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Alt. belt squealing ---

diesel4me

diesel4me

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I noticed something when I start my '85 Burb (6.2) up --when the fast idle is working after a cold start,the dam altenator belt squeals like a stuck pig for the duration of time the fast idle is "on"--soon as it shuts off and lets the engine go back to normal idle speed,the squealing stops--and wont return even if I rev it up ,so I asume the belt isnt slipping,U've adjusted it and tried a few different types of belts,a few seemed to not squeal as bad but they did not fit well in the pulleys and one got launched...so I'm back to the correct Gates # belt,the one that squeals the loudest..

I'm wondering if the fast idle solenoid is drawing too much juice??--seems like it drags the altenator down a lot until the engine warms up and it shuts off the fast idle...I haven't looked to see of its fused or not,I'd asume it is,and would pop the fuse if its drawing excessive amps??..
Anyone else notice their alt. belt squeals after a cold start ??...My '82 pickup with a 6.2 doesn't do this,but I'm pretty sure the fast idle isn't working on it too,it never has a fast idle ,nor do I hear a drop in idle speed after it warms up...
 
Tighten that B***h down. Mine when mine starts squeelin, I just get it a little tigher and it goes away till the belt stretches some more.
 
you have a serp style belt without a tensioner like me then? In the vbelt styled configuration? On my 86 it squeals like you describe, gasser motor, and ive got it to the same tightness I do my v-belt style with just a little play, but im ready to just torque that thing down. So annoying starting up my truck and having it squeal on me. AC belt on my 83 needs tightened too.
 
I just crank mine down and keep a few spares in the glove box.
 
Cranking the snot out of them can make them too tight which then glazes them and the pulley and the problems continue until and after the belt breaks.

I played hell with the V-belts on my older Trackers. They're a crappy setup and squealing is common on them.
 
I get the same from mine when I start it up. Has always done it, even with new belts and pulleys. Also if you go to tight you can burn up the bearings in the alternator.
 
Tighten them and use belt dressing. The truck hardly needs any power at all to run... just recently I learned just how far you can go without an alternator :haha:
 
My 83 with the 6.2 does the same. I have my HPCA on a toggle switch, it squeals a little until I toggle the HPCA off. It will be quiet, except for everytime the GP's cycle on...then it squeals again.

It's been enough of an issue I have partially stripped the hold down hole on the alt. I had to thread a stud into it to find some good threads and carefully tighten it down with a nut. So far it's holding.

i think the alt's on the 6.2's need some sort of viscous damper on the pulley...it's the separate ignition event spikes that break the alt belts traction.

Rene
 
I'm leery of tightening the belt too much--I dont feel like changing a water pump om a 6.2,it looks to be a nightmare--(even if it were easy it wouldn't be for me!)...

So Rene,yours does the same thing with the HPCA on huh??....my Burb had it wired to a manual rocker switch on the dash next to the glow plug push button someone wired in,but it wasn't working--when I put the original wires back on the IP ,it started working normally,so I just left that switch dissconnected....no need for a "manual over-ride" on it really....

I tried using a kevlar belt on it,a 1/2" x 48" I had kicking around,but it was well used and it had a twist in it from its former application,and though it did run silently,it didn't stay on long before it flipped over and shredded itself--was lucky it did not trash my new radiator or de-rail all the other belts..it rode a bit high in the alt. pulley,but I bet if I had used a new one it wouldn't have had any issues...it never squealed with that belt on it..I noticed the altenator is a NAPA rebuilt and the pulley looks very glazed and worn,and the Gates belt I now have back on it rides right on the bottom of the pulley groove,which of course adds to the slippage...

I'm almost tempted to put a spring loaded idler pulley on the Alt. belt,like a lawn tractor would have,to keep constant tention on the belt--you definately can see the belt "flapping" every tinme a cylinder fires no matter how tight it is...maybe an idler would absorb the impulses and keep the belt tight??..

I had the joy of the threads in my altenator adjusting bolt strip too--must be a diesel thing!..now adjusting the belt requires 3 hands,I had to put a bolt in the hole ,with the head facing the firewall,and use a washer and nut on the front side now...:(

So,I assume the HPCA draws quite a few amps whens its solenoid ie energized??...seems weird it dont blow a fuse if its drawing enough to make the belt slip & squeal,its almost like a semi dead short curcuit!...maybe I'll see if I can get the HPCA to work on my pickup and see if its belt starts screeching too..that truck has always started good even in the cold without it working--maybe someone cranked the IP timing up and didn't want any further advance,that engine seems peppier and more "crackly" than the Burb dies..
 
