Another Alternator Belt Tensioner - 3VX belts?

[jonny]

You guys may want to check:

http://www.mcmaster.com/

They have a large selection of bolts and possible some bearings. I like your set up and I may try it on my '89 NA.

thanks,
jonny

[MagicBus]

Bearings are apparently on backorder from Grainger. Will need to wait a few weeks on this.

In the meantime, I have a new idler pulley for the tensioner assembly on its way. Either way, I'm planning on being as gentle as possible with the current setup.

[MagicBus]

Decided to get proactive. Checked Grainger and found a nearly identical alternate bearing in stock: # 5U561

http://www.grainger.com/Grainger/NTN-Si ... ing-5U561#

Called them and had them switch my order. I'll have them on Tuesday.

[TylerDurden]

How's your setup holding up?

I haven't put many more miles on it yet, it's in winter storage.

The other setups looked like too much work for a lazy person like myself... I think this version may be sufficient, but only time will tell.

I may install the setup on the Blue Devil (AKA the Jetta from Hell), but right now I'm ruminating on how to recondition the dented and rusty pulleys that devour belts.

[diesel freak]

Made all the necessary alterations and had to increase my alternator belt to a 10 x725 which was readily available at any NAPA store for $10.00. I still have a small problem that I discovered after removing my alternator to thread the longer bolt in. The large tension pully for adjusting the alternator belt does not move. I tried tightning and loosening the 13 mm adjustment bolt and the tensioner does not move at all. It looks as if it should slide in or out to take up the slack of the belt. Any suggestions on how to fix that tensioner pully to move in or out? At this point I adjust the belt by moving the alternator itself up or down but it would be nice to have the tensioner pull functional.

[TylerDurden]

...The large tension pully for adjusting the alternator belt does not move.

The 17mm nut on the end of the original tensioner needs to be loosened before its adjuster bolt gets turned.

You may need to remove the 17mm nut, idler assembly (take care with the thin shields); then clean the standoff-post and surface of the bracket, so the idler adjustment operates smoothly.



Edit: updated image

[the vegenator]

I've installed belts a few sizes smaller to give them a little extra room to stretch, but sometimes that has meant removing the idler pulley altogether in order to get the belt is in place. Once the belt is in place I slip the pulley back onto its shaft.

But yeah, I imagine if you just loosen the nut on the idler then you'll get that tensioner bolt to move where you want it.

[Fatmobile]

Link to another one,
that allows you rotate the alternator up higher:

viewtopic.php?f=8&t=10618&view=unread#unread

[MagicBus]

How's your setup holding up?

I haven't put many more miles on it yet, it's in winter storage.

The other setups looked like too much work for a lazy person like myself... I think this version may be sufficient, but only time will tell.

I may install the setup on the Blue Devil (AKA the Jetta from Hell), but right now I'm ruminating on how to recondition the dented and rusty pulleys that devour belts.

Well, I DO put a lot of miles on my car (roughly 400-450 weekly commuting) so my car can certainly serve as another test case for this setup.

I'll post periodic updates when I have it up and running.

[MagicBus]

This past weekend I got around to two jobs – replacing the screaming speedometer cable (car is MUCH quieter and nicer to drive now) as well as the alternator belt drive modification. Here are some photos from that and another Youtube video I did:









Can't see a way to embed video here, so you'll need to follow the link:
http://www.youtube.com/watch?v=9LR6kaRbCiA

[Fatmobile]

It is nice to look in an old engine bay and see some shiney stuff.
I've never seen an alternator adjuster pully that shiney.

[TylerDurden]

Looks good. Keep us posted on how it behaves.

[MagicBus]

Looks good. Keep us posted on how it behaves.

I've been keeping an eye and ear on it. I was planning on posting an update this coming weekend, but since you asked, here's the progress report. I've probably put around 400 miles on the setup since installation last weekend. When it gets cold out, I am still getting a little bit of squeal, at least momentarily, when the car is cold. We've had some wild temperature swings this week, ranging from single digits to in the 40s, so I know that affects things a bit. This didn't start until Tuesday evening, and literally only lasts a second or two. I find that it's still best to start the car and idle it a minute or two to warm the belts up before I drive. When the car is warm, there is no slip.

Overall, the alternator belt situation has been more stable since I switched over to the Continental belt in the correct size (9.5 x 695). I did get some belt stretch and slip while cold before installing this new idler, but it was much less extreme than it was with the previous, probably lower quality belt in the wrong size. The new belt had around 600 miles or so on it before I installed this new setup.

One thing possibly working against this solution, at least for me, is the fact that this setup still uses the original tensioner setup. I did intentionally keep the belt on the looser side (though not completely loose) when I installed this setup last weekend. Right now, I'm hesitant to tighten it up. With my last two belt breakages, I would tighten, it would run quietly for a week or so, two tops, and then stretch and squeal. I think the factory setup just naturally overstresses the belt. As I said previously, though, I think the higher-quality new belt I put on makes a pretty big difference. I popped the engine cover on my Vanagon this past weekend and took a good look at the belt setup while in there. All the belts have been in there for years now (I've only put 40K miles or so on the Vanagon since I bought it in 2003). I checked the tension and they could be described as loose. However, there is absolutely NO slippage and they run quietly. (Incidentally, I bought the van in 2003 with severe squealing belts. New belts and a fresh water pump cleared that up nice and quick). It's a better belt drive setup, overall. If I recall correctly, each accessory had its own belt (water pump, power steering, alternator).

Back to the diesel, though, one MAJOR plus of this new belt setup is that it compensates for belt deflection and keeps the belt from bouncing off the timing cover, which I'm sure added even more wear to the belt in a short period of time. The other major plus, and I think you yourself said this, is taking stress off the alternator pulley bearings.

As for now, my plan is to keep an eye on it and see how this setup behaves as the weather warms up heading into spring. My prediction is that as the weather warms up and stabilizes, belt slippage will disappear entirely and I'll be able to run this setup without having to tighten the belt any further, at least until later in the year.

If this needs additional modification, I will keep the new ider in place, but may try replacing the new stock tensioner pulley with a flat pulley that tensions the reverse side of the belt. Bottom line, though, is that I'm pretty confident in this, and will be putting a lot of miles on it in a short time. I'll keep you all periodically updated on how this works for me.

[MagicBus]

More info: started up quiet this morning (temperature in the low 30s). Drove 45-50 miles in to work in moderate rain, temperature in the 30s, and the car stayed silent.

Will continue to monitor.

[MagicBus]

Time for more follow-up. After approximately 600 miles, the belt nearly failed. I noticed that there was a little bit of belt slip and squeal a few times this week. I popped the hood tonight to take a look and possibly tighten the belt, when I noticed that several cogs had sheared off the belt. The belt was still intact, but upon close inspection was pretty beat-up.

I think the backbend introduced by this new idler put a little too much stress on the belt. I did some thinking, and comparing against what belts I had on hand, and decided to swap out the standard Continenal belt for a top cog belt, which I think will take the stress of the system a little better. Actually, I had to run to the store to get a belt in the correct size range.

Thankfully, since I've done belt replacement so many times already, I was able to replace the alternator belt in about a half hour today. I'm just glad it didn't snap again while on the road. Overall, I'm still optimistic about this modification.

Here are a couple of photos and some video of the job:







http://www.youtube.com/watch?v=JV1BfeXccsw

I'll keep you all posted.