'powdering' of alternator belts...

[Pants]

I thought my old alternator was toast (after all, it was 15 years old), but a brand new one is doing exactly the same thing: the belt is snug (and only a month old), but my system is barely charging, or not charging at all, but the belt is squealing and heating up the pulley at moderate RPM, as if it's really working hard...and leaving a steady accumulation of belt-powder around the general vicinity. I replaced the old belt recently because it had become too worn to put tension on it within the confines of the adjustment. My voltage never gets above 12.8-ish. Brand new battery - a few days old - still starts fine, but is not getting charged much if at all. Ign lite either dims, or stays on full brightness, regardless of RPM. There's no visible drop in headlight brightness when the engine is switched off.

But from the squeal and heating of the pulley, it's like the alternator is being taxed heavily, the charge being dissipated in some invisible load-bank. I've retensioned the belt a number of times, and each time am greeted with more squealing. And no, it's not OVERtightened, either. So where's all that energy GOING?

Since I can't think what else to do, I'd like to make temporary bypass connection/s to the new alternator, now in the car, so as not to assume anything about my existing wiring. I've always run the previous alt (this one's a Lucas 45A replacement for 16ACR and 17ACR) on two wires only, and this model has only two connections (see photo)

so it should be simple to test in situ. Can someone please confirm, then, that to test the basic functions, I might wire/test as follows:

1) run either fat (wide quick-disconnect lugs) brown lead to +12VDC
2) run small brown/yel lead, connected through an auto test-light, to +12VDC

Testing:

a) with power in place as above, and engine not running, test light should be ON.
b) with engine running - and perhaps RPM revved up and then kept up a bit above idle - test light should dim and go out, and voltage on fat brown lead should be somewhere in the range of, say, 13.5-14.5V
c) With belt snug (about 1/2" up/down play with pressure from thumb on belt), no squealing should be heard.

What else could be the problem?

 

[jon small]

before going to the trouble of running temporary wiring etc first check earth strap connections to body and engine and battery connections as this sounds like a high resistance at one of the connection points.try a jump lead from battery earth to alt casing.
if you try the temporary wiring set up also run a lead from earth terminal of battery to the alternator body as some alternator mountings have rubber bushes and need an earth fly lead and have come even across solid mountings that had a poor connection to engine block,
good luck and let us know how you get on - jon

 

[Ib≤In≤Iz]

I would be investigating the squealing first tbh, check all the pulleys/bearings are ok. Is it tensioned correctly?

 

[ifindoubtdont]

It sounds very much like you have a seized or out of line pulley somewhere, as Ib says check all the pulleys and bearings first.

 

[telectrix]

years ago, had similar problem. a new belt got chewed up in 2 days. seized bearing on a pulley.

 

[Pants]

Thanks, guys...I'm going to go flog away at this some more later today...
(jon small): I was thinking along the same lines about grounding/earthing, but I get less than an ohm resistance from alt case to ground strap (to the stranded copper itself, which runs directly to the battery in the boot), and there's no hesitation or laboring while starting...so testing and the starter-motor seem to be telling me that battery connections are both OK. Still, it's an easy check, so I'll try that, as well as the direct-to-alt grounding. There are no visible insulators on the alt, though, and the resistance to ground-strap as I mentioned is almost nil.

Belt/pulley issues? This couldn't be a simpler setup - it's on a 1960 Austin mini - and so the belt touches only the crank, water-pump, and alt. The water-pump spins freely and runs as true as could be required of a belt-drive component (I've checked it twice while futzing with the belt, something I've done many times now). Aside from belt-squealing/powdering (note the powdering is definitely not from any bearing) the other symptom is the heating: it takes but 30 seconds of squealing-belt operation at, say, 2500RPM, for the alternator-pulley (and ONLY the alt pulley) to be uncomfortably warm to the touch. Yes, the pulley alignment is slightly off, by perhaps 1/16" (for some reason the new alt had different geometry and my attempts to shim were not quite perfect), but rather than focus on this side concern, it's more of concern to me that this is EXACTLY the same behavior as with the previous alternator: squealing, intermittent charging leading to no charging, powder buildup, eventually a loose belt needing to be replaced because there's no more adjustment range.

