[Stuckinda60s]

Ideally, a straightedge will give an indication of misalignment even if the pulley flange thicknesses vary. You should be able to see a difference in the gap if they don't match up. The strings are a great method for the grooved pulleys, you can run them groove to groove or face to face, but they won't tell you anything about the idler alignment.

You might have to use a level to determine if the idler is misaligned. You'd have to jack the back of the car up to get a bubble on the belt pulleys, once they're square, and then check the idler.

[Ollie]

I just purchased one of these, Dayco Laser Alignment tool
http://www.ebay.com/itm/DAYCO-Belt-D...:B:SHOP:US:101
This is a link to a demonstration on how it works.
http://www.dayco.com.au/products.aspx?G=1987&P=18039730

[Stuckinda60s]

That looks like a great set of tools. There doesn't appear to be any provision for checking idler pulleys, though. I suppose you could draw a line on the pulley and use the laser.

[jimmo]

Very Very Very nice tool Ollie. I wish I had thought of investigating something like that earlier. I didnt know it existed. Cant wait to see what the findings are.

Also, good point about checking idler pulleys stuckinda60s. Im sure with everyone on this forum we will come up with something.

[jimmo]

Originally Posted by AROWHED

Like Jimmo said, I had the same thing happen back in September, the front-most rib of my belt separated. I figured it was stressed from 6 passes at Norwalk and that I had it just a little too tight. I will be changing out the VW alternator pulley now as well.

I took this pic just tonight...note that the idler is polished on half of it's contact face with the belt, and the belt is shiny in the same travel path area as well. Obviously uneven loading against the pulley face but what is the root cause? There is no belt squealing. I wonder if may be necessary to weld some reinforcement metal to the backside of the alternator bracket at the idler pulley mount, to prevent pulley deflection.

Im noticing as I look at your photo, the front rib of the belt is riding on the raised unworn area of the idler and the rest of the belt is down in the worn area. Ive since swapped my idler with a new one and dont have the old one anymore to check but Id bet I had the same situation.

To clarify more to everyone else, Arowhed and I both started of with used idlers that already had a patch worn in. In hindsight, A new idler with a smooth surface should have been installed so that the belt can make even contact right from the start and wear together. I would think a new belt riding partially out of the groove had to contribute to the issue.

Maybe I jumped the gun and swapped the vw pulley for no reason??

[Ollie]

I am thinking belt tension, watch the video I linked in post 242.
Dayco recommends 100 to 300 lbs.
on the tension idler there is a slot on the back side with an indicator pointer.
I set the alternator and power steering pump to the closest position. set the center of the AC compressor shaft 15 3/8 inch from the center of the water pump shaft. When the belt is installed, the pointer on the tension idler is centered in the slot.

[jimmo]

Originally Posted by Stuckinda60s

That looks like a great set of tools. There doesn't appear to be any provision for checking idler pulleys, though. I suppose you could draw a line on the pulley and use the laser.

Sorry, I must have been half asleep when I read that the 1st time. I missed the part about drawing the line around the idler.

[AROWHED]

Actually Jimmo the idler in my pic is a new unit, got it since it was only $20. After eyeballing it a lot closer recently while running, and getting the fan shroud out so it isn't blocking a good line of sight, it is apparent the alternator pulley is too far forward. The reason is the 12SI alternator fan is too far away from the alt housing, and most likely causing insuffcient alternator cooling as a result. So I am going to reduce the height of the collar bushing between alt fan and bearing. It is currently 3/8" tall...it just can't be the correct fan bushing for a 12SI. I would bet .200"' or so would be plenty.

[Stuckinda60s]

Originally Posted by AROWHED

...it is apparent the alternator pulley is too far forward. The reason is the 12SI alternator fan is too far away from the alt housing, and most likely causing insuffcient alternator cooling as a result. So I am going to reduce the height of the collar bushing between alt fan and bearing. It is currently 3/8" tall...it just can't be the correct fan bushing for a 12SI. I would bet .200"' or so would be plenty.

That's the way it appears from the pic you posted.

There are some problems with modifying the alternator. First, the longer moment from moving the pulley out increases the torque the bearings have to support and they're already absorbing more than they would if you were running a V-belt. Second, you're stuck with that setup if anything happens on the road, as another poster mentioned. As you've noted, cooling is an issue, as well. The clearance should be quite close to minimize slip and move as much air as possible.

I haven't followed the mechanics of the set-ups on here really well, so I can't address each one, individually. But, the way I would do any installation is to modify the mounts, rather than the pulley placement on the shaft. Think about it. If you mount all the driven units the way they were designed to be mounted, and, if possible, use off the shelf new idlers, you're ahead of the game if you have any trouble.

