12 volt?

[martinald]

Hi All,

I am new to both the club and 356 ownership and am in the throes of doing my homework before the car arrives.

I am unfamiliar with 6 volt systems but they obvously work. My questions are
1) what are the benefits from converting to 12 volt and,
2) how easy a job is it?

Martin

 

[Robin]

The 6 volt system in the 356 works fine if you keep all of the connectors clean so there is minimal loss of voltage through the system particularly with the lighting circuits. Changing to a 12 volt system is not completely straightforward but can be done and will allow you to have some of the modern electrics in the car like CD player and better headlights if you intend to drive it in the dark. Changing to 12 volt will need to change the generator/dynamo and the regulator to a 912/914 type and change the battery to 12 volt. All of the light bulbs will need to be changed to 12v and you will need to install step down resistors (12v to 6v) to feed 6v electrics to the dashboard gauges, including the fuel tank sender unit and the windscreen wipers so you can benefit from the variable wipe speed facility of the 6v operation. The one thing you dont have to change is the starter motor which will take the change to 12v without any problem. Oh and you will need to change the spark coil to a 12 volt one as well.
I am presently installing a new wiring harness into our 356C coupe and considered changing over to 12v at the same time but felt that installing the 6v system was difficult enough. I have added extra features to the loom when it was being made by YNZ to give me separate stop and indicator lights and some other wires for a high level third brake light but keeping for now the 6 volt electric supply.
Good luck with the car when it arrives.

 

[jdpef356]

Robin

Great coverage as ever and advice - I still run on six volt and don't have any problems (touch wood) but would be interested to see
a side by side comparison of the lights 6 and 12 volt next time we are at an event.

 

[Robin]

Good idea John, I met Mike ? who had the Togo brown 356C RHD coupe that was at Castle Hedingham who had changed his car to a mixed system of 6v and 12v (I was going to say a Hybrid system!) where the lights and most of the electrics were run on 12v but using a 12v battery with external straps between the cells he had tapped into half of the battery to take off only 6v to feed the dashboard and all the guages with only 6v. It seemed to work and did not look too dificult to repeat.

Meanwhile my problem with the electrics is where do the relays go under the dashboard on a RHD 356 ? there seems to be very little information in the various books and manuals about RHD cars which seem to be quite different from the LHD models.

 

[jdpef356]

Robin

I have a few books you can borrow if you wish. I also have the workshop manual for 356C

 

[chas3.2]

On my 356b super 90 1962 I have fitted Wipac headlight lens, with clear headlight glass as USA, with H4 Halogen bulbs also modern day relay all in 6v this was 2 years ago, all's well so far and he said let there be light and I can see for miles. Don't forget a 6v 10w bulb gives the same light as a 12v 10w bulb. It's the watts what does it. Someone will say I am wrong.??.
To get bright lights you need good reflectors.

 

[martinald]

Robin, thanks for the very detailed response to my first ever post. Wow - why buy the
book when you're out there in the ether?
To date the replies indicate to me that there does not seem to be a compelling reason to change what has stood the test of time, so I won't. Well, not early on, but if I suffer electrical gremlins I may well revisit the subject.
The car arrives early next week so expect posts a plenty.
Thanks for your good wishes and expertise.
Martin

 

[jdpef356]

Further to my previous posts - my car is still on 6 volt. I have never had any problems (touch wood) or with starting or any
related e; electrical problems. I would say the lights are a bit dim but then back in 1964 no one was on the bright side.
Since I don't drive it much at night I don't see this as a problem. However, I am one of those If it aint broke don't fix it types'[]

 

[jdpef356]

Another plus is I forgot to say that my last 6 volt Battery lasted ten and a bit years[]

 

[Robin]

I have a few books you can borrow if you wish. I also have the workshop manual for 356C

[/quote]
Thanks for the offer John, I also have many books and photos of the fuse block arrangements in the 356 Registry magazine which is a superb scource of restoration, however none actually show me the exact area I am needing. I will phone to speak about the problem.
There is one thing about the workshop manuals and repair books, they all show how to remove the object or whatever is to be repaired, but they do not give the information for me or anyone to do what Porsche did in the first place when they actually built and put the car together. My car has now been in pieces for so long I cannot remember where the bits all go and to make it worse I can't find some of the parts !

 

[Helen Goff]

ORIGINAL: jdpef356

Robin

Great coverage as ever and advice - I still run on six volt and don't have any problems (touch wood) but would be interested to see
a side by side comparison of the lights 6 and 12 volt next time we are at an event.

i litrally had side by side comparison in my 356a cab. as the main car was 6V but the police accessories (including the yellow fog lights) were 12V. i would have struggled driving it at night without the 6V headlamps on full beam and the 12Vfog lights on.

my 356C coupe was 12V and we had no problem driving it at night.

having said that if i bought another 6V 356 i would only convert it if the wiring needed doing anyway. as most of the driving i'd doing with it, would be in daylight anyway.