One of the most Frequently Asked Questions about the 356 has to do with the 6-12volt conversion. Probably because this isn't covered in any factory material, it's "not original", and a lot of folks go it on their own when they decide they want to make the switch.
Here you'll find links to a number of pages on this site which discuss various issues for consideration during and before you decide to convert your 6 volt system to 12 volts. Remember, some of this is opinion, most of it is hard-earned experience, and all is shared by those who Keep the 356 Faith!
Main Sources, complete conversion descriptions. Most are listed on this site, others are links or lists of other sources (books, articles)
The 356 Registry Magazine has printed a number of articles on this topic. The most recent is available online. Here is the index of the older articles
(Credit Robert Laepelle):
By: Tom Farnam
A recent conversation about converting a 356 from a 6 volt to 12 volt electrical system led to me sending a friend a lengthy email about how to keep that 6 volt system performing properly. Recent posts on the 356 Talk List make it reasonably clear many think of the "conversion" of their systems as the only way to deal with dim lights, starter problems and similar issues. I think that you will be amazed at just how well a 6 volt system can work if properly cleaned and maintained.
First and foremost, if you have that car in "project" status, go through and CLEAN EVERY electrical connection on the car. The biggest single issue is corrosion, either in the form of copper oxide or iron oxide. So our objective is to get the metal clean (as if a Concours judge were going to be taking these connections apart) and then apply a light coating to reduce the air/water contact in the future. Not in "project" status? All of this can be done on a fully oper...
By Larry Coreth
[This article also available as an Excel spreadsheet]
The following data and charts are intended for those who are equipped with the necessary measurement tools, shop manuals and the desire to setup the ring & pinion having swapped out either the differential carrier or said ring & pinion set. The use of these tables (right) and graphs (below) are straight forward in that you can use either the tables or the graphs since the graphs are made directly from the data tables.
Once you have assembled the intermediate plate with all the gears, shafts and bearings and inserted this assembly into the trans. housing, then the differential with bearings and shims (estimated) and finally bolting all this up tight you are ready to do the backlash measurement per the manual. If as usual this measurement is outside the spec. of 0.15+ or ñ .05mm you need only look up the measured backlash on the X ordinate and read up or down to the curve and then over to th...
Text by David Jones, Wil Mittenbach, Bill Strickland, Ab Tiedemann, and Al Zim
Ab Tiedemann: First, make sure that all of the cotter pin is removed.
Then, you will need a good reaction bar. If you have a disc brake car, you can get a very good one from Ashley Page. I purchased one and it works super. It is my understanding that he will also make one for the drum brake cars.
You need a very good breaker bar and socket combination. Good ones are not cheap. (Snap-On about $100-130). A 3/4 inch drive 30 inch length is what I have been using for 40+ years. This, in combination with an impact, six point 36 mm, 3/4 drive socket will whisk most of them off. You most likely waste time or break tools or both if a 1/2 drive combination is used.
Sometimes you will have to resort to the impact wrench. On really stuck ones, you may need one that develops 750 lb-ft of torque. These guns require a lot of air and will quickly run down most air compressor...
By Alan Klingen and Gerry McCarthy
Alan Klingen: The split boot will seal very well when installed correctly and the right boot is used. To put on the solid boot correctly you really need to take apart the axle tube.
I like the FEBI brand split boots from Germany, as the fit and the hardware is right. The most common error I see at the shop is the sealing of the halves at the clamp. You must position the clamp so that the action of both halves of the clamp coming together also draws the open seam together. Get as closed as possible by hand and the clamp will do the rest. No need for any sealant when done correctly.
Screw together the split first being careful not to tighten the bolts so much that the seam opens up again. I would guess the washers sink into the rubber about 1 mm on each side.
You want to position the seam at 10 or 2 o'clock. If possible get the axle level but don't if the method you use is getting the car off it's jack stands. Place the clamp for the big end f...
