The 1933 Ruston generator diesels at Moorside Edge radio transmitting station started by admitting compressed air to one of two out of six cylinders. Woe betide you if you failed to start the engine as the compressed air bottle only held enough for one start and failed start would often put the engine in the wrong position. You'd have to bar it round with a six foot steel bar in serrations on the flywheel. A light person would not have enough weight and would need help.
Basically a ship engine from the period. Exposed rockers, oilers to keep full and all of that stuff.