Crank pulleys.

[68Stepbed]

OK my wp pulley dimensions are:
2 13/16" tall
5 13/16" wide
GM part #3995646 AH

Crank pulley dimensions are:
2 1/16" tall with ps pulley (this dimension will only be about 2" if installed to balancer)
6 3/4" wide
Single crank pulley for wp and alt part # 3755820 BC
ps pulley part # 3751232 BB

[68Stepbed]

Crank pulley and ps pulley seperated.

[68Stepbed]

Here was the original alt. brackets. They bolt to the driver's side head. Is this what you have?

The cast bracket part # is: 3951357
12

[Sport/Truck]

Originally Posted by 68Stepbed

S/T here's my setup now. It should help to see what you need. I have a 2-groove wp pulley for a short water pump and a 3-groove crank pulley. My old setup in the pictures above were taken before the restoration. I had(I believe) a 2-groove wp pulley and a 2-groove crank pulley. The crank pulley had two peices. The crank pulley that turned the Water pump and alt. was directly aginst the balancer. The second piece of the crank pulley was basically an add on extension to work the power steering. Your crank pulley has three grooves. The one directly against the balancer should drive the wp and alt. The middle groove will be for A/C if you have it. The outside should drive the p/s.

I wouldn't be able to tell if you have the correct wp pulley just by seeing it. I'll try to check my old pulley in a little while to get dimensions for you. I'll try to see how long and deep the wp pulley should be. The oulley is at my dad's place, so I'll have to check it in a few minutes. Meanwhile, here some of my current setup.






They are Dayco TOP COG. They are the only kind of V-belt I will buy. Don't buy cheap stuff. You get what you pay for. My brother learned this lesson with his truck. He went to Auto Zone and told them he needed new belts. They automatically gave him the cheap ones. They haven't stopped squealing after a year.

Do you have any information on the pulleys in your last pictures / part #s? Are they hard to keep clean?
s/t

[Sport/Truck]

Originally Posted by 68Stepbed

OK my wp pulley dimensions are:
2 13/16" tall
5 13/16" wide
GM part #3995646 AH

Crank pulley dimensions are:
2 1/16" tall with ps pulley (this dimension will only be about 2" if installed to balancer)
6 3/4" wide
Single crank pulley for wp and alt part # 3755820 BC
ps pulley part # 3751232 BB

Thanks for the pictures Matt. I’ll check the other pulleys when I get home. I can quite make out if the pulley is 5/8 form the table I looks like it could be, but the angle is a little off for me to see for sure. The pulley on the bottom is the one that goes against the harmonic balancer?
s/t

[Sport/Truck]

Originally Posted by 68Stepbed

Here was the original alt. brackets. They bolt to the driver's side head. Is this what you have?

The cast bracket part # is: 3951357
12

Yes I have the alt bracket, but not sure about the number (are they all the same?). I noticed you are missing the roll Pin in the picture. Do you have it? If not I can probably get you one.
s/t

[68Stepbed]

Originally Posted by Sport/Truck

Do you have any information on the pulleys in your last pictures / part #s? Are they hard to keep clean?
s/t

S/T those pulleys I bought at a performence shop. Summit sells them also. They are about $40-45 a peice. You can get them in polished or machined finish. Mine are machined finish. I've never had much trouble keeping them clean. You can also paint them for a nice custom look. I painted the set I had on my 86. It's the last pic. I also have a decnt shot of my new aluminum pulleys.

Originally Posted by Sport/Truck

Thanks for the pictures Matt. I’ll check the other pulleys when I get home. I can quite make out if the pulley is 5/8 form the table I looks like it could be, but the angle is a little off for me to see for sure. The pulley on the bottom is the one that goes against the harmonic balancer?

The bottom pulley actually almost butts completly against the balancer. It sits about 1/16" of an inch off the table because it has a lip that slides into the balancer hole to keep it lined up. I've reposted this pic so you can see where it sat against the balancer. You can tell the way the paint is rubbed off. The second pic you can copy and blow up to see how close it is against the balancer.

[Sport/Truck]

Originally Posted by 68Stepbed

S/T those pulleys I bought at a performence shop. Summit sells them also. They are about $40-45 a peice. You can get them in polished or machined finish. Mine are machined finish. I've never had much trouble keeping them clean. You can also paint them for a nice custom look. I painted the set I had on my 86. It's the last pic. I also have a decnt shot of my new aluminum pulleys.




The bottom pulley actually almost butts completly against the balancer. It sits about 1/16" of an inch off the table because it has a lip that slides into the balancer hole to keep it lined up. I've reposted this pic so you can see where it sat against the balancer. You can tell the way the paint is rubbed off. The second pic you can copy and blow up to see how close it is against the balancer.

