Belt-eating Duke

[dguy]

Kitten's car... not mine.

For the two years it was in there, the 84 drivetrain would go through roughly one v-belt per year.  The 86 drivetrain can kill them faster than that; I doubt that there are more than 3,000km on the current belt.  I may even have to change the bloody thing in the parking garage before leaving the office today.   

The only component in common between the two drivetrains is the alternator & the lower alternator bracket.  I upgraded the 84 to a CS-130 at one point during its life, and the 86's original bracket snapped when I made the transfer to the 86.  I was suspicious that a slight difference in the lower bracket may have been contributing to pulley misalignment, but the 22P confirms that the lower bracket went unchanged rom 84 through 86.

I don't recall noticing any elongation of the bolt holes in either the bracket, or the alternator body when I performed the transplant.  The upper bracket does not appear to be loose or allow any play.

Pulley alignment is straight & true as far as I can tell by eyeball.  A new belt will have no obvious curve or tangent in the transition from "free space" to where it contacts the pulley.  I have yet to verify it with a straight-edge however.

Pulleys are clean, dry, and undamaged.  I don't do belt dressing.

Not sure how relevant some of the following is given that some of the observations may be the result of the currnent (worn) belt, but...

• Polished areas on both the crank and alternator pulleys indicate that the belt is making good contact across both sides of the V, although it has always sat a little deeper in the grooves than I care for.
• Polished areas on the water pump pulley suggest that the belt is only making contact at the upper edges; i.e. at its widest part.

My current suspects, not in any particular order, are:

• I've been consistently provided with belts of the wrong size.  Current one is a 11AV1270 Gatorback; considering tracking down a 12mm wide belt for shits & giggles given my dislike of the "installed height" of a 11mm belt.
• There is some serious pulley drag going on.  Doubt it.  The only pulley which doesn't spin freely by hand is on the crank.    Not to mention that I would expect charging or cooling problems should either the w/p or alt. be showing enough resistance to constantly drag on the belt.
• One or more bad pulleys.  I have NFC how to verify whether or not they're correct at the moment.

Insight, ideas, even some simple pointing & laughing in my general direction is appreciated.

[Kevin]

  I used to have problems with my belt as well when I first got my Fiero. One of the first things I clued into was the state of the pulleys which I sanded as they ran, not smart but the ones on mine were bad. Get a good quality belt, I used to get mine at CTC then I got one from GM and will never go back. Check your belt alignment, when I first started to play with this I kept snapping belts I finally figured out there were two grooves on the crank pulley just make sure you have it on the right one having the belt run in a straight line will make it last longer (go figure). I hope this helps, it has been a while since I have played with belts, if anything else comes to mind I will let you know.
    Kevin

[2ML67]

Sounds strange and part numbers will call me a liar but I have found differences between 84 and newer water pumps, as far as pulley alignment goes. Bought an 84 years ago for next to nothing because they couldn't keep belts on it among a few other small problems. The water pump was a new after market one. I put on one from an old 84 engine I had stripped and problem was solved. Of course using my kind of logic this would be a good reason to upgrade to a l67 or maybe even a "N". Dan

[GoFast88]

or maybe even a "N". Dan

Sounds like heresy to me. You loosing it Dan?? 

[dguy]

Sounds strange and part numbers will call me a liar but I have found differences between 84 and newer water pumps, as far as pulley alignment goes.

That wouldn't surprise me, actually.  I can only guess as to whether or not the current water pump is the original.     One of the benefits of obtaining it from a donor car which had been abandoned in someone's back 40...

Though I did discover one thing...  the 11AV1270 belt is not 11mm wide; it's 9.5mm.      I could swear that once upon a time when I was working in a dealership parts department that belt #s were an indication of width & length, but apparently no longer.   

Oh well... double checked the condition of pulleys, mounting brackets, etc. last night, and installed a new belt.  Seems that when I thought it was riding low in the w/p pulley it was really just one badly worn spot on the old belt.  The new one seats in the grooves where it should.

...and Kitten now knows how to change/re-tension a belt.    Gonna toss a spare belt & a couple of tools in the trunk as insurance, methinks.  Though Murphy's law says that once I do that, it'll never be a problem again.