seals.

    I gather there are two designs - one with the seal on the outside of the sprocket cover (see items 28/29/30 on the attached exploded view) and another with the seal on the inside (items 35/36/37)

    It seems that the design changed at engine 01105 on the dry sump engines (see parts table from the hard copy i have)

    It seems that to change the later design it needs an engine out :shocked:

    So has anyone had to change these seals ? and were you able to get the sprocket cover off without the engine coming out?

    Also can anyone help confirm that my understanding of the design change DID happen from engine 1105 (my engine is 1434)
    Image Unavailable, Please Login
    Image Unavailable, Please Login
     
  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,794
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    No, the seal (and the outer bearing) can be done on the later design without removing the engine nor the timing case cover -- it just requires using the bearing puller with the flattened ball studs that fit into the ball raceways (after breaking the cages and sliding the balls around to give space. And, even if you had the earlier design, replacing those seals without replacing the outer bearings would be insanity -- so they need the same puller too. Many prior threads with photos here...
     
  3. AndrewE

    AndrewE Karting

    Aug 29, 2008
    123
    Sevenoaks, England
    Thanks Steve

    any links to prior threads as my earlier search wasn't very productive

    Andrew
     
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,794
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
  5. Ehamilton

    Ehamilton F1 Rookie
    Rossa Subscribed

    Jun 13, 2010
    2,635
    Durham, NC; USA
    Full Name:
    Eric Hamilton
    I finished doing this job just this summer, with the engine in. Not hard at all with the magic bearing puller.

    (Although because I'm that sort of person :eek: I spent a day or so messing around with grinders and welder trying to improvise something before I gave up and bought the right tool).

    You'll need the special socket for the nuts on the end of the cam drive shafts. I replaced mine with hex nuts from Superformance.
     
  6. Brian Harper

    Brian Harper F1 Rookie
    Owner Silver Subscribed

    Feb 17, 2006
    4,078
    San Jose area
    Full Name:
    Brian Harper
    ...because there's a high likelihood the reason those seals are leaking is because the bearing is shot and the shaft is wobbling around.
     
  7. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,794
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
  8. AndrewE

    AndrewE Karting

    Aug 29, 2008
    123
    Sevenoaks, England
    Eric,

    Thanks

    did you have any trouble locating the seal in exactly the right place (did you make a tool to help it seat?) also was the fact that the seal has to pass over a circlip groove any issue?

    Andrew
     
  9. andyww

    andyww F1 Rookie

    Feb 7, 2011
    2,775
    London
    Just had to pass a seal over a groove and keyway on a shaft this morning (on a Sanden A/C comp), used aluminium foil tape around the shaft.
     
  10. Albert-LP

    Albert-LP F1 Veteran
    Owner Rossa Subscribed

    Sep 1, 2010
    8,171
    around Modena, Italy
    Full Name:
    Alberto Mantovani
    #10 Albert-LP, Nov 9, 2014
    Last edited: Nov 9, 2014
    that's a very interesting reading. I have the same leak on my dry sump car 34465 and my mechanic (No. 1 vintage Ferrari mechanic in the world as popularity) shop says that it requires an engine out service: i will inform him immediately. He says that from engine 01105 the seal is inside the engine and they cannot change it without taking out the engine. Maybe this time they need to learn something.

    Thank you (all) very much!

    ciao
     
  11. AndrewE

    AndrewE Karting

    Aug 29, 2008
    123
    Sevenoaks, England
    Steve,

    I did so late last year (Christmas Eve actually)

    'Just got this back from Ferrari,

    Regarding your kind request we inform you that the manufacturing date of your car is October 1979.

    So Chassis Nr 29875 (Euro RHD Dry sump carburettored - engine number 01434 fitted when built) is built in Oct 79 and first registered January 1981'

    Andrew
     
  12. Steve King

    Steve King F1 Rookie

    Feb 15, 2001
    4,367
    NY
    I did bearings and seals on my 77 last fall after discovering the leaks. I was a little fear full at the time but once I got into the job it was pretty simple. Just like doing a belt change which I did at the same time. I had the old seal/bearing set up and I replaced the original set. The seal was hard as a rock and I used the screw and pull method to remove it. Took out the outer bearing by breaking the cage and used a ball end socket wrench with two flats in between the balls. Just pulled it out without a problem. reassembled new parts and job done. Easier then I thought it would be. Belt changes were done every 3-4 year at about 2500 miles a year. It was a cheap investment for me as I could not afford the cost of a broken belt and didn't want the fear of the potential grenade going off. Call it mental insurance.
     
