VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 Fan belt, 1922

Hi

After five years and about 6 000 kilometers (3 700 miles) with a modern, stiff, 1/2 inch V-shape fan belt I've got a problem. The fan pulley is now loose from the axle. It slided forwards so it began to touch the radiator. It was easy to slide it backwards, almost one inch. I could see and feel a play between the pulley and the axle. This happened on a tour the other day. It was now possible to turn the adjustable flange (the adjustable part of the pulley) one turn. I've tried that one or two yerars ago, but at that time it was not possible. I got home safely, listening carefully for any noise and checking a couple of times.

My guess is that the modern, stiff fan belt has caused a wear on the axle, in the goods of the stationary pulley flange(the stationary part of the pulley), on the woodruff key or a combination. Why? - I guess because it is not possible to adjust the fan belt in a way that suits this construction; either it is too hard causing wear on the water pump bushing, or it is too loose, causing repetetive varying pressure on the fan pulley (spasmodic jerks?) that the pulley sooner or later comes loose.

I had a new bushing in the water pump made four years ago, and I cannot see or feel any signs of wear.

I have a couple of questions.

1. Does my guess seem reasonable?
2. Any recommendations to fix the stationary flange to the axle? Could it be enough with a new woodruff key? Combined with som kind of Loctite?? Or should I drill through the stationary flange goods and the axel, and fix with an expansive pin (I cannot find a better word - hope you can understand).
3. What kind of fan belt should I use, equivalent to the original V-shape belt, made of several layers of leather
riveted together? I guess it should be less stiff than a modern fan belt, possible to adjust quite tight, but without hard pressure on the water pump bushing.
4. Where can I find such belts?

Now I have removed both the adjustable and the stationary flange. There is no visable wearing on the axle. After cleaning the axle and the stationary flange it was possible to install the flange with a small 0.05 mm gauge blade, so the free play is a little more than that.

I've checked Loctite 648, for cylindric mounting. The instruction says that the "limspalt" (glue thickness?)should be 0.05-0.15 mm. Is it worth trying?

The fan belt should be 5/8". Now I've checked Early Chevrolet Parts - Gary Wallace offers a fan belt for 490 and Superiors 1918 - 1925. I'll check what type of fan belt he offers.

If you're not too worried about authentic looks, a "B" v-belt can be had for a few bucks at a farm supply store. You just need to measure to find the right size. The "B" size is 5/8".

My '19 FB used a leather segmented belt. Not sure when they went to rubber belts.

I think Øistein Getz might hava a suitable fanbelt type for sale.

Hope to see you in Styrkeprovet in August.

In view of the fact that the pulley flange is not tight on the shaft, I think Loctite would be good insurance against future movement. You would have to heat the pulley to de-activate the Loctite if you need to remove it in the future though. I doubt you would need an expansive pin (known as roll pins if you should be looking for them) as well as Loctite, and I suspect if you used one without the Loctite that it would eventually fatigue and break with the movement between the loose flange and the water pump shaft.

Another alternative, if the water pump shaft really is not worn at all and there is sufficient thickness of metal in the pulley flange, would be to bore out the flange and press in a bush with a bore and keyway of the correct size to return the pulley to the original standard. Do replace the Woodruff key if it is worn or loose in the shaft.

Frank.

Thanks, Frank

I guess you're right about heating the pulley if I have to remove it in the future, especially if I use Loctite 648. Maybe that woldn't be nessecary if I use Loctite 641, but I'm not sure the 641 would do the job. Any experience, someone?

My Dads 21 490 with 10,000 original miles had a leather segmented belt on it also. I hear they are still available but not made of leather any more but a belting type material. A good bearing and belting industrial supply house should be able to get them if they don't have them on the shelf. the way to install them is the flap in the inside of the segments should be facing backwards of belt direction. My 15,000 mile 21 490 has a rubber belt but someone had changed it.