308 engine bearing blocking oil flow? | FerrariChat
Buy

308 engine bearing blocking oil flow?

Discussion in 'Technical Q&A' started by hammerson, Feb 9, 2009.

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

  1. hammerson

    hammerson Rookie

    May 1, 2008
    33
    Massachusetts
    Full Name:
    T.Hammerson
    #1 hammerson, Feb 9, 2009
    1978 308 GTB engine. Replacing two bearings for the cam drive shafts. These are the two shafts that drive the cam belts from the engine, and these are the two INNER bearings.
    Stock, these bearings are non-sealed. There is one oil passage behind each bearing allowing engine oil to pass through the bearing itself !!!

    The replacement bearings (SKF 6201) are apprently not available as non-sealed bearings anylonger(?), so I had to buy a sealed version of the bearing.
    The plan was to peel the seals off the bearings and then install them.
    When peeling the seals off, I realize that the "cage" that hold the actual balls in place inside the bearing are much more restrictive to oil flow than the original bearings in this engine.
    Do I stop here and look for another set of bearings (non-sealed), or do I continue ?

    I do not have a good feeling for the volume of oil that needs to pass through these bearings, and would hate to create a problem !
    .... so I worry, and thus post my question here.
    (Can show pics if needed)
    Thanks,
    Hammerson
     
  2. 350HPMondial

    350HPMondial F1 Veteran
    Silver Subscribed

    Feb 1, 2002
    5,325
    18 mi from the surf,, close to Pismo, CA
    Full Name:
    Edwardo
    #2 350HPMondial, Feb 9, 2009
    Last edited by a moderator: Sep 7, 2017
  3. hammerson

    hammerson Rookie

    May 1, 2008
    33
    Massachusetts
    Full Name:
    T.Hammerson
    #3 hammerson, Feb 10, 2009
    The 6201 bearing is 12x32x10 mm. I will keep searching for one that is "open" without seals.
    Seems too risky to use a sealed bearing without the seal with apparently restricted access for the oil to flow through it.
    Thanks,
    H
     
  4. FF8929

    FF8929 Formula Junior

    Apr 12, 2008
    799
    Livonia, Michigan
    Full Name:
    Fred Flynn
    #4 FF8929, Feb 10, 2009
    Last edited: Feb 10, 2009
    Try All Ferrari Parts, in Ohio.
     
  5. Artvonne

    Artvonne F1 Veteran

    Oct 29, 2004
    5,379
    NWA
    Full Name:
    Paul
    #5 Artvonne, Feb 10, 2009
    I have the bearings out on my early 77 308 (march 77). Both bearings are SKF 6203/C4. While I havnt yet replaced them and havnt researched whats available, you can clearly see these were sealed bearings someone popped the seals out of. While I dont have any idea when these were installed, based of other evidence I would say it was quite some time before. 10 years prior wouldnt suprise me. And these were still very quiet in operation and show no looseness.

    A bearing supply company should be able to see the specs of the various bearings and advise as to the compatibility. Remember, bearings of simular dimensions often have different running clearances for different applications and that is usually the reason for a different part number (6201/6202/6203 etc.. As long as the replacement has simular running clearance, same number and size balls, there should not be any problems. More than likely the 2Z/C2/C3/C4, has something else to do with the bearing, running clearance, number or type oil seal, etc..

    The oil feed holes in the cover are gravity feed via splash coming off the gear train. I highly doubt the more restrictive cage is going to cause any trouble, so again, I would be more concerned with the bearings running clearance than the cage causing any percieved oil restriction. At the speed that bearing is rotating, the balls are going to be every bit as restrictive to oil flow as the cage. Perhaps more so.
     
  6. hammerson

    hammerson Rookie

    May 1, 2008
    33
    Massachusetts
    Full Name:
    T.Hammerson
    #6 hammerson, Feb 11, 2009
    Thanks for great feedback Artvonne !
    Not sure that my inner bearing dimension is different because of a later revision, or because I have a drysump engine where there is an additional oilpump inside the aluminum cover that the two cam drive shafts come through.
    ... anyway, thank you again.
    H
     

Share This Page