I can now confirm that many of the modern reproduction rotor arms are a disaster. They look perfectly serviceable and perform well for most of the time. However, there is a basic design fault which allows the rivet on the top to short out to the clip which grips the distributor shaft. You can sometimes drive very considerable distances with no problems, and then for no apparent reason the engine just stops. This usually happens when you slow down and then try to accelerate again. The engine very often restarts again immediately: sometimes it needs to be left for 5 minutes or so. In retrospect, I realise that my car had been doing this for some considerable time, particularly in very hot weather. The only part I have not had replaced, in trying to identify the problem, was the rotor arm. My recent complete engine rebuild also replaced everything, EXCEPT THE ROTOR ARM!!!!!!!!! Someone had suggested that this might be the cause of the problem and I ordered one of the special "red" ones from the Distributor Doctor. In the meantime, I found a very very old rotor arm at the bottom of my spares bag: this has no rivet or clip and is far more solid and substantial than the modern one on the car. It has been a revellation using this during the first 320 miles of running in (180 still to go). The engine is much smoother and pulls much better - AND there has been no sign of any hint of the previous behaviour. I will continue to use this very ancient rotor arm and keep the "red" one as a spare. It is amazing that such a seemingly simple component can cause so much trouble. Posted by DavidMJS 11/02/2014 18:08:43
