So just finished a build with Aus gel 1.38 spring, SHS 16:1 metal gears, metal nozzle, chi hai purple motor, 11v, plunger head and rack. Shimming seemed pretty good when I put it together. Anyway after two mags it ran super hot and the trigger melted!! It didn’t sound great initially but I played with the motor height and it sounded ok. Rpm wasn’t super high but I put that down to the larger spring.
I’ve done the same build in another HK with 18:1 and 1.28 and it runs fine. Would the 16:1 and 1.38 be the issue or is it likely to be a shimming issue? After looking at the shell it looks like there is some wear around where the pinion would be. Teeth looked fine. Maybe bevel height is wrong and pressing down on the pinion/motor shaft??? The sleeve on the motor is the one that came with it but I changed it in the other build. Could this make a difference??