Converting a Jowett 7 to 12v

[steve51800]

Is it possible/practical to convert a 1927 Jowett 7 to 12v from 6v. Apart from the obvious (bulb's, coil,) is there anything else thats going to pose a major problem...
Steve

[george garside]

the problem would be the dynamo which is completely different on the vintage engines to the 12 volt unit fitted on cars from 1933. It may be possible to have the existing unit rewound but probably not worthwhile particularly if there is little or no night running involved. Starting on 6volts should not be a problem provided ignition system in good and battery kept on charge when not in use. Startup after period of inactivity probably best using handle just like they used to do

george

[ian Howell]

Another problem might be the windscreen wiper.

If it is the Pull and Spin to start' type are quite rare in good order and very expensive!

You could use a later type, which might fit the existing holes, but that would spoil the 'original' look.

I have just invested in a new 6v 84Ah batery and as George says, everything works well including the starter.

Question is - why bother?

[James Baxter]

Unless you plan to do night rallying there is really no need to convert to 12v, infact in my humble opinion you are spoiling an original feature of the Jowett light car.
Just make sure your earths are good and as others have said your battery well charged.
I start on the handle 95% of the time, as i am young and able and like showing off frankly! Either electric or handle needs the ignition retarded of course.
Also make sure the charging cutout points are in good order.

Good luck. Please persevere with 6volts!

[BobCulver]

This is a topic mauch laboured in Austin Seven circles. There is a lot of incomplete and misleading advice about. A dynamo will produce 12v after a fashion. Ideally the field should be rewound. Otherwise the main problem is to limit the field current to approx the original...by fully retarding the 3rd brush and/or adding series resistance. For those with a limited grasp it all becomes quite a puzzle, on top of the complexity of the 3rd brush operation and any summer/Winter charge arrangement.
Some convert to 2 brush and add various regulators, which makes things even more complicated, and a puzzle for auto elctricians.
Many are spurred by cheap 12v batteries. Some avoid night running and opt for just a trickle charge which reduces the problems.

Bob Culver