I wouldn't think the HPCA would pull any significan amps. The belt squealing and high alternator load are more likely due to simply charging the batteries back up after running the glow plugs and starting the engine. Those two items would cause way more drain than a single little solenoid. Plus you have increased engine speed which would also contribute to the higher load and belt slipping and letting it continue to slip. The stopping of the squealing is also probaby a function of the engine speed decreasing when the HPCA qucks off and idle drops, versus a reduction in amps.
 
Thats what I thought--till I raised the RPMs up past the speed it was running at with the fast idle on,and the squeal never returned ,even if I floored it....I can see the batteries being in need of a healthy dose of amps right after draining them with the glow plugs and cranking it quite a bit to get it started,but I find it very coincidental that the squealing vanishes as soon as the HPCA kicks out!...maybe I'll try unplugging it and see if it acts the same..

.seeing a different belt silenced it also,I am leaning towards it being slippage or the altenator pulleys condition might be to blame...the thing squeals so loud now I thought at first the altenator had seized up!..but its silent the monute the HPCA shuts off...
 
I had the same problem with my 84. I was replacing the belt every 10,000 miles or so, using only top grade Gates belts and with tension that made me fear for my water pump. I finally figured out that the pully was glazed and I took off the beltand took my Dremel tool with a small stone to the pully grove. I roughed it up pretty well with a series of lateral strokes as far down as the little stone would go. I put on a new belt and tighten is "normal" and I haven't had any problem since.
 
I had the same problem and did a couple things .While the engine was running I held a file to the pulley .Second I found a belt that didn't go so far into the pulley . i found that helped more . sometrimes the pulleys get wore and the belt rides too deep and hits the center of the V
 
Yeah,I found using a 1/2" belt eliminates the squeal but it can also want to ride too high in the pulley and possibly flip or come off...I think what I'll try is a Dayco belt ,instead of the normal 15480 number that is 15/32" x 48" I will try a 17480 which is 17/32" x 48" and see if it sticks up above the pulley any--the Gates 7480 on it now is hitting bottom,probably from being worn down every time ir squeals...I think my pulley is glazed badly too,maybe I'll try to deglaze it by sandblasting it--or just get a better one..too bad I cany use double belts,I have a double altenator pulley but I doubt you could find a water pump one to match it..
 
diesel4me said:
Yeah,I found using a 1/2" belt eliminates the squeal but it can also want to ride too high in the pulley and possibly flip or come off...I think what I'll try is a Dayco belt ,instead of the normal 15480 number that is 15/32" x 48" I will try a 17480 which is 17/32" x 48" and see if it sticks up above the pulley any--the Gates 7480 on it now is hitting bottom,probably from being worn down every time ir squeals...I think my pulley is glazed badly too,maybe I'll try to deglaze it by sandblasting it--or just get a better one..too bad I cany use double belts,I have a double altenator pulley but I doubt you could find a water pump one to match it..
Click to expand...

You got your finger on the issue, it's the alternator getting overloaded after cranking, glow plugs with the added drain from the fast idle relay, and since after it warms up it also would have topped off the battery, even if you rev it at that point it wouldn't squeal.
Solutions: either a wider belt.
or double pulley,
or a bigger alternator and bigger battery because if the battery is bigger the drain would be less percantage wise and wouldn't draw as much from the alternator, and if the alternator is rate higher, it wouldn't starin when it's at half capacity.
But if you can find a double pulley setup, it would still work out.
I like having things comfortable so would go bigger.:waytogo:
 
Just chiming in, my alt is also stripped, Ive used a longer bolt, two washers and a split washer before the nut, no problems now. Otherwise, I marked the thread for future reference, good info here on the pulley and glazing.

Andrew
 
Ok Gents, its been about 15,000 on the current alternator belt, and it is just starting to squeel again. Tomorrow I'm gonna take a picture of the belt in the alternator grove and see how deep it has sunk. I will also check tension and probably go get a 17/32" wide one if it looks fried. I am also thinking serpentine conversion at some point... Since I have an 84 with AC, I would have a lot of belt driven things to replace. My water pump is at 50K so I know this all has to come off at some point... Anybody done this conversion?
 
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