Belt Woes..

[KyleSeal]

Ever since I got this truck the alternator belt has given me so many issues. The second day I had the truck the alternator belt wrapped itself around the fan and just tore itself to shreds.

I replaced it in the parking lot and got home, ever since then my belt has just been giving me issues. I replaced the alternator today, and tightened the belt as much as my back would allow up on that big tire. Yet as soon as I left work my voltage dropped and I could smell the belt burning/slipping on the pulley. And then I pulled over to inspect, but the belt has cut itself in half and flown off!

Whats going on? I tighten it as much as I humanly can but still slips and comes off. I've heard of deeper V belt pulleys helping but I am not sure on what to do. Maybe a special tool to yank the alternator to put more tension on my belt?

Its a built 454 with AC, PS but no air/smog pump.

[Captainfab]

It is impossible to say without seeing what you have, but it sounds like an alignment issue with the pulleys. Is this in the '84 K30 in your signature?

['63GENIII]

Miss alignment or possibly one or more of the accessories are dragging causing too much strain on the belt? If you look from the side of the belt(s), they should be darned near in line with each other. If one pulley is slightly off, you can have some problems. Id also try watching (make sure to stay out of the line of the belt) all of the pulleys while the engine is running to see / hear if you can pinpoint the problem. The belts on my 396 required a little maintenance more than I liked. I went with a factory serpentine set up and never looked back. No power steering belt squeal since.

[KyleSeal]

Yes this is on my '84 K30. I looked to see if I could visibly notice any misalignment on the belt system but I can't see anything. I will double check though.

[storm9c1]

V-belts are not supposed to ride deeply in the groove. Too much friction is generated that way. I'd lean more toward a wider belt if you can find one. Ideally, the flat side should be flush with the pulley.

If there is any way to post a picture of your setup, perhaps a side view so we can look at alignment, that might help.

[KyleSeal]

I'll get some taken and post them soon. My coolant/heater and AC lines are in the way some so it'll be hard to view but I'll post some up.

[KyleSeal]

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[KyleSeal]

heres some more.

[68is4me]

The alignment looks good, but it looks like your alt pulley is to wide. The top of the belt should be even with the top of the pulley. Just like your other pulleys.

[KyleSeal]

Yeah I noticed that myself earlier taking the pic.. the alternator is literally two days and maybe 25 miles old, and look at that belt dust on it. I supposed I can find an alternator pulley to fit? Too bad the dudes at carquest took mine without me getting the pulley back.. stupid cores..

[Marshy]

Originally Posted by KyleSeal

Yeah I noticed that myself earlier taking the pic.. the alternator is literally two days and maybe 25 miles old, and look at that belt dust on it. I supposed I can find an alternator pulley to fit? Too bad the dudes at carquest took mine without me getting the pulley back.. stupid cores..

Go back and see if they still have the core sitting in the back. Maybe they have a pile of cores and dont send them out very often. Its worth a try I guess. Maybe they will let you dig for it if they just throw them in a pile. Otherwise you could slip the handle of a breaker bar down between the bracket and the alt and get some more tension on the belt but I suspect that will shorten its life faster. That one pulley looks better. Look at the wear on that belt, is it even across the whole tapered face? Hard to tell from the one pic but once you get the right pulley I'd put a new belt on again.

[Dead Parrot]

Here is a similar alternator and pulley on my truck.

[KyleSeal]

I'll post some photos of an extra alternator pulley I have.

[KyleSeal]

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[GASoline71]

Belt is too deep in the groove of the pulley.

You can see from this pic you posted that the belt is actually twisting as it comes out of the pulley. It's also only contacting the outer top edge of the V on the belt.

Gary

[PGSigns]

There is something else going on. The high performance GM big blocks ran deep grove pulleys to help keep the belts on. Nothing wrong with a deep groove pulley. I would look at the crank and water pump pulleys for wear. If one has a bad wear pattern in it it will eat the belts. Also you can over tighten the belt and speed up the failure if a grove is worn out. The lean in the top of the belt on the alternator looks like it is being caused by the water pump pulley. I has a lean in it also.
Jimmy

[A1971Blazer]

Look for a cracked or broken bracket on all the belt driven stuff....also I had one that had the bolt on the radiator hose clamp too close to the belt....it didn't touch until the engine revved up then it would contact and sling the belt off...

[storm9c1]

Yeah, alignment seems OK. Belts are forgiving and can withstand a little bit of misalignment. But a cracked bracket (as mentioned) could cause an accessory to flex into a worse position under load. So definitely check for that.

I don't like how that belt is riding through the alternator pulley. As mentioned, something is causing a slight twist and ride too low in the groove. That particular pulley looks like it's made for a wider belt. Whereas the water pump pulley seems right for that belt width.

If you watch the WP and crank pulleys turn as the engine idles, do you notice it being out of round or wobble at all? What about the alternator? You said your old alternator was doing this too? So swapping pulley's won't matter.

But I do like the spare pulley that you were holding in your hand in that pic. Can you try that one?

There is such a thing as too tight. Lacking a belt tension gauge, the next best thing is to push on the belt in the middle of the longest run with your index finger and you should feel strong resistance at 1" flex. Meaning it shouldn't have any more flex beyond 1" pushing with a finger. But should allow up to about 1/2" of flex. Any less than about 1/2" on a used belt means it's too tight. A brand new belt may have as little a 1/3" flex but once run, even once, it's now considered used. This is all a generality but is a reasonable reference to start with. FSMs usually call out their own methods of testing proper tension for each accessory.

[KyleSeal]

Went back to Carquest and got my old pulley back, slapped the new one on and it seems to be working okay. It sits nice and flush with good contact on the pulley, when I took it for a drive it squeaked some but it cleaned up right after and was charging the battery properly. Everything else seems fine, I only tightened it up as much as I could with no other assistance, so its tension is about equal with the other belts. I will be replacing the other belts in the system sometime soon, as they are old and a little dry, and I will check all my pulleys for bad patterns.

[AcampoDave]

My crank pulley wore out. Drove me crazy 'till I figured it out. Not the first thing one thinks of when trying to diagnose a belt noise that's for sure, but once I finally took it off and inspected it, the wear was pretty bad.