splasher bearing question

Kdancy
Kdancy Senior Contributor
edited November -1 in HUDSON
My machine shop guy called and discussed turning the crank for the 39 engine. In talking with him and Harkin, the man doing the main bearings, I have a question --
Why would all 3 mains have different bearing sizes?
I am hoping to have these honed to fit without using shims. What is the clearence supposed to be?

Comments

  • Geoff
    Geoff Senior Contributor
    The main bearings were different sizes, increasing in size from front to back, on all 6"s and eights. On the '39 engine you must have .021" of shims. Failure to do this will raise the centre line of the crank when line bored, and cause a tight fit of the timing gears, which could lead to failure.
  • Geoff
    Geoff Senior Contributor
    Sorry I forgot to give the clearance. .001"
  • Uncle Josh
    Uncle Josh Senior Contributor
    The reason for progressively smaller diameters for the mains and camshaft, is so you can go in the big end with a boring bar and/or reamer and do the smallest one without scrubbing the others on the way back out.
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