71 bus --2 alternator belts in 50 miles

[grapedaddy]

I just picked it up from a shop in Wytheville VA USA where my 2003 VW of Mexico long block purchased in 2005 was installed. My fan belt twisted off 2 times on the way home and I changed it along the side of I81 and it is about to come off again. By my crude measurements using a string and a lead sinker the pulley alignment looks good, but I am far from an expert. This is a new problem to me, but I've read several posts covering this subject. I have the Bentley. I"m stumped. Note the engine had an Bosch alternator conversion in the 90's. The alternator was replaced last year with a Brazilian Bosch. The fan belts I"m using are Contenental Contitech 11,3x912. I"m sure the angles are not optimum in the pictures because I'm wrangling an iPad around inside the engine compartment. Do you see anything I can't see?

Note that I"ve already seen the fuel filter in the engine compartment on the high pressure side.

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grapedaddy
1971 Westfalia "Buttercup"
2003 Westfalia "Tourmaline" (sold)
2021 MB Metris Getaway “TheDarkSide”

[SGKent]

post a better photo from the side view of the belts and the top view so we can see the alignment. Also a photo of the belt deflection (tension).

The first photo you posted sort of looks like the alternator is sitting up at a slight angle. It isn't good enough that two pulleys align at the bottom and top like you string test, they must be in the same plane. wrong stand, wrong shroud, wrong alternator, loose shroud, missing spacers, wrong pulleys etc - anything that causes the two pulleys to be in different planes.
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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

[TomWesty]

[Angus II]

Hello
Well, it looks like your alt. pulley is sitting out past the crank pulley. You may try loosening up the hold down bracket on the Alt. and see if you can get it to move forward a bit, so the groves line up.

[grapedaddy]

Thank you. I'll post the deflection when I change the belt again this afternoon. The photo angles we need may be unobtainable with an iPad.

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grapedaddy
1971 Westfalia "Buttercup"
2003 Westfalia "Tourmaline" (sold)
2021 MB Metris Getaway “TheDarkSide”

[SGKent]

also be aware there are different fans and mounting plates. The original generator on a 1971 was a 38 amp generator. The bugs had a 30 amp generator. The 38 amp unit had a fan and mounting plate that was set into the fan shroud a little to allow for the longer generator body. I don't know the history on your swap but if you had a 1971 generator that was 38 amps and the same shroud and mounting plate was used but converted to an alternator in the swap, then the alternator would be sitting closer to the fan I think. Someone who has done that conversion can tell you what parts are needed to make it work right.

Or it can be that the deeper mounting plate is needed. I still can't tell from the photos how the pulleys align because of the camera angle and the twisted belt. The pulleys aren't aligned and in the latest photos it looks like the alternator needs to go towards the fan but the photo may be skewing how it actually is. If you straighten the belt out you can tell which way they are.

The belt fraying looks like the side away from the engine has more fraying on it. That might imply that the alternator pulley is closer to the engine than the lower pulley. If so and the belt climbs the lower pulley, that may roll it over. outside up and in like it is. Straighten it to get a better sense of what is going on.

You can put a straight edge on the upper pulley outside edge and see how that aligns compared to the lower pulley. The outside edge of the pulley should be even enough to do that.
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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

[grapedaddy]

Thank you. It has been out of my sight so many times it's hard to say exactly what parts are on there right now. In the 90's a Gene Berg kit was used that included a German Bosch Alt, an Alt pulley and a backing plate and an Alt stand. That Alt was replaced with a Brazilian Bosch a few years ago reusing the same Alt pulley. Last year that Alt was replaced with another Brazilian Bosch and a new Alt pulley showed up, but throwing belts is a new problem that only appeared after the Mexican long block was installed. I'll try the straight edge alignment check shortly when I replace the belt again.
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grapedaddy
1971 Westfalia "Buttercup"
2003 Westfalia "Tourmaline" (sold)
2021 MB Metris Getaway “TheDarkSide”

[grapedaddy]

The straight edge check across the Alt pulley didn't tell me much because the new Alt pulley is so much thicker than the crank pulley
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grapedaddy
1971 Westfalia "Buttercup"
2003 Westfalia "Tourmaline" (sold)
2021 MB Metris Getaway “TheDarkSide”

[TomWesty]

Drop your home made plumb bob from the center of the belt track of th top pulley. Assuming the bus is level and the motor is level, the weight should align with the center of the crank pulley belt track. The pictures say it won’t. The alt pulley track center looks farther toward the rear of the bus than the crank pulley track center.
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If you haven't bled on them, you haven't worked on them.
Visit: www.tomcoryell.com and check out my music!