As for over/under-tightening of belt: 1) overtightening wouldn't cause squealing, nor such immediate overheating (nor was the belt overly tight); 2) if I'd indeed actually overzealously tightened the belt on some occasion, it wasn't that way the next, since squealing + heat yield rubber-powder + loose belt. This is the second belt/alternator that have done this on the same car - thankfully not my daily driver - since November.

Wits end on near horizon.

More on that previous alternator: not that I trust one of our ('yankee,' but Hawaiian-style) auto-parts shops to accurately test a Lucas alternator, but I brought the old one in to my standby domestic parts shop yesterday, and...yep, they say it's good. Chances of a false POSITIVE in that test seem small to me, but I will take it to a specialty rebuilder to test before I make a conclusion.

One way or another I will fix this and post back - please let me know of any other inspirations.

 

[ruston]

Have you converted this Mini from a dynamo?

 

[Pants]

Have you converted this Mini from a dynamo?

Yes, but that was in about...1982...? Been running on a Lucas rebuilt alt for many years since then - only recently replaced due to still-present problem.

--Dave

 

[ruston]

Yes, but that was in about...1982...? Been running on a Lucas rebuilt alt for many years since then - only recently replaced due to still-present problem.

--Dave

Is the pulley new with the new alternator ? If not check that the Vee is not coated with burnt belt, this will cause the belt to slip and squeal.

 

[R G]

Another thought , is the pulley from the old dynamo , it could be the pulley itself needs to be a larger diameter , this would allow less strain on the belt I'm sure ...

 

[mache]

Although you have the right tension is the belt sitting correctly in the pulleys. I.e. needs to be sitting up in the Vee. If it's anywhere close to sitting at the base then the pulleys themselves are worn and will result in slipping, excessive heat and premature belt wear.

 

[ruston]

Although you have the right tension is the belt sitting correctly in the pulleys. I.e. needs to be sitting up in the Vee. If it's anywhere close to sitting at the base then the pulleys themselves are worn and will result in slipping, excessive heat and premature belt wear.

All good points. The pulley condition is very important.

 

[PEG]

Most points have already been covered,but if other components in drive are OK,does belt size (width A,B,Z etc) match ALL the pulleys?

If voltage is as you suggest,it will not be charging,therefore not be under load.

Also,check charge lamp,this will be about 2.2 W,from memory,and is matched to the field coils on your alternator. If polarity,and grounding is OK,it could be a rogue unit....happens,especially from budget re-manufacturers :icon12:

 

[Marvo]

This sounds like one of those chicken and egg scenarios where probably a belt has worn and started slipping which made excessive wear on one or more of the pulley wheels. The worn pulley then causes belt slip even with a new belt which prematurely wears the new belt which further wears the wheel and so on.

Chances are if one pulley is worn they all will be but the smallest pulley will have the most pronounced wear. If you can get replacement pulley wheels at a reasonable price I'd replace all three at this stage in the game or get down your local scrap yard and vernier a few second hand ones before you buy them.

The power required to drive the alternator will be relative to the current it's supplying into the battery or electrical system. First get a brand new belt and run the alternator disconnected and see if it still squeals or whether excessive heat is produced in one of the pulley wheels. It's important to work with a new belt because if you've burned the running surfaces of the old one it will squeal regardless of high or low loading. As already stated check the new belt is seated at the right height in the groove of all the pulley wheels, if it's low on one of them then replace it before it damages the new belt.

 

[ruston]

This sounds like one of those chicken and egg scenarios where probably a belt has worn and started slipping which made excessive wear on one or more of the pulley wheels. The worn pulley then causes belt slip even with a new belt which prematurely wears the new belt which further wears the wheel and so on.

Chances are if one pulley is worn they all will be but the smallest pulley will have the most pronounced wear. If you can get replacement pulley wheels at a reasonable price I'd replace all three at this stage in the game or get down your local scrap yard and vernier a few second hand ones before you buy them.

