Thanks Arwyn - I think my pump is a very old replacement. 1/2 BSF is 16 TPI. Mine is definitely 20 TPI.
I have a plan:
1. I managed to find a shop that sells 5/16-20 nuts - 4 on the way. Straight-eight.com, they specialize in Deusenbergs and pre-war cars.
2. A 5/16-20 tap is on the way. I’ll use it to chase the threads on my M8-1.25 nuts and then can compare.
Could always slice up some hex bar and make my own, but we’ll start with this. The fact that they even make a tap means this size has been used, albeit rarely.
Once am done with this pulley business I can get back to refitting my new crosshead. I’ve replaced the timing chain and tensioner, water pump rebuilt and back on. finishing my C40 rebuild now as well. Slow and steady wins the race.
