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52 Hydro w/ 56 308 questions
  • GrimGreaserGrimGreaser
    Posts: 541Platinum Member
    I just got a 56 motor (thanks Don!) to replace the buggered up one in my 52. So, looking at things... the bolt patterns are different between the 56 crank flange and 52 hydro flywheel. Now, in addition to the spacer from 21st Century - I take it I'll need a different flywheel (can I just modify mine?) and/or torus cover (I did a quick search...but want to make sure)? I'm not adverse to switching cranks either, just want to know where I stand.
    Six in a row makes it GO!
  • Ken U-Tx
    Posts: 1,102Platinum Member
    If you are going to rebuild the 56 block, then you can use the earlier crank in the 56 block. That may simplify things for you.
  • GrimGreaserGrimGreaser
    Posts: 541Platinum Member
    Can I just modify my flywheel to accept the new bolt pattern ect... Still using the spacer of course.
    Six in a row makes it GO!
  • russmaas
    Posts: 475Platinum Member
    Just use a 55/56 flywheel with the spacer if you got one. There are plenty out there if you dont. I have some extra's
  • maasfhcenturylinknet
    Posts: 45Hitchhiker
    May have extra 55/56 flywheels--will check if you want.
    Randy
    309-267-6158
  • GrimGreaserGrimGreaser
    Posts: 541Platinum Member
    Thanks, I sent Russ a PM earlier.

    Could I modify my flywheel though? I have a cnc at work and access to a lathe. Or are there other differences between the two.
    Six in a row makes it GO!
  • maasfhcenturylinknet
    Posts: 45Hitchhiker
    Yes, that would work just fine.
    Randy
  • Ken U-Tx
    Posts: 1,102Platinum Member
    If you do machine the 52 flywheel to fit onto the 55-56 short crank with spacer, try to do so that the timing marks are correctly positioned to show in the timing window of the Stepdown engine rear support when Cyl's #1 & 6 are at TDC. I have a 56 308 with the 56 flywheel and the spacer on my 1953 Hornet, so the timing marks are hidden in the Stepdown rear support plate timing window.......no biggie, I can still time by ear and vacuum gauge, but it is nice to be able to see the marks in the correct place if possible, especially if you are changing out the timing chain, oilpump/ distributor, or the drive gear! It all depends on where the bolt patterns/ dowel pins of the two different flywheels are in relation to each other.
  • GrimGreaserGrimGreaser
    Posts: 541Platinum Member
    Nice reminder. I was planning a timing mark up front on the dampener, my custom mini starter is a bit in the way of the flywheel window. It's nice to keep things lined up properly though.
    Six in a row makes it GO!
  • TwinHTwinH
    Posts: 536Platinum Member
    Here's a couple pics of a timing tab that the previous owner fabbed for the 308 in my 49.

    image

    image
  • Tallent RTallent R
    Posts: 1,574Platinum Member
    Neat little addition
    Roger :D
    Retired Tech.
  • maasfhcenturylinknet
    Posts: 45Hitchhiker
    Good Job
    Randy
  • hud nut
    Posts: 13Hitchhiker
    the 308 that I just took apart has been modified and seems to be a 54. What are the differences
    in length of the flange on the crank and what is the starting point of the measurement?
    Thanks Dan
  • Ken U-Tx
    Posts: 1,102Platinum Member
    The 55-56 cranks are 1/2" shorter, to allow the bellhousings to clear the Nash/ Hash firewall. The difference in length is on the seal surface of crank not the thickness of the flange itself.
  • hud nut
    Posts: 13Hitchhiker
    Thanks for the reply. Dan
  • hudsontechhudsontech
    Posts: 4,042Platinum Member
    If you can find the engine number 1954 serial numbers (engine number the same) run 269060 thu 319720

    Hudsonly,
    Alex Burr
    Memphis, TN
  • hud nut
    Posts: 13Hitchhiker
    The engine number is 5321039 found on the engine deck surface on the extention of the deck on the distributor side. The casting number is 5325000. The other numbers are L125. CWC is under the casting number These numbers are under the distributer. Thanks Dan
  • Ken U-Tx
    Posts: 1,102Platinum Member
    Dan has a block cast on December 12, 1955. Would be from an early 1956 model year Hornet, if it wasn't a replacement or surplus motor.
  • hud nut
    Posts: 13Hitchhiker
    I would say it is a replacement as i took it out of a late 52 hornet sedan.
  • 53jetman53jetman
    Posts: 873Platinum Member
    It's not likely that a replacement engine would have a vin number stamped into the block
    Jerry
    email: HudsonJetman@mail.com
    2nd Generation Hud-Nut
    HET Tech Adviser on Hudson Jets 1953 & 1954
    HET Registrar of all Hudson Jets