The power required to drive the alternator will be relative to the current it's supplying into the battery or electrical system. First get a brand new belt and run the alternator disconnected and see if it still squeals or whether excessive heat is produced in one of the pulley wheels. It's important to work with a new belt because if you've burned the running surfaces of the old one it will squeal regardless of high or low loading. As already stated check the new belt is seated at the right height in the groove of all the pulley wheels, if it's low on one of them then replace it before it damages the new belt.

That little car will be worth a lump of cash. It's worth spending a bit of cash on to do it right.

He might have a bit of a chew getting parts for it where he is.

 

[Marvo]

Didn't realise he was stateside. He'd probably be better to join an owners club, they're invariable able to supply spares and expertise and I'm sure there'd be more than one of them in the US.

 

[ruston]

Didn't realise he was stateside. He'd probably be better to join an owners club, they're invariable able to supply spares and expertise and I'm sure there'd be more than one of them in the US.

Yes there are plenty owners clubs over here . That car will be one of the first Mini's , I would like to see a picture of it.

The starter button will be between the seats, be worth a fortune here.

 

[Pants]

Thanks all, belt isn't sitting at bottom of the pulleys, though with all the powder being generated, you'd think it quite possibly so.

Question: when I set this up in 2000 with the now-dead alternator, I retrofitted an LED/resistor in lieu of the basic charge-light, since I don't have a standard speedo with a charge light at all. That LED setup worked fine for 14 years (six of them with my last battery). Is there any reason that would change with this replacement alternator? That is, is there any electrical "need" for the voltage-drop across the typical incandescent charge-light, vs my setup, which has some some forgotten small dropping-resistor to protect the LED, and no "filament?" I've always thought the charge-light is simply a diagnostic/alert item, and in a pinch the small lead can be hot-wired, but perhaps that's not a safe assumption.

I re-tested yesterday in situ, and again, found nothing wrong with basic setup - really no reason to run separate connections to test it. But this time, I ran my ammeter directly to the small terminal to see what kind of current might be flowing there, at about 1500RPM - something less than an amp, as close as I can say. But as soon as my probe made contact, there was a soft, but noticeable hum..as if the diodes had suddenly decided to kick in, even though the normal connection is in place? I swapped over to DC volts and got 14.5V off of the system.

Too soon for cheering. Walking around to the driver's seat, the charge light glowed brightly. I revved it up, and...no change. Went back to the bonnet side, put my leads on, and...back to 12.5V, the basic battery voltage, even at 2500RPM.

I hope I'm not missing something, but as of that, I've concluded it's a dud alternator, even if new.

Another thing on the belt-squeal: it NEVER squeals when I have the alternator plug pulled out, therefore I tend to think the squeal is from electro-mechanical loading, not loose/tight/misaligned pulley. Still, I've readjusted tension, yet again, after taking out extra shims that were first put in to deal with a slight crookedness that seemed to appear after installation and testing. Shimming alone can't deal with it, since once bolted up solid, if you're looking for it, you can detect that the alt axis isn't quite parallel with WP or crank...my only guess there is that the alt case was screwed together such that the pivots are shifted off-axis, though it bothers me that it didn't appear so when I first mounted it...so now I am wondering if the case is actually loose, and has 'wandered' a bit since I installed it.

I'm trying to get the seller to send me a replacement, in any case...how much time can one spend trying to replace an alternator, after all?

 

[Barry White]

Quick question a 1960s mini would have been +ve earth from memory have you changed the battery recently or charged it and fitted it the "wrong way" sounds such a simple mistake but the battery is in the boot away from the engine and the original clamps if still there will be marked in reverse of what they should be. all but a few alternaters on cars are -ve earth (heard +ve exist on old cars but I have never seen one)
If indeed this is the case the rectifier pack will be burned out or shorted on both the old and new unit. causing the load on the pulley you describe.

 

[Pants]

Good observation; you're right about the original +earth setup, but this one is far from original...in fact, it's a fiberglass body that's identical (well, mostly) to the original, so my battery leads (both) run all the way from the boot to the front, where I had to ensure that everything got a negative as well as positive connection where required. But no changes in that setup since 2000, and no starting problems, etc, so I'd say that's the wrong tree.

