Water Pump Pulley unbalanced

[V8Cowboy]

Hi,

(1970 Challenger, 383)

I got a sudden squealing when revving over 3000 rpm recently. First I tightened the belts properly, still there. I looked at the belts while revving and realised a flattering power stearing belt when the noise appeared, thought this might be the trouble. I tried to clean the pulley and the belt, sanded it, but still no solution. What I found out is that even while running the Motor only for a few seconds, the water pump pulley/belt area got extremely hot.

So I wanted to remove the belt for a final check. While removing the fan/waterpump belt (car is with AC) i noticed that the water pump pulley is slightly unbalanced, maybe 0,5-1 mm. Running the (of course cold) Motor again without belt for a short test revealed that's the problem. Well, either the pulley or the belt.

A few questions came up: 1) How can that be, that the pulley gets unbalanced? No squealing until two weeks ago or so. 2) Can this imbalance be the source of the squealing or rather the belt itself? 3) Can I try to balance the pulley and if so, how?

Any answer would be appreciated!

[Katfish]

2 belts for the AC right, get 2 new belts and try them together and single only.
Slight variations in belt length or stretch may be your problem.

When I converted to a Sanden compressor, I had to buy 6 belts (all the same PN), and mix and match still I found 2 that worked together, then returned the other 4.
At 1 point you could buy matched sets of belts, don't think that's and option now.

[burdar]

Also check the water pump for a loose hub.  Excessive paint buildup can also cause the pulley bolts to loosen up over time. Check that the pulley is tight.

[V8Cowboy]

Hey Katfish: I don't think it's the AC-belt, they were quiet. It must be the waterpump belt.
burdar: good idea. I meanwhile had a look at the pulley and found 4 washers that are placed between water pump and pulley. Don't know if they belong there? They were sort of glued in there, so not evenly positioned, I cleaned no everything to the bare metal.

I mounted the pulley without them and the imbalance got better. Question is, whether they are needed to align the pulley with the other two or not. Mounting the Pulley with them results in a bigger imbalance. I guess that the washers are too big and touch the side of the pulley, so they are somewhat skewed. I try to find smaller ones but at first I have to find the screw I lost somewhere underneath the car 

[burdar]

There shouldn't be washers between the pump hub and the pulley. Someone put them there to align the pulleys. You probably have an unmatched set of pulleys. You'll have to check the alignment and make sure the washers didn't damage the pulley at all.

[AARuFAST]

Only install a cast iron water pump.
Never install  an aluminum water pump ON 383, 440
Back in the day there was a gauge you placed on the
belts for the correct tension.
Napa auto parts store helped me with a matching set of belts same batch number from warehouse.

[V8Cowboy]

I don't know if the pulleys are right, got the 4 on the crank which seem to be original. The tightening pulley aligns with the crank side.

I thought so.... tried to install the pulley without washers, but I didn't like the alignment. Tried to use a laser level as help for determining, which actually worked quite well.
But in this case you could even see the belt running weird.

Had a closer look at the washers then. They wheren't even of the same thickness, so I changed them to a set of 4 new and matching. Again gave it a try and the alignment seems to be way better, as well as the imbalance.
Ok, they do not belong there, but as long as they help...
I tightened the belt as long as I couldn't turn the wp-pulley by hand, as it slipped quite easily. Cranked it up and squealing has totally gone. Took it for a ride and even though accelerating hard it did not come back.
But belt tension is too much atm, so I will definitely change it to a new one, as the old seems a bit cracked anyway. I hope that will finally help without tightening the belt so much that the wp-bearing will suffer.

[brads70]

FWIW, now that you know what thickness to shim out the water pump pulley. I'd shim it out the proper way. More surface area prevents cracked pulleys.
http://www.jegs.com/i/JEGS-Performance-Products/555/51106/10002/-1

[Katfish]

Good info. Never knew that was available.

[V8Cowboy]

Hi,

thanks for the info, I will stick to it  Obviously the alignment problem is not that uncommon...

[V8Cowboy]

Hey guys,

sorry but I have to get back to this topic 

Thought everything is fine now, alignment looked good, got me a new belt as the old one was glazed and cracked and could then go faster than 90 km/h without squealing. But... I did not drive on the Highway yet with continuously higher speeds. Last weekend I went to a Mopar meeting @120 km/h. After about 15 miles I made a short stop, looked under the hood, everything fine then.

Another 5-6 miles later i smelled some rubber and thanks to my paranoia, got alert. Temperature increased to a bit under "H" (ofcourse in the middle of a road construction, so another 1-2 miles to a safe place to stop, hope nothing overheated  )

Waterpump belt was gone, even flipped the PS belt on the crank side  Thank god nothing else got damaged (fan, radiator). Put then back the old WP belt I had with me and continued my way a few miles at 90 km/h as I knew that belt would squeal going faster - then the same, smelled rubber, heard some strange noises, temperature rose. I got towed by the automobile club, they had a spare belt and I could at least attend the meeting, driving like a snail all the remaining way and back.

No the actual question:

If you put the pulley on an even surface you can see and feel it is not even on a certain spot, like pushing at 12 and 6 o'clock, while 9 and 3 is fine. You know what I mean? Maybe 1 mm.
Therefore I was looking after an original part to give it a try, I guess it should be 2951092 for A/C, but that revealed that my pulley seems to be smaller, 5 1/4" diameter and 1 1/4" height.  Do I have an underdrive pulley and may that be the cause, together with the higher speed/momentum of the fan, that my car is eating v-belts??

Wow, this got a long story, hope you find some time to read through tough.

[brads70]

sounds like it's bent, and in need of replacement. A smaller pulley will make the water pump go faster.

[V8Cowboy]

I was looking for a replacement, that's why I found out the probably original part should be bigger in diameter. At least if Google doesn't lie

Now my thought was, that a smaller pulley propels the fan faster at a certain rpm, and therefore the centrifugal forces may make the whole construction to flatter or whatever. Possibly someone built in a smaller pulley to take part in acceleration races for more water flow and cooling, short revs to higher rpm without continuous load like i drove it. 

[734406pk]

I suspect that you don't have the right pulley on the water pump. Check with Yearone or Bouchillon Performance Engineering. The diameter may be too small, resulting in belt slippage etc.

[1 Wild R/T]

The correct A/C pulley is smaller than the non A/C pulley, and shallower.. Here's a picture, hope it helps cause the hood latch chewed on my head while I was taking pictures..