[jimmo]

Originally Posted by AROWHED

Actually Jimmo the idler in my pic is a new unit, got it since it was only $20. After eyeballing it a lot closer recently while running, and getting the fan shroud out so it isn't blocking a good line of sight, it is apparent the alternator pulley is too far forward. The reason is the 12SI alternator fan is too far away from the alt housing, and most likely causing insuffcient alternator cooling as a result. So I am going to reduce the height of the collar bushing between alt fan and bearing. It is currently 3/8" tall...it just can't be the correct fan bushing for a 12SI. I would bet .200"' or so would be plenty.

Oh ok, Do you happen to know how many miles your belt lasted?

[AROWHED]

Jimmo, I would guesstimate 200-300 miles...and those six Norwalk 1/4 mile blasts.
Do me a favor, if you can...measure the height of the bushing between the alternator's fan and front bearing of your 12SI alternator. I think the alternator rebuilder shop here in town put the wrong one in....too tall. As a result the fan is not recessed into the alternator housing like it should be. You can see it in the pic above. The fan wont get good air draw through the housing...and of course it had my serpentine alt pulley too far forward. Stuckinda60s, I think this is the real problem..the wrong fan bushing was used. Jimmo already worked out the correct offset for the alternator housing, and I have all the spacers he made in place.

[Ollie]

I installed the spacer between the fan and the pulley.
Not between the alternator and the fan.
It is 0.203thick.

[jimmo]

Originally Posted by AROWHED

Jimmo, I would guesstimate 200-300 miles...and those six Norwalk 1/4 mile blasts.
Do me a favor, if you can...measure the height of the bushing between the alternator's fan and front bearing of your 12SI alternator. I think the alternator rebuilder shop here in town put the wrong one in....too tall. As a result the fan is not recessed into the alternator housing like it should be. You can see it in the pic above. The fan wont get good air draw through the housing...and of course it had my serpentine alt pulley too far forward. Stuckinda60s, I think this is the real problem..the wrong fan bushing was used. Jimmo already worked out the correct offset for the alternator housing, and I have all the spacers he made in place.

Wow, thats not long at all. No problem the space is .277" and the spacer between the fan and the pulley is .095". That is with the GM pulley not the VW. I was digging through the posts to see if I had noted the sizes I used originally with the vw pulley but couldnt find it. Im pretty sure when I made the swap I went to a slightly smaller one between pulley and fan. Let me know if ya need anything else.

[jimmo]

Originally Posted by Ollie

I installed the spacer between the fan and the pulley.
Not between the alternator and the fan.
It is 0.203thick.

There is already a factory spacer between the fan and alt, on my stock one and the 12si anyhow. What is your alt/pulley combo from?

[jimmo]

ok, found it. The spacer I used between the pulley and fan on the stock alternator with the vw pulley was .213". not far from Ollie's

[Ollie]

I installed the spacer between the fan and the pulley.
Not between the alternator and the fan.
I purchased the alternator from E-bay seller dbelectric
10si Alternator 140 amp. I called them and requested the stock electrical connectors with a 6 groove pulley. the pulley shaft is long enough to permit installing the spacer with about 1/4" extra.
Checking with a straight edge the alternator pulley appears to line up with the water pump and crank pulley.
This will be the first thing to check with the Dayco alignment tool.
This is the link for the spacers. Correction they are 0.228" thick.
http://www.ebay.com/itm/Delco-Remy-A...92b8a0&vxp=mtr

[Stuckinda60s]

For those who don't have the Dayco tool, I would think a thin piece of acetylene welding wire would work. If you lay it in the grooves, it's stiff enough to show if they don't line up. Lay it in one of the grooves, run it to the other pulley and it should indicate any difference in alignment just by the way it lays from one side of the pulley to the other.

[AROWHED]

Today I removed the VW pulley,then the alt fan, and then the 3/8" thick bushing behind it. Put in a new bushing that is around half the height of the 3/8" part...didn't measure it exact though. Put it back together. Note there is and always has been a flat washer between the fan and pulley, but it is only there to make up for the offest recess that the 12SI fan has built into it...the washer must be in there to prevent distorting the fan when pulley nut is tightened and forces the larger diameter VW pulley against the fan. The washer I used was the exact thickness necessary to allow the VW pulley to sit flat and flush against the front face of the fan without distorting it.
Picture attached here is the result...note that alt fan in now correctly recessed into the alt housing further, and belt alignment is much better. The fan should draw air through the alternator much more effectively as well, since the gap is gone.

[Stuckinda60s]

Things do look a lot better. It might just be the picture, but it looks, to me, as if the alternator pulley is at a slight angle from perpendicular to the water pump pulley. As if the top of the alternator is angled slightly toward the back. By the way, your first picture looks as if it's like that, also.

Not trying to be picky or find fault, but that's the way it looks, to me. I hope I'm wrong, I know you're going through a tedious process and it gets tiresome.

[Fishin2Deep4U]

So who has a line on the proper pulleys? My local yards are a joke. Spent over a day and have one bent pulley to show for it. I can mill and drill everything I need to make them fit.

Dave