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MG MGB Technical - MGB GT 67 Dizzy and HT leads

Hi guys,

Just got my hands on a 67 mgb gt as a bit of a project and it's my first attempt at "working" on a car.

In light of this i unsuprisingly need a little help.

The first problem i have is a HT lead that doesn't fit, so i've taken of the distributor cap and removed it from the car with the leads attached, but i'm not sure how to remove the offending lead and worse still i have no idea which lead is for which cylinder!

I assume if i put them on in the wrong order the cylinders will fire out of sequence.

The cap is a side entry Lucas 25D if that helps?

Thanks for your patience and your help!

Cheers,

Tim

T Jevon

Tim,

Look under the cap. You should see a small screw in each terminal. It is pointed and pierces the wire, thus making the electrical connection and holding it in. When you put the wires back on, to get the right firing order, remember that (as I recall) the distributor turns counter clockwise.

Charley
C R Huff

Thanks Charley,

I've managed to remove the offending lead following your instructions and believe i've got the correct order (fingers crossed!).

Is there any benefit in changing to a top entry cap and adding an electronic ignition module?

Thanks,

Tim
T Jevon

The top entry cap offers improved metal to metal contact and allows for the use of RFI suppression ignition wires. However, the coil will need to be replaced with one from a '68 to '74 model B, since it has the screw down connection, for the coil wire, and not the push on connection. RAY
rjm RAY

Hi Tim,

If you have a multimeter, do a continuity test between the terminals and the HT wire. I've had that little screw miss the internal conductor.

Herb
Herb Adler

Not answered so far, but far more important, the firing order is 1 3 4 2 counting *anti*-clockwise round the distributor.

No.1 (which is the cylinder at the front of the engine (don't be offended, this question has been asked in the past)) is *usually* at about 1 or 2 o'clock as you stand at the side of the engine compartment and look at the top of the distributor cap. But depending on what has been done to the engine and distributor in the past it could be any one of them. So if you have lost which cap contact No.1 plug lead connected to, or the car was a non-runner when it came to you, first you will have to determine which *is* No.1 cap contact. Remove the plugs and turn the engine by hand, with a thumb over No.1 plug hole, until pressure from the piston rising on its compression stroke (both valves shut) lifts your thumb off the plug hole. When the piston gets to the top of that stroke, where the rotor is pointing is connected to No.1 and the rest counted round from there.
PaulH Solihull

This thread was discussed between 14/03/2011 and 20/03/2011

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