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Re: Alternator on way out?

To: mgs@autox.team.net
Subject: Re: Alternator on way out?
From: ejrussell@mebtel.net
Date: Thu, 22 Jul 2004 15:44:03 -0400
> Subject: Alternator on way out?
> 
> 1980 MGB LE
> 
> The ignition light has a faint glow.  After tightening the belt it is 
> still there at times (not as often) and the alternator has a high 
> pitched whine.
> 
> I assume the whine is attributed to the bearings going - does the faint 
> ignition light suggest I should be looking for a rebuilt alternator?
> 
> How can I test the alternator's output?
> 
> If I need a rebuilt do I need a MGB alternator or can other units do the 
> job with minimum fuss and bother?
> 
> Thanks
> Preston
> 

I just went through this exact scenario on our '78 MGB. A faint glow from the 
ignition light, noticeable only when driving at night. Some days more 
noticeable than others. Some days the car would crank with good speed, other 
days it seemed slower when cranking. The battery was less than one year old.

First I took the 'B to 'Auto Palace' (chain auto parts store) that offers free 
battery/charging tests. Their test showed the alternator was putting out 13.3V.

I checked the drive belt, seemed ok to me. I took the alternator off and could 
feel play in the shaft. I took it to an old fashioned auto electric rebuilder. 
He checked it over for me, discovered one of the bearings was loose in the 
housing. Speculated that it was causing an intermittant short. He peaned over 
the housing so the bearing was again tight (said the bearing itself was fine). 
Charged me $20.00US.

No play in the shaft, 14.3V

Call around or visit a few different rebuilders. I got quite a range of 
estimates to just 'look at it'. Most wanted $75-100 for a rebuild & more if 
they found any real problems.

Another option is a GM Delco unit. I can forward a link to someone's web page 
if you want to go that route. A rebuilt Delco can be had for $35 - $50. It is 
mostly a bolt-on modification, you just have to modify or adapt the MG plug to 
fit the Delco & use a generic arm for the adjustable piece. If my Lucas 
alternator was not repairable, I'd go that route. (more amps, less money)

Eric Russell
Mebane, NC





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