Installing Alternator Belt - Need Help?

[sweeds]

I was "attempting" to install my new pulley and belt last night, but the belt seemed to be WAY too small. I have a 73 Westy, does anyone have a belt size they use? I have a newer engine in the bus, replaced the original, and the belt I bought (CONITECH AVX10X888) is about an inch too short. I did put the belt on the pulley first and then tried to wrap in around. Any ideas, different belts to look into?

Thanks

[pawesty]

your belt should be Conti 10x965

dave
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79 westy
78 westy

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[sweeds]

I have a Gatorback 11x965 from AutoZone, so could I get a Gatorback 10x965 from the same place. I just purchased a Dynaflex by Dayco at Pep Boys. Anyone else have any suggestions?

[AhnwS71]

[Zed999]

To get it to ride up on your partly tightened top pulley, turn the nut, the pulley ( and the engine) will turn and the belt will ride up as the nut tightens down. If the pulley half is still not square you need more shims between or a longer belt. Only when it's all looking good should you lock the pulley and tighten to spec.

[AhnwS71]

[Zed999]

[Wildthings]

Got enough shims between the pulley halves? A 11mm belt is going to effectively be shorter than a 10mm belt of the same length as it will ride higher in the pulleys.

[SGKent]

we have multiple alternators and designs here being discussed. The original 2004 post discusses a North American 1973 pancake engine with an alternator under the tin, that rotates to adjust. A 1971 upright came with a generator, is managed with shims, and someone has upgraded it to an alternator. Two different animals.

To the latest poster - if the belt on the 1971 bus worked for a long time all you need to do is look at the numbers on it to see what it is and buy one that size. If it fails frequently then maybe the alignment of the belt is off. Who upgraded it?
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[kreemoweet]

[Abscate]

You can do this with a screwdriver while the engine is running.,,,wait,,,is this allowed ??
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[AhnwS71]

[Abscate]

I’ll guess you have the wrong parts in the shroud, forward of the alternator.

The pulleys have to align or the belt will either flip off or wear prematurely
Y
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[SGKent]

I think you may have hinted that you changed the fan shroud. The original 1971 engine had a 38 amp generator. Earlier buses had a 30 amp. The 38 amp pulley is different I believe, and the fan backing plate sits deeper. A mis-alignment because of the parts may be playing into this if the shroud was changed. My suggestion is work with someone who has been thru a fan shroud changed, and who knows what parts work together. I can see that the belt is offset and that is probably causing it to roll. Talk with any of the early bay guys on this. I'd start with Robbie ( Asiab3 )
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[airschooled]

Thanks for the shoutout Steve I was actually supervising AhnwS71 with the shroud, tin, and oil cooler swap, and engine installation. I remember sighting the belt alignment and not seeing any flagrant issues. He has the correct backing plate, pulley, and fan/hub parts for his new doghouse cooling system, complete with Hoover Bit, and stepped oil cooler seals with proper washer distribution. We dotted our I’s, crossed our T’s, and umlauted our.... umlauts?

We did notice the chrome pulleys on hand had visible radial and axial runout when spin by hand. I don’t need my micrometer to know trash when I see it.

When installing a new belt OR pulley on a Type 1 engine, start with all your shims inside the pulley halves, no exceptions. This makes the belt as loose as possible and ensures the pulley halves can sit down flush. If too loose, remove one shim (stick it under the special pulley washer on the outside!) and try again. I can’t overstate the importance of alt/gen pulley seating enough, and the biggest mistake during installation is pinching the belt before the pulley halves are fully seated.

Do you remember during our work day when we installed the belt and debated shim movement, where we let the pulley spin a few times during tightening? This ensures the pulley halves are mating symmetrically, as the belt won’t bind up in one spot. That’s what your new pulley pictures look like to me.

Another problem I have witnessed with almost every new aftermarket pulley, is that the metal isn’t not stamped symmetrically. Take each pulley half and lay them large side down on flat glass, (a clean rear window works in a pinch.) There should be NO knocking, clicking, or rocking. Most pulleys stamped with a “Made in Germany” (but in Russian) stamping are out of round, probably from excessively pressure, or stamping without supporting properly.

If it passes this test, and many don’t, install it with a properly and thoroughly adjusted belt, warm up the engine until it’s idles smoothly, and sight down the pulleys, keeping dangly hair, clothes, or jewelry out of the skinny bits! Are the pulleys perfectly parallel with each other? Or is the belt making a jog front to back?

I wager your new pulley wouldn’t make it past the unpaid intern inspection for the Rocket City Trash Pandas.
Robbie
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[SGKent]

maybe it is just the angle but something looks cocked in the photo and the belt looks distorted at the top to me. The exterior part of the pulley looks caddywhompus to me too. Maybe it is a warped pulley.

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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[Wildthings]

[AhnwS71]

update: took engine out to see it better. installed belt and it appears to be off by a small bit. i placed the new pulley parts against glass with the outside of the pulley touching the glass. no movement on one and barely any one the other. Pulley seems ok.

https://www.youtube.com/watch?v=SFDLjiQrUzk

see what happened to the old belt

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[Wildthings]

Your upper pulley just doesn't look right and the belt is running way too far down in the pulley. Put a paint mark on the nut and pulley, back the nut off counting the turns and then remove the belt. Now turn the nut back in the same number of turns you counted until the paint marks align. Are the two pulley halves now bound tightly to each other as they should be?

[busdaddy]

Looks like the belt is way too short from here.

Why is your vacuum advance port on the distributor capped off?
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