MTFCA Forum

What is supposed to hold the crank pulley pin in place? I see large hole/small hole in the pulley, and cotter pin hole in pin. Is the pin supposed to fit tightly through the crankshaft to hold it in place, or does the pin enter the small hole tightly holding it in place? I don't see any taper on the pin. I have read several articles on the pulley and pin, but still not really sure what holds it in place. Thanks. I am at that point so trying to figure it out. Tommy

The pin does fit tightly in the pulley. Many don't, and have to be knurled to fit properly. Don't mess with the small hole in the pulley. That is to keep the pin from coming out. The cotterpin in one end keeps the pin in place at the large hole end of the pulley.

Here's a picture of what Larry said. The parts are in poor condition, but they serve for illustration. The small hole in the pulley (left) is for punching out the pin when it needs to be removed. It is, or should be, too small for the pin to fit through it. The large hole (right) is for installing and removing the pin. A cotter pin in the end of the crank pulley pin keeps it from backing out of the large hole. You're right, the pin is not tapered.

Original Smith wrote: ↑

Sun Feb 14, 2021 12:16 pm

The pin does fit tightly in the pulley. Many don't, and have to be knurled to fit properly. Don't mess with the small hole in the pulley. That is to keep the pin from coming out. The cotterpin in one end keeps the pin in place at the large hole end of the pulley.

So, with the pulley removed, I should have to tap the pin in, and it just goes up to the small hole, but not in it?

Steve Jelf wrote: ↑

Sun Feb 14, 2021 12:45 pm

IMG_3836 copy.JPG
Here's a picture of what Larry said. The parts are in poor condition, but they serve for illustration. The small hole in the pulley (left) is for punching out the pin when it needs to be removed. It is, or should be, too small for the pin to fit through it. The large hole (right) is for installing and removing the pin. A cotter pin in the end of the crank pulley pin keeps it from backing out of the large hole. You're right, the pin is not tapered.

Thanks..Thanks for the picture.

So, with the pulley removed, I should have to tap the pin in, and it just goes up to the small hole, but not in it?

Correct. The small hole is only for a punch to drive out the pin when you remove it.

Took a look at mine today. My pin seems to be much shorter than the diameter of the pulley, and it is not tight. If it goes in tight, why do you need the cotter pin? Not sure what is incorrect with mine. Either the pin is too short, or the pulley is too large. Are there different size pulleys? I will take some pictures tomorrow.

You're not reading your emails, are you?

Scott_Conger wrote: ↑

Sun Feb 14, 2021 10:14 pm

You're not reading your emails, are you?

Just read it. Been in the shop all day..Thanks

Yes, there are different sizes.

Be sure and put in the cotter pin. I left one out one time and started the motor, I didn’t have a fan belt on it and that pin worked out and hit the pan. In addition to bending the pin, it made a tight pulley loose. A fan belt might hold it in place if it started to work itself out but I know I’ve had to come home without a belt for one reason or the other before.

Ford Service instructs and shows photo of cotter hole in the crank pulley pin, at the big hole end. Place the crank pulley pin into the large pulley hole, with the cotter hole of that pin up, facing the large pulley hole.

That cotter keeps the crank pulley pin from protruding out, wearing the fan belt, or worst, slipping out.

Although the pin is driven in and should be tight fit in both the crankshaft and pulley holes, the big crank pulley pin can get loose, wiggle, and move. Lots of stress on that pin with hand cranking.

Steve Jelf wrote: ↑

Sun Feb 14, 2021 10:41 pm

Yes, there are different sizes.


28 PARTS 28.jpg

Thanks for the info.

DanTreace wrote: ↑

Mon Feb 15, 2021 9:14 am

Ford Service instructs and shows photo of cotter hole in the crank pulley pin, at the big hole end. Place the crank pulley pin into the large pulley hole, with the cotter hole of that pin up, facing the large pulley hole.

That cotter keeps the crank pulley pin from protruding out, wearing the fan belt, or worst, slipping out.

Although the pin is driven in and should be tight fit in both the crankshaft and pulley holes, the big crank pulley pin can get loose, wiggle, and move. Lots of stress on that pin with hand cranking.

crank pulley pin.jpg

Crank pulley starting pin.jpg

Thanks..I will have to examine my parts some more. I think loose, wiggle, and moves sounds like the pin I have. Tommy