I know this has been covered, however I am looking for a very old post or presentation by Ole in Norway that showed the pump differences. If thats not available I would like information on the differences of the five pumps.
The early pump with the counter sunk screws in the backing plate. The revised pump with the hex head screws on the backing plate. The pump with the D stamped in the nose corner The pump with DD stamped in the nose corner. The cast iron pump or the finale pump.
Any information on gear size and output would be appreciated.
Finally any suggestions on testing the output. I have a number of these pumps and would like to see how each performs
Gee Richard, you like opening a can of worms, next you will start an oil thread!
The early style pump morphed into the interim pump used in 67/68. There is some disagreement on when exact changes occurred. 67/68's likely had the improved end plate and small bolts instead of screws, but gear sizes remained the same length. There may have been a change to a coarser tooth in that era. My memory is foggy. The coarse tooth pumps had a wee bit more volume.
The D pumps are supposed to be single dowel, DD pumps are supposed to be 2 dowel. And longer gears for more volume. There seems to be 2 gear lengths. I have one D pump that has gears that are longer than the previous pump, but shorter than the final gears. The DD pumps are the best next to cast iron. DD, cast iron, and SRM pumps are all same gear length.
But this wouldn't be BSA without confusion. I have a D pump with one dowel. DD pumps with one dowel. D pumps with 2 dowels. 1 unmarked pump with 2 dowels and long gears.
Flow I can't help you with. It isn't a lot. When I was helping Alex with his race bike, you are marginal at sustained high RPM. For normal use, the late pumps are fine. Even the interim pumps do ok.
Pressure is limited by the OPRV. The fit of the relief and location of the oil drain drilling have been beat to death on this board. So you know the drill.
No doubt you know the drill on what needs done to an A65 to make sure the pump is all it can be.