Vacuum advance / Distributor

The little pipe that goes from the Plenum to the advance bellow on the dizzy had a black and red non return valve fitted inline. One side said "dist" the other "carb".

It was plumbed in the correct way, but what is its purpose??

It only passed air towards the dizzy (ie pressure not vacuum), but i dont understand how it would work, because the non return would lock the advance in position.

Another thing I noticed was that the dizzy seemed to "click" clockwise if I turned the rotor arm, not easily move and spring back like I have known in the past?? Is this normal??

I think it uses balance weights to return it rather than a vacume both ways , mine only has a pipe one side and its how it should be. No valve on mine and no carb either lol

I am no expert though!

Not sure what engine/version you have. But looking through the Land Rover parts catalogue, the 3.9 classic had a similar valve fitted. But this was only on the American export models. Something to do with their higher emission controls.

Try going to/ringing up your local stealership, they should be able to tell you. Actually as its an older model you may be better off finding a good independant as most dealers have to look up the classics

I dribble oil in to my dist to lube twice a year. The advance mechanism is seizing on yours, which will effect performance. Remove rotor arm, then plastic shield and dribble oil down eachside of dist ,about spoonfull, leave for an hour or so before starting. Oh and if the rotor arm is stuck, dont force it, cut it off with a Dremel small cutting blade and fit new rotor. There is a plastic clip that will break if you use to much force. The valve is to stop petrol entering dizzy wich would cause explosion. Its suction that advances dizzy.