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View Full Version : V-Belt advice, recycled.



CleviteKid
09-01-2003, 10:36
With the loss of archived posts, this advice may be worth repeating - for the "Over-the-Hill-Gang" trucks (1982-1987) with multiple V-Belts.

The V-belt advice is: Keep 'em tight, and change 'em frequently.

Also, check alignment of the pulleys; I had to shim my alternator's mounts to align it properly with the fan and crankshaft pulleys to get acceptable belt life. I now change the alternator belt yearly, and use a GOOD belt, like a Goodyear Gatorback (Autozone) or a Dayco Top Cog (Advance/Discount Auto) and pull it TIGHT to prevent slipping. If it even STARTS to slip, it will glaze and will not function properly at high alternator loads, and you will need a new belt. Retighten a new belt after 25 to 50 miles of use.

Last week I was driving back home from a little late-night session of checking my 2-3 shift point on my new 700R4 (3700 rpm, I want it to be more like 3500 rpm) and was 2 miles from home, and as I took off from the traffic light (conservatively for a change) I heard CLANG BANG BANG under the hood, and all of the sudden my power steering was VERY tight. Knowing that the HydroBoost brakes are also powered from the PS system, I tested the brakes, and found it took a lot of push for very mild deceleration. Hmmmmmmmmmmmm. What else ??? The A/C was blowing warm air, so I switched it off (a major concern in the summer in Miami) and the temperature gage was climbing toward 220 F, and the voltage was dropping, and the lights were getting dimmer . . . . but everything else was OK ! ! !

I made it home, and used some spare muscles to horse my truck aroung the curves, and slow it down, and to make the right-angle turn into the driveway.

When I shut it down and popped the hood, one belt was shredded and the other two were off their pulleys and hanging around the fan. I suspected that the alternator belt had let go and pried the other two off, but when I got into it the next morning, it was the A/C belt that had popped, and the PS and alternator belts were the innocent collateral damage.

So - if you have one of the older trucks like mine, keep the belts tight, inspect them for signs of degradation, and plan on changing the belts and the hoses on a regular basis, and hope you are only 2 miles from home if you DO have a problem. By the way, I do carry a complete set of three spare belts all the time in case I am farther away from home when such bad Karma chooses to strike.

Dr. Lee :cool:

britannic
09-01-2003, 13:55
In addition to Clevite kid's excellent advice, whilst it's important to keep the belts tight, they can be adjusted too tight and cause damage to bearings etc.

If you have a belt tension gauge or a spring balance measuring up to 200lbs, the adjustment would be:

New alt. belt (before operating engine): 146lbs
New/old alt. belt (after running engine): 67lbs
New PS pump belt (b.o.e): 146lbs
New/old PS pump belt(a.r.e): 67lbs
New a/c compressor belt (b.o.e): 189lbs
New/old a/c compressor belt (a.r.e): 67lbs

Another way to adjust the belt without a gauge is to tighten until you get about 1/4" of deflection when pressing down hard with your thumb halfway between pulleys spaced 7-11" apart, and about 1/2" between pulleys spaced 12-16" apart.

None of this applies to serpentine belts or course, because they are automatically tensioned :D .

[ 09-01-2003, 10:56 PM: Message edited by: britannic ]

CleviteKid
09-01-2003, 16:13
I use the "Thumb Pressure" method described by Britannic. I have never been able to put TOO MUCH tension into my alternator belt, and I have a custom prybar I made that goes thru the hole in the bracket and against the side of the alternator, and just touches the bottom of the open hood. I yank as hard as I can on the bar with my right hand, and tighten the adjustment bolt with my left hand, and end up with exactly ;) the thumb measurement recommended by Britannic.

The PS and A/C used to be a real pain-in-the-belt until I invested in the threaded expander that goes between the pulleys and pushes them apart.

Dr. Lee :cool:

mhagie
09-01-2003, 19:59
Dr Lee, I read the article by Jim Bigley about torsional dampers, and since the donor 83 blazer I used had the upper rad hose practicly worn thru by the a/c belt vibrating against it I decided to try the newer style damper and now there is squat for belt vibration.
Of course for the bucks there should be a difference.
Oh yes I am about to look for the spreader as it is a PITA to adj the p/s belt. :mad:

78Chev
09-02-2003, 08:35
Dr. Lee:
Do you know the part number for the damper pulley for an 82 era engine? MP had posted them at one time but they seem to be gone now. One damper that I looked at at my local GM dealer had all 3 pulleys the same diameter. My stamped pulley has the inner A/C and P/S pulley's smaller than the outer Alt pulley, which looks like is necessary to clear the turbo crossover (Banks).

Also, does the damper style pulley help reduce belt groaning and moaning? I've got official GM belts on order. Thanks.
Randy

CleviteKid
09-02-2003, 12:09
Sorry, I do not know the part number, but my 1984 has the same pulley you are looking for, larger pulley for the alternator belt, smaller for the PS and A/C, and no, you can't have it.

With my belts properly tightened I don't see any particular belt flop. And the damping layer in the damping pulley is one more thing to keep an eye on, lest it go bad and screw something else up.

Dr. Lee :cool:

Eric Deslauriers
09-02-2003, 13:02
78 Chev,

But you might have my extra. I'll check it this evening and see if it's what you need.

Eric Deslauriers
09-02-2003, 13:12
78 Chev,

But you might have my extra. I'll check it this evening and see if it's what you need.

78Chev
09-02-2003, 13:29
Thanks, Eric.
Randy

mhagie
09-02-2003, 20:30
Randy,Go to the members section and read the article by Jim Bigley titled Torsional Dampening it is good reading.
The part # is 15592125 it is shaped exactly the same as your stamped steel pulley.
After reading the article I personaly was sold on the dampening pulley, for instance for the engineers to come out with this change in the 85 model year and also make one to fit the 82-84 model years implies to me that they took its value quite seriously other wise they would have made it 85 up.
True its just another damper to keep an eye on but to me no big deal I'll just change em both at 100K for insurance anyway. :D

78Chev
09-02-2003, 21:10
mhagie:
I knew I saw the number somewhere; thought it was in the forum but you are right it's in one of the DP books that I own! Thanks.
Randy

Eric Deslauriers
09-03-2003, 09:48
Randy,

I unexpectedly got home quite late last night. I'll check this evening. Sorry for the delay.

78Chev
09-04-2003, 09:36
Thanks Eric. Did you get a chance to look at the pulley?
Randy

Fumes
09-14-2003, 20:25
So what is different with '85 damping pully than a pre '85? Can they be interchanged?

mhagie
09-17-2003, 09:18
FUMES, WITHOUT HAVING SEEN A 85 I WOULD GUESS THEY CHANGED DIAMETER ON ONE OF THE PULLEY GROVES
REFER TO THE ARTICLE ON TORSIONAL DAMPERS IN THE MEMBERS SECTION.

Eric Deslauriers
09-19-2003, 14:18
Randy,

Sorry for the delay, had a friend pass on, then wife had chest pains. Finally winding down. Whew.

That said, I have a pulley w/ 3 Vs in it. My memory's going, but one of them was larger than the other two (or vice-versa).

Let me know -> eric at lvmt.net

78Chev
09-19-2003, 14:39
Eric,
That sounds like what I need. The outer pully (alternator) is bigger than the PS and AC pulleys. If you want to email me at knuthr at comcast dot net we can talk terms. Thanks again.
Randy