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Pilot Bushing ? for the masses.

Discussion in 'Manual Transmission & Clutch' started by SquareRoot, Jan 4, 2021.

  1. SquareRoot

    SquareRoot Full Access Member

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    That big hole and the tapers about on the convertor acts mostly as a locating dowel pin like those on the block/bell housing. Everything is bolted together as one unit otherwise as previously noted.
     
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  2. DoubleDingo

    DoubleDingo Drain The Swamp, Completely

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    Vortec with quadrajet calibrated for vortec. It's a C20 with minimal emissions bs on it. Looks stock, but runs really strong.
     
  3. SquareRoot

    SquareRoot Full Access Member

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    Vortec manifolds lack the heating passage under the carb. Mine ran like shit when it was cold because the fuel would puddle. All that, and many more problems were solved with the EFI pro-flo. Sold that pretty Edelbrock manifold for half what I paid for it... as usual.
     
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  4. DoubleDingo

    DoubleDingo Drain The Swamp, Completely

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    I was always wanting to run the heat tube to the EGR port of the driver's side of the intake, but, it only runs badly until it warms up. I just need to run it for 20 minutes or more for it to get warm enough to run properly. After that it runs great.
     
  5. Turbo4whl

    Turbo4whl Supporting Member Supporting Member

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    I can tell you why there is a bushing in the center of the crankshaft for the converter to ride in. The converter balloons up, you know, gets larger.

    For those of you that understand how a converter works this may be easier to understand why. For the newbies, here is the basics. Oil from the pump is directed to the fins welded in the outer housing. those fins are very close to the stator fins. The oil dumps off the angled stator fins pushing them to turn. When no more oil can fit past the spinning fins of the housing dumping onto the stator fins, this is the stall.

    So as all this is happening the bell shape of the converter gets a little bit longer. The center of the converter moves in and out in the bushing.

    Okay, bring on the cats with their buttered toast!

    PS: the converter housing unpainted looks like spring steel, because it is a type of spring steel. Made to flex.
     
  6. SquareRoot

    SquareRoot Full Access Member

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    I call BS on the bushing. In all my years, I've never once seen a "bushing" in the crank or on the nose of a converter. I don't dispute your explanation, just the mere existence of such a bushing. Let's see a photo or part #.

    Bread and butter....and cats.
     
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  7. Ricko1966

    Ricko1966 Full Access Member

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    The converter bolts hold the converter in place.There is a snout called a pilot that locates the converter in the center of the crankshaft.If the end of the crank is damaged it can be bushed with a pilot bushing to accurately center the converter.If a converter is damaged the pilot can be turned down and the crank can be bushed to locate the converter. Some manufacturers use bushings right out of the factory so if there ever is damaged its bushing to change and it allows the same engine to bolt to different application transmissions. Instead of need 2 or 3 cranks just bush as needed. Aftermarket sometimes you have to bush the pilot because the transmission and engine were never designed to be used together.

    Ohh!!! The poor cats.
     
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  8. Blue Ox

    Blue Ox Turning Diesel Fuel Into Fun

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    I always understood that the converter piloted on the back of the crank. Just not in the same place as a manual input shaft. I'd be hard pressed to imagine that they could center something as big and heavy as a converter that spins at the speeds it does with just the bolts.
     
  9. DoubleDingo

    DoubleDingo Drain The Swamp, Completely

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    I need to see the engine-side of a torque converter now. As the whole assembly turns the same amount of revolutions as the crankshaft, and the automatic transmission input and out shafts are identical centers as the crankshaft center. So when the torque converter is bolted up, it is already seated in the transmission, and thus turning on the same center axis. It is then just a matter of bolting up the three or six bolts depending on the application.

    Personally, I will never run a pilot bushing in the back of the crankshaft with an automatic transmission.
     
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  10. DoubleDingo

    DoubleDingo Drain The Swamp, Completely

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    And I did look up if a pilot bushing is used with an automatic transmission, and except for this thread, the answer is "no" across the board. I am still curious to see the engine-side of a torque converter and how it utilizes the pilot bushing.
     
  11. Ricko1966

    Ricko1966 Full Access Member

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    I've never tried ,but I assume if there is nothing for the torque converter to center in it will Waller out the bolt holes and Waller out the front pump and maybe even crack the flex plate by using just the flex plate to locate the converter.When you go LS on a th350/700r4 don't you have to use an adapter bushing?
     
  12. Ricko1966

    Ricko1966 Full Access Member

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    Screenshot_2021-01-05_185124.jpg

    Should I keep going? How many examples do you want? See why I didn't want to start this.
     
  13. Turbo4whl

    Turbo4whl Supporting Member Supporting Member

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    I guess I work on too many medium/heavy duty trucks.
    Pictures as requested:

    s-l400 (1).jpg
    Caterpillar rear crank bushing for a Allison trans.

    maxresdefault.jpg

    Perkins engine.

    Allison automatics have a much larger converter.
     
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  14. Ricko1966

    Ricko1966 Full Access Member

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    Th350 pilot bushing for a car with a motor plate. Yes. Sometimes automatics have pilot bushings.I think Mecedes uses 1 but I'm not looking for anymore.

    Screenshot_2021-01-05_190908.jpg
     
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  15. DoubleDingo

    DoubleDingo Drain The Swamp, Completely

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    Cool. My old truck doesn't have one, but I learned something today.

    Edit: I am boring. I only run what came as a factory option in my vehicles. A lot less headaches, and easier on the wallet. And the only foreign jobber is my 2007 FXT Forester. It is 5 speed with pilot bushing/bearing.
     
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