S4 Ignition light

The ignition light on my '71 Elan S4 is glowing constantly - is it a reasonable assumption that the dymano is defective (it seems to be recharging the battery though), or is something else amis? Thoughts welcome…

A reasonable assumption…Yes, but it could be voltage regulator problem/connection, a bad generator connection or an earth (ground) connection.
Connect a voltmeter across the battery and see what the voltage reads @ about 2500 rpm…as far as I remember should be about 12.5 to 13.8 volts, try again with the headlight and wipers on, if it goes below 12v you have a problem. Further test by an auto electrician are called for OR you could just fit an alternator and “live happy ever after”
And I am NOT restarting the generator versus alternator debate!
Brian

Hi there,
Seems like a regulator generator problem. Vheck out the link below for a fix.

racemettleltd.co.uk/dynalite.html

Seems like a good idea, an alternator in a dynanamo housing for origionality buffs.

cheers
Mark

I spent the day yesterday diagnosing the same problem. Mine was the dynamo. There are links below with usefull information for testing the dynamo and regulator.

members.aol.com/PODtronics/generators.html

ponypics.com/spitfire/regulator.html

My generator was turning when I did the first test on the generator but was not producing any output on the second test. I figured I had nothing to lose so I pulled it apart and cleaned it up inside. Brushes were in spec (>6mm) but the commutator diameter is warn to below its limit of 36.4mm.

I cleaned it all up, the internals were coverd in a layer of oily yuck, put it all back together and it works but I don’t know for how long! I think it’s a sign to get my act together and install the alternator that’s sitting in the corner of the garage.

Cya,
Steve.

My light comes on and stays on every once in a while. I squirt some electric parts cleaner in the rear holes of the generator, a little with the engine off and then some with it idling (watch out for the hot exhaust manifold.) The light goes out and stays out, for quite a while. My problem is oil on the worn brushes. I’m using CRC 'lectra-motive cleaner, it comes with a little extension tube like WD 40.