1971 Mk1 - Wiring to Coil & Ballast

[Alec1978]

1971 Mk1 - Wiring to Coil & Ballast


Hi Everyone,

I have recently purchased at Mk1 1971 stag and I'm looking for some help with the wiring to the coil and the ballast. The car starts and runs, however is hesitant under power and develops a slight misfire from the exhaust. - I'm not sure if this is related to the incorrect wiring to the ballast & coil?

A previous owner has been fitted an accuspark electronic ignition and coil - the coil reads 1.9 ohms resistance across the positive and negative terminals.

There are 3 wires that are not connected to anything around the coil area, these are:

• 2 - white / red stripe wires
• 1 - white / purple stripe wire

The above wires look like they are part of the original loom and all 3 read 12v when the ignition are on.

Can you anyone help with regards to what these wires are and where they should be connected and if the coil is wired correctly?

I've added a few pictures to help.

Kind regards,

Alec

coil3.jpg

coil2.jpg

coil1.jpg

[Goldstar]

As you suspect, not much of that looks original except the white/orange which is to the starter motor and the white slate is correct and is fed from the tacho. The white orange looks badly crimped but shouldn't be your issue. Have you checked rotor arm, inside the distributor cap and the HT leads?

Have you got electronic ignition fitted? If so check the sensor isn't moving and if it has a "chopper" that it isn't cracked.

White/purple is for the temp sensor, if yours is working there's either another wiring change or you might have a combined gauge with oil pressure? The sensor is at the back of the LH head (passenger side) just below the cam cover, it will have a spade (lucar) connector sticking out but you have to hunt a little.

As an aside get those water hoses changed when you can, those kevlar ones are rubbish and split for fun.

[Alec1978]

Hi Paul, thanks for your response.

The previous owner had fitted an accuspark electronic ignition and coil. - I will check the sensor and chopper this afternoon to see if there are any cracks.

I've changed the dizzy cap / rotor arm & HT leads.

Re the white and purple wire - My temperature gauge works, and is a standard 71" gauge. No after market oil pressure gauge has been fitted.

I will check the colour of the wire going to the temp sensor.

I have purchased a kit that replaces all the water hoses as they are all well past their sell by date - I think the car has been lying for many years.

The hose in the pic is actually from the brake servo - which I intend to replace as well

It looks as though it was in the club at one point as its sporting an SOC sticker on the windscreen.

I've attached a few pics of the car

stag1.jpg

Stag2.jpg

[Goldstar]

Looks nice. Accuspark has a Hall effect sleeve over the distributor centre spindle. I don’t like accuspark, they’re prone to failure in my experience (2 fails) but others have had decent service from them.

[Alec1978]

Thanks Paul - looks nice / runs like a bag of spanners though !

I was going to change it out for a powerspark unit. I've used this on my TR6 for +10 years with no issues

[DJT]

As Phil says, get the coolant hoses changed asap. Those so-called 'Kevlar Reinforced' hoses were being touted and the best thing since... around 20 years ago. Many owners had them split with no warning, including me! I am amazed that there are still any around.

IMG_0625.jpg

[mikethemechanic]

Hi don't be confused by the WHITE/PURPLE wire this was originally connected to a transmitter on the rear of the o/side head and illuminated a warning light in early cars dash cluster -- due to problems on new cars the wire was disconnected under factory instruction - just tuck it out of the way - some later cars had wire but later cluster without the warning lamp -- Mike

[Alec1978]

Many Thanks for your help - Mike / Phil / DJT

Looking at the MOT history and mileage of the car I think its been in storage for circa 20 years