Part Number Help for '85 QV Damper/Pulley | FerrariChat
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Part Number Help for '85 QV Damper/Pulley

Discussion in '308/328' started by Alex308qv, Jul 21, 2022.

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  1. Alex308qv

    Alex308qv Formula Junior

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    #1 Alex308qv, Jul 21, 2022
    Can someone please help me with the part number for the damper pulley for my US 308GTS QV, May 1985 build, #057973? Not finding it through searches. See picture, it has three belt grooves (inner for York A/C, water pump, outer for alternator). My outer pulley has a dent and the p/n will help me find a correct replacement. Thank you.
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  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #2 Steve Magnusson, Jul 21, 2022
  3. bitsobrits

    bitsobrits Formula Junior
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    #3 bitsobrits, Jul 21, 2022
    I would be inclined to just straighten the pulley. Remove the pulley, grind up a V shaped bar to use as a mandrel, heat the bent area, and use your new mandrel and a hammer to tap your way to straightness.

    You don't have to be from India to use heat and hammers. Being from the farm country helps, though.
     
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #4 Steve Magnusson, Jul 21, 2022
    +1 -- the resourcefulness of those typical Indian repair youtube videos are scary, inspirational, and remarkable -- like Farmers ;)
     
  5. thorn

    thorn F1 Rookie
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    #5 thorn, Jul 21, 2022
    You wouldn't worry about it not being in balance?
     
  6. Alex308qv

    Alex308qv Formula Junior

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    #6 Alex308qv, Jul 21, 2022
    There is no discernable wobbling or out of balance... just the bent rim. While I might look into heating/bending it back in shape, is there any other resource that lists the correct part number?
     
  7. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #7 Steve Magnusson, Jul 21, 2022
    Maybe you are right to be concerned about what part number. I found another 361/85 SPC reference that says 122869 is for the two-belt system with the Sankyo AC Compressor, and the 10-10 Service Bulletin shows another (different) one for the two-belt system, 121570:
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  8. Alex308qv

    Alex308qv Formula Junior

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    #8 Alex308qv, Jul 21, 2022
    Thanks Steve but mine is a 3-belt system per OP, which seems Ferrari switched to during the QV run. Hoping to find the 3-belt p/n.
     
  9. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #9 Steve Magnusson, Jul 21, 2022
    You are miss understanding me (and Ferrari):

    singe belt = water pump and alternator driven by same belt (system has 2 total v-belts)
    two-belt = water pump and alternator driven by separate v-belts (system has 3 total v-belts)

    See pictures of 121570 (with 3 v-belt grooves) here:

    https://www.ferrariparts.co.uk/part/ferrari/121570?id=66527
     
  10. bitsobrits

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    #10 bitsobrits, Jul 21, 2022
    Not at all. Heating/bending does not add/subtract or radially redistribute mass, so no concerns there. I would be concerned about ensuring accurate belt alignment and it's impact on belt life. But this isn't rocket science, and truing a belt pulley within a few thou runout can be done without specialist equipment.
     
  11. Alex308qv

    Alex308qv Formula Junior

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    #11 Alex308qv, Jul 21, 2022
    Yes I certainly was! Now I get it - two-belt means three belts. So, looking at picture of 121570 you kindly sent me, its outer pulley diameter is smaller than mine. My outer pulley diameter is almost the same as the damper ring diameter, and that 10-10 Bulletin is "through '84," so something may have changed for '85. So maybe the other 122869 is my p/n, but that says for Sankyo AC, whereas mine has York.

    Right now I feel like finding the right part requires matching dimensions and photos, versus by p/n. It's pushing me in the heat/hammer direction. Appreciate all you've sent me to help!
     
  12. smg2

    smg2 F1 World Champ
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    #12 smg2, Jul 21, 2022
    Technical info incoming...
    Belts are driven by the sides or 'face' that face on the pulley is called a 'sheave' and that sheave face is convex.
    Depending on how much is been dented it can either be easy enough with little drama to fix or tweaked enough that the face in that spot no longer contacts the belt correctly and abnormal wear is introduced.

    Is the dent effecting the sheave face? Interfering with the belt? If not, I'd leave it alone.

    I think we've got a good used one in the spare parts bin.
     
  13. Alex308qv

    Alex308qv Formula Junior

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    #13 Alex308qv, Jul 21, 2022
    Yes it affects the sheave face. You can tell from the picture in my post #1 how it would put an extra squeeze on the belt each revolution. Now, I'm not eating through alternator belts by any means, and for all I know it may have been dropped when the motor was assembled in 1985, but like most of us I'm OCD and want everything on my 308 correct.

    I'm checking with used Ferrari parts places for one, so if you have one please DM me. To help confirm, the OD of the outer pulley is 130mm. The diameter of the "spacer" section between the first and second groove looks like 90mm. Thanks.
     

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