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'S' block

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  • 'S' block

    Don said:
    Kelley, Can you give a brief description of the differences between an "s" block and a non?

    Then Rodney said:
    That would be a great thread in tech.

    Then I said:

    The 'S' block is the only large bore (1275) block that has cylinder side covers (tappet covers). Otherwise there isn't much difference between the 'S' block and any other large bore block. They're a fairly strong block but not the strongest, the A+ is better. The only really important thing about them is that they haven't made one in almost 30 years and they aren't likely to start any time soon.


    If you can afford the car, you can afford the manual...

  • #2
    Then Rachel said that the broken 1275 block was of the "thin flanged" ilk.
    So Don wondered if the flange refered to was the tranny mating flange or another flange entirely. A 1275 's' block has open tappets and thin flanges?
    One can't have too much education can one? Don said.


    • #3
      Yes, D. The worst of the 1275 blocks to base a race engine on is probably the thin flange one; as you suggested, the mating flange between the block and gearbox. The 'S' came with a thin flange and went to a thick one sometime around Mk II time, but I don't remember exactly.

      In racing the high revs and torque of the more powerful engines tends to pull the block away from the gearbox slightly causing oil leaks and even cracks if enough power and a thin flange. The thicker flange helps as does the standard trick of tapping out the 1/4" holes between the gearbox and the block to 5/16" and using stronger bolts/cap screws.

      As Kelley indicated, the A+ block seems to be the one of choice and easier to get; although, "easy" is getting to be a relative term.

      Save the Whales! Save the 'S' blocks! (I have three in my "retirement fund.")
      The more I know about Minis, the more I know I don't know about Minis.


      • #4
        with all the retro fitting and remaking going on with all the other pieces and parts of a mini, what are the chances of them ever remanufacturing a mini 1275 block? wouldn't someone have the forms somewhere?
        Bother free is the way to be- Winnie the Pooh


        • #5
          A plus blocks

          If you use an A plus Block you also need to have a A plus distributor and drive