Wiring the ignition switch - which wire where?

[WorldClassAccident]

I have an ignition switch with 4 terminals on the back and 4 positions on the key.

Terminal 1 = Power
Terminal 2 = Ancillaries
Terminal 3 = Normal Engine running position
Terminal 4 = Momentary Switch for Starter motor

Key Position 1 = Off
Key Position 2 = Ancillaries
Key Position 3 = Normal Engine running position
Key Position 4 = Momentary Switch for Starter motor

I also have a bundle of 4 wires in the wiring loom marked Ignition. Two of the wires are thicker than the other two. 1 x Thick Brown, 1 x Thick White, 1x Thin White, 1 x Thin Red/White. The details from the guide that came with the loom are below:


Colour Size Destination
BROWN 44/0.3 BATTERY
WHITE X 2 28/0.3 FUSE - SWITCHED LIVE INPUT
WHITE 28/0.3 IGNITION COIL +VE
RED / WHITE 28/0.3 STARTER MOTOR

I believe that the wiring should be as follows:

BROWN = Terminal 1 = Power
WHITE = Terminal 2 = Ancillaries
WHITE = Terminal 3 = Normal Engine running position
RED / WHITE = Terminal 4 = Momentary Switch for Starter motor

Any idea how to tell which WHITE is which? In the guide they are shown as the same size but in reality one of the WHITEs is the same thickness as the BROWN.

My guess is THICK WHITE = Terminal 3 = Normal Engine running position

Anyone actually know or know how I can tell?

[Nike55]

Hi WCA, is this the standard Scim loom or a new replacement?

I'm sorry I don't have access to my Scim but the physical details I noted from the back of the ign switch (when I had a problem) was:

White/Red = Starter
White = Distributor Coil
Brown = Alternator

Only three wires.

Looking at the attached wiring diag for the SE5 it shows the wires from the ign switch as:

North = Four wires (All White) 'W'

1. 'W' to ign warn light then from ign warn light to alternator as Brown/Yellow (NY)

2. W to Tacho then on to ballast resist. then earth

3. W to Tacho

4. W to o/Drive fuse

East = W/G (White/Green) to Instrument Fuse

South = W/R (White/Red) = to Starter solenoid. With a spur to Inhibitor switch

West = N/W (Brown/White) to Ammeter (then to Alternator)

------------------

Not all Scim wiring may be the same, they may have wired up mine (or yours) with whatever was left on a reel.

Also there were early/late SE5's which differed.

Also you may have a wire or two that has possibly lost a trace colour.

This diag came from the ROSSC:-

[WorldClassAccident]

Not a standard Scimi wiring loom and not a standard ignition switch unfortunately.

My loom is a 'deluxe modular loom' for kit cars and similar. My ignition switch is from a local auto electric supplier.

I have decided to wire it up quickly in a way that is easy for me to get to the connections and change then around quickly if necessary before I wire them in permenantly

[Nike55]

OK, good luck with that.

I'm hoping to make my home made loom simple by avoiding 'Wipe', 'Wash', 'Fog', 'Heater', etc!

Looking forward to seeing how yours develops.

[Mister Towed]

Yes, I thought 'ind L/R' was a bit ott, until I worked out what it meant...

[WorldClassAccident]

Electrics update.

I have working:

Side light
Dip Beam
Main Beam
Indicators
Hazard Warning
Horn
Washer Bottle
Ignition switch (can actual turn the engine)

I have fitted but not yet tested

Fog light switch (no light to fit yet)
2 speed Heater motor switch (no heater motor to fit yet)
Thermo fan switch (no fan and no engine heat yet)
Windscreen wiper switch (no windscreen to wipe yet)

Not working - no spark in for the engine. :-(

[garyh]

Nearly there? Would you recommend that wiring harness.

[WorldClassAccident]

The wiring loom is well made and well labelled.
It comes with a guide showing what connects where.
It is reassuring to be using modern wire rather than brittle 40 year old stuff.

I have had a few problems but I really don't know if that is because I don't know what I am doing or because the build guide that comes with the loom is not clear.

Having said that I had problems, I only had to email Rapidfit Looms with two questions and both were replied to in full and clearly the next day.

So in summary, yeas I would recommend them.

If you want to help me find the spark, there is a description of the problem over on the Scimi forum : http://www.scimitarweb.co.uk/sgwrs/v...hp?f=1&t=16276

[garyh]

I think you still know more than me... i won't be much help.

[WorldClassAccident]

I think you still know more than me.. Don't count on it, I only found out what I diode was on Saturday.

They are useful when wiring the hazards and indicators to their switches.

On Sunday I found out that they are 'directional' and mine were the wrong direction.

On Monday I found out new 10amp fuses can only be bought in pairs

[WorldClassAccident]

My engine turns over on the starter motor and there are sparks from the plugs.

Anything else I should check before squirting Easy Start down the carbs?

I want to see if there is any chance of it starting before pouring petrol into the tank.

[oxford1360]

If you have some oil pressure, and no leaks, get the video camera and go for it.

[Mister Towed]

Originally Posted by WorldClassAccident

My engine turns over on the starter motor and there are sparks from the plugs.

Anything else I should check before squirting Easy Start down the carbs?

I want to see if there is any chance of it starting before pouring petrol into the tank.

Probably teaching you to suck eggs but make sure you use fresh petrol, not what was left in the Scimitar tank which will probably be past its best.

[Mister Towed]

Oh, and if you haven't already got it fitted, electronic ignition made a huge difference to the way my Vitesse engine starts.

[WorldClassAccident]

Fresh petrol. Fresh petrol tank. Fresh fuel lines. Fresh fuel pump. Fresh fuel filter.

Cold beer.

Car can wait for a while.

[Nike55]

Good step forward WCA (you lucky devil). The guys over on the Scim forum are a great bunch aren't they.

Keep an appropriate extinguisher nearby? And don't forget the high Viz vest, hard hat and safety boots - you never know.

[WorldClassAccident]

Planning a test fire at the weekend as I am busy for most the week.

I may end up with the first G46 one the road...

...the driveway
...the neighbours garden
...the roof

[Nike55]

' ..tin hats, everybody'

[WorldClassAccident]

Just realized that I don't know the firing order, or which of the dizzy leads counts as number 1, or which cylinder counts as number 1.

At he moment the leads are just connected to the spark plug they landed nearest. I kind of assumed that the lead had acquired their shape over time so would lie correctly until someone asked me to explain it.

I might just find the right order out before the test start.

[Mister Towed]

Naaa, that'll be fine...