454 Crank Rod & Main size

Discussion in 'Engine Topic' started by PetieG383, Oct 27, 2010.

  1. PetieG383

    PetieG383 Veteran Member Lifetime Gold Member

    480
    0
    Oct 28, 1999
    Wynnewood, Pa USA
    What are the measurements for the journals on the crank for the rod and mains for a stock crank? I'm looking to do a quick rebuild and need to order bearings.

    This is a 454 out of a 1988 truck if that matters.
     
  2. 79ZED

    79ZED Veteran Member

    2,998
    0
    Jan 31, 2000
    Nanaimo, B.C., Canada
    Mains:

    1- 4: 2.7494"
    5: 2.7488"

    Rods: 2.20"

    Personally, I wouldn't be ordering bearings till I had a chance to inspect and measure the crank and rods.

    John
     
  3. PetieG383

    PetieG383 Veteran Member Lifetime Gold Member

    480
    0
    Oct 28, 1999
    Wynnewood, Pa USA
    I've just disassembled the engine, so I'll be doing that. Thanks a ton.
     
  4. badazz81z28

    badazz81z28 Veteran Member

    12,554
    7
    May 4, 2001
    Las Vegas, NV
    Where do you order bearings? Everywhere I took they are advertised as

    "std" ".010" ".020" ".030" ect....no actual measurements.

    If you look at the old bearings, the size is stamped on the backside
     
  5. 74RAT

    74RAT Veteran Member

    3,400
    0
    Dec 28, 2003
    ft. stockton,tx,usa
    badazz81z28,
    you might call i.e. clevite or federal mogul and order a current bearing catalog which lists all the "spec range" sizing info for mains/rods on the crank as well as block housing bores and connecting rod housing bores and cam bearing housing bore sizes. maybe your local machine shop can order you one if you're in "good graces" with them. maybe they'd pass you an old one?

    something important about factory sizing is,, when it's a std/std crank as in a g.m. factory ground crank,, all the journals aren't necessarily exactly the same as it's neighbor on the next journal.

    g.m. uses various sizes of bearings in a "mix and match" method,, but sizing ranges from within a couple of ten thousandths over or under std size up to +/-.002 over or under std to "set clearance" on the standard size from the factory.

    the cranks are ground assembly line style and are not perfect from journal to journal. it measures.

    for example, they may use a +.002 in the lower cap half and a -.005 in the upper block half to "create" the clearance they want to the crank.

    chrysler used to color code paint spots on the pan rails for the assy line techs to know if a single journal needed a specific size like a .010 bearing on one journal only,, or a .020 bore piston in that one hole. yes, they mess up sometimes, or an air pocket in the casting or such.

    olds and chrysler used to stamp a lifter bore .010 or .011 here and there as well when they goofed up at the factory. seen bunches of those. check everything closely!!

    don't EVER trust a factory sizing stamp,, i'd recommend to always measure everything.

    when i personally grind a crank,, i can put every journal within .0001 of each other so all bearings will "theoretically" have the same clearance "if / providing" the block mains and connecting rods are sized right in the first place and are all within .0001 of each other. nothing is perfect and you'd be surprised of what'll go together and actually run,, but i'd prefer to see it as mentioned here.
    hope it helps,
    andy
     

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