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Spitfire Spitfire Charging Issues

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doates

doates

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Hi,

A couple of weekends ago my ignition light came on while driving. So last weekend (sort of using the Lucas manual) I convinced myself that my generator was bad. This past Saturday I installed a new generator, started the car and the ignition light went out so I thought all was well and I went about some other chores. Later that day I was going to go for a spin and as soon as I revved past idle the light began to glow, return to idle and the light goes out. My voltage meter shows 13 volts at the battery at idle.

Should I just order up a new control box or is it worth me trying to fix?

Thanks...Dennis
 
I found at one time I had a short in the light and how it attached to the speedo. When I revved the engine it would come on but if it was at idle it went off. Once I got the light not grounding out then it worked fine after.

This most likely will not help but it was a gremlin I chased for while. How I found it was to pull the light out of the speedo and it started to work correctly after.
 
My opinion, you need to trouble shoot the problem until you know for sure which components are bad. The reason is because a bad control box can damage the generator; and a bad generator can damage the control box.

But chances are, your control box just needs to be cleaned and adjusted. Even new ones frequently require adjustment before they will work right. If it does actually need to be repaired (burned out coil or whatever), then you should probably look for a new one.
 
Lots of resources on the net in regard to control boxes and how they operate.

First step would be to make sure that proper volts are getting to the box from the generator.

Second would be to see what voltage you are getting at various RPM's.

Definitely sounds like one set of contacts is not working the best, but without further testing its tough to pinpoint.

jb
 
Hi Again,

Well it was charging at almost 14 volts so I took it out for a drive and it died on me (see other post). Today I got no charging activity. Went through the Lucas tests for dynamo and cables to the control box and all checked out great. When I did "Test 5", with the bull dog clip on the voltage regulator contacts I got no amperage reading and it let out some "white smoke" from the back of the control box. The interior of the box looks brand new.

Any suggestions?

Thanks Again
 
I guess I'm confused. In my Lucas book, test 5 is done with a piece of paper in the cutout contacts and no bulldog clip. And you shouldn't be taking an amperage reading, test 5 is voltage.

Using an ammeter (or a DMM connected to the ammeter shunt) as a voltmeter will definitely cause problems of the smoke releasing kind.
 

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I have trying to figure out how to show the page from the Lucas Manual for the RB340. It does show the bull dog clip and amp measurement. This also matches the test in the Haynes book (which is actually a little clearer). Anyway, I think I am supposed to read between 24 and 26 amps and I get nothing but white smoke. I took the control box off it appears to be in excellent condition; no burnt areas.

Thanks
 
By the way, could this charging issue be the cause of my freeway stalling discussed elsewhere?

Thanks Again
 
Ok, I said I was confused ... forgot that Spits used RB340. Somehow, I had it in my head that only the GT6 & Vitesse/Sports 6 had the RB340. Sorry bout that!

I don't have "the Haynes", but I agree, the Lucas book is missing several steps. I just added them to my copy (which I'll put back up on Google Docs). After shorting the VR contacts (engine not running at this point):

<span style="text-decoration: underline">Disconnect leads from both B terminals.

Using a suitable jumper, connect all removed leads together, and to the load side of a 0-40 amp ammeter.</span>

I'm not sure what would be smoking at this point, assuming your clip isn't accidentally touching something else. You were able to measure current before the F & D leads shorted together, correct? No current now would suggest something wrong with your test setup. Unfortunately, this step is kind of important, since if the current setting is too high for your generator, it will eventually overheat and burn itself up, most likely on a cold rainy night (when the electrical load is highest).

It is possible this is related to your stalling problem, but I would say they are more likely to be unrelated.

On the stalling problem, does it simply die like the key was turned off? Or does it gradually lose power, cough and sputter a bit before dying? Although not a hard and fast rule, typically fuel delivery problems result in a gradual fade (as the fuel in the bowls runs out), while electrical problems tend to be more of a "now it runs, now it don't" nature. That said, I've had both a condenser and a coil die somewhat gradually, so again it's just a suggestion, not a definite thing.
 
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