Hello Olds-forum!

Been reading for some time here, and gotten lots of great help. Appreciate it tremendously. Norwegian, so excuse my errors.

The day has come when I've encountered a problem that has me stumped. Hoping for some advice.

I have an Olds 350 (Vin-R engine, late 70s). The engine unfortunately does not have its original water pump pulley or alternator bracket, but everything lines up. My problem is this:

My drive belt keep slipping on the waterpump pulley (going to the alt on the passenger side) no matter what the tension (slack to tight) I put on it. The result of this is that the water pump pulley gets extremely hot very fast, and after a short driving period my belt literally disintegrates because the heat.

The belt is brand new (gone through a few before I found the culprit). The width of the belt is 9,5 mm (3/8 inches) at the top.

So - what to do? Do pulleys become worn out? Wrong belt size? Doesn't seem logical, but what do I know.

Thanks for any help guys.

Tommy

 

Pull the belt off and make sure everything spins freely. Also make sure your belt is the right one. Perhaps your replacement pullys are to wide for that belt. If all that checks out perhaps you've already stretched it to the point where it slips to far down into the pully.

 

Welcome.

Don't worry about "errors" - your English is perfect.

I, and I suspect all of us here would like to offer our sympathy regarding recent events.

I suspect that your belt is too large because the pulley is not original. You need to get one that will just snap onto the pulleys when the adjustment is as close as possible, and then tension it as necessary. I'm not home right now, but if you need me to, I can translate the part numbers of the fan belts, so you can pick the right size.

- Eric

 

Your sympathy is much appreciated MDchanic. What a shock to us all

Back to the problem:

Everything spins freely with the belts off. No resistance anywhere. The belt is brand new as stated. I stumbled upon someone saying that if the belt is too narrow, it will "bottom out" in the pulley, resulting in massive slippage.

My belt is not too large. In the past I've used (wrongly I might add) 13 mm wide belts, and these will be slightly raised above the grooves and getting "worn" down on the sides where the excess width is. All my pulleys seems to have the same width as far as I can tell.

So maybe I have too narrow a belt, bottoming down? I've not been able to track down the correct width number for my engine (the crankshaft pulley is probably not original either anyways). How does one measure this?

Tommy

 

It would be helpful to have pictures, but I doubt that your belt is too narrow, especially if your other belts are the same size and work well.
I would still say that I think your belt is too long - it's probably right for the car as originally made, but wrong for the pulleys that you have.
You need a belt one or two sizes shorter.

... Unless I completely misunderstand...

- Eric

 

I'll get some pictures later or tomorrow, with pulley groove measurement. This engine is unfortunately put together with bits and pieces in regards to pulleys and brackets, but as stated it all lines up and all the pulley grooves look identical in size.

So the alternator bracket is home made, but lines up with water pump and crank. I'm just able to slip the alternator belt onto the alt at minimum distance, and have lots of tension space if needed.

Still can't rid myself of the thought of too narrow belts, bottoming out and not providing decent grip

 

try to clean the belt with alcohol to clean grime off of it also sand the groves with some 180 80 grit paper to give the belt some bite. an old timer told me these tricks and they worked pretty good untill it got grimey again road grime that is . i have deep groove aluminum pulleys now and they squeel too just not as loud. i hope those tips work i know screeching belts can drive a man insane

 

If it was only screeching - my belt gets annihilated by the heat created.

Ok some pictures:

Here we're seeing the waterpump pulley from the drives side of the car. The inside groove is the culprit. Slipping, heating up and belt destroyed. Touching the inside groove is scorching hot, outside is "ambient" temp.



Here is a better overview angle. The inside one going to alternator is getting burning hot:



The measurements on the waterpump-pulley groove is 13 mm deep and 11,5 mm wide.

Belt on now is 9,5 mm wide. 11,5 mm wide belt might help?

EDIT: Checking my service manual that would be a 15/32" belt (11,9 mm). So the groove is probably 11,9 mm as well.

Tommy

 

The belt is too narrow!

 

Could it be the alt. Creating a big draw causing it to spin slower then the rest of the drive system causing your slippage disconnect the alt. See if it changes

 

Did a little test changing the belts around. The PS-belt is in the outer groove in my setup. But to test I removed the alt belt and placed the PS belt on the inside and fired her up. Same slipping problem.

Also tried with two different alternators since I suspected what you did early in the troubleshooting process. No change.

The draw on the alt is also minimal when testing occured since I've turned every electrical draw that I'm able to off.

 

I disagree. They look about right to me.

- Eric

 

They do "bury" themselves somewhat in the groove, leaving some room on the top if you get my meaning. And the measurement of the groove suggest that I might need a 15/32" wide belt instead of the current 3/8".

 

What is the voltage at the battery when car is running? Check with a volt meter.
If the regulator fails and allows excessive alternator output to overcharge the battery, excessive load on alt could be causing belt slippage.

This happened late last year with my 86 Cutlass - belt squealed no matter what. Battery was boiling and alternator got as hot as a pistol within minutes.

