Fan Wabble - 1980 SC

[Sean Hamilton]

I can wabble the fan from SIDE to SIDE and IN and OUT to the extent that the fan blades will come into contact with the inside of the fan shroud - I can see scrape marks where the fan blades have come into contact - R/H, inside of shroud.
I removed the air pump belt to accentuate the movement.
The nut is NOT loose - it moves with the fan as a complete unit assembly.
The Alternator was rebuilt 18 months ago.

Every time I start and stop the engine, as well as driving under load, I can hear a loud high pitched rattle emanating from the fan area - hence I suspect it to be the culprit. I've been hearing it for about 7 days now - today after a long drive it is noticeably worse.
As a mechanic....? I'm way better at my day job.
Hope I've described it well enough for you guys to assist me please.

Thanks.

[Jim Sims]

I would look for bad alternator bearings or failed plastic bearing retainer at back of alternator. Second possible cause is cracked fan shroud vanes caused by overtightnening fan shroud strap bolt. If it is the alternator bearings they could fail entirely, damaging fan and fan shroud. I'd stop driving the car until you get it sorted out. Jim

[Early_S_Man]

Sean,

It sounds like you don't have the required six shims on the pulley assembly. Regardless of how many shims are needede to properly adjust the fan belt tension ... THERE MUST BE A TOTAL OF SIX SHIMS ... EITHER BETWEEN THE PULLEY HALVES OR WITH EXCESS SHIMS UNDER THE CONVEX WASHER!

If the shims are too few on the shaft ... the outer pulley half can wobble around, even if the nut is tight! If belt tension was tightened too much to eliminate the wobble, alternator bearings will suffer!

[Sean Hamilton]

Thanks for you prompt reply,...... it's my daily driver so I've been anxiously hitting the refresh button waiting for any response.

I've just had a look at Wayne's 101 book "Alternator" section. I see the components you are both describing clearly.
Wayne gives it a two wrench rating and that's okay for me, so I'll have a crack at removing the entire assembly - first checking for the correct 6# shims and then see (hope) if it is just the bearings.

Jim, Nut is tight and the Pulley is moving together with the fan.... Does that sound like your "If belt tension was tightened too much to eliminate the wobble, alternator bearings will suffer" diagnoses?

Thanks again, I'll keep you posted.

[jabb]

One other thing to look at if the proper amount of washers is not used.... sometimes when over you tighten the nut it can colapse the cone shape washer......

I would not drive the car like this if you do drive it keep an eye out for the Alternator light (make sure its working) As soon as you see that light come on Shutdown the engine and check for a belt or Fan failure. You do NOT want to drive with out the fan working

[Sean Hamilton]

Joe, too right - that recent thread on driving without a fan belt put the willies up me! One positive thing out of this I was able to take up Warren's suggestion in that thread to go out and practice removing the belt - piece of cake.

Jim, definitely not driving it - the lateral movement in the fan is greater than the shroud tolerance - the shroud is actually containing the amount of movement and it will shatter with any more abuse I'm certain.

Warren, after removing the fan nut and dome washer I have all six shims in between the belt pulley halves - none under the dome washer. Is that the correct assembly?
After removing the entire alternator assembly and dismantling it from the fan and shroud, it appears that the rear bearing is knackered - significant fore, aft and lateral movement. Also very clunky when spinning the alternator shaft slowly. Front bearing seems okay but I will replace both to be on the safe side. The last time it was repaired it looks like the auto elec' only repaired the cooked diodes etc inside and didn't replace the bearings while he was at it.
Still, I'm none the wiser as to why or what would cause the bearing failure. I'd appreciate yours, and any others thoughts.

Wayne, thanks to the 101 book I was able to confidently manage this project - something I would have shied away from with out your assistance and clear instructions. Thanks heaps...... feeling preety proud of myself.

Thanks all,

[Moses]

I had the EXACT same problem a month ago. The fan chipped to pieces against the shroud. Expensive fix.

My mechanic told me he is reluctant to rebuilt an alternator without new bearings. Apparently they fail regularly.

Unfortunately, it may not be just your bearings. When the bearings go, the increased wobble inside the alternator can screw up the contacts and fry your alternator too. Hope that is not the case with yours.

[Jim Sims]

I confirm what Moses says about internal part damage. The "wobble" of the rotor can also chew up the brushes. I lost the brushes in one of mine (alternator light came on on dash) about the same time the fan wobble showed up. If the wobble gets bad enough it will damage other parts to the extent that the rotor can't be repaired. Have the internal parts checked too. Make sure the bearings are pressed on by applying force only to the inner races. Preheating the bearing with a special bearing hot plate or hot air gun helps reduce the force required to install them. Have the internal parts checked too. Jim

[Jim Sims]

