Crankshaft pulley pin loose in crank

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Bruce Compton
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Crankshaft pulley pin loose in crank

Post by Bruce Compton » Wed Aug 12, 2020 9:40 pm

The pulley pin on my '26 is sloppy in the crank hole. The pin is not worn (0.375"). Is it safe, or even possible to drill out the hole in the crank and the pulley to the next standard bolt size ( 0.391), or is there another fix. The hole in the crank is already 0.386". Obviously I'm concerned about keeping a hand held drill running true through the existing hole. Thanks : Bruce


Peter, Memphis TN
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Re: Crankshaft pulley pin loose in crank

Post by Peter, Memphis TN » Wed Aug 12, 2020 10:14 pm

I'm reminded of a similar task I had on a non-T project. I used a tapered pin and a matching tapered reamer. I kept going until the pin fit where I wanted it to. In your case, I think you'd want to drill a cotter-pin hole in the pin, to keep it in place. The amount of taper on a pin is miniscule, and the pin is hardened steel.

The advantage here is that the reamer won't wallow around like a drill would do, and it would give you a nice round hole with plenty of contact surface with the pin.

I'm sorry to say I don't remember where I got the pin and reamer, but I was about 15 years old, and didn't have much money, so it was probably fairly cheap. You might be able to borrow a reamer from a machine shop -- I always recommend going to such a place in the Model T. When a machinist sees it, and gets to look under the hood, he'll probably open his stock to you, and be an eternal friendly supplier.


Kerry
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Re: Crankshaft pulley pin loose in crank

Post by Kerry » Wed Aug 12, 2020 11:31 pm

The crank can be drilled but if doing it in the car, make sure you can get to the hole from the other side as well so you can punch out the drill bits you are more than likely to break in trying. :o


Allan
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Re: Crankshaft pulley pin loose in crank

Post by Allan » Wed Aug 12, 2020 11:52 pm

I'd much rather make an oversize pin to fit the hole you have than drill the crankshaft.

Allan from down under.

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Steve Jelf
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Re: Crankshaft pulley pin loose in crank

Post by Steve Jelf » Thu Aug 13, 2020 12:07 am

I with Allan. I would rather make a pin to fit the hole than drill the hole to fit a bigger pin.
The inevitable often happens.
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Re: Crankshaft pulley pin loose in crank

Post by kmatt2 » Thu Aug 13, 2020 12:43 am

From the numbers you give that is only .005 that you need to remove. It is mild steel, take a extra long piece, put it in your drill press, or ha.nd held drill and turn it slowly against a flat file, check size offen. Drill the split pin hole and pulley holes out and cut off to correct length. Check the new pin fit in hand crank rachit to make sure it won't stick


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Bruce Compton
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Re: Crankshaft pulley pin loose in crank

Post by Bruce Compton » Thu Aug 13, 2020 11:31 pm

I rechecked the hole in the crank and it was worn like a funnel on both outside sides of the crank but almost no wear in the middle. The smallest drill that would create a proper hole all the way through was a 0.084" so I made a new pin from a bolt turned down to 0.083" and drilled the crank and the pulley. Not a difficult job and all is well . Thanks for the input; Bruce


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Re: Crankshaft pulley pin loose in crank

Post by Allan » Fri Aug 14, 2020 3:53 am

Bruce, I hope your oversized pin is a neat fit in the holes in the pulley too. For the crankshaft hole to flog out as you describe, the pulley must have been moving on the crankshaft. A shim around the shaft may also be necessary.

Allan from down under.


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Re: Crankshaft pulley pin loose in crank

Post by Moxie26 » Fri Aug 14, 2020 7:52 am

If you're only problem is the compensate for .005-in, I would take the pin over to the bench support each end of the pin give the center of the pin a few strikes with a hammer, install with the cotter pin. You'll find a pin not only will have to be tapped in but also will take up some of the looseness the pulley may have had....


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Bruce Compton
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Re: Crankshaft pulley pin loose in crank

Post by Bruce Compton » Fri Aug 14, 2020 8:37 am

Thanks; The pin had to be lightly hammered into the pulley/crank and I'm pretty confident it will be fine. Thanks again : Bruce


Jerry VanOoteghem
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Re: Crankshaft pulley pin loose in crank

Post by Jerry VanOoteghem » Fri Aug 14, 2020 9:16 am

Does the hand crank ratchet still engage properly, without wanting to slip off the pin?


Topic author
Bruce Compton
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Re: Crankshaft pulley pin loose in crank

Post by Bruce Compton » Fri Aug 14, 2020 11:20 am

Yes, the hand crank still works fine.


Stephen_heatherly
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Re: Crankshaft pulley pin loose in crank

Post by Stephen_heatherly » Fri Aug 14, 2020 9:29 pm

I very slightly bent the pin in mine and it fit nice and tight afterwards. It's still good several years later.

Stephen

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