There are three stock large-diameter pedestals (not counting the multion-function casting on an F.I. motor). Commonly called "12V" but there was a large-diameter 6V made too that requires the "12V" pedestal, strap, pulley and sheetmetal. The letter at the end of the casting number is "B" for the one used on singleports, "E" for the dualport (it's got a chamfer on the bottom to clear the DP intake manifold) and "G" for an alternator. You can use a G in place of an E or B, and you can use an E in place of a B - but it's a one-way interchange. Since we only got carbureted alternator engines in the US market for `74 and part of `73 the OEM pedestals are a little hard to come by, but Chiwanese counterfeits are readily available. I've noticed on the last couple new Bosch alternators I've installed that there are two ribs in the casting on the bottom that prevent it from settling down properly in the saddle of the pedestal - they need to be trimmed slightly shorter (file or grind). Alternators and all of the large-diameter generators with the exception of the 38A one use the same strap, fan hub, and three pieces of sheetmetal. There have been different styles of pulley but they had the same offset so the 043 903 109 fits any of them (except the 38A). As I mentioned before, the 38A needs a special pulley. It has a unique fan hub & spacer setup and the two larger pieces of tin are "dished" - it does take the same strap and small tin ring as the others. It's recommended that you use the wider 11.3x912La belt with an alternator since the 9.5x905La may slip under the added load. And be sure that there are at least 8 pulley shims total, else you risk the nut running out of threads before the pulley halves are firmly clamped together - the most common cause of pulley destruction. Since alternators don't have a large mass of magnetic material in them like a generator, they need an external source of power for the "field flash" that gets them started charging. Without that (provided from the ignition switch via the warning lamp filament) and alternator that's been idle for even a few days may not put out until the engine is buzzed to a high RPM, if then (not attainable by bump-starting). Generators can sit idle for many months before they lose all of their residual magnetism - at which point they require polarization - so even with NO battery in the car it's possible to bump-start a generator-equipped car, but you still have to get the thing above the "cut-out" speed of the regulator (approximately 760 engine RPM) so you'll need a steep hill or a push vehicle...or maybe an Olympic bobsled team. So, with no battery it's all but impossible to start an alternator-equipped car - just as well, because if you run an alternator with no battery in the circuit to provide a voltage reference there's a very real danger of it "running away" and putting out enough voltage to damage electrical components in the car (if it doesn't fry itself first). But as Glen points out, if there's enough juice in the battery to supply the coil (the warning lights are fairly bright when you turn the key to "on") you can bump-start either...if the lights are dim, there may still be enough to flash the alternator so in that case the alternator-equipped car could be slightly EASIER to start, since the alternator starts charging at a lower engine RPM. For the ultimate in vintage appearance you could use a small-diameter 12V generator from a 356 - but they're spendy and don't put out as much as a stock Bug unit. I don't recommend mounting the regulator to the fan shroud just because there seems to be a higher rate of failure when you do (fan vibration?). You could mount it on the firewall, tucked up in the far LH corner where it's not obtrusive. Mounting it under the back set is best, but that requires additional wiring and isn't very practical on an early body with the main harness running through the roof.
--- Sharkey's Garage <[EMAIL PROTECTED]> wrote: > An alternator stand features a notch designed to > allow the larger diameter > of the alternator to clear properly, and it will > accept a generator. An OEM > generator stand will NOT accept an alternator. > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf > Of GARRETT FELL > Sent: March 2, 2007 10:57 AM > To: Air-Cooled Volkswagen Discussion List > Subject: Re: [vintagvw] Alternator / Generator > conversion in an early car > > Getting back to the subject of generators -vs- > alternators. Is everything > the same between a generator and alternator > installation except for the > "stand" it sits on? I guess that'd just be the > backing plates that would be > left? Are the stands different shaped? I've seen > references to > "generator/alternator" stands which suggests they > are the same, but then > again I've seen references to one or the other.... ____________________________________________________________________________________ Looking for earth-friendly autos? Browse Top Cars by "Green Rating" at Yahoo! Autos' Green Center. http://autos.yahoo.com/green_center/ _______________________________________________ vintagvw site list [email protected] http://lists.sjsu.edu/mailman/listinfo/vintagvw
