Engineers will appreciate that with a combined piston and rod weight of four and one-half pounds, the strains from twenty-two hundred reversals of motion per minute at normal speed are very slight.
It has three rings together with fourteen oil grooves aiding the rings in retaining compression and assisting the oiling. All pistons are rough turned and then thoroughly annealed before grinding, to insure against warping in service.
The piston rings are of clean springy iron, ground all over. As a ring must be tight on the sides as well as where it comes in contact with the cylinder, there must not be a variation in width of over a quarter thousandth of an inch.
Cylinder:
The cylinder is symmetrical in design, insuring even expansion without distortion.
Valve-in-the-head construction gives an efficient shape of combustion chamber; the compact charge fired in the centre giving quick, complete combustion, and the large valves give free ingress and egress for the gases.
The water jacket is brazed to the cylinder-casting autogenously, the metal being a composition of nickel and copper known as "Monel" metal, which is proof against corrosion.
Cylinders are bored, ground and finished by lapping, to get a glass smooth surface.
Water Circulation:
The water circulation is so carried out that all cylinders are cooled equally, the water pump being divided by a partition which passes water in equal quantities to each set of four, thus avoiding any possibility of a steam-trap on one side causing all the water to pass through the other side. The pump is driven from the crankshaft by a floating joint. The pump shaft is made of a carbon spindle steel.