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Old 18-01-2021, 06:36 PM   #1
thebiglebowski0
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Default Alternator/dynamo belt

Hey dudes,

Stupid question of the day!

I have got an alternator in my 73 bug but the 'alternator belt' 11.3x912mm seems too big for tensioning (even without shims). I've got an 905mm belt, but can only get correct tension with one shim in between the pulleys. Is this normal? Which is the correct belt size for my bug? Initially tried to follow the tensioning procedure starting with 5 shims between and 5 outside the pulley, but not even close to being able to tension. Am I missing something?

Also, whilst checking it all over I found a horror show behind the pulley! looks like the woodruff key got spat out the back and butchered the alternator (see pic). Is this a major problem? Have been able to refit the pulley with a spare key and it seems to have located and secured ok. Anybody seen this before or know why the key would come loose?

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Thanks folks!

Last edited by thebiglebowski0; 18-01-2021 at 06:41 PM..
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Old 18-01-2021, 09:08 PM   #2
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On a Beetle, the stock Alternator belt is 11.3 x 912, (a Dynamo belt is 905 x 9.5, although shorter, it is narrower, so would also be difficult to tension).
Your Alternator pulley looks like an aftermarket item which may need a different size anyway, which may account for the tensioning issue, and even possibly also why the woodruff key came out.
The damage to the end casing may cause the bearing to become loose, you could try some plastic metal to give it more support and get a bit more life out of it.
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Old 18-01-2021, 09:39 PM   #3
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I use a 6216mc belt on my beetle with an alternator. Just had to order two last night after shredding one on the way to work
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Old 19-01-2021, 04:04 PM   #4
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Thanks dudes,

Managed to source a second hand alternator face/bracket from mega bug for 20 delivered, so hopefully that’s sorted.

I’ll give the 6216mc belt a go as well. Cheers for the advice 😀
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Old 20-01-2021, 08:36 PM   #5
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Had this on ours when fitted aftermarket pulleys just did a visit to local parts store with 912mm x 11mm part to cross reference

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Old 22-01-2021, 11:11 AM   #6
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Slightly off topic, but those nasty aluminium crank pulleys have a habit of disintegrating which can wreck the case and crank - I saw two customers in a single day with wrecked engines because of this - plus your engine will thank you if you fit the correct distributor. Further, the rear engine seal appears to be missing or improperly fitted.
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Old 22-01-2021, 04:39 PM   #7
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Quote:
Originally Posted by Beetlebank View Post
Slightly off topic, but those nasty aluminium crank pulleys have a habit of disintegrating which can wreck the case and crank - I saw two customers in a single day with wrecked engines because of this - plus your engine will thank you if you fit the correct distributor. Further, the rear engine seal appears to be missing or improperly fitted.
Thanks for commenting dude and good spot on the rear engine seal. It is there, I just had to raise the tinware after dropping a nut which got caught below the wheel!

It's funny you should mention the dizzy as I have had a nightmare with tuning lately and have come to the conclusion that the 009 isn't up to the job. Have been looking at going back to the vacuum advance, is there any you would recommend? Seems to be a choice between cheap or Petronix only?

Alarming to hear about your experiences with the crank pulley wheel, I thought I was doing my engine a favour (and making advance timing easier!).
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Old 22-01-2021, 09:22 PM   #8
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Quote:
Originally Posted by thebiglebowski0 View Post
It's funny you should mention the dizzy as I have had a nightmare with tuning lately and have come to the conclusion that the 009 isn't up to the job. Have been looking at going back to the vacuum advance, is there any you would recommend? Seems to be a choice between cheap or Petronix only?
A SVDA distributor would be my recommendation, I haven't felt the need for electronic ignition.

Quote:
Alarming to hear about your experiences with the crank pulley wheel, I thought I was doing my engine a favour (and making advance timing easier!)
Those alloy pulleys are notorious.
For ignition timing, the stock pulley has all the markings you'll ever need.
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Old 23-01-2021, 10:07 AM   #9
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Quote:
Originally Posted by thebiglebowski0 View Post
Alarming to hear about your experiences with the crank pulley wheel, I thought I was doing my engine a favour (and making advance timing easier!).
Even the timing marks will not be accurate; every engine is slightly different and the only means of determining TDC accurately is by the dead-stop method. This is equally true for any pulley, including stock VW, where there were at least five different variants of pulley markings. I have seen these ghastly 'time bomb' pulleys as much as three degrees out.
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Old 23-01-2021, 10:10 AM   #10
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Quote:
Originally Posted by Bada Ben View Post
A SVDA distributor would be my recommendation, I haven't felt the need for electronic ignition.
^^^WHS

Many people carry spare points for when the electronic ignition fails, but you never see someone carrying a spare Ignitor in case the points fail...
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