[asphaltgambler]

^^^^^^^^^^^^^^^Lot's of reasons as the engine / combustion chamber technology just wasn't there yet. Almost none of the old over-the-road trucks and industrial / off road equipment had turbos, so they made their power with through displacement and long stroke.

Also, there was significant drag in the rotating assy; largely due to piston design with extra long skirts. So long in fact, they employed additional oil and compression rings on the skirt. That idea was to stabilize the piston in the bore because of the very long stroke and to promote very low piston / ring / cylinder bore wear over 100's of thousands of miles ( or hours).

The injector pressure at the nozzle was very low compared to today's engines. So you have a combination of factors that worked against cold weather starting and performance:

You're trying to crank over a very large displacement engine working against the leverage of a very long stroke, significant rotational drag, poor combustion at cranking speeds, oils that would turn to syrup in cold weather.

Engine starters that consumed a lot of energy but barely had the torque needed, old battery technology, etc.

I can remember as a kid - the family next to us had an old Caterpillar crawler they'd use on the farm to do heavy work. In the winter they would build a fire using wood / sticks under the belly pan of the engine. Then crank it using a gasoline 'pony' engine that was incorporated from the factory mounted in the rear on the engine.

Once the fire deemed hot enough, you started the pony engine through an electric starter, let it run and warm up. Once it was warm, you'd go full throttle on the pony engine and engage the clutch to crank the engine with the fuel off. After @1 min or so when the cranking speed sounded good enough, you'd turn on the fuel with the throttle lever about 1/3 way 'up' - if all went well it would 'lite' after belching black smoke.

It was a manly task back then......................