v-belt question

[grumpyman]

i've tightened my alternator belt a couple of times and i think i've gotten it tight enough
my question is this...how much flapping should i be seeing on the part of the belt coming up from the bottom pulley to the alternator , the rest of the belt doesn't seem to have this flapping...could this be a sign of a bad crank pulley
i'm gonna tighten it up again tomorrow and see what happens

[ccatlett1984]

look at the crank pulley while the engine is running, does it wobble a lot?

you should have around 1/2" of flap as you call it in the middle of the belt

[john8662]

The early pulleys had more of this wabble of the belt. Some belts are better than others and retaining their shape, regardless of the vibration.

The 82 through Early 85 models had the stamped steel pulley, less belt life, like you're witnessing.

The Later 85 and up used a crank pulley that is dampened, the belts don't wabble near as much on these.

So, if you've got the early 6.2 with stamped steel pulley, then I'd say what you're seeing is normal.

The best belt (in my opinion and GM's) is the Dayco Top Cog belt, it was the OEM belt used.

J

[grumpyman]

i'm not seeing much wobble in the pulley i'll feel around behind it and see if it's got the rubber bit back there while i'm tightening the belt again

just for the record the pulley does not have a damper , it bolts to the torsional damper which has the damper or do they both have dampers?

[john8662]

All 6.2's have a harmonic balancer, some have an normal pulley mounted to the front of the balancer, and the later have a more complex pulley that's isolated with rubber, it's a damper by itself.

Again, the belt vibration at idle with the early pulley is normal.

J

[grumpyman]

the rubber at the back feel like its old and cracked, time to replace
am i stuck with the stamped pulley in front or can i use the later version??
of to napa now to see what they got

anything else to do while i'm replacing this part??

[john8662]

My recomendation is to keep your stamped steel pulley, it can prolong your engine life.

The replacement pulley can and will fail over time, leading to an out of balance condition on the front of the engine, which can shorten the crankshaft's life.

For the replacement balancer I can only recommend two manufacturers. OEM General Motors, or a Pioneer Balancer, sold at many chain part stores (and more.

J