Text and Photos by Jim Fleming
[Editor: We love our vintage cars, but many 356 owners also love their modern electronic gadgets, such as GPS systems, cellphones, and digital music players. When used in cars they all assume that a 12V electrical supply is available, but the 356 (with rare exceptions) was built as a 6V car. While some people are satisfied with charging their gadgets from the factory 6V cigarette lighter, others are more comfortable having 12V power available. Here's how one owner created a 12V outlet in his 6V 356.]
Here is what I did on my 1961 T-5. I went to Checker Auto supply and bought a standard replacement cigar lighter (which fits in the 356 dash hole just fine) and I ordered a 6 to 12 volt inverter from J C Whitney. I removed and stored the 6 volt 356 cigar lighter. I removed the 356 cigar lighter knob and installed it on the purchased lighter (so the dash looks authentic). I removed the heater element from the 12V unit so it can never be pushed in and oper...
By Barry Lee Brisco, David Jones, Alan Klingen, Ernie Puskas, Tom Martinez, and Al Zim
If your tires are over 9 years old, replace them! Not sure how old they are? Here's how to find out.
356 tire pressures are different from modern cars because of the lightness of our classic vehicles and the unusual weight balance: heavier in the rear, not the front. The factory 356A owners manual recommends 24/28psi front/rear, but that was for bias-ply tires 'back in the day'. The 1965 Elfrink Technical Manual suggests 24/26 for "normal" driving and 26/29 for "fast driving" on 165 tires for the C/SC coupe/cab that had a 2,061 lb. curb weight (the Porsche C Owner's Manual has almost the same figures for "braced tread" tires, the early name for radials). However, since that time, tires have changed dramatically — fortunately much for the better — so be careful applying old pressure recommendations to new tires. Certainly underinflation is to be avoided, as that can produce a lo...
Text and photos by Greg Scallon
My installation (more photos below) is a direct copy of the set-up that Alan Klingen did for Stan Jensen's speedster. I saw Stan's belts at EASY one day and decided to do mine the same way. Without an extra 4" I-beam welded into the rear bulkhead, I realize there's only so much strength this design has, but I'm confident it'll slow my face down measurably before impact if it ever comes to that.
After searching high and low, I was surprised to find that Deist seemed to be the only company with a Y-shaped shoulder belt set-up. I priced them on the Web but couldn't get a better deal than Jim at EASY and would much rather give my money to him than some Web company. FYI: The eye-bolts, washers, nuts, etc came with the belts.
The goal was to have the mounting point as close to that 90 degree bend in the bulkhead as possible for strength but to leave room for the eye-bolt on the inside. I drilled from the back, in the engine compartment, and tried to stop...
By Barry Lee Brisco
By modern standards, stock 356 brake lights and rear running lights are weak: difficult to see during the day, not particularly bright at night, and placed rather low. Today's drivers are used to very bright rear lights placed three to four feet above the road surface, and it's entirely possible they may not even notice your 356 brake lights when you really need them to. The unhappy result of their inattention could be a crunched rear end or even a totaled 356.
Happily, there is a solution to this problem. LED array lights are now available in several forms and offer significantly greater brightness than incandescent bulbs. LED bulbs that simply plug into the 356 taillight assembly sockets can be found in both 6V and 12V, for either BA15s (teardrop) or BA15d (beehive) socket types ,and they generate no heat. To my eye these bulbs appear to be about twice as bright as the stock bulb. They work fine with the stock flasher relay (no need to change to a modern ele...
By Bruce Baker, Bud Osbourne, Victor Wild, and Barry Lee Brisco
Roll bars installed in 356s that are only driven on the street, while looking undeniably cool, do raise the question of occupant safety, but perhaps not in the obvious way. Yes, they can prevent the roof from collapsing onto the occupants in a rollover accident, but they can also inflict lethal head injuries in more typical accidents (like rear enders), since they are located close to the occupants heads and 356 seats are very low compared to modern cars.
On race cars, helmets and roll bar padding are mandatory, protecting the skull from injury. But when was the last time you saw a 356 driver wearing a helmet for daily driving in his roll bar-equipped vintage Porsche?
What follows is taken from a discussion initiated on 356Talk, with additional comments by veteran 356er and racer Bruce Baker. It is a cautionary tale for those who have roll bars installed in their "street only" 356s. This article is not about how...