Several different things or a combination of them can
Letís start with cooling systems in the 30ís and 40ís.
We ran zero pressure radiators, which meant when the water temperature reached
212 degrees, it started boiling. (This is assuming no glycol antifreeze was
On a warm day (80 degrees or higher) with several people
in the car just going up a hill could overheat the engine.
The first thing to remedy this is to pressurize the
system. For every pound of system pressure, the boiling point of water
increases about 3 degrees. A 10 lb. Cap thereby raises the boiling point by 30
degrees. This alone would raise the boiling point of the water to 242 degrees.
(212 plus 30)
When water (or coolant) boils, it creates steam pockets
which causes damage like cracks.
Henry Ford made about 25 million flathead V8ís. For the
most part, they ran fair in stock form. Now the hot rod guys took the stock
heads off and put on after market high compression aluminum heads. From then on
many had overheating problems for two reasons.
Improper surface finishes on the deck surface of the
heads are still a problem today. It was always thought that a bit of a rough
finish on the gasket surface would help hold the gasket. Small lines from the
flycutting tool do not help hold the gasket. They are escape routes that
prevent the cooling system from being totally sealed.