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Technical water pumps for 8cm

Discussion in 'Traditional Hot Rods' started by 48fordnut, Jul 12, 2019.

  1. 48fordnut
    Joined: Nov 4, 2005
    Posts: 4,215

    48fordnut
    Member Emeritus

    In the roadster I'm building I have a 8cm eng with a crab dist. I need to know what w/p to order
    .I'm pretty sure wide belt but don't know which model pumps to order. I have tried phone calls and search but haven't found a definitive answer.

    thanks,

    jim
     
  2. Marty Strode
    Joined: Apr 28, 2011
    Posts: 8,798

    Marty Strode
    Member

    I used the early, 48 and older pumps, it required the early lower pulley to match. If you look closely, you can spot the soft plug above the top of the pumps. IMG_0605.JPG
     
  3. 51504bat
    Joined: May 22, 2010
    Posts: 4,755

    51504bat
    ALLIANCE MEMBER

    Merc pumps for '49 - '53 come in 2 or maybe 3 styles - 1953 may have been the 3rd but not sure. The early pumps from that period were wide belts and the later ones (pre '53?) were narrow belts. Both had a higher mounting pad surface than did 8ba truck pumps. Both required a spacer to make up the difference in mounting heights. If your engine currently has wide belts you can run 8ba truck pumps. If you want narrow belts you need the later Merc pumps which are not repopped. If you have cores you can send them to Skip, another rebuilder, or rebuild them yourself.
     
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  4. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,966

    V8 Bob
    ALLIANCE MEMBER

    The '49-'51 Mercury pumps all had the high located mount ears, vs the '48'-52 truck pumps with low mounts. The '49 Merc pumps were wide belt; '50-'51 were narrow belt and offset for the two belts. The '50-'53 Fords and '52-'53 Mercurys used the same narrow belt offset pumps that used lower angled engine mounts.
     
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  5. 48fordnut
    Joined: Nov 4, 2005
    Posts: 4,215

    48fordnut
    Member Emeritus

    I am using the late Edelbrock heads.

    Eng has no pumps at present.

    thanks

    jim
     
  6. Cliff Ramsdell
    Joined: Dec 27, 2004
    Posts: 1,343

    Cliff Ramsdell
    Member

    Jim,
    What do you have for a crank pulley right now?

    Cliff Ramsdell
     
  7. Mike51Merc
    Joined: Dec 5, 2008
    Posts: 3,856

    Mike51Merc
    Member

    Water pump selection depends on the car, not the engine. What are you installing the 8CM in?
     
  8. Cliff Ramsdell
    Joined: Dec 27, 2004
    Posts: 1,343

    Cliff Ramsdell
    Member

    He’s building a ‘28 Roadster.

    Cliff Ramsdell
     
  9. 48fordnut
    Joined: Nov 4, 2005
    Posts: 4,215

    48fordnut
    Member Emeritus

    Cliff I have a wide pulley off of a 59 a eng. Mike 28 a roadster on a model a frame.,

    thanks,

    jim
     
    Petejoe likes this.
  10. chopnchaneled
    Joined: Oct 21, 2004
    Posts: 1,428

    chopnchaneled
    Member
    from Buford Ga.

    On my 27 roadster with a 8CM and 28/9 radiator, i used the truck pumps wide grove's. If you don't the engine will set too high.
     
  11. flatjack
    Joined: Feb 13, 2007
    Posts: 975

    flatjack
    Member

    Be aware that the truck pumps will make for a longer engine. I'd use the standard early pumps with wide belts.















    be aware that
     
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  12. 48fordnut
    Joined: Nov 4, 2005
    Posts: 4,215

    48fordnut
    Member Emeritus

    How much longer? will this just be in the mount area?

    thanks,

    jim
     
  13. Marty Strode
    Joined: Apr 28, 2011
    Posts: 8,798

    Marty Strode
    Member

    Here is a side by side comparison between early and truck pumps. If you use truck pumps, your overall length will be 1-3/4" longer. The mounting height and length is the same. That's why I used early pumps on the 8BA engine pictured above. IMG_3178.JPG IMG_3179.JPG
     
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  14. Cliff Ramsdell
    Joined: Dec 27, 2004
    Posts: 1,343

    Cliff Ramsdell
    Member

    Jim,
    The 49-53 truck pumps mount the motor to the frame the same as the 37-48 pumps. The pulleys are farther out because of later cover and distributor.

