Odd Belt Issue, 49 Chrysler 8

[Bryan G]

I reached a milestone on my New Yorker in the last week; since getting it back on the road in the 2nd half of July, I have now driven 1,000 miles. Since I'd done a ring job I did an oil change last week. The car is running better and better. There is one odd issue that I haven't figured out:

 

When I bought the car the belt was old and stiff, though seemed okay otherwise. I ditched it for a new one, a NAPA 24489 made by Gates. This is one of the "wide" belts. It fit just fine and there were no squeals or other noises. All was good, but after maybe 100 miles I noticed it was too loose. I tightened it but in time it was again too loose. As I moved the generator out as far as it would go I noticed the belt was shrinking in width, have shed some rubber dust over the sides of the engine. The belt now sat quite a bit further down in the grooves. I verified this was the number belt that was called for. 

 

I tried ordering the next size tighter but it was too short (won't go on with generator all the way in). I then ordered a Gates "Truck & Bus" belt, same size as the NAPA. Heavier duty? Same results: starts out fine but quickly wears. In the trunk was a narrow belt in good condition so I tried it; too short. I took it to the store and got a size longer and that's what I have on there now, a Dayco 17480 "narrow". Like the wide belt, no drama, but it, too, is wearing. 

 

Why? All 3 pulleys appear normal and line up fine. The water pump & generator seem to spin normally. I'm not tightening the belt very tight as I'd experienced a bearing failure once on another car thanks to overtightening. Even with the belts incredibly loose it doesn't seem to hurt anything. Anybody else have this issue? Any ideas to try?

[lemondana]

Most belts these days are not made in the US.  The quality has went downhill. You said that you run the belt loose. When run loose, they slip and will wear out a lot faster.  They have to be fairly tight.  I'll try to find you a good belt.  PM me for info.  Myron

[Andydodge]

I've always tightened belts so that there is no more than 1/2" of "play" as measured in the longest span, admittedly I have not had any experience with straight 8 engines my only experience with the wide belts is on Plymouths and Oz GM Holdens........the 41 Plymouth used the wide belt & I installed a new belt of whatever size the old one was and had no problem........maybe as Lemondana says you may have the belt too loose.........but I'm no expert................have you checked the pulleys completely, there is not a crack or chip in one?............andyd 

[Dodgeb4ya]

This is the NAPA belt #25-24489.

I have always used this belt on all the 1946-50 Chrysler eights with no issues other than the occasional cackling noise so common on these engines with the wide belt.

I use the Gates too but cannot remember the #.

I never tighten the belts much...never any wear issues.

[kencombs]

Is it possible that one of the pulleys is not the original and is the wrong vee angle, 30 vs 40?  That type of wear is typical of a pulley and belt angle mismatch.

[Sniper]

I like to take a bore sighting laser and lay in it the notch of the V to align my pulleys.  I aim for center of the other pulley(s).

[Dodgeb4ya]

Possibly a generator or mounting issue...

There are two or more possible generator and pulley combo's used on the 8's.

"GGU" generators are the real oddball.

Rebuilt units sometimes end up with the wrong pulley which moves the belt in or out.

Edited November 2, 2021 by Dodgeb4ya

[Bryan G]

The belt shown by Dodgeb4ya is the first one I tried. It and the Gates were both made in the USA; the narrow Dayco I'm running now is from China. (If the store had it in stock I would have handed it right back to the clerk, but since they special ordered it I felt obliged to buy it.) I'm going to take look over the pulleys as close as I can. My thought had been the generator could be the most likely culprit as it's the only one really likely to have ever been swapped out. Does anyone on here have a spare correct pulley?

[Dodgeb4ya]

If the crankshaft, water pump and generator pulleys line up, and are not damaged or severely pitted then pulleys including the generator are not your problem.

Different width pulleys are a problem...out of line pulleys too.

Check for those problems.

As for simply getting the right generator pulley...you need to first know something is wrong with the one you have.

Carefully watch the belt and pulleys while the engine is running looking thru the centerline of said belt and pulleys..

Watch for the belt angled off a straight line or bent wobbly pulleys.

Look for the belt scraping some metal frame, bolt shroud etc.

You will find the issue.

[Bryan]

How rusty do pulleys have to be before they need replacing?   I can clean them up but..hmmm.

[Dodgeb4ya]

Bead blast them...they will be fine unless deep pits or you just want better pulleys.