crank drilled for pilot ?

Discussion in 'Street/strip 400/430/455' started by MilehighBuick, Jun 9, 2017.

  1. MilehighBuick

    MilehighBuick Well-Known Member

    Can anyone tell by this photo if I got lucky with an automatic car/crank to where it doesnt need drilled for pilot bearing or do I need exact measurement. Maybe I need to just bolt on bellhousing and then trans to see.. Or someone know the difference by eye.. Thanks
     

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  2. hugger

    hugger Well-Known Member

    Your good to go
     
  3. MilehighBuick

    MilehighBuick Well-Known Member

    Yaaaaaaaaaaaaaay, Thanks, I had a hunch. Looked awful deep and was comparing it to my olds but wanted to make sure. A few RPMs , and drop the clutch here I come because Ive had the shakes to do a few burnouts all winter and Im about to get a fix..ha
     
  4. BillA

    BillA Well-Known Member

    It may be drilled but that doesn't mean you'll have an easy time finding a bearing or bushing that will fit. I tried several bearings and a bushing ordered from TA and none of them fit. Measure the diameter of the hole and compare it to the bushing or bearing that you plan to use. You may need to have the crank machined slightly if it's not in the car, or you can trim the bushing slightly on a lathe. I ended up using a Dick Miller bearing that fits in the larger opening where the torque converter snout goes. Then again you may get lucky and a bushing/bearing fits without modification. Good luck.
     
  5. Ziggy

    Ziggy Well-Known Member

    X2 on the hole size/ location question. My 67 4 speed crank has a hole for the pilot bushing that looks just fine, but on close inspection, is about .010" off center. It will go together and run, but it makes the clutch mad due to misalignment and the transmission is noisy in first gear. A Dick Miller type setup cured my issues.
     
  6. Jim Weise

    Jim Weise EFI/DIS 482

    Every engine we build here, I have a pilot bearing modified to fit that hole, whether it's an auto or a stick. I then include that pilot bearing with the engine, so the customer has it, in case he wants to run a stick later.

    I do this because while every one I have ever seen has been drilled for a pilot bushing, it's very rarely ever the right size. I have seen them with a step in them even (two different diameters)... but they are always undersized.

    The very common GM pilot bearing (bushing), listed for all 67-up Buick big and small blocks, is 1.093 in OD. On big blocks, we usually find the hole for it in the crank is about 1.075 to 1.085.

    Ron over at the dyno had a "special" worn out pilot bushing he used for years for my Buicks... but at times, he would misplace it, and we would waste time looking for it, so I became pro-active on this issue, and I thought it was a nice, inexpensive "perk" for engine customers.

    We built a special jig to put the normal bronze bushing in, to turn the OD down so it would fit properly in the crank.

    For anyone out there doing this, and your stuck on this deal, carefully measure the hole in the back of the crank, and give me the dimension, and I can supply you a bushing that will fit in your crank.

    Measure it with a snap gauge, or small inside mic or small dial indicator, because your going to get back from me something exactly that size, plus a bit for press fit.

    $20 should cover the bushing cost, time for machining and the postage.

    JW
     
    Last edited: Jun 10, 2017
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  7. Jim Weise

    Jim Weise EFI/DIS 482

    Wow, in over 100 engines that have been put on the dyno, every one of them with a pilot bearing, drive plate and input shaft, just like a 4 speed, I have never encountered this.. every one has just slipped right together.. and if that drive plate was .010 off, you would know it.. the dyno cart would be dancing... if you could even get it together.

    Good to know, and watch out for, should a problem arise in the future.

    JW
     
  8. MilehighBuick

    MilehighBuick Well-Known Member

    Thanks for the info. I will try to get a measurement between the hole and OD of the bronze bushing to see where its at. Ill reach out Jim if it needs turned, thanks. I have mics, dial bore gage, etc, just will have to grab a friends thats smaller. DM bearings work well? I have heard of maybe not so much,spinning inside the hole shortly after installing. I know a Ford bearing was close for my olds OD in doing this but had the crank turned instead. Of course some going that, lets call it special route, cutting the input shaft. tisk tisk.
     

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