1923 Dennis Trailer Pump


This is a 1923 Dennis trailer pump on solid tyred disk wheels. It is fitted with the Dennis No.2 pump which was only in the second year of use with Dennis. The engine rather than being a White and Poppe unit is a four cylinder Dorman. Rated power output is 20HP. Unfortunately the pump had been partially disassembled for many years and some parts are missing. This is the continuing story of the restoration. For the start of the story click HERE.

All the pistons are now free but still attached to their rods. The big end caps have been removed so that the pistons can be pulled clear of the bores so that the rings could be freed off.

Number 2 piston was the one which caused all the problem. You can see the pitting in the piston and the corrosion on the head face around it.

Before attempting to rotate the engine clean new oil was circulated  through the engine under pressure. A connection was made to the oil pump pick up port and then to a temporary tube oil tank which could be pressurised.

Here we see the connection to the oil pump. With oil dripping out of all the right places the engine was rotated with the starting handle. After a few swings the crank rotated very smoothly and would continue to rotate under the momentum of the flywheel for two or three additional revolutions.

Attention has also be turned towards the fire fighting water pump. The pump arrived without it's deliveries.. Temporary aluminium gates have been made (before attacking expensive gunmetal!) so that the delivery coupling adapters could be produced.

The rear face of the coupling adapter has to be a sliding contact fit with the gate so that the gates will seal correctly. Unless the gates provide good seals it will be difficult to prime the pump.

This is the coupling adapter in place. The female instantaneous hose coupling still needs to be polished.