Belt Squeak

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imjohnny

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I have been working on the burb and have an issue. Wanted to replace the belts. I bought the same belts that were on it when I bought it....but none of the 3 belts are actually listed as belts for this truck. I have a 77 350 5.7 with the 3 belts. But considering it was running great and quiet I bought the same belts to replace with. Everything is working, but I now have a squeak/chirp coming. Can't find definitive information on which belts I need. I am not even sure if my belt routing is correct. It is just what was on it when I bought it. I have also noticed the accessory drive pulley with 3 belt spots isn't spinning straight. Has a little wobble to it. Can't seem to find that pulley anywhere. Harmonic balancer is spinning straight and true, but that pulley mounted to the front of it has a wobble. Seems like that could be causing my chirp.

Current routing is:

Belt 1 - AC, Power Steering, Crank
Belt 2 - Power Steering, Waterpump/Fan, Crank
Belt 3 - Alternator, Waterpump/Fan, Crank

Here are a couple pics for reference.

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Trying to find what belts and routing I should be running, and if anyone knows where to get that pulley from? Appreciate any help.
 

Snoots

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Belts should be just a hair above or even with the pulley and have no more than 1/4" stretch/slack.
IIWM, I'd check the bolts on the bottom pulley before going to the dealer to buy a new bottom pulley.
 

fast 99

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Belts appear to have been sprayed with dressing? If so, all the belts will have to be replaced, pulleys cleaned.

A bent pully will also cause noise sooner or later. Get the part number off the pulley, do an internet search. GM probably made a million of them.
 

imjohnny

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Pulled the pulley off, and it was a little wonky looking. Like the back of it has just a slight warp to it. I am going to replace it. But the problem is, I can't find it. It has 3 grooves, but 1 is larger than the other 2. I can find one that has 3 identical grooves new, but the one with 1 larger groove doesn't look like is made anymore. Can get a used one on eBay, and there are a few online people that have them old stock, but a longer wait. So I think I will replace it with the 3 identical grooves and adjust the belt size. While I am there, I couldn't tell if the harmonic balancer was contributing to the wobble, so I am gonna replace that too....so I pulled that off as well. Looks to be a very old one, so it is a little preventative maintenance anyways.

Here is my question.....can I replace the crank oil seal on the timing cover without removing the cover? It is weeping a little oil. Not tons, but figured if I can pop a new one in I would do it while I am there. Looks like I can, just wanted to see if that is possible. You guys like the idea of the switch to the newer style pulley?

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fast 99

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Just had an epiphany. The 2 groves on the crank are different diameters. Those 2 belts are running on a single sized water pump pully. So, in other words, the crank is turning the belts at different speeds on water pump pully. One belt has to slip.
 

fast 99

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Here's pictures of a non-ac 81. Water pump belt groves are not the same diameter.
 

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imjohnny

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Just had an epiphany. The 2 groves on the crank are different diameters. Those 2 belts are running on a single sized water pump pully. So, in other words, the crank is turning the belts at different speeds on water pump pully. One belt has to slip.
You are totally right. Wow, I feel so dumb now. It's obvious, but I just never caught it.

When I picked her up, only one of the belts was on the water pump. The alternator belt went up there. But the power steering belt was shorter and didn't go up there. I wondered why it had an empty groove on it. When I put new belts on I bought a longer one to make sure it routed up there. That was my problem. I am wondering if someone put a different pulley on the crank at some point. Or did it come from the factory with an empty groove on the water pump pulley? Either way, I am getting the new pulley that has all of three grooves the same size. So that should take care of that issue right? I would prefer to have all the grooves in all the pulleys being used like they should. Just looks weird under there when it isn't. If they are all the same size that should eliminate that part of the problem.
 

fast 99

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Reason the outer grove on crank is larger is to spin the alt up. That is correct. Get a replacement water pump pully and crank pully if it is bent too much.
 

imjohnny

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Reason the outer grove on crank is larger is to spin the alt up. That is correct. Get a replacement water pump pully and crank pully if it is bent too much.
Do you think dropping it down on the alt belt is gonna hurt me any?
 

imjohnny

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Yes, it will lower alt output. Fix it right.
What would be the right fix? It had all the belts routed that same way originally. I think the lower crank pulley was changed at some point. Anywhere I look it lists the pulley with 3 identical sizes as the correct one for my year and engine. No one even makes the one with 2 different sizes. The only one I can buy that isn't used is the one with all same size grooves. The water pump pulley looks original to me. So it originally had two belts on it. Just trying to figure out what the correct fix could or would be.
 

