MGB Register Forum

Hi all,

I'm hoping some one can help. My B isn't starting and I think I've tracked the issue down to a broken cable on my electronic ignition. It attaches to the protuberance shown on the photo but is loose at the other end.

I have two questions: a) Where should it connect to and b) what is it called so that I can buy a new one?
Any help would be greatly appreciated!

Electronic switching only needs two cables, the red and black ones in your picture, red to a power source like the + on the coil, and the black to the negative on the coil. The thing you have circled is the port for the vacuum pipe from the inlet manifold or carbs. The suction applied to the vacuum can on the side of the distributor is there to advance the ignition timing at certain revs to improve the engine's power. I don't think the loss of the pipe would stop the engine from starting.

If that pipe is not plugged into the manifold, too much air will be drawn in, weakening the mixture, and might be the cause of your non-starting. What age is your car, as the position of the pipe on the manifold moved to the carbs at one point. Have a look around the manifold and carbs area and you should see a open nipple where the pipe should be. See my photo - I have circled the pipe on mine, plugged into a nipple behind the rear carb.

Thanks Mike, that’s really helpful; I now know I need a new vacuum pipe. Mine is a December 70 build - the set up looks like yours.

Mine is (was, as it is now sold) a 1971 car so should be the same as yours.