Eating Alternator Belts?

[thesameguy]

I've been told that the new-to-me '84 Suburban with a 6.5l transplant eats alternator belts on a disturbingly regular basis. This was confirmed by it eating one on the way from its previous home to its new one.

I picked up a new belt, and was going to install it this afternoon, when I noticed that the alternator is not parallel with the engine - I'm sure this is why it eats belts. Is this normal, or some adjustment I can make? The only manuals I have (Haynes & Chilton) don't seem to indicate there is any adjustment possible.

http://www.cal.net/~jvanabra/burbanalternator.jpg

[murphyslaw]

That alternator is way out of alignment with the other pulls I had this problem on one of my gassers I had to modify the bracket and make a spacer to push it forwad bout 1/2" to get it to light up mine was doing the same thing. I would make sure that any of the brackets arnt bent up and that its the correct alternator.

[HammerWerf]

'Guy,

From my looking at the provided picture (thanks), it appears the waterpump bearing is out of alignment and is causing the problem.

Check the alignment of the crank pully and the alternator pully. If they line up, then it's the waterpump. Could also be the pulley is bent out of parallel.

To check if the two pulleys are parallel, look down the alt. pulley at the outermost pulley on the crank. They should be inline with each other. A yard stick can also be used as a reference when laid inside the grooves or layed along side the pulleys. Do the same for the other sets of pulleys.

Another item I saw is the fan blade tip that is visible in the picture is shinny. It must be contacting/rubbing against the shroud.

Another item to look at. The powerstearing pump belt. It does not pass over the fan pulley. Did the prior owner tell you that it eats this belt too?

Looking closely at the picture, I see a bolt that has its head between the CDR hose from the oil fill tube and the water crossover and goes to the left in the picture. My question is, What is this bolt used for? I do not have a similar bolt on my 6.2's. If it is being used to hold the lower end of the alt bracket, it could be the source of the problem, and I agree with Murphyslaw.

Let us know what you find, and ask more questions. These parts are stout, and don't lend themselves to gross misalignments easily.

HammerWerfer

[thesameguy]

'Guy,

From my looking at the provided picture (thanks), it appears the waterpump bearing is out of alignment and is causing the problem.

Check the alignment of the crank pully and the alternator pully. If they line up, then it's the waterpump. Could also be the pulley is bent out of parallel.

The water pump and the crank appear to be inline, as does the power steering pump. The only thing I've noticed pulley-wise that doesn't seem right is that the crank pulley has a nasty vibration to it - with the engine running, it looks substantially out of round. Is there a dampener in there that may have gone bad?

I took the lower alternator bracket off the car and beat the snot out of it with a sledge hammer. It is much more in line now - it seems it may be slightly off, but not like it was. I'm wondering if maybe it was damaged at some point by something. It is pretty stout...


Another item I saw is the fan blade tip that is visible in the picture is shinny. It must be contacting/rubbing against the shroud.

That I had not noticed, but I will look into it. I haven't heard anything with the engine running, but with that diesel in there it's hard to hear much. ;)


Another item to look at. The powerstearing pump belt. It does not pass over the fan pulley. Did the prior owner tell you that it eats this belt too?

You can't see that it does, but it does. There is one belt which is crank/water pump/AC that just touches the power steering pulley. It was in BAD shape, and the A/C doesn't work anyway, so I cut if off. :) The other belt is crank/water pump/power steering, and appeared to be in very good shape. I have a replacement, but it looked like moving the power steering pump was a PITA, so I figured I'd let it go for now...


Looking closely at the picture, I see a bolt that has its head between the CDR hose from the oil fill tube and the water crossover and goes to the left in the picture. My question is, What is this bolt used for? I do not have a similar bolt on my 6.2's. If it is being used to hold the lower end of the alt bracket, it could be the source of the problem, and I agree with Murphyslaw.

I'm not sure offhand what the bolt does - the truck is at home. But, whatever it is, it has nothing to do with the alternator bracket. That bracket is mounted on two studs from the water pump, and retained with two 15mm nuts.


Let us know what you find, and ask more questions. These parts are stout, and don't lend themselves to gross misalignments easily.

I will indeed... once this thing looks good under the hood, I have to do something about the exhaust. It's had its day in the sun... ;)

[CleviteKid]

Unfortuneately it is not uncommon for the alternator to end up slightly out of line with everything else. I had to shim mine about 1/4" to get everything to line up. Be sure you shim EVERY attachment point, or you will end up tilting the alternator out of plane with the crank pulley.

I ended up using only top-of-the-line Goodyear or Dayco or Gates belts. The $5 specials at the chain parts stores will not last well. Finally keep the belt really tight, and retighten it after the first 20 miles or so.

And finally, plan on changing the belt every two or three years as a precaution against one going bad at the wrong time, in the wrong place.

[mstockton]

Ummmm guys?....if this is a 6.5 and its crank pulley is vibrating, doesn't that mean that it has a dampned pulley that's gone bad, or the balancer it bolts to is bad some how, which may lead to a crankshaft failure? Anyone?


The only thing I've noticed pulley-wise that doesn't seem right is that the crank pulley has a nasty vibration to it - with the engine running, it looks substantially out of round. Is there a dampener in there that may have gone bad?

Just trying to make sure this guy doesn't end up with a problem later....

[thesameguy]

That would be interesting if it does.

The truck has more or less stopped eating belts since I "adjusted" the alternator mount.

However, I've noticed an increasing frequency of screeching from the engine. I assumed it was a belt slipped badly, but it sounds to me like a harmonic balancer that's giving up the ghost. I didn't realize there was one on this truck, but if there is, that might explain both the screeching and the occasionally intermittent power steering... :)

Is there a dampener? What's a good source for a new one? And, shouldn't they last more than three years?

[mstockton]

I just bought mine from NAPA, but I'm going on a budget, I would guess a GM damper would be best, and the pulley should be bolted directly to the balancer. Perhaps the outer ring is smacking the pulley sometimes, i don't know, but it don't seem good, you should be able to see it from the underside i would imagine. Hope this helps

[britannic]

I'm biased, but I have to say that the NAPA balancers are excellent - I know because I've been able to compare a GM new one to one of ours out of our stock.

[gmctd]

The later v-belt accessory pulley is also rubber isolator\dampened - the rubber shifts, alowing the pulley to clack against the hub.

Time for a replacement................

[thesameguy]

Alrighty then ... looks like it's off to NAPA. Hope their pulleys are better than their fuel return lines (which leave you stranded in the middle of Central California three months after you install them). :D

[thesameguy]

Okay, here's a winning problem: The boys at NAPA can't find the harmonic balancer without referencing it to a vehicle first.

Can anyone give me an example of something that would have a 6.5l NA in it?

Thanks!

[EWC]

95 Chevy G 30 van with Y engine