Dear all,
For a couple of seasons I had troubles ith my vintage race car (1930
Morris JAP) boiling at ONE particular circuit. The circuit was unusual in
that it had a very slow twisty bit for 1 mile, and the rest was virtually
flat out. The problem, it turns out, was all down to the direction of
water flow
The direction of flow of the water is more important than some would have
you believe. The water pump works by pushing the water off the impellors,
this creates a pressure drop and water flows into the pump to replace the
stuff that has just been "pumped". The important part of this is the
"pressure drop". If your car is running close to boiling point (be that
100C with no pressure cap or 110C with a pressure cap) then the drop in
pressure will cause thewater to instantaneously boil and turn to steam
within the pump. Remember Water boils at something like 50C on top of
Everest. The water pump does not pump steam very well and the flow
around the engine stops.
Thus it is much better to suckk cool water from the rad into the pump than
it is to suck the hot stuff out of the block.
Having built a new rad for my car andnot cured the problem, I reversed the
direction of flow and have never had rthe problem.
Hope this helps
Geraint
*************************************************************
Dr Geraint Owen
School of Mechanical Engineering
University of Bath
1930 Morris JAP
1928 deHavilland Riley
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