Coolant - problems and solution --- yet another thread

[Greg Hermann]

>My youth was spent racing Imps  --- 1000 cc rear engined saloons  made
>by Rootes/Chrysler (UK). They had engines based on the old
>Coventry-Climax FPE engine and used to have a major problem with
>overheating at peak revs (9600 rpm), one trick we found worked which was
>I believe borrowed from the Cosworth MAE "Screamer"  F3 unit was to fit
>a very small crankshft pulley to slow the water pump down to about 1/3
>crankshaft speed  - this stopped cavitation  (water truning into micro
>bubbles of superheated steam) in the water pump rotor and made the whole
>cooling system work much better --- it also reduced the power used by
>the water pump.
>
>Andy MacFadyen

Absolutely a valid, and practical, solution. slower speed got the pump to a
point on its curve where NPSH requirement was not as demanding. Another
elegant solution is to compromise on pump speed, and pre-pressurize the
cooling system using compressed air, N2, or whateverso as to give the pump
more positive suction head.

Regards, Greg