Bearing failure causes: 1) time, revolutions and weather; rolling element bearings (these bearings are probably ball bearings; balls held in a cage or separator and rolling between inner and outer races) have a finite life usually ended by metal fatigue but also hastened by loss or degradation of lubricant or internal corrosion. These bearings live out in the weather (air flow from fan to engine passes over and by them) and if the built in seals fail and cause loss of lubricant or allow the entry of water and dirt the bearing will fail earlier. 2) improper installation; if the bearings are pressed on by loading against the outer race the races and balls and seals can be damaged. The damage can be tiny dents in the races and flat spots on the balls which can precipitate fatigue failures and produce noise. 3) overloading; bearing life is in general a product of load times revolutions. If the fan belt is excessively tightened the bearings are overloaded and will have a shorter life. 4) poor quality bearings; made from relatively "dirty" steel which lowers fatigue life and with cheap seals and shorter life lubricants. Install your new bearings properly and don't over tighten the belts. I find where my fan belt just starts to squeal during shifts and then remove one shim from between the pulley halves (moving it to the outside under the cupped or domed washer) or one can use the belt delfection method. Cheers, Jim

[Paul W]

Hi Sean

Highly recommend you do this yourself.

I had mine rebuilt a couple of years ago, and with the help of Warren and other board members, removed and replaced it. Total cost: $160 incl the spanner to hold the fan.

I've a great auto elect. in West Melb who rebuilds these things in a day or so.

If you need hand let me know.

Cheers

[Adam]

Sean..

What a bummer. Still, I'm glad you made it home without further incident.

If you need any help spannering, let me know. I'm no expert, but I'm eager!

[Sean Hamilton]

Jim, wow, you certainly know your onions with these issues. Okay.....I wouldn't have known that the electrical innards could go as well due to the failed bearings. I'll get the total overhaul now - Elec & bearings.
I had all six shims in between the two pulley halves so I'm assuming that the fan belt wasn't overly tight, but the air pump belt was really tight - I could twang it. I'd like to remove that waste of space - can I do that? Get rid of the complete air pump? Does the engine need to be retuned with it gone?......I'll do a search.
Thanks again Jim.

Paul, how ya doin' Get back okay?
Yeah, pulled it myself and it;s at my local sparky now. But I tell ya there's no way I would have done without Wayne's 101 book. Curious, he says something like the fan is "pressed" onto the alternator shaft?...... mine just came adrift no problem. Maybe it's a different type of alternator.

Adam, mate....... me neither - we'd be two eager peas in the same pod.
Paul's done this himself, so I cant let that go. I'll have a crack at reinstalling it when I get it back, but yeah... I'll let ya know - OFF forum if I quietly need bailin' out. Thanks.
Hey, this has given me an excuse to beak out my old British TR to drive to work.

[Paul W]

Hi Guys

Sean, I didn’t have too much of a battle separating the fan from the axle either. It looked as if the last person who’d none it had put some anti seize compound on it. Assuming you clearly labelled the plugs and wires you will not have any problem getting it back together. Very satisfying job to do.

As mentioned if you need a hand let me know – promise won’t tell a soul.

Cheers,

[Jim Sims]

You can remove the air pump and simply plug the hose going down to the bottom of the car with a rubber cap or plug (I used a rubber chair leg tip or cap). However, without a flow of air into them, the air injectors on the exhaust side of the heads may eventually clog and no longer function. This is only an issue if the car has to pass an emissions test. You can remove the lines and injectors from the heads and put plugs in their place. Pelican sells the plugs. This can turn into a "can of worms" and become a bigger job if the injectors are corroded into place (which they often are). I am waiting until I install SSI's and then when I have the heater boxes off I'll also pull the injectors and plug the ports. There will be more room to work with the heater boxes out of the way. Save all the air pump parts in case you or a future owner needs them in the future. Cheers, Jim

[Sean Hamilton]

What prompted me was when Matt Holcomb asked "gwad, what's that thing do"
So okay, then I'll remove that too. Why have the extra load on the fan pulley? Might even extract anther 10 hp.

Strangely, I noticed a smell of burning plastic coming thru to the cabin and then it would disappear. Hmmm, melting diodes? Yet, the dash light didn't come on.

[Matt Holcomb]

Sean,

How did you go?


Matt Holcomb
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[Sean Hamilton]

It's at the shop now, so I'm sittin' tight for the next few days....... steel wool polishing the fan and shroud in the mean time - a total PITA that job is!! Stupidly I started it and now can't stop, committed to get at least some consistency in the finish. The Fan blades and shroud are pitted so it'll only ever be reasonable. Still, I live on an unsealed road so it's not worth going ballistic on it - I've got the TR for that.

[WydRyd]

Yeah, what a bummer Sean. Hope you get your baby back soon.

Keep us posted on progress. At least your fan and shroud will look like new again

Merv.

[Sean Hamilton]

A fully rebuilt alternator, bearings and innards - as Jim suspected, the internal windings were knackered.
Thanks all for your assistance and support, especially Jim's p.m.'s - mate, you saved my bacon several times with both the Alternator and Air pump removal - thanks.
I do feel cheated tho' - I didn't get the extra 25 hp I was hoping for by removing the Air pump.
Anyway, it runs silky smooth and less clatter without the Air Pump.

[Adam]

Sean,

You'd better not drive that thing! You'll get the fan all dirty!

I'm dead jealous of that fan, it looks classy!