The Ford Barn

alexiskai · 02-16-2025, 11:19 PM

This discussion started elsewhere but I don't want it to hijack the thread.

For those who may not know, the Horne harmonic balancers are thicker than the stock pulley (same diameter but "taller"), so they take up more of the hollow in the front crossmember. This makes it impossible to remove a conventional fan belt without jacking up the engine. However, a link belt or segmented belt can be used instead. This type of belt uses a series of urethane links, like links in a chain. It can be resized and detached easily, so the belt can simply be pulled off.

This means we need to ask what sort of link belt to use. To do this, we need to measure the dimensions of the channel in the pulley sheave. I didn't have access to an original pulley but I took some measurements of a few two-piece aftermarket pulleys. The width at the top of the channel was .60-.62 inches. The Horne pulley is .625" at the top. The depth of the channels was at least .625" on all.

Best-practice with a V belt is that the belt should ride at or slightly above the top of the pulley, meaning that the belt must be at least as wide as the pulley. This causes it to grip the sides of the pulley.

Looking at an explainer page on V-belt sections, the correct one for the crank pulley would seem to be a Type 5V belt. This type is .62" wide at the top and .54" deep. However, the pulley on the aluminum two-blade fan is only .50" deep, so a 5V belt would not fit properly. Instead we need a Type B belt, which is .66" wide and .41" deep.

Some belts that appear suitable include:
Power Twist 5/8 x 5 B type industrial transmission V Belt
Jason Industrial Accu-Link B-Link-4 or B-link-6
BDH DuroDrive B Size, 6.5 Ft. Sleeve

The BDH DuroDrive belts are made in the USA and consequently are 2x the price of the others. Supposedly they are very high quality.

02-16-2025, 11:19 PM	#1
alexiskai Senior Member Join Date: Apr 2018 Location: Mebane NC Posts: 2,848	Correct link belt for Model A This discussion started elsewhere but I don't want it to hijack the thread. For those who may not know, the Horne harmonic balancers are thicker than the stock pulley (same diameter but "taller"), so they take up more of the hollow in the front crossmember. This makes it impossible to remove a conventional fan belt without jacking up the engine. However, a link belt or segmented belt can be used instead. This type of belt uses a series of urethane links, like links in a chain. It can be resized and detached easily, so the belt can simply be pulled off. This means we need to ask what sort of link belt to use. To do this, we need to measure the dimensions of the channel in the pulley sheave. I didn't have access to an original pulley but I took some measurements of a few two-piece aftermarket pulleys. The width at the top of the channel was .60-.62 inches. The Horne pulley is .625" at the top. The depth of the channels was at least .625" on all. Best-practice with a V belt is that the belt should ride at or slightly above the top of the pulley, meaning that the belt must be at least as wide as the pulley. This causes it to grip the sides of the pulley. Looking at an explainer page on V-belt sections, the correct one for the crank pulley would seem to be a Type 5V belt. This type is .62" wide at the top and .54" deep. However, the pulley on the aluminum two-blade fan is only .50" deep, so a 5V belt would not fit properly. Instead we need a Type B belt, which is .66" wide and .41" deep. Some belts that appear suitable include: Power Twist 5/8 x 5 B type industrial transmission V Belt Jason Industrial Accu-Link B-Link-4 or B-link-6 BDH DuroDrive B Size, 6.5 Ft. Sleeve The BDH DuroDrive belts are made in the USA and consequently are 2x the price of the others. Supposedly they are very high quality. Last edited by alexiskai; 02-17-2025 at 10:20 AM.