6 volt or 12 what should I do

[Robert Dudley]

I have had my Bradford for ten years and it has never started very well on the button. I have checked out the motor and replaced wiring and battery. Last year I put a 12 volt battery in the back with independant switch for a busy working weekend. It worked well. If I convert the whole thing to 12 volt what do I need to replace? Dynamo, bulbs, Wiper, gauges. I have been told the motor will be Ok. No problems with lash up so far. What do other people do convert or not to convert.

[Forumadmin]

Bad starting could be down to any of the following.
1. Poor conductance in the feed or return from the battery. Less than .005 ohm on both is preferable. Rusted or oxidised connections on battery, to chassis and on starter. Starters can take 400A, so generating a drop of 4V.
2. Check voltage when cranking. not sure what is good for a 6volt but I would worry if it went below 4.5 v across the starter motor or 5v at the battery. A good battery should have resistance of .005ohm so cranking 100Amps should give a volt drop of .5v (that is for 12v, half for 6v).
3. Check voltage across ignition coil when cranking. I had a high resistance ignition switch and bypassed it direct to battery. Alternatively use another battery from the one driving the starter motor to prove this problem. Switch ignition off and connect other battery to ignition coil, then press starter without switching ignition on.
4. Ballast resistor and low volt coil have ben used to overcome low cranking volts. Electronic ignition helps as well.

5. Switch to 12v probably will cure most problems or use two batteries when starting.

[PAUL BEAUMONT]

Robert, sorry been off line for a bit. 6v Bradfords can be notorious for poor starting - mine never starts on the starter, but then again I suspect my starter. Most points have been covered, but there are a couple of things that you need to check. You need watts to start the engine. Watts are volts times amps, so with only 6 volts you need twice as many amps as you do with 12v. Sadly heat is directly proportional to amps so any resistance anywhere will result in the amps causing heat not watts! Check and recheck every connection on the thick wires fron the battery including any body to engine straps (Bradford wiring seem to vary in this respect!) Also check the commutator in the starter motor to make sure that the brushes are polishing every segment. If it is a CB take care if the starter is dodgy as they have a bit of a habit of breaking the starter motor mounting off the gearbox.
Also check your battery. You need a decent 6v battery with at least an 80Ah rating. half a pair of MGB batteries is rarely heavy duty enough.
It is a shame to convert to 12v though. Unless you do a lot of night driving the lights should not be an issue, and when all else fails using the crankhandle is good exercise!

[Alastair Gregg]

Hello Chaps, sorry to butt in but I happened to be looking at old the classic car website and happened to notice John Fox has placed an advert this year for a 6V starter motor. Now its in the Javelin section so it might not be right but its worth a quick look. I have heard of John Fox in JCC circles but don't know him so I am not getting any benefit in linking to his advert.

http://www.oldclassiccar.co.uk/freeads/ ... avelin.htm

Hope this helps

[Keith Andrews]

Also check for worn bushes in the carb...this can also cause the odd 'pop' out of the exhaust when one lifts off the accerator.

[Robert Dudley]

I have had the starter motor checked but I suspect they just connected it up to a battery and it worked. I have replaced the starter cable and earth. I have had the gearbox out twice so the connections are ok. As I said I have put in two extra wires to the motor and put a twelve volt battery and switch behind the seat. When I connect the six volt up to this it is no better so it has got to be the starter motor. I think you are right. Life is too short I will leave the twelve volt in the back and leave it all six volt. The van is not concours it has all the old perished window seals, the doors do not fit very well and it has sixty years of repairs and patches so an extra battery is just part of its character. Thanks for the help.

Robert

[Keith Andrews]

There is an issue whitch SB chevy starter motors after many yrs and a lot of hard starts (usually because modded engines intial advance is high) the solder joints on the armiture breack down..become dry jounts

Not many auto shops/sparkies have what in the old days was call a growler to check the armitures
Sonetimes the armiture has to be very warm...warm enough to put your hand on but not hold it there too long, to find the dry joints.

Other than that...the cumuntator...where the btrushes run...
Normally re shaped on a lathe..at home... wrape some emery paper around lubed with some thin oil, take a long leather boot lace wind around the emery once or twice then alternatively pull the ends of the boot lace to spin the emery..

Bearings and bushes...these are cheap and easy to replace
new bushes.
And where there is a solenoid check the main contacts, often these can be reversed or turned
You basically end up with a new rebuilt starter motor for a couple bucks
Note: do NOT lube the bendex, clean and leave dry.

looking at several 6 volt starter motors it appears they would be ok on 12v
Not sure on the generator but a change to 12v and 12v regulator would fix that
Change the light bulbs..

Have you checked the 4v battery cells with a hydrometer?...dont worry too much abut a low reading, look for a cell that is significanty different to the rest.
The starter button contacts could also be worn, corroded

[Tony Fearn]

The van is not concours it has all the old perished window seals, the doors do not fit very well and it has sixty years of repairs and patches so an extra battery is just part of its character.

I'm with you Robert, the fun is in the ownership and the driving of the Jowett. My 'Mary Ellen' is slowly coming into the "needing to be restored again" category as her last comprehensive restoration was around 1979-1980. The thing is though, I just love pottering about in her just as she is.

Regards,

Tony.

[Keith Andrews]

I take a different attitude, thu my classics are not concourse.
They have to be in a state at anytime even after a month of sitting, I can go out, jump in and fire up and go do the shopping or pick up a new set of gas bottles etc...just like a new car.
Pottering is keeping the car in such a state

When it comes to a rebuild, one doesnt have to deal with 'upgrades'

The best part is when friends visit, want to go for a ride..
So it is "hmmm havnt driven her for a few weeks"
And they expect , being and old car not to start or something...
Jump in behind the wheel, turn over for a few seconds, pump the gas, hold the pedal down and a second latter she fires up...let idle for a 1/2 minute, push the choke in and she put putts away nice, then dive off.
They just dont expect an old car to do that...