I did a search on this and got some answers, but still have a question.
After replacing the waterpump/radiator/fan on my 69 396, I keep throwing the alternator/water pump belt when I go over 4000 rpm.
I have checked alignments with a straight edge and the alternator is just a bit off. It angles a bit inward when tightened. So I know I need some work there. There is also some bearing play in the alternator (probably from me over tightening) so a rebuild is in store there as well.

My question is regarding the waterpump and crank pulleys. I have a triple groove crank pulley. The 2 inner groves are ~ 6 1/8" diameter and the outer groove is ~ 7 1/8 diameter. (Measurements are approx)

I have a single groove water pump pulley. I believe it is a small block pulley, but not really sure. It measures ~ 6 1/4. The so called "big block" pulleys I have seen are all double groove, but same diameter and width, and nose cone as well. I would like to have two belts on my pump but can't figure out how that would work.

How can two belts work with different diameters on the crank?? Am I missing something in physics here?

I have power steering (2 groove/belts) no AC and no AIR. Stock pulley depth.

I've checked on the CRG site for pulley sizes and the 2 diameter crank pulley setup seems correct.

What is the second groove of the BB WP pulley used for?

Should I try and find a triple groove crank pulley that all 3 are same diameter? (Is there such as animal?)

I will be changing brands of belsts as suggested in the earlier postings. I've been using Goodyear Gatorbacks. I did not have any belt issues before "fixing" the pump and radiator.

Sorry for the long winded post, but wanted to give as much info as possible.

Thanks in advance for all the help here! http://www.camaros.net/forum/biggrin.gif

Joe

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69 396 w/SS Trim
Badboatdude@CS.com
69 Pics http://albums.photopoint.com/j/AlbumIndex?u=1506559&a=11674961

[This message has been edited by Joe G (edited 04-16-2001).]

Hmmmmmm.......?????? http://www.camaros.net/forum/biggrin.gif

Well, I found a big block pulley at a local resto shop that has 2 different size pulleys that I'm going to try.
The outer pulley is 6 1/4" diameter; the inner is 5 1/2". Itlooks like I can use 2 belts on the pump with this one.
Anyone use a pulley like this? Part #14023155.
CRG site doesn't list this but I guess I'll try it....

Well, this worked Ok until I rached 6000 rpm today. Threw ALL the belts this time; shreaded 2 of them.

Back to the drawing board.......

I would think you don't really want 2 belts on the waterpump since it would probly wear it out quicker. Go with the one small powersteering belt and on for the crank/waterpump/alt. With the waterpump/alt belt use a solid belt. One without the notches in the bottom. We had to do this to a small block '68 cause it would throw em also. The parts counter guy said the notches are just for less heat on the belt but for a muscle car who cares, the belt may get hotter and not last as long but at least they won't fly off and get shreaded.
Good luck

Thanks for replying! http://www.camaros.net/forum/biggrin.gif

Took one of the P/S belts off. With two belts, I couldn't get even tension.
I have 2 belts on the W/P now. One to P/S, one to alternator.They are pulling from opposite sides, so I don't think the wear on the pump should increase. I would think just the opposite since the bearing has load 180 apart now. (I could be wrong!)
Took it to 5000 and they stayed on. http://www.camaros.net/forum/smile.gif

I found some Dayton "Top Cog" belts that are smooth inside, ridged outside. Seem to fit much better. Maybe I have success?

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69 396 w/SS Trim
Badboatdude@CS.com
69 Pics http://albums.photopoint.com/j/AlbumIndex?u=1506559&a=11674961

I'm going to assume that you have the tension right on the belts; and you just didn't make a guess on how tight these belts should be set at. I think you should switch to the the gogs type of belt "not sure if thats how you spell it", but anyway they are the kind that have little teeth type on them.

Belt tension is good; ~ 1/4" deflection on short side, a bit less than 1/2" on long side.

I was using Goodyear "Gatorback" belts (all I could find around here); toothed inside, smooth outside. Finally got my store to order some Dayton "TopCog" with the "teeth" on the outside. (No one could get Gates belts this way; said they stopped making them). So far so good!

Joe

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69 396 w/SS Trim
Badboatdude@CS.com
69 Pics http://albums.photopoint.com/j/AlbumIndex?u=1506559&a=11674961

[This message has been edited by Joe G (edited 04-25-2001).]