McDonald SPI Diesel


 Manufactured in 1954 by A.H.McDonald & Co.

Imperial Engine Works, Melbourne, Victoria.


The SPI was first made in 1950 and remained in production until 1974.  It remained largely unchanged during its production life except for modifications to speed and priming controls.

From 1918, McDonaldís produced diesel engines, either using the Hvid (pronounced 'VEED') fuel vapourising system or hot bulb ignition. The advantage of the Hvid or Brons system as it was sometimes called was that it could use any heavy 'distillate' as fuel, from kerosene to crude oil. McDonaldís maintained this was cheaper and easier for the farmer and argued that the system did not require specialist mechanical skills as it was simple and easy to repair. However in 1950 McDonald stopped the production of the Hvid diesel engine and turned to fuel injection.  The engine has a pressurized lubrication system, is a four stroke overhead valve engine and cooling is by evaporation from the water filled hopper.

It is surprising to me that an older style engine like this remained in production for so long when one realises in the 1960ís and Ď70ís smaller, lighter, more powerful engines had been developed and were widely available from a number of manufactures.