Question on fan pulley
 

When replacing the fan pulley on the crankshaft there is a keyway inside the pulley and a notch. I first slid the pulley on using the keyway, tightened the bolt, rolled over the engine by hand and it seemed to hang up. Loosened the pulley and installed it using the notch in the pulley then could roll it over by hand with out it hanging up. Why does the pulley have a keyway and a notch?
This is confusing on which to use. This is on a 37 flathead in a 40 ford.

Re: Question on fan pulley
 

Just removed and replaced the crank pulley and fan on my '41 because the pulley got put on without the Belleville washer to hold it in place. The fan pulled hard enough to slide the pulley forward on the crank snub, and the fan went into the radiator. With as much stress as fan, water pumps and generator put on that pulley, you must use the key. Mine went back on with no problem and turns freely. I am not sure why the notch is there, but it certainly isn't to fix the pulley to the crankshaft. Maybe someone can explain that for us. I happened to have a picture if pulley showing the keyway and notch.

Re: Question on fan pulley
 

...

Re: Question on fan pulley
 

Does the old 37 21-stud have a later long snout crankshaft or does it still have the short snout crank? The two use different fans. The generator fan was used up through the 1939 standard vehicles. The 39 Deluxe had the fan on the crank and this was used thru somewhere in 1941.