RanchWelder

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This concerned me as well. The 87' has the serpentine 6 rib, without the idler wheel, and 2 regular belts for A/C and PS in the rear of the pulley. I eliminated a/c. The lower pulley is very hard to find.
Most cheapo kits are crap or very expensive from Marsh. The PS fix brackets are not strong enough for off road, from fleabay... they flex badly and do not align...

This pulley set uses the long water pump. The water pump pulley has the 6 rib, for grabbing the alternator and 1 v-belt for the PS. I have not tried to add a/c to my system, and I'll bet it could be done with some mods... or adding a compressor for on board air... never tried it though.

Deleting the A/C caused a missing bracket with headers and the PS pump had no back brace and would squeal due to bending under load. My PS is press on... not the old threaded style. in 87' they went to the 14mm ps fittings at the pump...

Instead of buying a kit I made a plate that bolts on the head and used the POS bracket from an old Chevy... (Secret Sauce...) This allows headers and PS to line up correctly. AC Delete.

If you click my profile and find my welcome page, the pics of the plate and the style PS tensioner are there. You'll have to zoom into see the alt tensioner I make.

You'll see the alt has the wheel for the 6 rib, which is significantly better for turning the high amp alternator, and why GM wet 6 rib on only 1 pulley wheel section, in 1987. I had to pull my old 6 rib wheel for the alt with an impact wrench and re use it on my 200a alternator.
It's the adjustable voltage charge version, you'll need if you ever swap to AGM or Lithium batteries, because the stock alt will kill either of the new batteries by charging at the wrong voltage...
This is very important for anybody buying newer batteries^^^^^^^^^^^^^^^^^^^^

Make certain you tighten it up with an impact, or it will go flying... The alt wheels are different sizes, and why fast99 said fix it right...^^^^

It has to be the correct diameter for charge ratio and proper current or **** will burn up...

You really have to get the correct size alt pulley... I can measure mine if you are going to ask one of the vendors for 87 pulleys... so they can find you the correct set.
Most people throw them out when they go serpentine, reverse water pump or buy the Marsh for a custom rod, so they are around...

Maybe one of the parts sellers here can locate you an 87 lower pulley, the h20 pulley and a six rib for your alternator, with the correct diameter and then you'll have enough ass to pull the amps your 140-200 amp alternator requires... no more squeal... stock looking pulleys and a lot cheaper than Marsh..?.

Ditching the old pulleys will solve your problem. Marsh makes a kit that actually works. Not all aluminum pulley kits can be trusted... Cheapest is $389 for what you need...
Post a wanted ad or find a parts stripper here for the one's I mentioned... if you can buy the OEM 1987 set, email me for the plate you'll need.

Check out my mod:
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This allows you to do the one thing almost every aftermarket kit will not do:
Re-use the metric PS pump with the press on pulley. Only Marsh offers you the ability to do this and it's not cheap. This allows you to use the stronger bearing and seal the metric pump offers, rather than the smaller bearing the threaded pump takes you back in time with, using the old style PS pump.
GM improved the pressure system when they went metric. This is why the high dollar pumps are so expensive, they merge the technology with screw threads and upgraded bearings. $$$


The pulleys line up perfect. Exact alignment for every belt. No BS.
The press on pulley for PS just needed a lil' extra using a socket to get that extra 1/8" on the PS shaft.
It came out very well. It took me months of anguish and research to come up with this... It saved me hundreds in aftermarket parts overall. "Zero Squeal".

How's the name sound for the kit?

-Welder
 
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RanchWelder

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Here's a shot from the alternator side...
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You re-use your lower alt bolt and spacer...
If you look close at the first pic, you even have the pulley number for the PS unit you want!
 
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imjohnny

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This concerned me as well. The 87' has the serpentine 6 rib, without the idler wheel, and 2 regular belts for A/C and PS in the rear of the pulley. I eliminated a/c. The lower pulley is very hard to find.
Most cheapo kits are crap or very expensive from Marsh. The PS fix brackets are not strong enough for off road, from fleabay... they flex badly and do not align...

