Advice Please, Alternator Voltage and Coil Voltage.

[langlj00]

Evening, Just had the car out for a spin and it didn't start without a jump (very unusual) and then was a bit lumpy when very hot.
First the starting:
Just checked the voltage at the alternator when running : 12.3V . So question 1 (I'm assuming I should have about 14.2V). Can I buy just the regulator and re-build, or is it new alternator time?

Second:
Not running quite right when VERY hot, (yes it could be fuel/carb related, but go with me), checked the timing - all good.
But noticed that the voltage being presented to the coil was 11.5V (not 8V as I thought it should be), Am I cooking the coil running it at 11.5V?
My understanding is that on cranking the coil gets 12V from the key switch and when running gets 8V via the original 'resistor wire'.
I did change the starter last year for a 'higher torque version (which did have the R terminal (but I never checked the output)).

Thanks for any sage answers to either question.
Jeremy.

 

[Oneball]

I’d just get a new alternator, that way you get new brushes, bearings etc as well as a regulator.

The ballast resistor type systems as well as protecting the coil also increase the life of the points.

The first thing I’d check is that you have the original ignition system as it may have been converted to run a 12v non ballast system.

 

[langlj00]

I’d just get a new alternator, that way you get new brushes, bearings etc as well as a regulator.

The ballast resistor type systems as well as protecting the coil also increase the life of the points.

The first thing I’d check is that you have the original ignition system as it may have been converted to run a 12v non ballast system.

Thanks.
I'm running a Crane Cams electronic points (rather than mechanical), I can't remember the voltage - I'll have a search.
The resistor wire is still there, so I suspect that the 12V must be coming from the ignition switch. (I'll have to separate the two wires (crimped together) on the +ve side of the coil to see which does what.
Cheers, J.

 

[Oneball]

Check whether a ballasted coil is recommended for your Crane system, I reckon it probably isn’t. In which case 12v is what you want with the appropriate coil.

 

[langlj00]

Check whether a ballasted coil is recommended for your Crane system, I reckon it probably isn’t. In which case 12v is what you want with the appropriate coil.

Cheers, Crane XRi - Balast is required (it is wired for it, with the original resistor wire, but think the ignition switch might be at fault, will separate the wires and report back.
Thanks again.
J.

 

[langlj00]

Well, here is the alternator fault.
Top right diode in the picture (from the 3 phase rectifier) is short. I suppose 46 years isn't that bad
J

 

[Jimbo64]

Well, here is the alternator fault.
Top right diode in the picture (from the 3 phase rectifier) is short. I suppose 46 years isn't that bad
J

Well done in dissing it out and hopefully an easy enough fix

 

[Jimbo64]

"Sussing" even - predictive text, should really re-read before I post!