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L4 cog belt accessory drive

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Gordo View Drop Down
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    Posted: 06 Jul 2016 at 12:09am

Been wanting to do this for some time,

make a HTD 8mm belt accessory drive for one of our Datsuns (my son's 510, my pickup).

 

I keep a few of the Pfeifer 40mm wide pulleys in stock, mostly for supercharger drives, so I started cutting shavings.

The hub was originally an Unorthodox aluminum 7M crank pulley that I bought 18 or so years ago, and then came to my senses, and never installed.

The bore just happened to be the same as the Datsun, so I cut the sh*t out of it, just to have a drive flange.

Then made the adapter to place the pulley in the right position.

 

The water pump was a lot easier, the adapter just amounts to a flanged hub-centric ring, mates the Datsun register up with the 40mm bore of the standard pulleys.

Moroso just happened to have an 8mm x 20t pulley meant for the Denso alternators, so I just bought that.

 

Now I'm just waiting for the 10mm wide belt to show up, so I can verify the belt track on the larger pulleys.

Then the teeth will be machined off where they are not needed.

 

Sized the alternator ratio, to keep it under the 20k rpm that Powermaster recommends, and the water pump under 7000 rpm.

Kind of the accepted standard for centrifugal water pumps, but that is a track (aka, out around at night) ratio, and I expect to have to go smaller for daily driving, where I will get stuck in rush hour trafic.

 
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Braden620 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Braden620 Quote  Post ReplyReply Direct Link To This Post Posted: 06 Jul 2016 at 10:09am
Awesome job!   This looks very very nice and a major upgrade. Have you considered offering this for sale as a kit? What alternator is that?
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Gordo View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gordo Quote  Post ReplyReply Direct Link To This Post Posted: 07 Jul 2016 at 9:46pm
I could do a kit possibly, but would have to go with a reaily available center hub for the crank.
Unorthodox no longer makes the pulley I used, and the chinese ones all have large holes that would interfere with putting in more threaded holes to bolt the adapter to.
 
The only one I know of is made by ATI, and $165 (well worth it due to it being steel).
The Moroso pulley is $40
The two Pfeifer pulleys are about $50 each.
The belt is $20
Then there would be the two hubs that tie everything together.
That makes for about  a $600 'kit'.
Not so sure I could justify even making one, and hope to sell it.
I work with really old manual machines without even DRO.
Set-up time on every cut is substantial.
 
Someone with a CNC shop, that could buy parts in quantity to get a discount from ATI, and Pfeifer, to make at least 20 sets,
and run the custom machined pieces all in one run (20 bottom adaptor hubs,  20 top),
could cut much of that cost out.
Unfortunately, that's not me.
Maybe someone like Futofab could/would do it.
 
The alternator in the picture is a burned up eBay pos that I thought would be almost as good as a PowerMaster mini.
It wasn't......
So I bought the real thing after throwing away $100.
So instead of having a $300 alternator that worked, I have a $400 one that does.
 
It is a 1-wire, model 8182, that I use with a very small Oddessy PC680, and the system has been trouble free for 18 months, except for keeping the belt tight (about once a month it needs to be tightened).
 
The really nice thing about these mini alternators, is they fit so much better in the 620 than the original.
It bolts to the stock bottom mount with a single M10 bolt, and the top is handled with a double 5/16" heim end rod.
To adjust, I just back off the bottom bolt a 1/4 turn, loosen the 2 lock nuts on the heim ends (one right hand, one left hand), turn the rod until the belt tension is correct, and tighten everything back up.
 
If I get a chance, I'll snap a picture or 2.
 
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Gordo View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gordo Quote  Post ReplyReply Direct Link To This Post Posted: 07 Jul 2016 at 11:19pm
OK, here is my top alternator adjustment rod.
Note that the adjustment is almost maxed out, due to belt wear.
Was going to just pick up another belt, but decided to change the drive in order to take care of the problem.
 
 
 
And my belt came in.
Looks like I will be cutting about half of the 40mm wide teeth off.
 
 
And my little baby alternator rated at 70amps, but test tag shows that it will put out 80 amps.
 
 
I'll post another picture once I trim the teeth.
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Gordo View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gordo Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jul 2016 at 2:23pm
Finished the trim work.
Now just have to finish the engine.
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote alleycat Quote  Post ReplyReply Direct Link To This Post Posted: 15 Jul 2016 at 7:47pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gordo Quote  Post ReplyReply Direct Link To This Post Posted: 09 Aug 2016 at 5:53pm
Was going to just mark the bottom pulley with a notch to show where TDC is, but then thought about it too much, and had to complicate my life by doing this.
 
The engraved wheel is from CB performance, and was meant for a VW sand drag car.
Will match my red cam cover, and air filter assembly :-)
 


Edited by Gordo - 13 Aug 2016 at 1:23pm
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Gordo View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Gordo Quote  Post ReplyReply Direct Link To This Post Posted: 13 Aug 2016 at 1:30pm
Here is some of the machine work to get the VW timing wheel to fit on my set up.
The disk was 10mm thick.
It was recessed on the front, to sit more forward on my hub, and the back relieved to clear the crank seal.
Then 10 M3 FHCS were used to attach it to the hub.
You can see the remains of the 8 holes that were there to attach it to CB's VW crank hub.
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