fan belt alternative for 21-stud motor

[Adam/Mill Valley CA]

I've been using 5L560 fan belts from NAPA for my '36 pickup with a stock poured bearing 21 stud motor, but noticed the life span didn't seen to be very good, they seemed to stretch out and start chirping pretty quickly. I thought I would try the same belt but strengthened with Aramid fiber, however NAPA wants $49 + tax for that size (part # 5L560W)! Looking around, I came across a site in South Dakota, V-belt Guys (www.vbeltguys.com) and they seem to have the same belt (their part #B53LGXLVR7161) for $18.50 including tax + shipping, and it has a nice tan color to boot (see photo). I'm hoping this will have a better service life. The dimensions are 3/8" deep x 5/8" wide x56" long.

Adam

 

[Flathead Fever]

We used the Gates, heavy duty, green stripe belts at the phone company and they held up really well. The only better belts than those were the factory Motorcraft belts. They would go ten-years whereas some of the aftermarket Autoparts stores belts only lasted two-years. Later on, we lost that warehouse supplier with the Gates belts, and we had to switch to Dayco. They seemed to be okay too, but probably not as tough as those green stripe Gates belts were. That has been 15 years ago, so I don't know if those Gates belts are still the same quality. They won't be tan like the early original belts were. I see Tractor Supply has tan belts hanging on the wall. I doubt they are anywhere the quality of those Gates Green Stripes.

On flatheads, I lower the generators down to their lowest point on the mount. Then I have an old cut belt I wrap around the pulleys and measure its length, then I order one that length. By the time you raise the generator to put tension on the belt it's in the correct position and still has more room for any future adjustment. New belts will have an initial stretch after about an hour of running time and might need to be readjusted. The Gates catalog has a section that lists them by width and length. With aftermarket aluminum intake manifolds the belts are not always the same length as the originals. A nice reproduction Ford script belt might be too short with an aftermarket intake. Seems like I remember going through that a long time ago.

If anybody is running the flathead truck pumps with two pulleys, you need to order the belts as a "matched set" The belt are made in large rolls and then sliced off. The roll varie in size slightly from one end to the other. You want two belts that were sliced off the roll side by side so they will be exactly the same length. They will have corresponding numbers on them besides the part number that lets you know they were next to each other on the roll. If you just randomly get two belts with the same part number. one belt might be tight and the other loose. Make sure the person you're ordering them knows you want a "matched pair". This is real common request on the larger trucks like F600s and F800s in the 1960s-1980s that ran two belts to drive heavy duty alternators and power steering pumps. The catalog will even tell you to order the part number with "MS" after it for those two-belt applications.

I see people running the narrower belts on the earlier wide grooved pulleys. This is in correct as the side of the belts is what grabs the angled sides of the pulley. The belt should not touch the bottom of the pulley. If you run the narrow belts on the wide pulleys the bottom of the belt will be turning the bottom of the groove in the pulley, and it will slip. Don't Magilla Gorilla overtighten the belts or you'll wipe out generator and water pump bushings and bearings. I had one guy tell me he went through a lot of rear generator bushings on one of his flatheads until he installed one of late model flathead generator rear covers with the bearings in them (maybe a 1953) and that solved his problem.

 

[petehoovie]

I've been using 5L560 fan belts from NAPA for my '36 pickup with a stock poured bearing 21 stud motor, but noticed the life span didn't seen to be very good, they seemed to stretch out and start chirping pretty quickly. I thought I would try the same belt but strengthened with Aramid fiber, however NAPA wants $49 + tax for that size (part # 5L560W)! Looking around, I came across a site in South Dakota, V-belt Guys (www.vbeltguys.com) and they seem to have the same belt (their part #B53LGXLVR7161) for $18.50 including tax + shipping, and it has a nice tan color to boot (see photo). I'm hoping this will have a better service life. The dimensions are 3/8" deep x 5/8" wide x56" long.

Adam

 

[petehoovie]

https://www.vbeltguys.com/products/...dry-kevlar-v-belt?_pos=3&_sid=ef5cf843f&_ss=r


5L560W NAPA AUTOMOTIVE Aramid Replacement V-Belt | 5/8 x 56

$ 11.51 $ 15.01

Original Equipment Manufacturer NAPA AUTOMOTIVE OEM Part Number 5L560W Belt Type Aramid FHP Replacement VBG Replacement Id KVLR37803 Technical Specifications: (Inches) (mm) Outside Circumference 56 1422.4 Top Width 0.625 15.875 Belt Depth 0.38 9.53
Material Dry Wrap Aramid Cord Belt Section 5LK/BK

 

[Adam/Mill Valley CA]

Fever, thanks for the interesting information, particularly about the matched sets; I didn't realize belts were sliced off a large roll. Pete, thanks as always for the picture enlargement, and posting the link

Adam