Re: [xj-s] Dual drive water pump (was overheating)

["Robert C. Warnicke" <Obstinate@worldnet.att.net>]

Richard F. Dixon wrote:
> 
(Snippers)
> As for water pumps to circulate hot engine coolant, forget the water
> pumps at the RV store. Those are diaphragm pumps that wouldn't last more
> than a few hours pumping hot coolant. 

IMHO, I think just concentrating on a
> good electric fan with suitable circuitry to power it would do the job
> of post shut off cooling.
> 
> Richard F. Dixon
> 82 XJ-S HE


I think it is pretty clear that the jag's cooling is marginal, and that
post-shut the hot water migration is not fast enough to stop valve seats
from dropping.

There were windmill posts about how it might be ok to let an electric
motor that is switched off freewheel... what if we were to put a ac
clutch on the water pump so that it would disengage the motor drive when
the car was off and a dc motor could turn then turn water pump with
another belt.  This is not too dissimilar to what is posted at
stewartcomponents.com, except their DC motor is always engaged and
special roller pullies "idle" the DC motor drive when the engine RPM
goes over 1500 and let the engine drive "idle" when the engine RMPs are
under 1500.  Their DC motor never freewheels, ours would, and that
wouldn't be any worse than a fan blade turning a "switched" dc motor...
right?   

Or did I not make any sense again?  I have a headache.

73XJ12

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Follow-Ups:

• Re: [xj-s] Dual drive water pump (was overheating)
• From: Mike Morrin <mikem@southern.co.nz>

References:

• Re: [xj-s] Dual drive water pump (was overheating)
• From: "Richard F. Dixon" <rfdixon@chs.cummins.com>

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