Front Pulley Issues

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Something was up with the crank from the get go. Careful shimming could do great if the taper is a perfect match to the pulley. Then you have to dress an oversized key to fit....Tapers matching is the real key to any success on that path. Or just order an .005" or so undersized pulley & hone slowly by hand.
Asking RGM to go on guesstimation is ...I figure a toss up, so I'd try the elbow grease method prior to dumping beaucups hours and feria on tearing it down. This is when you need one of those old yankee farm boys from 80 years ago as a neighbor who could pull this magic off without batting an eye, and make it last.

I know..I'm in conflict here because I don't really care for patching on this, but the worst case is you only get the clunk back without major losses and can then pursue another option. I would be near tears over this.
 
I would add shims until it fitted correctly, the total shim thickness and if the pulley runs true would then determine the next step. Being able to use a single shim up to say 25 thou then use a shim, above that and I would go for bespoke pulley, if the runout is bad then it has to come apart to have the taper seen to.
 
jbruney said:
Something was up with the crank from the get go.
I know..I'm in conflict here because I don't really care for patching on this, but the worst case is you only get the clunk back without major losses and can then pursue another option. I would be near tears over this.
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I’ve already said the crank was funky. But it’s not something that’s easy to catch. Does anyone know the spec on how far out the pulley should sit from the crank cheek? Or the minimum distance?

Tears? No, I didn’t cry when the other engine was sh!tting itself on the side of the freeway. This certainly isn’t going to bring tears. This can be addressed and without opening up the engine. No big deal.
 
Know you stated such. Just thinking out loud in repeat mode is all....Disgust & disappointment sounds more appropriate. Glad you've got a fine spare as a back up anyway.
 
jbruney said:
Know you stated such. Just thinking out loud in repeat mode is all....Disgust & disappointment sounds more appropriate. Glad you've got a fine spare as a back up anyway.
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And my back up has a back up. I’m good.
 
swooshdave said:
I’ve already said the crank was funky. But it’s not something that’s easy to catch. Does anyone know the spec on how far out the pulley should sit from the crank cheek? Or the minimum distance?

Tears? No, I didn’t cry when the other engine was sh!tting itself on the side of the freeway. This certainly isn’t going to bring tears. This can be addressed and without opening up the engine. No big deal.
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The distance would be limited by the point at which the back of the pulley makes contact with the engine or chaincase. You would want at least .020 clearance to avoid contact with heat expansion. You have quite a bit of leeway. Probably minimum of .020 and maximum of .100 -I would start with a .005 shim. That will move it a long way so you might want to pick up some .002 or .003 while your at it.

PS. shops that rebuild hydraulic cylinders is a good place to pick up small samples of shim stock.

[and yes, I grew up on a farm in the 50's. I have used lots of shim stock.:)
I helped my father repair a v-4 Wisconsin motor with a wallerd out wrist pin hole once with an adjustable reamer and some brass shim stock. It ran for several years before the rest of the combine was worn out.]
 
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I picked up a packet of mixed thickness brass shimstock at Napa a few years ago.
It came in a regular sized postal Envelope, maybe 20 pieces in all.
My BSA has shimstock on the ATD to magneto connection.
It looks to have been in there for many years. Works fine, although the power requirement is tiny.

Glen
 
You recall pouring babbit then...What fun old motors & equipment were. I grew up on a waterfront with plenty of mechanical drives.
 
I'd probably buy a six pack of beer in cans and drink a few while playing with shims cut from the aluminum to see how it felt when I put shims in there. Then I'd drink the rest of the beer, sleep on it and decide in the morning.
 
One more trick.
After you have determined the right thickness and have a nice fitting shim -use a very thin coat of valve lapping compound on the id of the pulley before you install the shim. This will lock the shim to the pulley so it does not end up moving as you are pushing the pulley onto the taper.
 
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jbruney said:
You recall pouring babbit then...What fun old motors & equipment were. I grew up on a waterfront with plenty of mechanical drives.
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I think there is still a couple of bars of babbit in my storage barn...
 
Adding machine paper & razor blade makes nice template for shim wrapped around shaft. It'll make you a perfect pattern, if you don't already use the method.
 
jbruney said:
Adding machine paper & razor blade makes nice template for shim wrapped around shaft. It'll make you a perfect pattern, if you don't already use the method.
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I will have to remember that. I have always just used glossy photo paper. It makes enough of an impression to follow with scissors.
 
rvich said:
I'd probably buy a six pack of beer in cans and drink a few while playing with shims cut from the aluminum to see how it felt when I put shims in there. Then I'd drink the rest of the beer, sleep on it and decide in the morning.
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I believe a beer can will be too thick.
 
worntorn said:
I picked up a packet of mixed thickness brass shimstock at Napa a few years ago.
It came in a regular sized postal Envelope, maybe 20 pieces in all.
My BSA has shimstock on the ATD to magneto connection.
It looks to have been in there for many years. Works fine, although the power requirement is tiny.

Glen
Click to expand...

Shim stock assortment ordered from Amazon.
 
The little roll of paper which adding machines use, or use regular paper. trim the ends & cut a straight line down the overlap and you've the shape of the cone-shape formed by the taper. Notch for keyway and you've got a full area shim. Just like rolling paper into a funnel, except this is sized to the shaft taper.

It's just plain white paper about 1.5" wide on a small plastic roller which should be available at any place carrying office supplies. Most machines have a separate ink tape I believe...Dunno. Inexpensive & very handy. I've use it for speedy pipe layout for years.
 
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