 

[Marvo]

Quick question a 1960s mini would have been +ve earth from memory have you changed the battery recently or charged it and fitted it the "wrong way" sounds such a simple mistake but the battery is in the boot away from the engine and the original clamps if still there will be marked in reverse of what they should be. all but a few alternaters on cars are -ve earth (heard +ve exist on old cars but I have never seen one)
If indeed this is the case the rectifier pack will be burned out or shorted on both the old and new unit. causing the load on the pulley you describe.

I like the way you're thinking Mykey

Good observation; you're right about the original +earth setup, but this one is far from original...in fact, it's a fiberglass body that's identical (well, mostly) to the original, so my battery leads (both) run all the way from the boot to the front, where I had to ensure that everything got a negative as well as positive connection where required. But no changes in that setup since 2000, and no starting problems, etc, so I'd say that's the wrong tree.

And it's not the other way around where you got a replacement alternator that was specified for the original car with a +ve earth and you've fitted it on a converted car with a -ve earth?

 

[Barry White]

All lucas 16 and 17 ACR are -ve earth and I can confirm the small spade conection has no other funtion other than illuminating a test lamp and the unit will funtion without it conected.
the other 2 large spade connectors are the 12+ volt output and connect directly to the battery via the solenoid (in later years by a fusible link or recently a fuse)
A simple test of the rectified pack is remove the belt and spin the alternater pulley by hand (while it is still connected) it should spin free if the pack has gone you will feel a pulsing resistance

 

[Pants]

I like the way you're thinking Mykey

And it's not the other way around where you got a replacement alternator that was specified for the original car with a +ve earth and you've fitted it on a converted car with a -ve earth?

Actually that would be JUST like my vendor to supply such an item and not know it themselves - but I'm thinking that minis left the realm of "positive-earth" when they made the leap to alternators from dynamos in the late sixties. The online parts catalog doesn't show any options for alternator polarity, anyway.

 

[Barry White]

The leap to negative earth was to do with galvanic corrosion and dynamos output either you just flashed the field terminal to polarise it.so negative earth dynamo cars preceeded alternaters (but this aint solving the problem)

 

[Pants]

All lucas 16 and 17 ACR are -ve earth and I can confirm the small spade conection has no other funtion other than illuminating a test lamp and the unit will funtion without it conected.
the other 2 large spade connectors are the 12+ volt output and connect directly to the battery via the solenoid (in later years by a fusible link or recently a fuse)
A simple test of the rectified pack is remove the belt and spin the alternater pulley by hand (while it is still connected) it should spin free if the pack has gone you will feel a pulsing resistance

Interesting...gonna try the hand-spin test ASAP.

But as to that small-terminal connection: truly, this is not required for the alternator to charge? I thought that kind of alt function was possible - but only in alternators called something like "one-lead" or similar. (I think I once rebuilt an American alternator with a very simple retrofit kit that worked thusly - just one connection plus mechanical ground, and it was good to go.)

--Dave

 

[Barry White]

Cut the fault in half by removing the leads from the alternater (insulate securly) then run the engine and see if the belt squeels or powders)
If all runs smooth its unlikly to be a mechanical/belt problem
Then make up 2 cables run one from the earth on the alternator to the earth cable from the battery. the other from the large spade connector to the +ve side of the battery cable (use 8gauge wire) start engine if all connections are secure you should have 13 to 14 v at the battery if not the unit is goosed.

Ps did you try this i mentioned earlier A simple test of the rectified pack is remove the belt and spin the alternater pulley by hand (while it is still connected) it should spin free if the pack has gone you will feel a pulsing resistance

 

[PEG]

...just try a 2 ish watt lamp,wired from 12v,and connect the other side to the charge indicator terminal,via a female lucar connector.
It should take 10 minutes,and will confirm two facts,regarding your issues.
If you were down the road,i would come and do it tonight! :icon12:

*cannot believe it,i still have my old,paper notes on alternator testing,taken from original Lucas workshop procedure.
It clearly states,"voltage should be present,at charge warning terminal,engine off,igniton on"
This is present due to above^ wiring. I have an old Coventry Climax stacker,which has an acr alternator,and stops charging,when the charge lamp fails.

