Broke my crank pulley. Now what?

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Model T Ford Forum: Forum 2014: Broke my crank pulley. Now what?
Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Wells on Monday, July 07, 2014 - 10:43 am:

Yesterday my crank pulley pin fell out. The pin got bent and the hole in the pulley is ruined. How are these pins held in? I never really looked at this part. There is a hole on one end of the pin only for a cotter pin I assume? Is the other end just peened? I read some earlier threads on this subject and it appears these stock pulleys are a real pain. I know there are aluminum replacements and I have not heard much good about them either. I really want to stay stock appearing if I can. It's a pretty important part considering I can't hand crank without it. I think I have good access to parts but am really lost this time. What should I do?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Wells on Monday, July 07, 2014 - 10:45 am:

Forgot the pics.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Monday, July 07, 2014 - 10:53 am:

Dave,
There should have been a cotter pin in the hole. Then one of the hole in the surface is supposed to be too small for the pin, so the pin will not fall out that side and the cotter key keeps the other end in.

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Roger Karlsson, southern Sweden on Monday, July 07, 2014 - 10:55 am:

I haven't had any problem finding stock late pulleys in good condition that could be dressed up with a file and used, but I know many have had problems with loose fitting worn pulleys. If your crank shaft isn't worn from a flopping pulley you can likely find another that will fit fine. The pin is reproduced. The pin is held in place with only one cotter pin since only one of the outer holes in the pulley is large enough for the pin to go through. The smaller hole is for a drift pin when removing the pin.

An easy fix for a loose pin is to bend it slightly before pounding it in place.

I think the alu pulleys looks way too modern, plus I may save a few $$ by resurrecting an original pulley.. :-)

They can be restored in many ways if shimming won't last, see one way to do it this thread: http://www.mtfca.com/discus/messages/411944/450092.html?1401977051


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Monday, July 07, 2014 - 11:14 am:

If you look closely at the outer holes, you should find that one is big enough for the pin to fit through and the opposite one isn't. The big hole is for installing or removing the pin and the cotter pin hole should be on that end of the pin. The smaller hole is to allow using a drift to drive out the pin through the larger hole. I say "should find" because I've encountered a couple of pulleys with the small hole drilled out to match the larger one, in which case you'd need two cotter pins.

There are a lot of original pulleys around, but a lot of them are also not in great shape. There are ways to fix a worn one, but first I'd call around and try to find a good one. Remember that most of the dealers have used parts that aren't listed in their catalogues. The new pin costs less than a dollar, but a new pulley is mighty dear. That's why I'd rather find a good used one or fix a worn one.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Monday, July 07, 2014 - 11:51 am:

Check out this earlier post. Shows how to restore a crank pulley, really neat work by a machinist.

http://www.mtfca.com/discus/messages/411944/450092.html?1401977051


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Wells on Monday, July 07, 2014 - 12:09 pm:

Great. It's clear as day now. I know people with scrap engines. Probably every one of them has pulleys. I will find one I'm sure. Thanks so much.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Gary H. White - Sheridan, MI on Monday, July 07, 2014 - 03:54 pm:

Never worked on a pulley but would it be possible to drill new holes 90 degrees from old holes. Just a thought.


Top of pagePrevious messageNext messageBottom of page Link to this message  By A. Gustaf Bryngelson on Monday, July 07, 2014 - 08:35 pm:

I think the biggest problem is the inner diameter of the pulley, it needs to be a tight fit on the crankshaft.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Monday, July 07, 2014 - 09:34 pm:

Herm, why foam rubber inside the pulley?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Craig Anderson, central Wisconsin on Monday, July 07, 2014 - 09:57 pm:

If you are really bent on originality you COULD have this one crowned.
I wouldn't but yours isn't my car so........

http://www.modeltford.com/item/3963B.aspx


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Wells on Monday, July 07, 2014 - 10:11 pm:

Thanks Craig. I gotta stay as original as possible though. Gary, I just thought about your idea about re drilling. What have I got to lose for such a simple job. I might even be able to straighten the pin. It will cost me nothing to give it a try. Thanks. I'm going to visit someone tomorrow who might have the parts. I guess it will depend on the price.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Richard Bennett on Tuesday, July 08, 2014 - 05:56 am:

Steve, I had to look back at the previous post to work out what you were on about. My guess is the foam is used as a sound deadener while the pulley is machined. Sometimes things can get a real howl up at certain speeds/loads.

Just guessing.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith on Wednesday, July 09, 2014 - 10:37 am:

It appears that you have the large one, which is good, because they are the easiest to find. You want a pulley that is a snug fit on the crankshaft. Same thing with the pin. If the pin is loose, knurl it in the middle, or you can center punch it all over to hold it in place. Be sure to put the pin hole where the large opening is on the pulley when re-installing.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Wells on Wednesday, July 09, 2014 - 11:07 am:

Thanks for all the tips. I did acquire a real nice one plus the pin. I need a puller to get it off the crank which is a good thing. I bet I'll have to pull the rad to install it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Wednesday, July 09, 2014 - 07:05 pm:

My tip. If the crank is worn a bit making the pin loose? Flash a coat of braze all around the middle of the pin. If you do so carefully, it may not even need to be filed or cut down. If well done, it can usually shear the surface of the braze as the pin is driven in (if you have to really beat on it, you need to do some filing). Has worked for me a few times.
Drive carefully, ans enjoy, W2


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole on Friday, July 11, 2014 - 01:26 am:

Wayne, I put JB Weld on the crank and let it harden. The pulley goes over it, tight as a drum. Results are pending getting the car back together and running.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Semprez-Templeton, CA on Friday, July 11, 2014 - 12:44 pm:

Eric, I'm afraid the JB will wallow out in short order. Shim stock would be a better short term fix, but braze welding the pulley would be a permanent repair. I have tried the patches in the past, but ultimately found a good pulley which solved the problem.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Wells on Saturday, July 12, 2014 - 10:15 pm:

I got my new pulley on. I pulled the rad and used a large 27mm socket turned backwards with a half inch extension inserted through the crank handle hole to drive it on and two sizes of extensions to drive the cross pin in. The pulley and pin went on very tightly and smoothly. Clearly a perfect fitting pulley is the answer. I picked up the parts from a nice T man named Wayne Anderson and he refused to take my money. He is an asset to the car hobby. Thanks for the help everyone.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Eric Sole on Sunday, July 13, 2014 - 08:46 am:

John, I had a senior moment or it was just too early in the morning when I read Wayne's post about brazing the pin. I was thinking of the crankshaft.

When you mention shim stock are you referring to filling the space between the crank and the pulley or between the hole in the crank and the pin? I did try the thinnest shim stock I could find (.001") between the crankshaft and the pulley but it was too thick, that's when I thought to try the JB Weld.

After checking though, I suspect that the hole in the crankshaft is worn oversized. Local post office says I'm about to receive a box of parts I ordered from Lang's on June 6th (not their fault, it's been in Spanish customs for a month now) so I will finally have the new crank pin to check for sure just how worn the hole is. May have to resort to Wayne's brazed pin idea after all.


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