After an 8 weeks process of striping the 500 F to bare metal and completing my first car restoration I am now on to the final touches. Today I started it for the first time since the rebuild and I have noticed with my new gauges that the generator output is going up to 18.6 v when the car is reved. I also confirmed this with a multimeter. my question is, I know this is normal and I expect 14.2 at the most. Are the regulators adjustable or do I need to replace it? could the problem be steaming from somewhere else ie: Generator.
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Technical Suspected issue with Regulator 18v output
- Thread starter mhatzis
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Technical Suspected issue with Regulator 18v output
I would expect voltage to be around 13.v , anything much higher will boil the water in the battery and blow all the bulbs etc.
I had a customer with a Bedford Midi van who fitted a new battery before coming to me as his new battery was going flat also.The reason was there was no acid in the battery, it had boiled away and stopped working, he had to have a new battery, also in his case the acid had gone all over the battery case..
In your case I would check the voltage regulator contacts haven't stuck, clean them careful and see what output is then. It is unlikely unless someone has messed with them that it would need adjusting, so more likely contacts have stuck and want cleaning. Unless someone has put wires back wrong.
The regulators on old style dynamos were adjustable and on English Lucas type ones I have done this on cars and BSA motorbikes in the past many years ago, but not on Fiat ones particularly.
Unless you get all the relevant information on how to do it on your model I would be very careful as can cause many other problems.
Car looking good.
Last edited:
lazylobster
Established member
If you have the original / mechanical regulator, then yes, you could adjust it. But looking at my workshop manual it's one hell of a process. You'll be better off buying a new electronic voltage reg (available from pretty much all on line 500 parts co) as these are soooo much more reliable. If you want to keep the look of the mechanical reg then you can always take the cover off and adjust it to fit over the new electronic reg.
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opened it up and had a look at the contacts. even though they test ok the first two , voltage and current seem to have an arch between the top and Bottom contacts. I suspect when they open a spark may still be jumping across. I just ordered an electronic one to replace it with, so need to wait another week before I can drive it.I would expect voltage to be around 13.v , anything much higher will boil the water in the battery and blow all the bulbs etc.
I had a customer with a Bedford Midi van who fitted a new battery before coming to me as his new battery was going flat also.The reason was there was no acid in the battery, it had boiled away and stopped working, he had to have a new battery, also in his case the acid had gone all over the battery case..
In your case I would check the voltage regulator contacts haven't stuck, clean them careful and see what output is then. It is unlikely unless someone has messed with them that it would need adjusting, so more likely contacts have stuck and want cleaning. Unless someone has put wires back wrong.
The regulators on old style dynamos were adjustable and on English Lucas type ones I have done this on cars and BSA motorbikes in the past many years ago, but not on Fiat ones particularly.
Unless you get all the relevant information on how to do it on your model I would be very careful as can cause many other problems.
Car looking good.
I don't think sparks can jump across as it is only fairly low voltages unlike ignition coils.
More likely the contacts get pitted and stuck together so keep increasing voltage rather than regulating it.
Years ago I got the 6 volt dynamo on a 1956 650cc BSA motorbike I had to work reliably at 12 volts using a 12 volt Wartburg regulator, on first attempt it was set to high a amperage as for a 12 volt car battery system and burnt out the dynamo, so I reduced its regulated amperage and was able to use 12 volt Halogen headlight and air horns along with the 12 volt battery with no further problem.
