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Fan clutch differances....

Discussion in 'The Garage' started by CK5, Dec 28, 2005.

  1. CK5

    CK5 In my underwear Administrator Premium Member GMOTM Winner Author

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    So I am at the boneyard today and picked up a clutch fan off a 1982 6.2 diesel because it was a monster 7 blade job, didn't think much about it until I got home and noticed that it has the larger big block mounting pattern.

    I have a 1990 with full serpinteen (sp?) belt setup with the smaller mounting pattern, oh crap says me, then I think, maybe I can just get a different clutch and still use the large 7 blade factory fan, then I notice that the clutch mounts to the fan with a 6 bolt pattern deal.
    It has been a few years since I ran the stock fan clutch, but thought the 350 version clutch mounts to the fan with 4 bolts, oh crap again.

    Is there a fan clutch application that mounts the clutch to the fan with a 6 bolt pattern and then mounts the clutch to the water pump with the smaller 4 bolt small block pattern?

    P1010040.JPG
     
  2. WhiteBurb

    WhiteBurb 1/2 ton status

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    Is your 90 a stock gas engine? If so, I'm pretty sure the fan blade is reverse rotation from the older 82.
     
  3. CK5

    CK5 In my underwear Administrator Premium Member GMOTM Winner Author

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    Yeah, stock gas.
     
  4. opfor2

    opfor2 1/2 ton status

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    It won't work. Our 90's are reverse rotation and the rotate the "other" direction than the vehicle you pulled the fan off of.

    Sorry,

    Dan..
     
  5. diesel4me

    diesel4me 1 ton status Premium Member

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    might be..

    I don't know the answer to your question about the 7 blade fan and 6 bolt clutch availability for the small bolt pattern pumps...could be some factory wierdo setup like that is on something..???:dunno:

    I have used the 7 blade HD fan on the small bolt patten fan clutches that were on my 6 bangers and small blocks..I got mine off of Chevy Impala's and Caprice's (old police cruisers)-with HD cooling and AC..I think they were "V" belt motors though,not serpentine..

    I think a Caddy fan MIGHT work too,on the BBC and 6.2 bolt pattern water pumps....not sure,I got one off a 500 and I used it on my 454 in one of my trucks once....:crazy:
     
  6. beater_k20

    beater_k20 Banned

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    all serpentine setups use a reverse rotation water pump, which in turn means a reverse rotation fan.
     
  7. CK5

    CK5 In my underwear Administrator Premium Member GMOTM Winner Author

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    OK, thanks guys, it's been over 5 years since I put a flex fan on and completly forgot about the reverse rotation fan. Now the problem is finding something that new in a junk yard.
     
  8. Leper

    Leper 1/2 ton status

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    If you go to autozone, they ask for the gearing of the truck when you buy a new clutch. I was thinking that the numerically lower gears turn the engine slower, so the clutch will engage faster. Not sure on this though. I bought the one for the 3.08 gearing even though I am 4.56 because IMO the more cooling, the better.
     
  9. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    ive got 2 5 blade reverse rotation clutch fans in the garage that ill give ya if you want. just a couple dollars for shipping would be nice.
     
  10. mrk5

    mrk5 The Sticker Guy Moderator Vendor GMOTM Winner Author

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    You shouldn't have a problem. Even our little junkyard up here in the north had one when I needed it. it was even already removed laying on the ground.
     
  11. colbystephens

    colbystephens 1 ton status GMOTM Winner

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    do you know if that 6.2 was in a 3/4 ton model? i ask b/c mine is only the 4 bolt pattern and doesn't have 7 blades. my buddy has two 6.2 motors, and neither of his are the way you describe either. all three are off 1/2 tons tho.
     

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