Another Alternator Belt Tensioner - 3VX belts?

[CarlosA]

That's an interesting solution.
Because it seems like much of the problem with the custom tensioner setups is the belt no wanting to bend backwards.
Before this thread I didn't realise that,.. also didn't know they made special belts that bend both ways until just now, ha.

Yep seems like it would work. I was thinking about the link-belt on my lathe and wondering what else might exist. I`m also working on a set of lathe pulleys to use big o-rings for a slow feed, so been thinking about belts, lol.

[bbob203]

if you could get a long enough double sided belt you might be able to serpentine it if you could re align the pulleys.

[air-cooled or diesel]

what i tried is this a NAPA belt 25-72xx; stock would be xx75 i think; so try 7270 or around there. i always go 1 size smaller and seems to work for (52xx?), tried 72xx belt, seems to work real good so far.
clean all pulleys i use 420 sandpaper and you can touch it up more using 600 sandpaper second go around

[zloetakoe]

what? that's it? I just read through 10 pages of posts and there still isn't a solution for this? That's unacceptable.

Lots of good info here. Just wish there was a permanent solution. I just had a new alt belt put on and think it's showing signs of wear. Getting a new alternator this week though, that might help some, and the AC idler pulley was already replaced. We'll see what it all means. I'd love to be able to throw a belt on there that was short enough to use the tension side to tension it. Saw a post where someone had done something like that....

viewtopic.php?f=8&t=8173&start=15 (3/4 down the page)

I think a combo of new pulleys, and that setup could save us some major grief. If I ever get back to my car and can work on it I'll post the results.

Great forum by the way.

[bbob203]

Ive been thinking about trying something with a belt tensioner and running it inlace of the stock one. that way you can use the cam action of the tensioner as well as the bolt and a shorter belt.

[TylerDurden]

I've been driving the '89 with the stock setup.

Amazingly, the cheap belt I put on months ago only recently failed after about 6,000 miles, with very few re-tension tweeks during the period.

The pulley on the alternator may be different somehow (?), I'll need to compare them when I get some time.

The only other difference generally, is the '89 idles a bit higher and smoother. I tend to see the most belt-flapping during idle, when the piston pulses seem to yank the belt quite a bit.

Damnedest thing.

[air-cooled or diesel]

2 things i did, 1 was a smaller a/c belt (1 size smaller)that tightened up the alt belt.
also if belt keeps on loosening leave loose and dont snug up, as long as you have charge you may be ok. i found my belt kept stretching so i just left it, it was a little loose and ran fine, (check charge)
right now w/ belt on a/c my alt belt is holding good.
if it hasnt been said before (lot of thread to read) check all pulleys for rust, sand rust off. 600 wet or dry to finish should do it.
try NAPA belts

[91 NA]

Here's the solution I came up with a few years ago:
viewtopic.php?f=8&t=8173&start=15

there's a picture and writeup of what I did on page 2.

It ran for several years befoere I sold the car.
The larger flat belt (lawn mower) pulley provided less back-bend than the smaller bearing or pulley solution.

I have a writeup and parts list, if anyne wants..

regards,
Mark

[bbob203]

did something similar with mine I used a timing belt tensior as my idler pulley haven't seen it in action yet though. looks nearly identical to what you've done.

[bbob203]

Here's my solution a gates 10x675 for alt and a gates 13x955 I think it is. I replaced stock idler with a timing belt tensioner on same adjustable system as the old idler. I used a few jam nuts on the adjusting bolt to hold it in a fixed postion whilst still being able to adjust the idler tension. no real miles on it yet but it is smooth at idle in my garage.

[jonny]

my mechanic and I have worked through this by using a continental A/C belt that is slightly shorter that original - 938mm rather than 950. I also drille a hole about an inch toward the firewall on the alternator bracket to rotate the alternator closer to the Injector pump to allow stock tensioner to not run out of adjustment on after the belts stretch. We have had the best life out of NAPA (gates) original spec size alternator belts. Hope this helps.

jonny

[scottmartin49]

Having gone through most of these fixes before finding the one that worked, I'm surprised to not have found it here after all this time, hence the thread resurrection.

SPZ profile belts; it's the metric standard they were designed for, and nothing else will work for very long.


For an A/C and alternator setup, SPZ670's are the smallest that I know will fit without any adjustment at the compressor, although I think a 660 would make it as well- might have to loosen some mount bolts, adjust the compressor, etc.
....if you don't believe me, just pull your idler off and eyeball the way an SPZ runs in the channel- almost like it was made for it!

Cheers,
Scott

[uzzo2]

Having gone through most of these fixes before finding the one that worked, I'm surprised to not have found it here after all this time, hence the thread resurrection.

SPZ profile belts; it's the metric standard they were designed for, and nothing else will work for very long.


For an A/C and alternator setup, SPZ670's are the smallest that I know will fit without any adjustment at the compressor, although I think a 660 would make it as well- might have to loosen some mount bolts, adjust the compressor, etc.
....if you don't believe me, just pull your idler off and eyeball the way an SPZ runs in the channel- almost like it was made for it!

Cheers,
Scott

I've been fighting this issue for years myself. I just put the motor back together in my 86 golf and within a couple days of driving I'm already out of adjustment on the alternator belt. Do you happen to know which ones I would need for the stock setup on this car with A/C?