The belts should be contaced at the sides only. The bottom narrow side should not touch the bottom pulley floor. Also if the belt sides are smooth, then it is considered glazed and needs replacement. Clean pulley grooves with laquer thinner or solvent on a rag to make sure there is no oil or grease contamination.

BTW, your English surpasses that of many Americans - be proud of it!

 

Thank you for the compliment. Much appreciated.

Testet with two different alternators - one brand new. Both showed same amount of voltage. I would say in the vicinity of 14v (can't remember the exact number, but they didn't stand out either way).

More and more I'm suspecting that the belt is in contact with the bottom of the pulley, and causing my problem. Anyway it's the only thing I haven't tried at this point and it's worth a shot. Will be combing my nearby area for a 15/32" belt monday. But knowing my luck finding the right width AND length is never gonna happen. It's either one or another

 

Thats what it looks like to me! I bet when you switched belts it got worse also. On the top pic it looks like the outside belt is showing wear on the edges.

 

I had a similar problem with my '83 307 Cutlass wagon.
I fixed it by putting a belt on the non functioning A/C, seems like a poor design in the first place to me.
Looks like your car doesn't have A/C though, so maybe that isn't your problem. Just throwing in an idea.
Roger.

 

Agreed, sand all pulleys if they are shiny...100 grit would be ok too. You must be sure all pulleys that the same belt rides in are the same width else the belt will wear out quickly.

 

I'm pretty sure they all are the same width when comparing. I will get a 15/32" belt on monday, sand and clean the grooves before putting it on. Will report back with the results.

EDIT: Had to order the belt - things measured in inches always poses a minor challenge in my neck of the woods. I love my car, but the mix of metric and inches (imperial?) drives me mad beyond description.

 

Ok so here is the much anticipated update (?) regarding the belt-problem.

Fitted a brand new 15/32" belt on today, but problem is still there. Decided to remove power steering belt and ran her only with the alternator belt. Guess what - no more heat generated. Looking closely at my PS belt I noticed a slight misalignment going to the water pump pulley, so I guess the next step will be to try to align that properly.

I'm getting seriously tired of my unoriginal pulley setup. Given me lots of headache for a long time. So - if anyone have a crank and water pump pulley designed to go hand in hand into the sunset, I'm very interested. 2 grooves on both. Measured my water pump length and found it to be about 14 cm long (5 9/14"). I must verify this 100%.

 

Get a shorter belt for the P/S pulley that doesn't use the water pump pulley! Only the crankshaft pulley! No reason the w/p pulley should be with the p/s pulley!
More contact on both c/s pulley and p/s pulley, too!
What you have is 2 belts, NOT the same diameter, working against one another, at different RPM!
The crank pulley does all the driving, the rest are along for the ride!
W/p pulley should be single groove!!

 

Hmm. Not sure if I follow you.

First. It's not possible to relocate the PS-belt to crankshaft only. Quite sure the top of the belt would collide with the bottom of WP-pulley.

And what exactly do you mean by two belts not the same diameter working against each other? Remember I tested without the alternator belt, only using PS-belt. Still getting hot. But when I tried with only the alternator belt - cool as molasses. So there is something happening with the PS to WP- belt. Might be the slight misalignment as mentioned. Haven't found the will to try to fix it yet.

EDIT: Wait a minute! Do you think the difference in the waterpump pulley groove diameter is the culprit? The inner groove has a smaller diameter than the outer. That might just be it! Since the crank pulley is the same in all grooves, but the two on the WP is different, will that make the belts operate at different RPM and causing a conflict? Sounds logical.

 

The two sheaves of the water pump pulley are different sizes?!?

They are NOT supposed to be!

All sheaves on a given shaft MUST be the same diameter. (Technically, you could have different sizes if one belt didn't connect to ANY shafts that the other one connected to, but that doesn't happen in cars, only ride-on lawnmowers).

- Eric

 

Wow.

What a moronic thing to do. I got this pulley from a friend, and he told me it was ok. He knows a lot about cars, but this he obviously didnt know. What can I say? It never occured to me until now when I have pondered every other solution to death. Im just starting to learn about cars. Starting with this tossed salad of an engine.

My face awaits your rotten tomatoes. Sigh. Well now I need to locate a new water pump pulley. Will make a new thread on help identifying the correct ones.

 

That water pump pulley doesn't even look like an olds pulley. Maybe an old 70's buick.
It wouldn't be chev, pontiac, or mopar because those have a wider bolt pattern.

Let me know all of the letter stampings on all of your pulleys, and I can most likely tell you which ones are their mate.

 

They started the different size pulley sheaves, when they introduced the smog pumps on motors.

The larger sheave drove the air pump, and the smaller ones were for alt. and / or power steering.

See? look at that. We are teaching each other.

If you were to take the larger sheave's belt.....shorten it, and just run water pump to the power steering pump, and NOT around the crank pulley.
You may just solve your problem.

