70 amp alternator pulley with fan

[malcolm2]

I am in need of the subject.

I found that VW made a version for the bug. will that one fit?

WHat is the diameter of the shaft on a Bug Alt?

I believe the 70 amp alt has a 17mm diameter.

What do folks do when they need one of these?

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[Wildthings]

Not sure what your question is, but find a local mom and pops auto electric shop and see if they can help you out.

[Miklo]

They have a WTB up looking for one of these...

https://www.thesamba.com/vw/classifieds/detail.php?id=2146887

I believe they want to know if it will fit a type 4 alternator shaft? Let alone the tins? I don’t know...

Not sure about them being hens teeth though... I bought mine from Moore Parts, just like the picture shows.

As I remember, the pulley I bought from Moore Parts didn’t come in an EMPI package.

It’s very heavy and decent quality. Which doesn’t scream EMPI at all.

Not sure if they really work for cooling but they are great quality.

I first had thoughts the pulley weight and fan velocity would eat the bearing in my cheap china type 1 style alternator, but I’m two years of daily driving without any problems.

I will soon be swapping engines from my Beetle to my 70 Bus. Maybe the fan will stimulate some engine compartment airflow...
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'66 Type1 "Charlotte" RIP
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[malcolm2]

I don't WTB this part...UNLESS I get someone that knows it will fit on the shaft of my type 4 alternator, 70amp.

If someone can find the fan that goes on the 70amp alternator I will buy it at the same price as the photo. But they are NLA. NLA. Junk yards maybe, but very few buses came with this part.

Since they are no longer available... HENS TEETH. I would like to know what the Bus People do.

If you have taken the 50amp alternator off of your TIV engined bus and put on a 70amp (factory option in 1979). What did you do about the pulley?

[Randy in Maine]

One of my 1979 buses has a 70 amp and one has a 55 amp alternator. What do you want me to measure?

[Xevin]

Don’t worry about it. My 72 bus with a 76 2.0L engine has a 70 amp alternator. It does not have the fan style pulley. Has run fine for 20,000 miles and counting. The 76 bus has the fan style pulley on the alternator. I can’t tell the difference. If someone tells me I need the fan style pulley for the 72 for a solid reason I’m willing to change it out. But until then. I roll as is. Been doing so for 6 years. And yes I understand stand what the fan is supposed to do.
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[malcolm2]

[malcolm2]

[69BahamaYellow]

This might help a little:

If you can take your 55 amp pulley to an alternator shop, perhaps they have an offset fan that can be welded onto it. The key is to find a fan with an offset, since most are for a flat pulley. Here is a comparison of my 55 amp pulley to the 70 amp pulley.

As with everything, yes it will run without a fan, and probably be ok, since the insulation used on alternator magnet wiring today is way more heat tollerant than 40+ years ago. If you're running a 70 amp alternator with 40+ year old magnet wiring, then you probably should consider a fan. the 15 amp increase still represents a 27% increase in power output, but that's also an even larger increase in internal heat generated, which is why VW used a larger air boot, and the fan. In my case, my 70 Amp alternator was rewound to produce 110 Amps, so it definitely needs a fan.

[busdaddy]

AFAIK 50 and 70 amp shafts are the same and the pulleys interchange, I doubt that beetle pulley will work without issues so the fanless pulley may be your only option.
As WT's says a run down auto electric shop with blackened gouged up work benches, greasy handprints all over the walls and magazines from the 70's and 80's in the cluttered front room is your best bet, it has to smell like grease, coffee and cigarettes though, and the floors must be filthy except for a small path where everyone walks. Early watercooled cars used a similar pulley and they may have something amongst the mountians of crap under the bench. Other make alternators use a loose fan that sandwiches between the pulley and spacer sleeve, some mixing and matching could result in a reasonable facimile.
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[airschooled]

Honest question: does the 70-amp alternator need the fan if it’s replacing a stock 55-amp setup with no fridge, second battery, or gas heater?

Robbie
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[busdaddy]

[malcolm2]

Thanks for the input. Is it an optical illusion? some of the blades a different length or width? Man that looks funny.

I also found a chevy fan that slides onto the shaft. It has a notch for the key, but I don't think the key goes that deep.

Anyway, Once the ALT arrives I will try different things.

The ALT shop is a good idea. I have 2 that I will try. The one in downtown Nashville is the one that rebuilt my 50amp one. 2 times in 2 years!!! but maybe they can help with the fan. Not near the description you laid out.

Next time add, "a room full of shelves made with 2 x 4s, full of starters and alternators from the 50s." and you got it.

[Wildthings]

[malcolm2]

This is semi-OT but check out the 50amp rotor.

The brushes made the black marks. You can tell that they were not lined up properly. After 14 months of running the part of the brush that was over the gap was not wearing and I assume the brush was running in that crack and touching the shaft or the other copper piece.

Anyone know how the brushes could be adjusted? I don't believe these copper (commutators ??) move. every exploded parts layout I see has the rotor as 1 piece. And I have heard that part of rebuilding is the machine down the copper. You can see that the edge has an unmachined rib.

[Wildthings]

Going to plead general ignorance here, but I am going to guess that some washer either got left out or was installed into the wrong position.

[busdaddy]

Or possibly the replacement Chinesium bearing was too fat and pushed the whole assembly off kilter.
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Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
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[malcolm2]

Yes the VW engineers had a reason to add the fan. And yes, the shade tree engineers will always find a way to un-engineer, myself included. I hate it when my mechanics at work say, "that will work"

There are lots of stories about people removing the warm up dampers or the t-stat in a type 4 cooling fan.

Yes the car works, almost the same as if the dampers or t-stat were there. But in this case we have been told that the t-stat and dampers help the engine warm up faster by re-directing the cooling air until the t-stat opens. What that does is make the engine last longer. With thick, cold oil the oil does not flow.

So really when the bearings do fail in 100,000 miles no one really knows that they might have lasted for 150 or 200,000 miles.

I know I over stated the removal of a designed in feature, but we really don't know the exact reason why the engineers added the fan. We can assume. And in this case it might be to extend the life of the 70amp ALT.

Thanks for the side-by-side picture. From that, I can probably make a pulley with a fan on it. When I do, I will add it to this thread.

[SGKent]

the slip rings are replaceable at an electric shop level, and maybe those were pressed on too far - perhaps when the rotor was made. Could be the rear bearing wasn't pressed on properly. The front bearing also controls depth so the wrong pulley might change the depth of the rotor. I don't know for sure without taking one apart.If the alternator was putting out current and not shorting out just remember it is a 40 - 50 year old mass produced car.
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[malcolm2]