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#15
by
vanbcguy
on 07 Jan, 2014 18:26
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The GOOD thing about the serp belt though is it makes for way easier belt changes plus it opens you up to the world of high output alternators. No re-tensioning either.
FWIW it isn't so much the letting off the pedal that is the issue as it is the pulses of power as pistons speed up on the combustion stroke and slow down on the compression stroke. Hammers the hell out of the keyway on the crank sprocket. The "D" style is a million times better.
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#16
by
wolf_walker
on 07 Jan, 2014 18:59
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Porsche uses the same one way clutch on the M96 motors that have been out awhile. When they aren't failing in some other comical fashion, those little clutches fail on them as well.
Not the best little piece.
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#17
by
Gizmoman
on 07 Jan, 2014 20:30
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The GOOD thing about the serp belt though is it makes for way easier belt changes plus it opens you up to the world of high output alternators. No re-tensioning either.
FWIW it isn't so much the letting off the pedal that is the issue as it is the pulses of power as pistons speed up on the combustion stroke and slow down on the compression stroke. Hammers the hell out of the keyway on the crank sprocket. The "D" style is a million times better.
OK, makes sense - that would explain why the clutches fail so "quickly". They are typically rated for millions of cycles. I have used them for industrial shears cutting carbon fiber cloth and they perform for several years. The pulses from a diesel would chew through the cycles pretty fast.
I also get where the serp belt can drive a bigger alternator. Any idea how many amps the v-belt can safely drive? Mine is a stock 60. Could a v-belt drive a 90?
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#18
by
theman53
on 08 Jan, 2014 06:21
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Yes, most of the a/c cars got 90 amps in the mk2 anyway. And all that I have seen were v belt.
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#19
by
vanbcguy
on 08 Jan, 2014 06:31
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Yup, AC cars got a 90A, though they also have all sorts of belt-related issues. That has a lot to do with the particular conflaburation of belts that VW used to be sure.
FWIW the clutched alt pulleys do last a pretty long time. Seems they are good for 100,000km+ for most people. They seem to outlast the typical timing belt replacement interval for instance.
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#20
by
bbob203
on 08 Jan, 2014 06:55
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MK2 ac vbelt system is among one of VW's worst designs.
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#21
by
Spokerider
on 08 Jan, 2014 13:17
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Scarry stuff but I'm glad people are capable of it. I have yet to remove the crank bolt on the AAZ in the 82. Plan to avoid it as long as possible.
And to stay with V belts.
wolf-walker,
Wondering if you would provide more info on using the V belt and V belt pulleys on your aaz?
I too would like to use the V belt set up in my aaz that came from a 1993 Golf. My aaz is going in my Samurai, and I have the ACME 1.9TD installation kit with the alternator up grade......a bracket for a GM CS130 105 Amp Alternator.
For the belts, I'm thinking....... one V belt for the crankshaft pulley / Alt pulley, and a second V belt for the crankshaft pulley / water pump pulley. Is this how you have yours configured?
I realize that the 1.9 came with a power steering pump that was included in the crankshaft / water pump belt-group, and that the belt tension was adjusted through the power steering bracket adjustment.
I have no use for the power steering pump and bracketry and want to leave it out of the build, so I'm wondering how one tensions this belt when it is only on the crank pulley and waterpump pulley?
Place the belt on the two pulleys and THEN bolt the water pump pulley to the pump with the belt under tension?
I have seen a pic by "wazzuk" [ pretty sure he is one of the ACME adapter guys ] on the yahoo groups samurai diesel group showing V belts configured on a 1.9 TD like I just described.
Anybody else run belts this way?
I have done lots of reading on this and yes, that counter-rotational force from the alternator inertia via the serp belt is a keyway killer. I want to stay clear of the serp belt set up for sure.
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#22
by
Spokerider
on 08 Jan, 2014 15:11
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#23
by
wolf_walker
on 08 Jan, 2014 15:53
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Far as I remember, it was remove from 1.6 and place on 1.9 for the pulleys and brackets, had to hack on some of the covers, it all fits well enough though.
The belt sizes are not stock, every time I replace the things I have to figure them out again since I'm not usually bright enough to save what size fit before.
They are new enough I might be able to now though if you need. Or pics. Mine is the later plastic cover bit, mostly anyway. Think it was actually off a 1.6TD from an
85 Jetta. Stock AC and alt, etc, etc. I wish I had put the adjusting bolt on the bracket that I cobbled off something on my other truck a few years ago.
Stuff all runs together after awhile.
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#24
by
Spokerider
on 09 Jan, 2014 08:23
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Thanks ww, I'd like to see some pics of the belt set-up if / when you can.
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#25
by
Spokerider
on 09 Jan, 2014 08:30
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Have another question about welding up the crank nose....
This guy had a machinist "spray" weld the crank nose to fit the AHU sprocket. Is spray welding commonly used for this?
I never thought of spray welding, and just thought that it was tig / mig laying a bead-type welding to fill in the keyway and make the crank diameter larger before machining back to dimension.
http://www.vwdiesel.net/forum/index.php?topic=30980.60
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#26
by
theman53
on 09 Jan, 2014 16:22
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Spray welding is mig welding with a 95/5 or 98/2 gas with the heat and feed turned up. IIRC it is 40% more heat and 20% more feed, you have to play with it a bit, but it was mainly used at first for pressure tested stuff. Now I have Amish guys that do it for the steel work with wheels since it makes a nice self leveling bead.
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#27
by
Gizmoman
on 09 Jan, 2014 16:53
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There is also a technique where the shaft area is heated to cherry/white hot and metal powder is introduced through the flame. The concept is controlled disposition with little or no stress from a typical welding process.
Typically it is done while the part is rotated slowly.
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#28
by
Mark(The Miser)UK
on 10 Jan, 2014 06:00
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wolf-walker,
Wondering if you would provide more info on using the V belt and V belt pulleys on your aaz?
I have done lots of reading on this and yes, that counter-rotational force from the alternator inertia via the serp belt is a keyway killer. I want to stay clear of the serp belt set up for sure.
On the Quantum, the fixed distance for the crank to water pump is overcome by a split pulley on the crank, that has say 10 [9 actually] shims available that are stored behind the pulley as they are removed from in between the pulley, to progressively squeeze the v belt, making the belt try and climb out of the pulley, effectively increasing the diameter of the pulley, and so the tension increases...
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#29
by
Spokerider
on 10 Jan, 2014 17:28
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On the Quantum, the fixed distance for the crank to water pump is overcome by a split pulley on the crank, that has say 10 [9 actually] shims available that are stored behind the pulley as they are removed from in between the pulley, to progressively squeeze the v belt, making the belt try and climb out of the pulley, effectively increasing the diameter of the pulley, and so the tension increases...
Very cool. I think the Quantum in Canada was labeled as a Passat. Do you know what year Quantum had the split pulley? I can check that year Passat at the wreckers.
I was just going to roll a belt or two, or three, over and into the water pump / crank pulleys, and choose the belt that had the optimum tension.
Checked with 2 machine shops so far regarding the crank repair...... one declined the job as they have no C&C machine, the other shop wants to just cut the same keyway notch 180 deg from the original, and install a new sprocket 
......even after I explained that the crank was not buggered [ yet ] and how I wanted the repair done as per TDI sprocket. Spray welding was a no-go for this shop.
I have another machine shop to pester yet.