Coolant - problems and solution --- yet another thread

[am018]

Never though of pre-pressurizing    -- good idea  !  at times with these little
all alloy engines the temp gauge seemed to be connected to the tacho :-)

Greg Hermann wrote:





> >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
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