  13. Ehamilton

    Ehamilton F1 Rookie
    Rossa Subscribed

    Jun 13, 2010
    2,635
    Durham, NC; USA
    Full Name:
    Eric Hamilton
    I used tape around the shaft so the keyway wouldn't tear up the inner lip of the seal. The outer lip is rigid and easily wide enough to bridge the circlip groove without difficulty. Centering the seal properly was no harder than with any other oil seal on any other car - I positioned it, placed a flat piece of wood over of the edge, tapped gently with a hammer working around the rim until it was started. Once started, I found some suitable round object (don't remember what, might have been a stray PVC plumbing fitting or the outer race of the old bearing) as a driver to send it the rest of the way home.
     
  14. AndrewE

    AndrewE Karting

    Aug 29, 2008
    123
    Sevenoaks, England
    Thanks - I can see it being easy with the design where the seal is outside the sprocket housing

    Anyone any tips for the design with the seal inside the housing as there will not be anything for the seal to home onto


    Sent from my iPhone using Tapatalk
     
  15. waymar

    waymar Formula 3

    Sep 2, 2008
    1,354
    Northeast, PA - USA
    Full Name:
    Wayne Martin
    On my '82 I started the seal then followed it in with the C ring. Then I drove the C ring in until it seated and the seal was pushed only to the extent of the C ring.
     
  16. AndrewE

    AndrewE Karting

    Aug 29, 2008
    123
    Sevenoaks, England
    Thanks,

    so sounds like its very doable without an engine out and with a bit of care
     
  17. Hannibal308

    Hannibal308 F1 Veteran

    Jan 3, 2012
    7,177
    Arizona / Hawai’i
    Full Name:
    Hannibal
    I'm getting ready to tackle this job and have read the sticky threads on this, but was wondering if anyone has some better pictures of the two differing seal arrangements. A high quality diagram would also serve. I look at the WSM, but the detail is not so great. If not, I'll still do it, but will just figure it out as I go...and take pics along the way. My 77 dry sump should have the older arrangement and I know they have never been replaced. Great info here, so thanks for posting.

    Not sure if it's possible but this thread would be nice to tag to the end of the sticky DIY on the same subject...most of us read those first, but end up unaware that there are some really, really great "spin off" threads on the same topic that often contain additional info that can help us.

    Ciao!

    Hannibal
     
  18. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,794
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    There's a good cross-section figure of the later design in the Mondial8/QV WSM.
     
  19. Hannibal308

    Hannibal308 F1 Veteran

    Jan 3, 2012
    7,177
    Arizona / Hawai’i
    Full Name:
    Hannibal
    Great...I'll look at it and factor in the described difference for the old design.

    Thank you!
     
  20. AndrewE

    AndrewE Karting

    Aug 29, 2008
    123
    Sevenoaks, England
    So the team at the workshop are going to give the 'let's try getting the bearing and seal out without taking the engine out' method.....will see in a day or so how they get on.

    Feels like I have given them a challenge!


    Sent from my iPad using Tapatalk
     
  21. Bell Bloke

    Bell Bloke Formula 3

    Dec 6, 2012
    1,839
    UK
    What about the inner bearings, Gents? :)
     
  22. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    13,562
    San Carlos, CA
    Full Name:
    Mitchell Le
    Not much of a challenge if you have the right tool.
     
  23. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    13,562
    San Carlos, CA
    Full Name:
    Mitchell Le
    Almost never fails.
     
  24. AndrewE

    AndrewE Karting

    Aug 29, 2008
    123
    Sevenoaks, England

    Even for inner seal removal/ replacement?

    Is there a 'right' tool for that?



    Sent from my iPhone using Tapatalk
     
  25. waymar

    waymar Formula 3

    Sep 2, 2008
    1,354
    Northeast, PA - USA
    Full Name:
    Wayne Martin
    On my 82 I used a basic seal hook. Pulled it out on 3 different points a little at a time until it twisted enough to slide out.
     

Share This Page