1. Home
  2. Volkswagen, hot (Aircooled)
  3. Alternator top pulley

Alternator top pulley

Okay, have a weird one for you all. Subject car is a 1974 super beetle, stock Motorola alternator.

The pulley(not original) on the alternator sits out too far. There are no shims behind the pulley adapter or between the adapter and the rear pulley plate. It's just out too far to give the belt a straight path between the crank pulley and the alternator pulley.

Engine is sporting an aluminum degree wheel pulley. So my question is, was(or is) there a special pulley for the alternator with a different offset than the same type pulley that one might use on a generator? On the same vein, does the offset of the various aluminum pulleys that are available vary from stock, i.e., do the aluminum pulleys ride closer to the crankcase overall, thus throwing the belt routing all to hell?

Without any way to move the pulley on the alternator back the only option I see is to replace the alternator with a single wire variety and hope for a better alignment. I'm not wanting to go down that route if not necessary.

Any advice is appreciated.

Chris

Reply to
halatos
Loading thread data ...

Generator and altinator pulleys are different but you can losen the strap that holds it to the stand and see if it will slide back a little.

Mario Vintage Werks resto

Reply to
Kafertoys

I can't move the alternator as a whole more than a couple millimeters in either direction without having the fan start to hit the blower housing. I did notice while investigating moving the alternator that I have quite a bit of end play on the alternator shaft, don't know if that is related to my problem as it takes some light taps with a rubber mallet to move it in/out. As far as the pulley at the alternator is concerned, the shaft adapter and inner sheave are 'crap', probably brazillian. The outer sheave says "Made In Germany", so I know I have a mis-matched pulley on top.

The crank pulley on the bottom I removed and test-fitted to a crank I have sitting in the garage. There is a shoulder it butts up against, and while one could conceivably shim the crank pulley out, I have to ask..how many folks have had to do so? The shims for that purpose aren't something I've ever come across, leading me to believe that practice is rare, if it is indeed done at all.

Bottom line..I'm stumped. Could be the aluminum crank pulley has less offset than a stock steel crank pulley, but I don't have one to compare with. That seems like the most likely explanation right now. I need to try and get my hands on a stock pulley and see how it fits.

Chris

Reply to
halatos

Crank shaft pulley shims

formatting link

Reply to
anton

Alternator and Generator pullies are different? For Bosch alternators the location and spacing looks identical. I have had the same problems with mine with both alternators and generators.

Reply to
KWW

The offset on aftermarket pulleys varies too. Both top and bottom pulleys. You can shim both pulleys out if necessary.

Reply to
Jan Andersson

I have the local VW shop ordering me a set of the CB performance shims that Anton pointed out to me. Should be here in a day or two, hopefully that will fix it up.

I did notice that the thrust face on the alternator pulley adapter is very thick, but I don't have the tooling to turn it down evenly. I could conceivably take quite a bit of material off there, which would push the entire alternator pulley closer to the alternator case. The problem is without any way to accurately remove material from the adapter I'm likely to get a lopsided pulley in the end, which would be just as bad as having one that protrudes too far.

The late model single wire alternators have a shoulder on the shaft that is different than my 4 wire alternator. The shoulder looks to be the same diameter but it does not protrude from the case as far as mine. I could still go to a different alternator but don't want to...yet. That difference in offset between the stock and newer alternator has me still thinking that 1974 had a different pulley than other years.

I compared a couple crankshaft pulleys and they all had the exact same offset, so the only conclusion I can come up with is either the crank pulley or the alternator pulley had to be different for 1974.

Chris

Reply to
halatos

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.