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BulliBill
Samba Member
Joined: July 09, 2004
Posts: 4573
Location: St Charles, MO
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 Posted: Mon Jun 29, 2020 8:15 pm Post subject: Re: Generator pulley shims |
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| BulliBill wrote: |
Okay, it's a few years later and now I'm cleaning and sorting thru my pile of generator and generator pulley parts to make sense of it all. I thought I'd add to "tasb" four year old chart above...
Here is an example of each of the different washers and spacer shims that I have with their approximate dimensions and thicknesses measured with a digital caliper, noted as to whether they are flat or "wavy"... There may be more that I don't possess. The top row (with the flat sides on the inner diameter) I'm pretty sure are correct for 1955 and older generators. The bottom row middle and right washers are thick and I believe go on the fan end of the generator. And where the hell does that one in the upper right corner fit (smaller O.D.)?
Bill Bowman |
Okay, I tore into cleaning and re-storing a 90mm diameter 12 volt generator for the Porsche 356 and 912's. I discovered while cleaning and comparing parts that the slightly smaller "keyed" shim in the above quoted photo in the upper right is used on the Porsche distributor. Maybe that clears it up, maybe not.
Then while cleaning up an "L13" distributor from 1955 I dis-assembled the pulley from the generator and discovered a whole new spacer/shim for the pulley that I've never seen before. I'm wondering if you have? Check out the attached photos...
That beast of a shim/spacer is about 5.0 mm thick and has a flange which fits perfectly into the groove in the special rearmost 36 mm nut (see the third photo down) just forward of it, between it and the rearmost pulley half are a few normal 0.5 mm shim/spacers with even more between the two pulley halves.
Has anyone ever seen one of these before? I've never come across one of these beautifully made, maybe factory spacer/shims. It does not look homemade.
Bill Bowman
_________________
I'm looking for these license plate frames for my fleet:
Coeur D'Alene - Lake Shore Volkswagen
Mission VW - San Fernando
Thornton VW - Stockton
Thanks for any help! |
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mikeandkirsti
Samba Member
Joined: June 16, 2009
Posts: 286
Location: EU
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| Posted: Thu Jul 02, 2020 10:21 am Post subject: |
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| James Davies wrote: |
The correct number of shims inside the pulley halves is the number that makes the V-belt ride where it is supposed to - not too high, not too low, the Goldilocks position where it also has the correct tension. New belts need to be re-shimmed to get the correct tension as they stretch after very short period of use.
If you pull out too many shims so that the belt rides too high for the right tension, then you probably need to replace your belt as it is too stretched.
On early '50s Porsches, the Factory manual says the correct tension should be 2 cm of deflection for the belt. The pulley comes standard with 8 spacers (6 2mm and 2 1mm). Ones not used inside the pulley go on the outside behind the tightening nut. Not sure this is identical for VWs, but I would guess it is.
See below from the '54 Porsche Factory workshop manual.
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With a modern belt 2 cm is way too loose and belt will slip. With 2 cm it is so loose that you cannot turn the engine by turning the generator pully, the belt will only slip at both pulleys. 1 cm is closer to what it should be. |
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