    I would mount your distributor, cap and wires, generator and offset bracket, generator eliminator and fan assembly to see where these items all line up.

    Try the early pulley you have and see what lines up.

    Cliff Ramsdell
     
  15. Cliff Ramsdell
    Joined: Dec 27, 2004
    Posts: 1,343

    Cliff Ramsdell
    Member

    Yeah, like Marty said. There is a nice side by side.

    Cliff Ramsdell
     
  16. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,966

    V8 Bob
    ALLIANCE MEMBER

    JFYI, the late truck pumps that mount like the '37-'48 started in '48 and ended in '52. The '53 trucks used the same wide belt pumps as '49 Ford cars, but "float" because of the new front center engine/rear bell housing side mount design.
     
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  17. chopnchaneled
    Joined: Oct 21, 2004
    Posts: 1,428

    chopnchaneled
    Member
    from Buford Ga.

    WOW !!!!
    Thanks, Did not know, No wonder i had all the problems.
     
  18. Aaron D.
    Joined: Oct 27, 2015
    Posts: 1,037

    Aaron D.
    Member

    This may help you Jim.
     
    irishsteve, alanp561 and 48fordnut like this.
  19. Good thread guys.......thanks......and Marty that's a nice looking motor right there !
     
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  20. nobby
    Joined: Jan 8, 2006
    Posts: 1,206

    nobby
    Member

    ahh, so I can switch 3/8ths pulleys from 51 merfc pumps to 8ba truck pumps??
     
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  21. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,966

    V8 Bob
    ALLIANCE MEMBER

    Ford never ran a single 3/8" belt for both pumps so I would not consider this even though it's possible, imo.
     
  22. nobby
    Joined: Jan 8, 2006
    Posts: 1,206

    nobby
    Member

    oh I get it////… I think
    I think I must have a 1953 ford engine as its 8ba 3.75
    it has a twin 3/8 crank pulley
    car fitting water pumps - offset with 3/8 pulleys
    I didn't get a generator, but do have the front mounted fan
    so - from the crank, one crank pulley does one water pump and the fan
    the other belt from crank does the other pump and generator
    now the question is, it being 1.5 inches longer than a 59a
    will it fit with the stock fan in a 38 pick up?
     
  23. nobby
    Joined: Jan 8, 2006
    Posts: 1,206

    nobby
    Member

    ahh it makes even more sense now, they 'could' go to the thinner belts as the belt now doesn't have to turn both pumps
    I get it..
    I think

    so, I still need pumps to mount the 8ba into a 38 pick up - I gather I heat up the pulleys and switch them, my question is, I can use any 49-53 truck pumps?
     
  24. nobby
    Joined: Jan 8, 2006
    Posts: 1,206

    nobby
    Member

    ahh, I can switch out the stock 3 blade fan for a nylon 6 blade mardyne one....groovy!!
     
  25. 51504bat
    Joined: May 22, 2010
    Posts: 4,755

    51504bat
    ALLIANCE MEMBER

    I'm running a 8ba in my '39 p/u with narrow belt Merc pumps. Fits fine with the Merc U shaped spacers and I'm using the stock 4 blade fan behind a Brassworks 4 row radiator.
     
  26. nobby
    Joined: Jan 8, 2006
    Posts: 1,206

    nobby
    Member

    hello, I wonder if you might take the time to upload a picture of your set up, pumps - pulleys - clearance to radiator etc, as I have to buy the pumps and radiator next
     
  27. 51504bat
    Joined: May 22, 2010
    Posts: 4,755

    51504bat
    ALLIANCE MEMBER

    rad 3.jpg rad 4.jpg rad 5.jpg rad 6.jpg rad 7.jpg rad 1.jpg
    The first ones ar of the current install. The last 2 show narrow belt Merc pumps with the U shaped spacer needed to make up for the differences in mounting heights between the Merc pumps and 8rt truck pumps.
     
  28. nobby
    Joined: Jan 8, 2006
    Posts: 1,206

    nobby
    Member

    Hello thanks so much for your pictures
    phew - I didn't think it would fit
    - I don't think I am ever going to find merc truck pumps.
    I think I will have to switch the 3/8ths pulleys I have onto some ford truck pump cores
    I have a 3 blade fan.. I think I will be able to fit a mardyne 6 blade nylon fan in its place.
     

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