Fan Blade In 911sc Scrapes Housing ? Bad Bearing?

[toolhound]

I HAVE A 1983 SC TARGA AND I HAVE HAD A CHARGING PROBLEM . IF I DON'T RUN IT EVERYDAY IT'S DEAD . IT HAS A NEW ALTERNATOR INSTALLED SIX MONTH'S AGO AND NOW THE BLADES ON MY FAN HAS A CHUNK BROKEN OFF, AND SCRAPE'S THE HOUSING IN ONE SPOT . MAYBE BAD BEARING'S IN ALTERNATOR ? I'AM A FIRST TIME USER OF THIS SITE AND SO FAR I'AM IMPRESSED. THANKS TOOLHOUND

[Vipergrün]

Hey Toolhound, welcome!

A couple things.

First, turn off your capslocks key

Check that the fan shround band is not too tight,
try loosening the bolt and see if that helps.

May want to remove the housing/fan/alternator
and verify the alternator is mounted flush and that there
is nothing loose to allow it to *tilt* in the housing.

Have you had the charging problem since the replacement?
Were all the connections made?

good luck

-Brad
80SC

[GIBSON]

Toolhound, seems like a new alternator should not have bearing problems. Remove the fan belt and see if the fan moves laterally on the shaft. That's probably the best way to check for bearing problems. Also, it the bearings were that bad you should notice some noise that would give you a clue.
For the charging problems, put a voltmeter across the battery poles and see what the alternator is doing, it should read in the
14.6 volt range.
As far as the chipped fan, the alternator may not be seated
in the fan housing, you can only check this by removing the alternator and fan assebly.

[Chuck Moreland]

The problem is definitely with the alternator itself.

The bearing on the rear (front of car) of the alternator is held in place by a sort of plastic bushing. Sometimes these come off and allow some wobble in the shaft, hence the fan wobble.

It may look fine at idle. At higher rpm the extra torque on the shaft makes it move and the fan scrapes.

Don't run the car or more damage may result. Pull out the alternator and have a look.

[Early_S_Man]

When you pull the fan belt to get at the alternator ... make sure there are a total of EXACTLY six pulley shims, either between the fan hub and pulley half, or between the plley, AND also outside, under the concave washer and alternator shaft nut. If there aren't six shims, total, then find the extras in the tool kit or glove compartment ... or order spares and enough to make the total count of six!

Serious damage to pulley and fan hub can result from running too few pulley shims!!!

ps ...

Acceptable system Voltage is in the 13.5 Volt to 14.5 Volt range with the engine running above idle!

[john walker's workshop]

i've seen a lot of cracked fan housings. usually on the inside, so it would have to be removed to check. i had one a couple of weeks ago that had 2 big cracks which caused the housing to become out of round and the fan to scrape, even with a new alternator.

[tsniu]

I second John Walker's guess. Cracked fan housing, causing the fan and alternator to change their axis, and leading to fan scraping inside of blower housing. Happened to me. Was a nightmare finding a used replacement housing with the right offset. Good luck. Tom

[Early_S_Man]

If the housing turns out to be cracked ... it isn't necessary to replace it, because any good welding shop with Heliarc can weld the magnesium housing! Even if cracked in two places, assuming they know what they are doing.