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Dark Day! Info Please

Discussion in 'Technical Q&A' started by 50hdmc, Jan 8, 2009.

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  1. 50hdmc

    50hdmc Formula 3

    Oct 10, 2006
    1,211
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    mark s
    #1 50hdmc, Jan 8, 2009
    Well, in the process of a 30k on my '90 348, I have discovered that the drive pulley wiggles all over and the fence is loose. Question, I assume I have to purchase a special tool to remove the lock nut, what else am I likely going to find once I get that done. Everything seemed ok too...celebrating too soon. But, I guess this is why you do the maintenance. Ok fella's give me the rest of the bad news....

    thanks
    mark
     
  2. Miltonian

    Miltonian F1 Veteran

    Dec 11, 2002
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    Jeff B.
    #2 Miltonian, Jan 8, 2009
    Very sorry to hear that, Mark. Can you post pictures?

    By "drive pulley" I assume that you mean the toothed gear at the bottom of the timing belt. I can't imagine why this would be wiggling, but either the ring nut is loose, or the keyway on the driven gear has failed, or the bearing for the driven gear has failed. At least that pulley isn't attached to the nose of the crankshaft. I understand that it is fairly common for the fence to work loose, it can be spot welded back onto the gear if the gear itself is OK.

    I'll be interested to see what you find.
     
  3. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
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    Brian Crall
    #3 Rifledriver, Jan 8, 2009
    Last edited: Jan 8, 2009
    Bearing failure of the lower drive pulley on an early 348 should be considered normal. Very underengineered. Even the updated bearings are too small. The later cars changed the block design to accept larger bearings.

    Lots of bits and pieces for the update. Contact Ricambi.
     
  4. troy_wood

    troy_wood Formula 3

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    Troy Wood
    #4 troy_wood, Jan 8, 2009
    Last edited by a moderator: Sep 7, 2017
    Hi Mark,

    Don't panic - at least you didn't throw the t-belt.

    1. When you say that "the drive pulley wiggles all over", can you qualify what you mean here? When the t-belt is off it is normal to be able to rotate the drive pulley back and forth a bit as it is just taking up the chain slack.

    2. You can make one of these (from f-chat member jqpd99) to remove the pulley and spot weld that fence:
    Image Unavailable, Please Login
     
  5. Ricambi America

    Ricambi America F1 World Champ
    Sponsor Owner

    Dec 7, 2003
    16,464
    Winston Salem, NC
    #5 Ricambi America, Jan 8, 2009
    Last edited by a moderator: Sep 7, 2017
  6. troy_wood

    troy_wood Formula 3

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    Troy Wood
    #6 troy_wood, Jan 8, 2009
    Check your vehicle assembly number on the shock tower. If it is lower than 4384 you then need to check your maintenance records to see if it has had the upgrade. If not then you need to talk to Daniel.
     
  7. 50hdmc

    50hdmc Formula 3

    Oct 10, 2006
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    mark s
    #7 50hdmc, Jan 8, 2009
    I think my terminology had something to desire......Rifledriver is right I beleive. It is the lower drive gear I am speaking of. The fence rotates - should I weld it or purchase another gear (and weld that one too). thanks for the pic of the tool. I made one similarly by grinding a socket down but it wasn't strong enough. The movement I am speaking of isn't along the shaft but side to side.

    Rifledriver, what do I need to order to make this repair? (Or anyone else who may know - I appreciate any info/advise I can get).

    Well, maybe I can sleep tonight afterall!!

    mark
     
  8. 50hdmc

    50hdmc Formula 3

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    mark s
    #8 50hdmc, Jan 8, 2009
    Sorry Brian.....I see you had answered my question. I will call them tomorrrow for the "bits and pieces". Thanks.

    Thanks for all the responses...REALLLY appreciate it.

    Troy - is your car done now?

    WOW - I feel for ya on those bent valves - geez, that scares the heck out of me!
    ms
     
  9. FF8929

    FF8929 Formula Junior

    Apr 12, 2008
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    Fred Flynn
    #9 FF8929, Jan 8, 2009
    Been there, done that. 50hdmc was very lucky.
     
  10. fatbillybob

    fatbillybob Two Time F1 World Champ
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    #10 fatbillybob, Jan 8, 2009
    Last edited by a moderator: Sep 7, 2017
    You can see the bearing here and check the plastic crappy thing that monitors the chain. Those break all the time. Do a search for exploded pictures of of this problem.
    Image Unavailable, Please Login
     
  11. fatbillybob

    fatbillybob Two Time F1 World Champ
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    #11 fatbillybob, Jan 8, 2009
    Fences may or maynot be that critical. If the parallelism is correct you should not need the fence IIRC from DaveHelms. For example my 348 had them and my 550 does not use any fence to retain the belts at all. Perhaps the 348 being a giant single belt fences were a good idea. I can't remember if there were fences on other ferraris. They where a detail I just overlooked.
     
  12. Modeler

    Modeler F1 Veteran

    May 19, 2008
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    a.n.other
    #12 Modeler, Jan 9, 2009
    Last edited by a moderator: Sep 7, 2017
    Not Ferraris but have a lot of experience with early steam and horse driven machinery. Almost all had no fences on their pulleys, despite high rpm and belt speed.
    If anything, fences seem a source of belt damage.
    Image Unavailable, Please Login
     
  13. troy_wood

    troy_wood Formula 3

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    #13 troy_wood, Jan 9, 2009
    Can we make the assertion that the bearing failier caused the fence failier (mis-aligned belt riding the fence)? If so, I wonder if poor belt alignment is causing the majority of these fence failiers...
     
  14. 50hdmc

    50hdmc Formula 3

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    mark s
    #14 50hdmc, Jan 9, 2009
    ................called Daniel at Ricambi today and have the parts on the way....THANKS for all your help!!!!!!!!!!!!!!
     
  15. Rifledriver

    Rifledriver Three Time F1 World Champ

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    Brian Crall
    #15 Rifledriver, Jan 9, 2009
    In Daniels case and some others I have seen, because of the poor fastening of the fence to begin with and the large diameter of the pulley the centrifugal force dislodges the fence and it gets caught up in the belt. That is the blamo Daniel described. The wobbly pulley on the otherhand is usually the fault of a failed lower drive bearing.
     

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