Alternator Alignment MK1

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tollertdi
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Alternator Alignment MK1

Postby tollertdi » Wed Mar 10, 2010 3:17 pm

Replacing the alternator belt on a non-ac 83 Rabbit Diesel. Noticed that the alternator pulley is about 1/4 inch inboard from the waterpump and crankshaft pully. Waterpump and crankshaft pulleys look perfectly aligned.

This doesn't look normal to me. Does anyone know what's going on here?

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bscutt
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Postby bscutt » Wed Mar 10, 2010 3:59 pm

The water pump pulley is usually a bit off from the crank and alternator if I recall from my '80 with no AC. That was to increase friction on the water pump pulley since the belt only contacts about 100-120 degrees of that pulley. Not sure if that's what you are seeing but if it is, it's normal in my opinion. If the alternator is not in line with the crank you may have something else going on.
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tollertdi
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Postby tollertdi » Wed Mar 10, 2010 9:07 pm

The waterpump pulley and crank pulley definitely look like they're aligned properly. The alternator pulley is off. My Rabbit seems to be stock original, so I'm not sure what else could be going on here.

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Quantum-man
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Postby Quantum-man » Wed Mar 10, 2010 10:16 pm

tollertdi wrote:The waterpump pulley and crank pulley definitely look like they're aligned properly. The alternator pulley is off. My Rabbit seems to be stock original, so I'm not sure what else could be going on here.


Seeing as non a/c stuff over the pond is like hen's teeth [contrast here in the UK], chances are you have the wrong pulley on the alt.... which implies the wrong spindle lengrth, which means the wrong alt ;)
It appears that there are variations between gasser-diesel-a/c- non ac. Maybe upto 16 variations plus 5 cylinder v 4 cylinder. Probably less in practice,
Just anecdotally, if non a/c alts are as rare as non a/c brackets then... :mrgreen:
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Postby Vdub-bub » Wed Mar 10, 2010 10:39 pm

Is the alt. pulley too close to the alt. or too far away, if it's too close you might be able put a spacer behind the pulley. If it's too far away, maybe the pulley is offset and you can turn it around to align it.
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Postby tollertdi » Wed Mar 10, 2010 11:21 pm

I really think it's stock original. It's a Motorola 65 amp. I've had it off of the vehicle and in order to do that I had to break a factory tie wrap with an v-shaped anchor on it that anchored down the wire harness to the alternator.

Anyway it's too close to the alternator, so it sits inboard with respect to the crank and waterpump pulley. I considered putting a shim behind the pulley, but that means that I'm going to lose probably about 25% of the threads on the end of the alternator shaft.

My understanding is AC rabbits had about a 10mm longer pulley than non-AC. This doesn't really account for my difference which is about half of that ~5mm.

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Postby tylernt » Thu Mar 11, 2010 12:52 am

There may be a tiny bit of play in the alternator bracket. You may drip a little coolant doing it, but if you remove the alternator and loosen all of the bracket mounting bolts (including the little bracket that connects the alternator and injection pump brackets together), you may be able to tap the whole thing leftwards a bit before re-tightening.

To be honest I'm not sure 5mm is worth worrying about though. Mine isn't in perfect alignment either, so far so good though.
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Postby Fatmobile » Fri Mar 12, 2010 1:03 am

The alternator necks and pullys are so long already,..
but mine does the same thing.
Going to try a MK2 bracket/alternator on my next one.
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Postby Quantum-man » Fri Mar 12, 2010 8:12 am

Here's a picture of my 1985 Quantum TD non a/c

http://img717.imageshack.us/img717/562/ ... ulley1.jpg

Note that although pulley face is out of line by about 2mm, the belt is not, or at least within 0.5mm. This is because the pulleys have 'thicker' rims.
Not sure if it has been set right with the 3mm of spacers behind the alt pulley, or whether that is standard.
I suspect that you also could create 1 or 2 mm movement with the separate parts of the mounting bracket.
ETKA is unclear as to what the different series of numbers in the remarks column refer to....

