Ford V belts - 39-38
 

What is the correct width V-belt that drives the pumps and generator off the crank for the '39-48 flathead ? The ones I see from NAPA are truck & bus application, and say they are 3/4" wide. You measure them and they range from .600 to .655 or a little less or more than .625 or 5/8". They seem to sit a little high on the sheaves. Thank you Fordbarners.

Re: Ford V belts - 39-38
 

There were several belts in the time frame mentioned. The belt size was likely closer to 11/16" width with 34 degree side angle back in the day but no one company manufactures exact replicas of the original designs. Belt manufacturers changed over to metric sizing & who knows what angle a long time ago and they don't make all the variations that were from that era. They do have reproductions that look like the originals but fit is a different story.

Ford had different diameter generator pulleys starting in mid 1940 so a different shorter length belt was required for those that had the smaller pulley.

Re: Ford V belts - 39-38
 

Ford had different diameter generator pulleys starting in mid 1940 so a different shorter length belt was required for those that had the smaller pulley.[/QUOTE]

Rotor,
You are, as usual, quite correct.

Russ, IF you have small pulley on your generator, you can just barely "sneak" one of Drakes belts on.
His belts are NOT faithful reproduction's but I suppose, fill a need nonetheless.

Re: Ford V belts - 39-38
 

Thank you for your responses. I am not concerned with the length of the belts, just the width measured at the top outside edge. .600 to .650 may be some metric number, but it's a lot closer to .625 or 5/8" than 11/16" measured with a vernier caliper. I am also not interested faithful, just the right width, and certainly not something from Drake. NAPA has good range of belts for my needs, but I was curious as to why the are listed as 3/4" and what the original width was to fit properly in the sheave.

Re: Ford V belts - 39-38
 

V belts should run just a bit proud of the V groove on the sheave but that depends on all the dimensional factors involved plus condition of parts. They should not run down to the bottom of the groove or they will no longer have the friction they need on the sides. A lot of these old sheaves can have a lot of wear on them too.

Replacements parts were sold for a long time after the older cars were obsolete and replacement parts may have gone to 5/8" like the post war Ford 8BA cars did. Pickups still had the wide flange sheaves but the cars went narrow. Don't be surprised if your crank pulley is wider than the water pump and generator sheaves.

Re: Ford V belts - 39-38
 

I use a B belt which is 5/8" wide. Seems to fit good.

Re: Ford V belts - 39-38
 

The pictured belts are on my 39 mercury and 39 peekup, the FORD belt 78-8620-A on the Merc and NAPA B53 are both "B" width or 5/8.

A typical "A" or 4L belt is a tick under 1/2", good luck and let us know how you make out.

There is a gauge for checking sheaves depth and figuring belt size and width, I think Browning or Gates had a set available for the HVAC field several years ago.

Re: Ford V belts - 39-38
 

The B width for industrial belts is actually 21/32" so it's half way between 5/8" & 11/16". It has a thickness of 13/32" so it's a bit thicker than the light duty belts or L series. Any belt of the L series is considered a fractional horse power belt or FHP type and should be used on applications of 1 horse power or less. The 5L size belt is 21/32" width with a thickness of 3/8" so it's not quite as thick as the B size. It may work for a generator/water pump belt but it may have a shorter life expectancy. I don't know for any certainty how well any of the industrial type belts will work. At least they can still be sourced for the time being.

A person would have to check the sheaves when installing a B size belt to make sure it doesn't bottom out. The Narrow V Series belts are even thicker so they may bottom out in the sheave.

Re: Ford V belts - 39-38
 

Here is what a NAPA 25-24562 belt looks like on the the 59L in the test stand. The belt is about .650 wide, and is 56 5/8" long because I am using an early aluminum manifold and generator mount that is about 1" higher than the stock 59. It sits just proud of the '40 crank, water pump, and '40 generator sheaves as Rotorwrench pointed out.

Re: Ford V belts - 39-38
 

Thanks for the post. Any chance if you know if they offer it in a solid belt vs. the "toothed" version you have?

Re: Ford V belts - 39-38
 

Yes you can get them without the cogs which are for belts that use a small diameter pully.For commercial belts the letter is followed by a X . B54 vs a BX54.

Re: Ford V belts - 39-38
 

There is a very large hardware store in Ephrata, Pa. named Zimmerman's.
Hanging on the ceiling is about 10 or 12 rows of V belts. Each row is about
75 feet long. There are many different types of belts. You can look at them and order online. G.M.

Re: Ford V belts - 39-38
 

Thank you, G.M. I'll check it out.