Lotus Elan and Lotus Elan Plus 2 Forums

Anyone know when Lotus went from positive earth to negative earth? I
can't find any reference to it in the books.

I don't know when, but my guess is it happened when they switched
from generators to alternators.
---Ben

No...that is not true. I had a 73 Elan.and it had a generator..and was neg.
ground. S2 is where it ended. I am pretty sure. Now..I cannot a few early
S3 cars were not pos ground.but I don't think so.



We have all heard about stories of how people got their cars..



My brother in law.now living on the Hudson.has a white early S2. One day he
was driving on the University of Buffalo Campus.late 60's when he sees an
Elan with the hood up. Stops to see if he can help..Speaks with the guy for
a while.then leaves telling the guy if he ever wants to sell the car let him
know.



A little while later the guy calls my brother in law and asks him if he
wants the car.he cannot get it to run right.wont start.runs rough.gauges
wont work.etc etc. To make a long story short ..Jim buys the car and when
he gets it home finds the battery in backwards. Seems the guy took it to
Sears.they installed it like they do every other car. Neg Ground..but this
was a pos ground vehicle. My brother in law switched the leads.Car ran
fine. Still has it today..



I think that is a true story.





Tony Vaccaro

I believe the S2 cars were the last with the positive ground. I had S3.S2
and an a few S4's Only the S2 had a positive ground.



Tony Vaccaro

Ben,

Sorry, you're guess is completely wrong.

Tony,

Your guess is better, but there is a guy in our club who has a 1967 S3. It
is + ground.

Frank Howard
'71 S4 SE - ground. Factory Lucas generator replaced with Mitsubishi
alternator
Minnesota

My S3 Elan (36/7666) had a positive earth when I got it.
---Ben

I have an early S3 Coupe' (March, '66, IIRC). It came with a generator and
positive ground. I later switched to neg ground without much problem. Since
the tach is electrically isolated by the wood dash, I just swapped the
ground and power connections at the tach end.

Stan

I guess I was wrong on the S3 Cars. I only had one of those.and it was neg
ground.but it had been highly modified..



I saw several more.and I know they were neg ground.so they must have been
modified as well.



Tony Vaccaro

Frank, I'm curious. How did you come about selecting the Mitsubishi
alternator?
Dave 72 Sprint DHC

'''''''''I have an early S3 Coupe' (March, '66, IIRC).
It came with a generator and positive ground. I later switched to neg
ground without much problem.
Since the tach is electrically isolated by the wood dash, I just swapped
the ground and power connections at the tach end.''''''

My S3 DHC of April 67 was Pos earth but I to changed mine over without
too much trouble.

There was an British industry-wide change with the introduction of the
1968 models. This coincided with the introduction of the S4 Elan. My
late '67 S3-Super Safety pretty well confirms this. My late '69 +2S is
neg earth and a generator. If you have a factory shop manual, look at
the wiring schematics for further proof.

Roger

I could buy everything except the rough running. How, when the starter
is turning in reverse, does he get it to run? Pushing?

I suspect the change happened when most of the cars Chunky raided the
parts bins of switched. He bought a lot of stuff from Triumph, and they
went in the mid to late sixties, which is about what people are saying.
I know the MKIII Spitfires (68-70) were negative at least in the U.S.
market and had generators. Likely the UK market used up the positive
ground stock, 'cause they seem to like that kind of thing.



-- Doug Nicholls, 54/1822 Ma~

Doug

I recently was at a local British Car Club Show. There were about 10 very
nice MGA's. EVERY one of them had a very clearly marked label "This Car is
Negative Earth" in plane sight when you lifted the bonnet. Did the Elans
have such a label or did the labels cost too much?



Ken

Thanks, for all the response. As with most things Lotus there is no
absolute answer.'68 sounds right though. Out of the 5 Elans I have I
have two Elans I'm restoring two an s/3 and s/4 and am selling any
extra parts. I'm wondering what items would be exclusive to a positive
ground car? Tach, starter,fuelgauge,fuel sender,wiper,heater motor,
switches? Or can they just be hooked up in reverse as someone
suggested with the tach?

Radio?

The main reason I switched from positive to negative ground was I
couldn't find a postitive ground FM radio (not that you really need a
radio while driving a Lotus .

When I changed the polarity of my generator, I think the only thing
I modified was the tach (if you look carefully at the dial it says
"pos earth").
---Ben