Packard Forum Index » Pre-War (1899-1942)

Does anybody know the correct belt width for a 38 Packard 8? I developed a squeal at higher RPMs and my belt is aligned and tight but the belt looks like it's riding a little low in the pulleys. I currently have a 5/8" belt. I this correct?

The belt I have on my 39 120 is too small, and squeals as well. I'll go measure it as I know it rides too low in the pulley.

just checked the one on the 120. It is 7/16" wide at the top; probably called a half inch belt. It does squeal when you rev the engine. My mechanic has chastised me and told me to get a 3/4" or perhaps a 5/8" belt. The belt should be slightly above the surface of the water pump pulley. Soon as I find one, I'll post the number on the site.

here's what salty dog has listed on the Parts X-Ref file:

Fan belt 300192, 120&115C, 1935-1937, 25-11430 Napa

Fan Belt 320517 110&120 1938-1941 25-24489 Napa

Hi Phil:

Those belts have been a problem for ages. The squeal comes from the inside of the belt accelerating at a different rate than the outside of the belt as it goes around the pulley.

The wider belt rides higher in the pulley so that a portion is not subject to the acceleration change and absorbs the differential.

Anyway, try running a lower tension. The old timers used to set those belts so that they could turn the fan with their hand. There is still plenty to drive the generator and water pump, but there is enough slack to absorb the speed difference as it goes around the water pump.

Another option is ordering a custom sized belt. McMaster-Carr lists 11/16 and 7/8 belt widths. It takes a little work to estimate the circumference. I did this once for a Model 18 Packard. I don't remember off hand the width of the pulley on the junior Packards.

I'm diligently searching for my vintage Gates catalog which listed belts back into the teens; haven't found it yet but if I do I'll come back on this.

Dave Grubbs, pat your mechanic on the back and buy him a drink! My vintage catalog specifies Dayco 24490 for 38-40 Packard with 245 and 282 engines. You may have to convert that older # to their current system. Specs are:

Effective length: 49
Outside circumference: 49-23/32
Angle: 38 degrees
Width: 3/4