Trying to increase my knowledge about S-types. So I have a couple of questions.
1) Did the S-type go negative ground? If yes, when? Car Number?
2) Did the S-type ever get an alternator?

Thanks in advance

 

The short answer is no and no.

 

just in case, changing to Negative Ground is no big deal, I did it following simple instructions.

 

As Jose has stated the S type was always Positive earth or ground.and had a generator not an alternator. The 420 which shared a lot of its parts with the S type and was built during the same period (S Type 1963 to 1968, 420 1966 to 1969) was negative earth and fitted with an alternator.
If you want more specific details about the S type we have a forum dedicated just to the S Type which can be found at THE INTERNATIONAL JAGUAR 'S'-TYPE REGISTER FORUM - FORUM INDEX
There is also a register of S Type Jaguars run by the same forum so we can keep a track of thoses that are left and have lots of information regarding individual cars which might have been supplied by previous owners if your car is already on the register.

 

Here's the instructions I used to re-polarize my S type. It is so simple it's like duhhhh. Sure you should get a new battery that was charged Negative Ground from new:

https://starautoelectric.com/instruc...ing-generator/

 

Thanks everyone.

 

OK, I'll bite, why would he need a new battery, current flows from positive to negative, and even if one argued that it flowed from negative to positive, it shouldn't make a difference.
Whether the frame of the car is connected to the positive side of the negative side should make no difference to the battery and just because that is changed around, should make no difference to the battery.
I'm still using the same battery on my car after I changed to negative ground, or moved the negative terminal to the frame of the car.

 

There is no need to get a new battery when you change the polarity of your earth. The battery is marked up + and - so all you do is change the earth lead on your battery to the - rather than the +. Sometimes the way the terminals sit on the battery affects how long your leads are to reach them when you turn your battery around but there is no need to change your battery. It is so simple. Duhhhh?

 

During the discharge of a battery, the current in the circuit flows from the positive to the negative electrode/terminal. According to Ohm's law, this means that the current is proportional to the electric field, which says that current flows from a positive to negative electric potential. Electrons are what flow in the reverse direction.

Battery charge is irrelevant. No need for a new one.

Polarise Lucas Dynamo/Generator at the RB340 Lucas Voltage Regulator. RB340 Right.









S Type RB340 ~ Mk2 is similarly mounted but on a pressed bracket.

 

Bob, Are you considering making some upgrades to the electrics?

 

Hi Peter,
Thanks for asking but no I am not. As I said in the OP, I am trying to increase my knowledge of the S-type. I don't own a S-type but at some point I would like to own a 420 and since the 420 is built from the S-type there is a lot to be gained by educating oneself. I feel that the 420 and the S-type are under appreciated by the Jaguar community as a whole.

 

You are right there, very underestimated by all who do not own one. Being an owner of an S Type I can assure you it is only those who do not know about them that put them down. The S type was an upgrade on the Mk2 and the 420 was an upgrade on the S Type so mechanically and cosmetically both are better than what came before but the styling is not to everyone's taste. I like the S Type over the Mk2 as in my view the longer tail makes the car look sleeker. Conversely I do not like the styling on the 420 as I think the front end is too boxy and square. I prefer the rounder lines of the S type front end.
The 420 had a lot of upgrades over the S type. Bigger brake discs and calipers. Dual circuit brakes. 4.2 engine rather than the 3.4 or 3.8 in the S. Different gearbox which was actually an older model being the Model 8 Borg Warner but stronger to take the extra torque from the 4.2. Less wood but more emphasis on safety as the dash top was padded. Negative earth and an alternator whereas the S Types were all positive earth and had the generator. Power steering on the 420 was the Adwest Marles Variomatic which was fitted to the later S Types and powered by a different PAS pump. Other than these upgrades the two cars were the same mechanically just had different front wings and grill.

 

the MK-X, S type, 420 and 420-G have styling elements of each other, inspired by the MK-X that started the low wide styling..

the XJ of 1968 is essentially the inflated 420-G to which they let the air out. It can also be said the XJ is a flattened 420.

As to replacing the battery or not. I was told it was good practice to replace it when converting to negative ground and I did. Besides my old battery had the poles in the wrong sides so it had to be replaced anyway.

 

My battery was the same Jose when I changed over to negative earth. I found the positive terminal was where the earth strap was and the negative terminal was close to the solenoid on the bulkhead. I thought about it for a long time then decided the best way to solve the problem was to lift the battery up and turn it around 180 degrees. Worked a treat as the negative terminal was now near the earth strap and the positive terminal was now by the solenoid.

 

Cass that would place the poles towards the front of the battery and I wanted them closer to the firewall, away from possible accidents, like touching the positive pole with a wrench.

 

here's my S type with a Daimler grille, the only Daimler S type on planet earth. so you can all wipe your tears of envy and bite an oil dipstick tube

 

Congratulations, Jose! It looks great.

 

Thank you Peter, it looks even better in person. Very luxurious.