Alternator funny

Jun 28, 2004 7 Replies

Howdo,



The ignition light on the dash of the TR8 now doesn't go out when the car is running, indeed it glows more brightly the harder you rev the engine.



Output of the alternator seems to be unaffected at the moment - on tickover the battery reads 12.75 volts, and 12.5 with all the lights on. It's not losing charge, either. (and it's a new battery). The fanbelt is new and properly tensioned.



Any ideas what's up? It's been suggested that it's either dodgy contacts on the back of the alternator, or the rectifier is failing.



The engine is a Rover SD1-era 3.5 v8, but until I get the alterator off, I can't see any markings that might indicate who made it.


That's the normal suspects, 13.2V is more normal for charging voltage though, what's the voltage with lights on & engine off?

I had something similar caused by a conductive track on the alternator plug. New plug --> no more problems.

12.75v is too low. I'd say the rectifier is bunched. It's obviously putting out some charge but eventually will let you down.

Fairynuff - are they repairable, or is it a case of 'no user serviceable parts inside...'?

cheers,

You can usually replace both the regulator and rectifier assemblies on most alternators - assuming you can get spares. The rectifier often needs a pretty meaty soldering iron.

It's probably a Lucas alternator so they're fairly cheap as an exchange unit.

Just to add I've got a voltmeter in my SD1, and it sits at 13.8 under just about all conditions with the engine running.

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