Skewing a vee belt for extra grip, cannot be correct, even if it helps a slack belt a little. In truth probably polishes the walls of the pulley more, to increase future slippage IMO
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Postby tollertdi » Fri Mar 12, 2010 3:41 pm

Yes, I agree, the pulleys do have extra thickness and I did consider this. When I stick a straight edge between the crank and waterpump, I end up with about a 3mm gap. The gap is measured from the straight edge inboard to the rim of the alternator pulley. The thickness of the alternator pulley, like you said, is greater so this difference has to be added to the 3mm. This is because my pulley is inboard from the plane of the crank and waterpump pulleys. The difference can be seen just by sighting along the centers of the pulleys.

5mm difference is half of the belt width and will probably work but I agree this doesn't seem right at all. The factory must have messed up maybe? Or maybe VW wants extra friction on the waterpump pulley?

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Postby Quantum-man » Fri Mar 12, 2010 10:41 pm

tollertdi wrote:Yes, I agree, the pulleys do have extra thickness and I did consider this. When I stick a straight edge between the crank and waterpump, I end up with about a 3mm gap. The gap is measured from the straight edge inboard to the rim of the alternator pulley. The thickness of the alternator pulley, like you said, is greater so this difference has to be added to the 3mm. This is because my pulley is inboard from the plane of the crank and waterpump pulleys. The difference can be seen just by sighting along the centers of the pulleys.

5mm difference is half of the belt width and will probably work but I agree this doesn't seem right at all. The factory must have messed up maybe? Or maybe VW wants extra friction on the waterpump pulley?

So you are saying that your alt pulley centreline is 5mm in from mine.
Where I am slightly confused, is your reference to the waterpump pulley.

The tension on this vee belt is by altering number of shimms between the 2 halves of the pump pulley.
Does your alternator not lie under engine?

In my picture, the alt is on the left, crank in the middle, and waterpump on the right.

1.6 and 1.8 gassers have alt on top of engine driven by waterpump.

I also have a power steering model of TD, again w/o a/c .This has it's own belt, again driven from the crank, so the crank pulley has 3 belts. I think the Quantum TD with a/c has the alt belt driven off the a/c, which is in the position of the non a/c alt. IIRC :? .
"I'm not here to help... I'm here to Pro-Volke"

Be like meeee...Drive a Quantum TD
...The best work-horse after the cart...

Quantae grow on you...but Rabbits are like roses...
... girls like em ;o)

Only one Darwin, Einstein, Poe and Verne.
That is why if you listen, you will learn:
From the one and only Quantum-man,
Who sees the worms from outside of the can.

7 Quantae in 20 years; 4 dead and 3 TD's still alive [2 wagons & 1 fastback] oh and a GTD :o)

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Postby tollertdi » Mon Mar 15, 2010 11:49 pm

Looks like you have a different set up than me.

Here's a diagram looking from the front of my vehicle and down at the engine.

| |
| | Crank pulley
| |
ENGINE SIDE
| |
| | Waterpump pulley
| |




| |
| | Alternator pulley (Located above Waterpump pulley)




Alternator is inboard from the waterpump pulley about 5mm. Don't understand about shimms. Don't have any.

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Postby tylernt » Mon Mar 15, 2010 11:57 pm

tollertdi wrote:Don't understand about shimms. Don't have any.
My Fox (longitudinal engine) has shims for the A/C, but so far as I know, Mk1s do not have them and just swing the alternator on the bracket to tension the belt.
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Pulley alignment Mk 1.

Postby hagar » Tue Mar 16, 2010 8:40 am

tollertdi :

Good alignment is important BUT more important is a correct belt "10 mm" NOT 11 mm,

The geometry of pulley from VW are metric standard . "The wedging" is special.. This forum is full of information about that. SO ? read .

hagar.

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Postby tollertdi » Tue Mar 16, 2010 3:08 pm

Hagar:

My new belt is 10mm. I made sure it's German, Contitech brand. Nothing but the best for my Rabbit. Sorry, don't have the part number with me.

Just trying to understand why I don't have perfect alignment on my alternator pulley. Shouldn't I expect this from German engineering?


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