[Angus II]

Hello,
Try putting the old pulley back on, then???.
Is your doghouse shroud on correct?, it fits/slips in between the cylinder shrouds ears. Opps, that's right, you didn't do the work... so you wouldn't know.
You really should loosen the hold down strap on the Alt and stand, to see if you can move/shove it(the ALT.) forward towards the firewall.

[kreemoweet]

Those alt pulley halves do not look parallel to me. Also, the alt pulley should be much closer to the alt than is shown. It may be
that there are not enough shims between the pulley halves. It may be that you have one of the pulleys that will NOT accept
those 11.3x112 belts (and I have 2 of them), no matter what is done, and someone tried to force the issue.

You do not need to use the so-called "alternator belts" just because you have an alternator.
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'67 bug: seized by the authorities
'68 bug: seized by the authorities
'71 kombi: not yet seized by the authorities

Stop dead photo links! Post your photos to The Samba Gallery!

[grapedaddy]

I *was* able to shove the Alternator back toward the firewall a little after loosening the strap. I'm embarrassed to admit I only shorted out the Alt once! Yes, I knew better. After rechecking all of the above with my plumb line, that did seem to get the center lines of the pulleys more in line with the same plane. When I got it just about perfect, I could hear the cooling fan rubbing. I think I'm on the right track now. I'm hopeful that will keep a belt from twisting off for the 55 mile drive back to the shop at least. It's a good thing I had 4 spare belts. I don't have the other pulley that was taken off at last year's shop. When adjusted to what seems about right to me (less than a half inch of play on light thumb pressure), I can still see the belt flopping a little while running which is worrisome.
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grapedaddy
1971 Westfalia "Buttercup"
2003 Westfalia "Tourmaline" (sold)
2021 MB Metris Getaway “TheDarkSide”

[grapedaddy]

Hey kreemoweet,

I had suspected that inside surface of my Alt pulley wasn't quite round and the halves not being parallel would tend to cause that, but I think the image parallax distorts the view. Where do you get your Type I Alt pulleys ? . . .and what belt do you use if not 11.3 x 912? All I know about Alt pulley's is that they're different from the generator pulleys, but everywhere I look to buy one calls it a gen/Alt pulley like they're one size fits all when I'm sure they're not. One old school VW guy did tell me last month (with the old engine that wasn't twisting belts off) that my Alt pulley was "squeezing the belt" and that I should look for a new Alt pulley.
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grapedaddy
1971 Westfalia "Buttercup"
2003 Westfalia "Tourmaline" (sold)
2021 MB Metris Getaway “TheDarkSide”

[grapedaddy]

I also just remembered that my bus is never level, because the rear of it sags invalidating my plumb bob just-a-little.
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grapedaddy
1971 Westfalia "Buttercup"
2003 Westfalia "Tourmaline" (sold)
2021 MB Metris Getaway “TheDarkSide”

[aeromech]

How many shims are you using to adjust the belt tension? There should be a total of like 8 shims I think. Some between the pulley halves and some under the nut.

Also, the plate that bolts to the fan housing (4 bolts) needs to be the 38 amp generator type that’s dished in. Otherwise the alt will sit too far aft.

Lastly, they sell a shim kit (different than the others). There are two different types of shims. Some that go on the alt shaft between the forward pulley half to move the whole pulley assy aft and another type of shim used to move the crankshaft pulley aft. So use the shims you need to move one or the other pulley into alignment.
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VW Type 2 1971 (3 ea.) 1978, 1969
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[grapedaddy]

I have 5 shims between the Alt pulley halves and 3 under the nut. The belt deflection is about 1/2" now with what I would call light thumb pressure. i.e., I could squeeze it a tiny bit further, but the belt would be stretching.

Am I clear that I should have used the original dished back plate when that Alt conversion was done in the 90's? I still have it.

I now think that Alt pulley is my original 38 amp generator pulley which is not in the box with my other take off parts from that project. I now think that last year's shop just painted it. The paint is now worn off evenly in the right places
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grapedaddy
1971 Westfalia "Buttercup"
2003 Westfalia "Tourmaline" (sold)
2021 MB Metris Getaway “TheDarkSide”

[aeromech]

Yep, dished backing plate
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[Abscate]

You Can use a mirror to take that alignment shot, but I can see it isn’t aligned.
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.ssS!

[SGKent]

[kreemoweet]