Restoration of a 356SC Best battery to buy

[Peter Roberts]

Finished the 928GTS so the old 356 comes back this week after 2 years storage to start the restoration. In a previous post i inquired as to upgrading to 12 V but all things considered have decided to stick with 6V for originality. I have to get it running to move it around but starting it after such a long lay up fills me with dread.
This raises the question of the best battery to get. I have suffered in all the years i have had it with slow cranking and have replaced the battery several times for bigger AH versions but still not been happy with the cranking speed. One option is to fit two batteries to ensure enough power to get it to start even though this will not speed up the cranking. I know my first step must be a proper rebuild of the starter motor to ensure that is in perfect order or even to get a new one and that all the earthing straps are in perfect condition and corrosion free. Also the bush in the gearbox housing is in perfect condition and these will be addressed first
However i have heard that the Optima battery is the answer. Can anybody give me some advice on what is the best option.

[mrg3.6]

Good question, I need similar advice for my 356a which arrives in the UK next week and hasn't been driven for a couple of years.

I was also advised that 356 barrel bores attract rust so need to be very careful when starting after a long lay up - any advice on the best start-up procedure?

Thx
Martin

[TLC356]

Over many years I've tried a variety of batteries and the best are the sealed batteries such as Optima-(Note-they don't appear OEM). The original style batteries don't last as long and I believe they off-gas and cause fouled connections. Before I started with sealed batteries, my car often failed to start until I cleaned the terminals.

[neilbardsley]

Over many years I've tried a variety of batteries and the best are the sealed batteries such as Optima-(Note-they don't appear OEM). The original style batteries don't last as long and I believe they off-gas and cause fouled connections. Before I started with sealed batteries, my car often failed to start until I cleaned the terminals.

+2 for Optima

Sent from my X5pro using Tapatalk

[mycar]

I considered an Optima when I needed a new battery.

Like every damn thing on the internet there are those who love them and then those who are disappointed.

The deal breaker for me was that the Optima battery wasn't designed with the 356 battery tray in mind and the fit is a 'bit' of a compromise. Also, the question of whether you should or shouldn't use a trickle charger on the Optima... there are mixed reports.

I bought a traditional hard rubber battery that fits nicely and works well. I use a Ctek battery conditioner and don't worry one way or the other.

It won't last forever, no doubt about that, but if it lasts 5 years I'm a happy man.... It's the cheapest single item I've bought for my car.

https://www.tayna.co.uk/car-batteries/classic-car/511/

[mycar]

Martin, a bit of a search on the Registry turns this up about stating standing engines.

19 years is a bit extreme but Chuck Houses' post probably covers your concerns.

http://forum.porsche356registry.org/vie ... f=1&t=7475

[roy mawbey]

Mike's advice is the same as mine really. As you will have read from other threads on here, the slow crank hot or cold was completely solved by the electrics being made perfect by cleaning, the starter motor checked and rebuilt and a new standard black case battery with the correct ampere hour specification fitted.

I purchased my last battery 4 years or so ago and in my case use an Accumate battery conditioner I can plug in within 30 seconds to the garage mains supply. The battery still performs as new.

The 365 starting should then perform as new. I did change the bellhousing bush but not really sure it was actually necessary. No harm if you can do it though.I would take the plugs out and turn the motor over by hand on the crank pulley. If it moves that would help.

To start after a long spell and if the engine has been kept in the dry, do not attempt to let the engine fire but crank it on the key till it should turn off the green oil temp light. Then after making everything ready probably even more cranks then to fill the carb bowls. This can take a fair time. Then depress the accellerator pedal 3 times hold it mid way and see if it fires.

If the engine has not started in many years probably best to follow some of the registry advice regarding sticky piston rings. I presume the petrol would be new and the carbs jets clear of old stuff.

Roy

[356Monkey]

I've tried various options over the years, in the end I think the standard hard case version from:

https://www.tayna.co.uk/car-batteries/classic-car/511/

this is the best option as it is the same battery made by the same people that Porsche will sell you for almost twice the price. The key thing is, as previously suggested by others on this post, to have your associated electrics in reasonable order, get your starter motor checked or rebuilt (Broadway electrical in Grays essex are a good choice as they are an old school bosch dealer who have the knowledge and apparently build starters, wiper motors and dynamos for most of our UK based 356 parts companies)

Also, use a battery maintenance charger, I use an accumate and rigged up the connector terminal they give you so it comes off the fuse board (put the live on the same side of fuse 3 as the existing red wire - the other side should be empty unless you have added an accessory then find any earth on the car near by) and runs under the dash to near the steering column. I then hung the accumate on the wall right next to the drivers door in my garage, literally takes me 5 seconds to plug it in or un plug it when i want to drive the car from the comfort of the drivers seat!

[BD55]

As others. I have had a 6V Optima which have had no problems with, though i do use an accumate battery conditioner/charger.
My car was sitting around for years while i did other things, used the Optima to recommission the car and all that entailed ie getting lights working etc etc...i had the slow cranking to start with, the new battery didn't cure it. So changed starter motor bush and had the starter checked out and this cured the problem, not sure which of these was the cure. I also changed earth strap at battery and from gearbox to body and made sure metal was clean. As well as cleaning up all the starter connections. Also tidied up some butchered wiring to the ignition switch...Every little helps.
Downside of the Optima is the size, needed a spacer (block of wood) to help with the fit.
I do still have slower cranking when engine is warm, so will work on that when i get my engine out for a rebuild. I believe it may be the starter motor fields??

[roy mawbey]

Were your starter solinoid contacts cleaned up when they checked your starter. I thought it could be field coil problems with slow crank when hot , not so it was the solinoid contacts toasted.

Roy

[neilbardsley]

Good question, I need similar advice for my 356a which arrives in the UK next week and hasn't been driven for a couple of years.

I was also advised that 356 barrel bores attract rust so need to be very careful when starting after a long lay up - any advice on the best start-up procedure?

Thx
Martin

I think I've read about people talking about taking the plugs out and putting some oil in the cylinder. Then turn it by hand with the plug off too see how freely it turns (without the compression). I would certainly change also the oil and filter. Drop the slump plate and have a look.