Steam Engine Build/Optional Sensor Vent
Steam Engine Build Instructions
In earlier versions of the steam engine design, the sensor port was located at the top of the cylinder but in order to reach the cylinder clearance, it was necessary to drill a hole in the cylinder liner and then mill a channel in the cylinder case to bring it out to a place were clearance pressure could be accessed. Inevitably, this would mean steam would leak between the liner and the case.
In the new design, the sensor port is optional. It is a hole drilled through the valve case an cylinder valve seat plate into the cylinder clearance space. When used for measurements, a hollow nipple is threaded through these two plates. When not used, the nipple is replaced with a bolt.