 

[ruston]

...just try a 2 ish watt lamp,wired from 12v,and connect the other side to the charge indicator terminal,via a female lucar connector.
It should take 10 minutes,and will confirm two facts,regarding your issues.
If you were down the road,i would come and do it tonight! :icon12:

If he pays the fare I will come with you and hold your bag.:smile5:

 

[PEG]

My "bag" is happily suspended,where it is both secure and convenient :icon12: but thanks for the thought...

 

[Pants]

Cut the fault in half by removing the leads from the alternater (insulate securly) then run the engine and see if the belt squeels or powders)
If all runs smooth its unlikly to be a mechanical/belt problem
Then make up 2 cables run one from the earth on the alternator to the earth cable from the battery. the other from the large spade connector to the +ve side of the battery cable (use 8gauge wire) start engine if all connections are secure you should have 13 to 14 v at the battery if not the unit is goosed.

Ps did you try this i mentioned earlier A simple test of the rectified pack is remove the belt and spin the alternater pulley by hand (while it is still connected) it should spin free if the pack has gone you will feel a pulsing resistance

Mykey - thanks for all the pointers. I just tried the hand-spin test - no resistance felt (key on & connector in place, right?)

The other test (bypassing existing leads) seems unnecessary to me, though I'd do it anyway if I had a quick-disconnect female terminal of that large (1/2" or so width) size needed - without that, all I have is tiny jumpers that can't handle much current. Anyway, DVM tells me that the stock connections are getting full battery voltage, and have been all along. Same testing tells me alt earth is excellent as well, so I don't now see the point in creating substitute test connections, although it's nice to know it's as simple as making up one hot-lead.

No, the squeal never occurs when the connector is disconnected. I was tempted to conclude that this points to an electrical problem, but I suppose it doesn't entirely rule out belt issues (though I have no concern about that really being the problem at this point.)

I'd rebuild my two old alternators (both of them higher output than the new one, which at this point I really want to condemn 'cause...well, it's got ZERO output) but it looks like the separate rectifier/brush and diode assemblies would cost 3/4 of what each complete alternator would.

Specialty shop tested my old one, and told me yesterday that diodes are shot, and that this is typical of overworked alt trying to charge a bad battery. How crazy would it be to test/replace diodes right on the board? Seems to me diodes are cheap, and I've no problem soldering...

 

[ruston]

My "bag" is happily suspended,where it is both secure and convenient :icon12: but thanks for the thought...

I just knew ........ I just knew- thats why i didn't say hold your t..imp2:

 

[Barry White]

Replace the whole unit with a rebuilt one theres about 9 diodes in the pack some to do with regulation too and a lot of heavy soldering to the windings. Then theres the voltage regulator a square block filled with resin with 3 or 4 wires coming out to test.

 

[Pants]

My "bag" is happily suspended,where it is both secure and convenient :icon12: but thanks for the thought...

If I were Sir Richard Branson, I'd certainly fly the lot of you out here for entertainment...

 

[Pants]

I had a look at the two old rectifier boards in my spares, both presumably in need of replacement. And yep, those diodes are swaged in or some such - not a simple solder-replacement at all. And of course, they all test fine anyway, but...I musta taken them out of service for SOME reason, right?

Going back to the basic-test setup, though, I noticed, while disassembling the old alternators, that the other removable modular board - holding the brushes and regulator - won't get any connection outside the alternator case unless that small QD terminal (that "small wire") is connected - that's where that terminal connects via a short wire, within the alternator's internal connections. That being the case, only the brushes will be connected to the regulator board, if the "charge light" wire is indeed not landed on a 12V source. So is it really true that the small wire isn't needed for the alternator to charge? Or might it really be that it will still charge, but with no upper-limit on the voltage - so better not run it like that other than for testing purposes?

