356 voltage. 6V or 12V?

[Peter Roberts]

I have had my car for 15 years but only used it off and on during that time. Everytime I went to start it i said 3 hail Mary's and crossed my fingers as to whether it would turn over. Usually it was very sluggish but would eventually burst into life.
I started a major restoration last year and enquired on the forum the pro's and con's of upping it to twelve volt. There was a lot of support for upgrading but more than one respondent advised if every thing was set up right 6v would not be a problem, so for maintaining originality i stuck with 6V.
To ensure "everything was right" i reconditioned the starter motor with new solenoid coil and fitted a new bush in the gearbox housing. Obviously i also reconditioned the dynamo.
In addition to replacing the existing body to gearbox earth strap i added a new one from the engine support hoop straight to the starter motor bolt.
At the battery end I fitted a new heavy duty earth cable and double bolted it to the chassis using a thick strip of copper between the two bolts.
The result is unbelievable. The engine flies over as if it were 12 volt and the car bursts into life instantly even if i have not used it for a week or more.
So if you are having 6V woes i suggest you spend just a few pounds on getting your existing installation set up properly before embarking on a very expensive upgrade that you probably do not need.

[POR68]

Very true Peter. I went through the same process when I got my car. I also added a starter relay near the starter motor to reduce strain on the ignition switch. Finally I added on of Fred Winterburn's amazing 6V CDI units. These are easily switchable between CDI and Kettering system, if ever needed. The CDI gives a much larger, more consistent voltage at the points than any other system (original or Petronics, etc) and the start up is very potent and low RPM torque increased noticeably.

[roy mawbey]

Yes I went through many years of slow 6v cranking and finally after doing all the earth modifications, bell housing bush and wiring checks the final items that cured the problem, proved to be the hidden three off copper contacts underneath the riveted on starter solinoid cover. Broadway elerctrical services checked cleaned and then modified the cover to accept nuts and bolts.

I think you felt the same as me Peter the wonderful feeling of hearing that 356 turn over on 6v as fast as one with 12v !! Still makes me smile everytime I start it!

Roy

[Ignatzcatz]

OK old school guys but how are you going to run your phone charger, your amped up stereo your sat-nav even those big Marchals? And if you are thinking of hydraulics you may even have to go to 24volts.

[Peter Roberts]

But i have a 12v transformer under the floorboards connected to my cigar lighter. That will do the satnav and as i don,t even put the radio on when i am driving this gem why would i worry about the rest of the gizmos that are plaguing modern life.

[Ignatzcatz]

A 12V transformer! Jeez you must have some pretty big cigars to light.

[mycar]

Sat nav/phone changer work fine on 6v. The Marchals will too with LED bulbs.

[roy mawbey]

A funny post you guys ! Always good to smile. Would you believe I have a Tesco £10- pay as you go phone with £5-00 left on the voucher. My calls are never longer than about 10 seconds. I am really old school. I wondered why my 60 year old windscreen washers did not work the other day. After an hour or two I found the reason, after removing the foot push button pump fiddily thing to get off the rubber pipe had 6 inches of cracks that finally made it fail. Lucky it was the lower part, the top part of the rubber pipe seems to go under the fuel tank on the A.

Anyway got it sorted and really a rubber pipe is bound to fail after 60 years. You see I am an old bloke who thinks things last for ever.

Roy

[POR68]

I have an old 6 to 12 v transformer that was once used on my car for a tape player. I removed it when the original radio was reinstated. However the little transformer is useful to drive my 12v timing light if ever needed. Also fitted LEDs to the lights for safety and reduced drain on gen and battery considerably. SatNav? I always know where I am going but Google Maps from the phone via a Jabra is fine if needed.

[mycar]

Jabra is a new one on me. Is this a Jabra Drive ?

[S.J.Szabo]

In addition to all the usual perks of running on 12v, there is the valuable bonus that the 356's wiring ampacity is doubled under 12v. Thus, the issue of overtaxed wiring is simply eliminated (unless, of course, one wishes to run a couple Flamethrowers on the headlight circuit....).

Plus, native 12v makes convenience mods a piece of cake w/o having to rely on one more finiky piece like a transformer.

Add to this that 12v. batteries are more robust and long-lived (and add some of the heft lost to no spare), it's hard to find a downside to the conversion.

After nearly 40yrs. (and 150Kmi.) on 12v., I've never regretted the change for even a minute.

Just $.02 worth....

[neilbardsley]

Don't you mean the watts are doubled? Amp are about the same? Can you explain why this taxes the wires less?

Sent from my HTC One M9 using Tapatalk

[Ignatzcatz]

SJ, you're so right. Amps, watts, transformers, additional wiring and earths. Fergit 'em, Just fit a 12V battery and if you want the car to start before your fingers have even released the key, fit an MSD. Unless your car is a contender at Pebble Beach, 12V is a total elimination of starting and electrical problems.

[mycar]

I did consider a 12v conversion for my car but have so far decided against it.

The list of changes required put me off somewhat.

New...
Generator.
Wiper motor (a pig to get to)
Voltage regulator.
Cigarette lighter.
Horns.
Headlamps.
All other lamps.
Coil.
Radio.
Alterations to gauges and clock.
and a Battery of course.

Did I forger anything ?

Instead I cleaned all earths and spent a few quid on LED bulbs and a flasher unit which can be swopped back to original in 20 minutes should Pebble Beech call.

For those that fancy moving up to 12 volts, here's the low down.

https://s3.amazonaws.com/porsche356regi ... ersion.pdf

[Mike Smith]

Did I forget anything ?

Wiper and Headlight Switches with 12v Rheostats