Over the weekend I cleaned my tanks some more (IPA and DI water), installed the modified pin valve on one and partially filled it with nitrous. The fill tank made a little crackling sound during the fill which made me wary. Turns out the company I got it from turns CO2 tanks into nitrous tanks by adding a new valve to them... they use way too much PTFE tape on the valve threads and get some enough strands of it inside the tank for it to get ripped apart and sucked out when opening the valve (hence the sound). I found some in the valve of my flight tank, yay, fortunately it still seals but it's something that could really cause some problems.
The 54mm motor is also done now, the only parts I still have to machine are spares. I could use the same parts on both the 38 and the 54, but I'd rather have a set for each. Next is printing some ABS grains for next weekend's tests!
(Anodization will follow
)
For the 54mm I went with a 12mm (a hair under 1/2") nozzle throat and 6 1,5mm (0,06") injector holes which should be right at the maximum flow rate of the modified pin valves.