I need a single V-groove alternator pulley

[Gary Lewis]

I measured the pulley sheave i was using and it measures 0.38 inside lip to inside lip and the belt I was using measures 0.40. My pulley measurement agrees with the info that Number Dummy gave me but the belt I am using is definitely not a 15/32 even though your info says it should be. Strange as I don't see how a 15/32 belt would work in a 3/8 groove.

Jim - I'm confused. The pulley on the 3G you sent me is a poly-groove, as shown below. But are you referring to another pulley?

Whisler - I only have one unused pulley, and it is a 2-groove as also shown below. Its measurements are:

• 3 3/16" OD

• 1 5/8" front/rear

• Both grooves are 15/32"

• 27/32" recess on the front for a nut and washer

• 1/8" lip on the rear to keep it off the alternator's case

Will that work for you?

[Whisler]

Jim - I'm confused. The pulley on the 3G you sent me is a poly-groove, as shown below. But are you referring to another pulley?

Whisler - I only have one unused pulley, and it is a 2-groove as also shown below. Its measurements are:

• 3 3/16" OD

• 1 5/8" front/rear

• Both grooves are 15/32"

• 27/32" recess on the front for a nut and washer

• 1/8" lip on the rear to keep it off the alternator's case

Will that work for you?

If the grooves measure 15/32 at the top, then the grooves are too wide for my use. As stated above my old pulley and the one on the crank are 3/8. I still don't understand how NumberDummy's chart (on FTE) shows a 0.38 (3/8) groove as correct for the alternator pulley and your chart calls for a 15/32 belt for the alternator. Very strange.

I found the correct pulley on Ebay, but the guy is selling 6 of them together. If I get those, I may have some for the next guy that needs one.

Thanks a lot for checking for me.

 

[Gary Lewis]

If the grooves measure 15/32 at the top, then the grooves are too wide for my use. As stated above my old pulley and the one on the crank are 3/8. I still don't understand how NumberDummy's chart (on FTE) shows a 0.38 (3/8) groove as correct for the alternator pulley and your chart calls for a 15/32 belt for the alternator. Very strange.

I found the correct pulley on Ebay, but the guy is selling 6 of them together. If I get those, I may have some for the next guy that needs one.

Thanks a lot for checking for me.

I don't know where Bill got his information, but he's almost always correct. However, his info doesn't agree with what I see in Ford's master parts catalog. Here are the entries for the 1984 302 and 351W. Note that the 302 did have a 3/8" drive belt from the alternator to the AIR pump, aka T/E. But there isn't a 3/8" belt shown for the 351W.

[ArdWrknTrk]

I don't know where Bill got his information, but he's almost always correct. However, his info doesn't agree with what I see in Ford's master parts catalog. Here are the entries for the 1984 302 and 351W. Note that the 302 did have a 3/8" drive belt from the alternator to the AIR pump, aka T/E. But there isn't a 3/8" belt shown for the 351W.

Gary,

I think the "unused" pulley is the one I sent you when I got rid of my A.I.R. pumps and bought the L&L bracket it came with, but I didn't need it.

I know on my stock alternator the belt used to drive the pumps *from* the alternator was about 10mm (or 3/8") wide.

But I do not know what was stock on earlier trucks.

The biggest concern is that the belt rides on the sides of the sheave and not in the bottom.

So too wide is maybe ok, but too narrow is definitely a failure.

[Gary Lewis]

Gary,

I think the "unused" pulley is the one I sent you when I got rid of my A.I.R. pumps and bought the L&L bracket it came with, but I didn't need it.

I know on my stock alternator the belt used to drive the pumps *from* the alternator was about 10mm (or 3/8") wide.

But I do not know what was stock on earlier trucks.

The biggest concern is that the belt rides on the sides of the sheave and not in the bottom.

So too wide is maybe ok, but too narrow is definitely a failure.

Ahhh! So that's where I got that pulley! Dawn. Marblehead.

Yes, too small of a belt rides on the bottom and slips. But too large of a belt doesn't get down in far enough for all of the side to be engaged, and it doesn't have as much grip as a belt that is fully engaged.