 

I have some Olds pulleys here in England, if you have trouble finding one locally I would be happy to help.
They are for A/C equipped cars but should line up on your engine. Anyone able to tell us if I am right?.

Roger.

 

My car had AC once, but it was removed before I got it. Since I've changed the waterpump and quite sure the replacement pump is intended for non AC cars. Wouldn' t that make the pulleys not align?

Doesn't matter to me if the pulleys are for AC, as long as the align with each other and the original PS-pulley bracket. My alternator has room for adjustment.

EDIT: If you have crank and wp-pulley for AC-equipped cars, maybe I just need to get me a new waterpump for AC?

 

That's just it. Since I needed a WP-pulley, we added the smaller bolt pattern to this. Needless to say, I will not be using this again. Feel soo dumb

I have another pulley lying around (Olds - right bolt pattern), but it doesn't align with the crank by a long shot.

I think I have a bag of mixed nuts here - pulleys for AC from SOME car, and pump for no AC.

Will get you the numbers from the water pump and crank pulley. Never taken that off before though. Just four bolts? And where is the number stamped?

 

So that would mean that the AIR belt went between the AIR pump and the water pump ONLY, right, and did not touch ANY other pulleys?

I will admit that I've never heard of anything like that, but I suppose I successfully (and very intentionally) avoided having anything to do with any American car made after 1972 until I got my 2000 Jeep, so I have never actually seen an AIR pump in action .

- Eric

 

A ha. I see what you did.
If the belts align, you may still be able to use it!
As I said, try tying the water pump and ps pump together with a tiny belt.


They are usually stamped right on the front, and you don't have to take them off. Just clean them up well.

 

Allright.

First some pictures:







First two pictures is of my pulleys - from left to right: Crank, Water Pump (the culprit with different diameter grooves), and a second water pump pulley I had lying around. But, there doesn't seem to be a lot of numbers on them. Even after cleaning them with a wire wheel.

Crank pulley:

Marked "DO S" with the "S" under the "DO" on the back inside. 180 degrees from this the marking "H1" appears. Height of pulley is 58,5 mm. Diameter is 187 mm.

WP-pulley with different diameter grooves:

Marked "351680 AA". Height is 70,5 mm, Diameter is 155 mm.

"Spare" WP-pulley lying around:

Marked "LK P" with the "P" under the "LK". Height is 75 mm, Diameter is 155 mm.

Third is obviously my water pump. 14,3 mm long (5,6"), marked #413307

As you can see, my setup is all over the place. But I ain't giving up

Tommy

 

It looks like the sheaves of the two water pump pulleys line up pretty well, and their diameters are the same.

Why not use the "spare" pulley?

Also, wow, those two sheaves on the pulley you were using really ARE different sizes.
I may be ignorant in the ways of late '70's and '80's cars, but I have NEVER seen anything like that.

Finally, most GM pulleys had two character alpha codes (which made it easier for the workers on the assembly line to be sure they were attaching the right part), so two of your pulleys are a DO and an LK. I don't know of any reference for these codes, but someone else here probably does .

- Eric

 

None of my water pump pulleys line up with the crank. But I put a few shims designed for the purpose behind the one I used, and made it line up. The spare pulley however is so far out of alignment of the crank, that no shim can correct it What a nightmare this is. I just need to get my hands on a set that matches up.

In a bind I can take pulleys for an AC setup and just order a new Water Pump designed for AC.

 

Now I understand.

By the way, in the US, as least, a thin piece of metal used as a spacer is a shim. A shiv is an improvised dagger used in prisons .

- Eric

 

Haha - I knew that you know. But something got crossed Fixing it now.

 

The AA pulley is a late 70's Chevy pulley.

The other two....I have never even heard of before.

DO and LK I have never seen as Oldsmobile designations.

What was on your power steering? That might be the only Olds pulley remaining.
AND do you have the 5.1" water pump, the 5.6" pump or the 6.1" pump on your motor?

 

The W/P pulleys I have are designed for the P/S to be driven by one belt and the A/C by another (grooves the same diameter).
The alternator is driven by a third (smaller) groove in front of the other two, it only runs the alternator. Not a great design IMO but that isn't relevant.
When I first got the car I had belt slipping problems which I cured by fitting a belt to the non functioning A/C. As the A/C pumped freewheeled there was little power loss and two belts driving the W/P pulley gave enough grip to drive the alternator without slipping.
This was on an '83 307 powered Cutlass wagon BTW. It's possible the bolt pitch is different to yours, I will measure mine later today and get back to you.

Roger.

 

Thank you Roger.

If I understand the description of your pulley, I can just use the AC-groove for my alternator. This will keep two belts driving the water pump, one for the ALT and one for the PS. The small one in front that you mention will not be used.

 

I haven't checked my PS pump. Didn't occur to me. Always been pretty sure that at least is for an Oldsmobile setup with AC (2 pulleys). Looks identical to what is in my service manual for my engine.

My waterpump measures 14,3 cm from engine to pulley mounting. That equals 5,6" if im not making any mistakes. Stamped # 413307.