Running too cool--
20 deg retard for the warm-up!! (((Shudder))) Goes to show the difference
between a purpose designed race engine and a homemade one. I doubt if we
could ever have talked Doug King into trying that on one of his arduns.
Keith--Here's a little project for next winter assuming there's room on your
trailer for one more gadget. Package an RV hot water heater, a battery and a
1-2 gallon propane tank on a cart. Find a small 12vdc pump that can handle
180F, some hoses and quick connects. Even a fraction of a GPM would work.
Really trick- a small piston pump driven by a stirling engine running off the
water heater flue. Eliminates battery and electric pump that doesn't like
running hot water.
Last a point on running too cool. Not sure this is of any practical
application for race engines; but still interesting. Besides the obvious
problems of ring sealing and friction from higher oil viscosity there is the
phenomena of increased ring wear due to the presence of minute amounts of
liquid acid sulphates in the ring to cylinder wearing interface. Some 30
years ago I was poking around in the university library when I should have
been studying and found an late 1930's SAE paper on this subject. Seems the
authors mixed some radioactive tracer into a batch of cast iron they used to
make piston rings and then ran wear tests at various engine conditions and
cooling jacket temperatures. (Imagine trying to do that kind of project
today!!). Bottom line was that the wear rate was worst at the lowest
temperatures (80-100F) and decreased to a negligible amount at around
160-170F. They concluded that wear was caused by the presence of water from
combustion byproducts combining with sulphur to form sulphuric acid which
accelerated wear as long as it was cool enough to remain in liquid form. Wish
today I could find a copy of the original paper.........Ed Weldon
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