Octane Rating of Canadian WWII vehicles

[Dan Martel]

I originally read about this on the "Axis History Forum" under the thread "Unserviceable Lorries - Jul - Sep 44." It runs to 26 pages in total.

On post #12 it reads:

Something ELSE happened over the summer of 1944 that might have led to heating issues on particular motors...

The octane rating of Pool Petrol rose! During the war the octane rating of "Pool" went down as low as 67 octane, but in the summer of 1944 what would have been coming out of the pump at PLUTO in Normandy apparently rose to around 80 octane.

The nearest we were able to get to a breakdown of such magnitude was the engine failure of countless British Trucks following the introduction of Higher octane MT80 fuel. British Engines were not designed for operation on 80 octane petrol and as a result those of certain makes and types (we do not know which) developed severe burning of the valves. Changes were made to exhaust valves and guides for operation on leaded fuel and new engines were provided with valves made from an alloy steel containing 20 (Vs, 8) percent of chromium to lengthen engine life between overhauls.

In fact...it's entirely possible that in an engine designed for very low octane "Pool"....the range of adjustment in its magneto ignition system (it was WWII...) MAY simply not have allowed the ignition timing in the K5's new engine to actually be advanced enough to cope with what was - after all - a 20% rise in octane rating...and the heating problems that caused - within the design parameters of the original engine 8O ...

Warning, if you start reading this thread, it will suck you in to all 26 pages before you know it.

Cheers,
Dan.