--Dave

 

[ruston]

The alternator requires an exciter wire (unless it is self exciting) to energize the fields , Best google a wiring diagram to make sure you have it correct.

 

[electron1]

When I fitted a 17ACR Alt to a Ford Escort back in the 70's, the small terminal was indeed for the "Ignition" Light.
Literature at the time suggested that this wire fed the Field windings from the switched ignition supply.

 

[Barry White]

I stated earlier that the small spade conector on the alternator was used as an indicator only and had no other function (this is from personal experience) But 3 other people Peg, Ruston, and Electron say it also excites the wiring checking on google gives mixed reviews but most are for fitting a 2w bulb to excite the alternator.
Maybe I am wrong then? Its deffo worth a try you need a 12v 2w bulb conect one side to the small spade conector on the alternator the other to 12v supply the bulb should light up. Then start up and see if it charges.
Deffo worth a try

 

[Des 56]

I had a 1999 Vectra with no alternator output,could get no output until I renewed the knackered charging lamp
Changed lamp and problem sorted

 

[Pants]

I know, you thought I'd ****ed off...no such luck. Settle in. Long bumpy ride awaits...

I *did* think I'd got it sorted. I went back to the 15-year-old alternator, after doing a sort of ghetto-bench-test, since I didn't really trust the shop that said "the diodes are failing" - they are, I think, the only rebuilder in town, so how's that for an incentive to exaggerate or outright lie...especially knowing he quoted me $180 (GBP118!) to rebuild. But, "Ghetto-bench test," you ask? Clamped it to a workbench, applied +12V from small lead-acid battery to one large terminal, earthed the case to -, and clipped a test-lamp between the "small terminal" and +12V.
The lamp glowed right off, as it should have. Then with a cordless drill fitted with appropriate socket to drive the field, and...at maybe 1000RPM, the bulb dimmed, current flowed, and voltage rose. Wondrous to behold.

"So," concluded I, "...it was just the battery that was knackered all along...and the belt?... well, it must have nearly worn itself out while struggling to charge that old 2008-vintage battery..."

Thus I refitted the alt, drove out with the missus, enjoyed the absence of a charge-light, and voltage-reading of about 13V, and thought all was well.

But all was not well... Returning home in the dark, it was hard to miss that charge-LED, blinding me with it's infernal, mocking glow. Checked under the bonnet on the way home, and...the belt had SNAPPED. We headed the rest of the way home regardless, me gambling on a convenient theory of convection-current circulating coolant sufficiently to keep me below, say, 800F, what with the electric fan being on. (Actually, it was a short drive, so I chanced it, and did get away with it, somehow, though I watched my temp-gauge a lot more closely than the road.)

In the light of the next day, with the belt no longer a visual impediment, and a (slightly) more critical eye, I noticed finally that there was more than a slight roughness to patches on the cheap stamped-steel alt pulley surface. In fact, on close inspection, I realized that it had a patch that was more like 24-grit sandpaper than anything - though that, too, was masked by a glaze of rubber from the belt.

So THAT was it. Eu-freaking-reka.

Ebay hooked me up with a new solid-steel turned pulley, galvanized, and I futzed around with shimming the pulley to get it aligned just right with the pump and crankshaft. Ebay also provided a matched pair (one for later) of new drive-belts at a bargain. I installed this combination just this afternoon, tested it in the driveway, and all was bliss - no squealing, good voltage, even with headlights ablaze.

Took the same trip out as last week - a few miles each way, returning in the dark. (Can you feel it? Here it comes...) On starting, I had that charge-light, but that's normal - it has always stayed on until I rev the engine up a bit, then it's out for the rest of the drive. I pulled out into a long line of traffic, and it took about ten minutes to get moving, so the charge-light stayed on, since I hadn't wanted to aggravate other drivers by revving crazily. But when I finally got out of that jam, there it was again - that unbearable, miserable squeal, as I revved my way through an almost-red light.

Once at home, I checked under the hood. The belt wasn't too loose, nor too tight, but the new pulley was noticeably warm compared to the others.

So..."diodes are failing," after all? Pffft...