$45 each? I did a search on summit, and the ones I found $100 +! If anyone has a good source LMK.
If you could put a tape measure against the face of your harmonic B, and tell me what the measurement is to the center of the first belt. (I need 5/8) in one of your pictures it look like it could be...but a mounted measurement will be best.

I also checked my water pump pulley. It was within a 1/16 of your measurement. So I think it's ok.
s/t

[68Stepbed]

S/T, sorry I didn't get back to you over the weekend. I was finally able to check the measurement. The distance from the balancer to the center of the first pulley is about 1/2- 5/8". I couldn't tell exactly with the engine in the truck. It's kind of hard to get to with everything on. I hope I've been a help.

Edit- All my pulleys together were probably around $120-140ish. I bought them with other stuff, so I don't know the exact price. Did Summit want $100 a peice or for a set?

[Sport/Truck]

I got another pulley setup (not OEM) and it had the same offset on my truck. So I went down to a guy’s shop that has a few of these trucks around and are all original. One of his trucks was off set like mine, maybe not quite as bad, but still not aligned. The other one was perfect. Is this normal?
s/t

[swamp rat]

Originally Posted by Sport/Truck

$45 each? I did a search on summit, and the ones I found $100 +! If anyone has a good source LMK.
If you could put a tape measure against the face of your harmonic B, and tell me what the measurement is to the center of the first belt. (I need 5/8) in one of your pictures it look like it could be...but a mounted measurement will be best.

I also checked my water pump pulley. It was within a 1/16 of your measurement. So I think it's ok.
s/t

I found a great site at work friday night and saved it to my favorits on my work computer, I can get it and post it later monday night, heres the link that might help...

http://www.tdperformance.com/pdfs/66-67-Pulleys.pdf

[Sport/Truck]

Cool, thanks for the link. But I'm wondering if miss alignment is normal for some trucks?
I’ve checked my water pump and its 5 5/8 in. & the new pump is the same. All the pulleys are mounted flush with the harmonic balancer and the harmonic balancers are the same. I suspect the one I took off is original too. Is this why they make spacers? Is this a known problem?
s/t

[swamp rat]

All I can think of is that possibly you have a balancer or pulley(s) off of different year trucks... That link I have at work list all the pulleys and there spec's that Gm has made.

[Sport/Truck]

post it up on Monday..
Thanks,
s/t

[Gray Ghost]

67CRN is right....the one I have has two pulleys, then a spacer and then a third pulley. That said my alt is off a bit and it makes it squeal...gotta fix that someday.

[68Stepbed]

S/T, are your wp and alt. pulleys still misaligned? Is anythimg aligned at all? I'm not sure you can shim the crank pulley, but I know you can buy wp pulley shims. Do you have any pics of your system installed? If we could see everything you have as a whole we could probably help more.

[cstanley]

Stepbed, do you have/know GM part #s for the 3-groove setup? I just got my Vintage Ait unit, and I have the exact factory-style setup you had. It looks like I need another pulley on the crank between the existing two crank pulleys. is my situation an add-on single pulley between, or do I need a double-groove pulley and then use the original single add-on pulley?

Thanks!

[68Stepbed]

cstanley, I don't know the part #. You need a 2-groove with the add on ps pulley. Mine is just a single groove with the add on.

My new aluminum pulley is one peice with three grooves.

[Sport/Truck]

Originally Posted by cstanley

Stepbed, do you have/know GM part #s for the 3-groove setup? I just got my Vintage Ait unit, and I have the exact factory-style setup you had. It looks like I need another pulley on the crank between the existing two crank pulleys. is my situation an add-on single pulley between, or do I need a double-groove pulley and then use the original single add-on pulley?

Thanks!

cstanley you need the one piece two grove pulley PN’s 44043BAGM or 3744043GM They are identical from what I can see, and will work with your 3751232BB power steering pulley.
The yard I got mine from has more, but are a little spendy at $25 a piece. I’m considering taking mine back and using the one that was on my truck with a spacer.
s/t

[Sport/Truck]

I got all the factory pulley combinations mentioned above and still have the problem. So a shim is in order to space the pulley out a little from the harmonic balancer. (Summit sells them). But I wanted to make sure I didn’t have something else wrong. And after looking at another stock truck with the same problem (the owner didn’t notice it before) I’m convinced this is a common problem that probably goes unnoticed at times.
I want to thanks everyone for there suggestions & ideas. It made for some great discussion and will be helpful with someone else that runs into this problem.
I'll post some final pictures when I get my engine completed & installed in the truck.
s/t