[Whisler]

Ahhh! So that's where I got that pulley! Dawn. Marblehead.

Yes, too small of a belt rides on the bottom and slips. But too large of a belt doesn't get down in far enough for all of the side to be engaged, and it doesn't have as much grip as a belt that is fully engaged.

Part of the puzzle may be solved. The outermost pulley sheave on the crank is larger that the other two

(measures ~ 1/2 inch) and the diagrams show that sheave driving the alternator via the outer sheave on the alternator pulley. The thermactor pump was then driven by the inner sheave of the alternator pulley. I removed the thermactor pump some time ago along with the non-functional A/C. (weight savings, don't you know) and probably just ran a belt from the next crank sheave in toward the block (A/C) which was smaller (3/8).

That still leaves the question of why my alternator pulley sheaves both measure 3/8 rather than large enough to use a 15/32 belt as the chart show.

Whatever the reason, I still need a single sheave 3/8 pulley because my double sheave pulley is too thick to bolt up and a double would be needed to line up with the larger crank pulley.

Gary, could you measure the actual shaft contact surface length (surface in contact with the shaft) on the pulley that you have on the off chance it is shorter than mine and would allow more thread bit. If it is near 11/16" it might work.

[ArdWrknTrk]

Part of the puzzle may be solved. The outermost pulley sheave on the crank is larger that the other two

(measures ~ 1/2 inch) and the diagrams show that sheave driving the alternator via the outer sheave on the alternator pulley. The thermactor pump was then driven by the inner sheave of the alternator pulley. I removed the thermactor pump some time ago along with the non-functional A/C. (weight savings, don't you know) and probably just ran a belt from the next crank sheave in toward the block (A/C) which was smaller (3/8).

That still leaves the question of why my alternator pulley sheaves both measure 3/8 rather than large enough to use a 15/32 belt as the chart show.

Whatever the reason, I still need a single sheave 3/8 pulley because my double sheave pulley is too thick to bolt up and a double would be needed to line up with the larger crank pulley.

Gary, could you measure the actual shaft contact surface length (surface in contact with the shaft) on the pulley that you have on the off chance it is shorter than mine and would allow more thread bit. If it is near 11/16" it might work.

Gary has a lathe.

He can make it whatever you want.

[Whisler]

Gary has a lathe.

He can make it whatever you want.

A part and custom machine work is a lot to ask of a guy.

If he could make it 11/16, I would be delighted. A larger pulley and wider belt may reduce any tendency to chirp on start-up.

 

[Gary Lewis]

A part and custom machine work is a lot to ask of a guy.

If he could make it 11/16, I would be delighted. A larger pulley and wider belt may reduce any tendency to chirp on start-up.

Yes, I'll measure the length tomorrow. But, doing the math from the measurements I have I should be able to tell you now. 3 3/16" overall minus 27/32" recess gives 2 11/32" of shaft contact. Is that what you need me to confirm?

But, you want the groove to be 11/16" wide at the top? Why that size?

[Whisler]

Yes, I'll measure the length tomorrow. But, doing the math from the measurements I have I should be able to tell you now. 3 3/16" overall minus 27/32" recess gives 2 11/32" of shaft contact. Is that what you need me to confirm?

But, you want the groove to be 11/16" wide at the top? Why that size?

Obviously I was very unclear in what I needed or was trying to convey.

You measured the pulley front to back at 1 5/8" overall width, with 27/32" recess and 1/8' lip on the back.

What I was trying to say is that I need the distance measured from the face of the recess to the back of the lip to be 11/16". Converting to metric, overall width is 1.625" minus 0.844" recess makes the current distance from face of recess to back of lip to be 0.781. This is assuming your overall width was including the lip.

I need the distance from the face of the recess to the back of the lip to be 0.688" (or 11/16) or stated another way I need the recess deepened by about 0.1". The lip needs to stay to space the pulley off the alternator case. Nothing else about the pulley needs to be changed.

I hope that makes better sense. If not let me know.