OK well that suggests a complete overhaul which I will do although I dont have a new diaphragm but the old one is pumping with finger pressure. I will get a new pump with electronic control for the rebuild car but this was just to get the “donor” car up and running. My original car has positive earth pump so I don’t think this is worth messing with.
SU pumps can be converted to either positive or negative ground, but not both. In the early days they were neither, not polarity sensitive.
The short coil body is about 60mm long and the long coil body is about 72mm long.
Burlens and Moss and probably others sell the diaphragms and points and electronic conversion parts.
1938 pump
1950 pump
1950 pump transistorized
I bought a new pump which is now fitted. I am replacing water pump which failed. I did a compression test today and got readings of 130, 128, 120, 120, 125, 70, 130, 80.
Putting oil in the low bores brought those readings up to 110 and 100 respectively so not disastrous but maybe the rings are a bit stuck as it has been sitting for so long. ??