This pulley set uses the long water pump. The water pump pulley has the 6 rib, for grabbing the alternator and 1 v-belt for the PS. I have not tried to add a/c to my system, and I'll bet it could be done with some mods... or adding a compressor for on board air... never tried it though.

Deleting the A/C caused a missing bracket with headers and the PS pump had no back brace and would squeal due to bending under load. My PS is press on... not the old threaded style. in 87' they went to the 14mm ps fittings at the pump...

Instead of buying a kit I made a plate that bolts on the head and used the POS bracket from an old Chevy... (Secret Sauce...) This allows headers and PS to line up correctly. AC Delete.

If you click my profile and find my welcome page, the pics of the plate and the style PS tensioner are there. You'll have to zoom into see the alt tensioner I make.

You'll see the alt has the wheel for the 6 rib, which is significantly better for turning the high amp alternator, and why GM wet 6 rib on only 1 pulley wheel section, in 1987. I had to pull my old 6 rib wheel for the alt with an impact wrench and re use it on my 200a alternator.
It's the adjustable voltage charge version, you'll need if you ever swap to AGM or Lithium batteries, because the stock alt will kill either of the new batteries by charging at the wrong voltage...
This is very important for anybody buying newer batteries^^^^^^^^^^^^^^^^^^^^

Make certain you tighten it up with an impact, or it will go flying... The alt wheels are different sizes, and why fast99 said fix it right...^^^^

It has to be the correct diameter for charge ratio and proper current or **** will burn up...

You really have to get the correct size alt pulley... I can measure mine if you are going to ask one of the vendors for 87 pulleys... so they can find you the correct set.
Most people throw them out when they go serpentine, reverse water pump or buy the Marsh for a custom rod, so they are around...

Maybe one of the parts sellers here can locate you an 87 lower pulley, the h20 pulley and a six rib for your alternator, with the correct diameter and then you'll have enough ass to pull the amps your 140-200 amp alternator requires... no more squeal... stock looking pulleys and a lot cheaper than Marsh..?.

Ditching the old pulleys will solve your problem. Marsh makes a kit that actually works. Not all aluminum pulley kits can be trusted... Cheapest is $389 for what you need...
Post a wanted ad or find a parts stripper here for the one's I mentioned... if you can buy the OEM 1987 set, email me for the plate you'll need to fabricate.

Check out my mod:
You must be registered for see images attach


Willing to fabricate a set for you if you like. My post count is not high enough for selling yet, but after it is, Was thinking about fabricating the plate, tensioner and PS bracket as a kit and selling them here... If you have accessory holes, this will work. You can also use a thread post alternator, however it may require additional shims to line PS pulley up. Have not tested one out yet...
The gold plate requires special care when installing...

The pulleys line up perfect. Exact alignment for every belt. No BS.
The press on pulley for PS just needed a lil' extra using a socket to get that extra 1/8" on the PS shaft.
It came out very well. It took me months of anguish and research to come up with this... It saved me hundreds in aftermarket parts overall.

-Welder
Mine is the 77 though, not an 87. No serp belts, no ribbed belts. I have the 3 v belt set up. Can't get rid of ac. I am in Florida and with the kids in the car that is not a recipe for success with no air. Haha. Everything is stock on mine including ac and I am not off roading her. So I think the best option for me is to go with the crank pulley that has all 3 grooves the same height (that is a super easy pulley to get from good manufacturers), and see how it affects the power. Luckily, it is a 77, so there isn't much of power being pulled or needed other than the blower motor and lights at night. If the power isn't what I need, I can always swap to a smaller alternator pulley, or better yet, get mine rebuilt to a higher output and put the smaller pulley on it at the same time.
 

RanchWelder

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Here's one retail option:
https://www.amazon.com/dp/B01D0L81RE/

CVF Racing... The rest from Marsh or the HQ Brands are double, triple or more...
I have never used this kit.
Look closely when shopping, most DO NOT COME WITH PULLEYS.
They sell separately...
Never used them... contact them for fitment

Post edited for clarity and accuracy...
 
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