Crankshaft sprocket

Transmission, clutch, chains and belts
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Crankshaft sprocket


Post by Panchop » Fri Apr 11, 2008 11:23 am

Description: The crank sprocket is on tighter than dicks hatband

Post by PanChop

Trying to pull the motor out of a 50 Pan. Got the top end out, however the crank sprocket is on tighter than dicks hatband. The manual I have doesn't mention that it is a press fit, so what the hell am I doing wrong? Do I need a puller and if so what kind. Any help would be appreciated.

Post by Weez

1950 had a tapered shaft as opposedto a splined mainshaft. I believe it changed in 1954. You will need some type of 3 legged puller after you get the nut off, is that the problem the nut or nut is off, Then a puller for sprocket. Not sure what name of puller is. Good Luck don't damage the crank shaft.

Post by Cotten

Believe it or not, the tapered sprockets were meant to be loosened by smacking them with a soft hammer or a brass drift. Shocking them distorts the metal momentarily enough to release it. Unfortunately, it could also knock your flywheel out of true!
Fortunately, you are facing a total rebuild anyway.

Post by VintageTwin

Try the two-jaw puller available at Pep Boys (aka. Mannie, Moe & Jack's) They usually stock two pullers, one smaller than the other. , mfg. by Performance Tools - Kent, Washington- The big puller part number is W139 or the smaller version # W140. Either will work on the '36-54 tapered shaft.

Post by Cotten

Geez Kirk, do you really thing that putting puller jaws upon sprocket teeth is a good idea?

Here's a half-way compromise:
Put the puller on and torque it up firmly, and then smack its drive screw sharply. That might be the gentlest way to release the taper without damaging teeth or the flywheel true-ing.

Post by VintageTwin

Sounds good. Grease the threads on the puller shaft, make sure the innermost taper of the sprocket shaft doesn't take a direct hit. The pullers I named have a small blunt point on them, that will not touch the bottom of the shaft taper. An undamaged taper is needed when truing the flywheels. I have to ask Stett about this tapered motor sprocket pulling. He always has the last word with anything I print. If he gives me the OK on our compromise method I will come back and say so. It's got to be right.

Post by VintageTwin

I talked to Stett about using the tension on a two jaw puller with the '36-54 motor sprocket and then giving the puller shaft end a rap with a brass hammer to free up the sprocket. He said that was OK, but that we should use a brass center-locating adaptor between the puller shaft tip and the crankshaft. This brass locator was essentially a disc with a tit on the crankshaft side and a dimple on back for the puller shaft tip to register in. That otherwise the puller shaft tip sometimes wants to "walk" off the end of the crankshaft. He said "Flanders" use to sell them, or "Pat's Tool", or "MSC", or "Grainger" carried them. I looked in Grainger and the MSC catalog, but couldn't find one listed.

Post by Cotten

Just cut one on a lathe.
Or why not just stick a penny between your puller and the shaft.
I just tap on the dammn sprocket with a brass hammer and be done with it.

Post by 57stroker

If the crankshaft has a small tapered hole drilled in the end of it (and it should have), be sure not to bugger up the hole. This hole was put in when the shaft was built and everything else on the shaft was created around it. (It's real name is the center drill mark.) It will be needed to true the flywheels again. It can be fixed if it gets screwed up, but the machinist will cuss you (and probably charge you extra for his efforts!) Just do as Cotton suggested and use a penny between the puller and the end of the shaft. Tighten the puller down with an end wrench (not an air gun) and smack the puller bolt with a hammer. It will probably need a pretty good whack to get the two apart. One really good hit is probably better than several small taps. Good Luck!

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