ALTERNATOR PULLEY WIDTH!
Thread Starter
Instructor
Joined: Aug 2001
Posts: 156
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From: Toronto Ontario
ALTERNATOR PULLEY WIDTH!
Does anyone have a pic of the way their drivebelt rests in the alternator pulley? :confused:
I'm afraid that the pulley on my alternator may be too narrow (the belt rests flush with the walls of the pulley, not sure if it should "sink into" the groove instead.
Please help! Thanks! :)
[Modified by 78RedShark, 3:54 PM 8/1/2003]
I'm afraid that the pulley on my alternator may be too narrow (the belt rests flush with the walls of the pulley, not sure if it should "sink into" the groove instead.
Please help! Thanks! :)
[Modified by 78RedShark, 3:54 PM 8/1/2003]
Burning Brakes
Joined: Apr 2000
Posts: 1,145
Likes: 1
Re: ALTERNATOR PULLEY WIDTH! (78RedShark)
I had a problem with a billet pulley. The belt was just a tiny bit above the pulley and it kept twisting around when I ran it. If your belt stays in when you run it, I would say it is fine. I went back to a stock type pulley and the belt sits deeper in the groove.
Chris
Chris
Melting Slicks
Joined: Jul 2002
Posts: 3,128
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From: Deltona (son of Deland and DAYTONA) FL
Re: ALTERNATOR PULLEY WIDTH! (78RedShark)
mine is actually about 1/16" above the side walls of the groove. Never had a problem with it jumping or even slipping. Even at my mind blowing redline of 5.5K rpm
2nd Gear
Joined: May 2018
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Old thread, but, my belt keeps slipping.
The alternator and belt is new and the belt seems to sit too deep into the waterpump pulley? The car is new to me so I dont have the old alternator/pulley...
Should I get another alt. pulley with wider groove and wider belt? My current belt is 10 mm or 3/8".
Best regards from Sweden
Safety Car
Joined: Sep 2005
Posts: 4,205
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From: Orange County Ca
If the belt is too thin, it may ride on the bottom of the pulley and not get full contact on the sides. If it's too wide, it may ride above the top of the pulley and not get full contact on the sides.
You generally want the top of the belt to be just below the outside edge of the pulley.
Belts do come in different widths. There is a method to the numbering of the belts, where you can order a same length belt in different widths.
Some of the corvettes with air conditioning used deeper pulleys because chevy was afraid of throwing the belts at high rpm.
OP, does your belt slip?
Try cleaning all the rust, gunk off of your pulleys. Wipe down your belt contact surfaces with acetone, laquer thinner, etc. Also, I've found that different brand belts are harder/softer/grip better. Try another brand.
The photo's above seem to show a deep pulley at the water pump and a standard pulley at the alternator.
You generally want the top of the belt to be just below the outside edge of the pulley.
Belts do come in different widths. There is a method to the numbering of the belts, where you can order a same length belt in different widths.
Some of the corvettes with air conditioning used deeper pulleys because chevy was afraid of throwing the belts at high rpm.
OP, does your belt slip?
Try cleaning all the rust, gunk off of your pulleys. Wipe down your belt contact surfaces with acetone, laquer thinner, etc. Also, I've found that different brand belts are harder/softer/grip better. Try another brand.
The photo's above seem to show a deep pulley at the water pump and a standard pulley at the alternator.
Last edited by Sayfoo; May 12, 2018 at 03:46 PM.
Team Owner
Joined: Jul 1999
Posts: 65,492
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From: Orange Park Florida
The pitch of the V varies with it being old INCH/American or Metric a metric belt rides lo in an old pulley, and the converse is of course also true....a more common metric belt will wear heavily on the upper edge of the V and cause a concave surface on the back of the belt, along with frayed edges.....
Race Director
Joined: Jul 2015
Posts: 13,082
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From: SW Florida.
I built alternators for a long time. I don't recall standard pass car stuff having any kind of deeper groove pulley. And I handled more alternator pulleys than any 50 guys on this forum added together.
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Le Mans Master
Joined: Jan 2001
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Deep groove alt pulleys:
Here is reference I found for Z-28s..... See post #22:
https://www.corvetteforum.com/forums...post1595076650
Which leads us here where we can find the uses:
http://gmpartswiki.com/getpage?pageid=88980
Which identifies 1970831 for Sp hi-perf applications (superseded by 3844100).....which then leads us to:
https://www.ebay.com/itm/NOS1970831-...YAAOxy9tpR-8Ir
So, yep, looks like deep-groove stuff, I had original ref info because of my 68 L-79. Hope this helps, but it really looks to me like your belt is well seated in your pulley at the present time. I recommend getting a quality brand-name belt before you go off chasing pulleys.... I didn't believe it when the parts guy told me-- until I got one and the I immediately quit having squealing problems.
Here is reference I found for Z-28s..... See post #22:
https://www.corvetteforum.com/forums...post1595076650
Which leads us here where we can find the uses:
http://gmpartswiki.com/getpage?pageid=88980
Which identifies 1970831 for Sp hi-perf applications (superseded by 3844100).....which then leads us to:
https://www.ebay.com/itm/NOS1970831-...YAAOxy9tpR-8Ir
So, yep, looks like deep-groove stuff, I had original ref info because of my 68 L-79. Hope this helps, but it really looks to me like your belt is well seated in your pulley at the present time. I recommend getting a quality brand-name belt before you go off chasing pulleys.... I didn't believe it when the parts guy told me-- until I got one and the I immediately quit having squealing problems.
Last edited by carriljc; May 12, 2018 at 09:59 PM.
Had a 1976 L-82, 4-sp
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Royal Canadian Navy
Put a wider width belt of the same length on. I use a 1/2" wide alt belt. I just went down to the local parts store with my older, narrower belt and they sized one up.
