X-Mozilla-Keys:                                                                                 
JMLBlues@aol.com wrote:

I've been avoiding commenting on this thread until now, hoping it would die
on its own. Someone earlier on summed up my thoughts that the pump is a
non-issue. There was some data early on to indicate maybe a problem, but the
data was probably misinterpreted. Unless you totally block open the
thermostat main flow passage and totally close the bypass passage, you will
not get an accurate reading of pump flow. The early data with a high delta T
across the radiator and a low flow rate only indicated that the system was
functioning properly -- the thermostat was modulating the flow to maintain a
stable coolant outlet temperature. The cooling demand was not maximum, so the
thermostat only let out a little of the 180 deg coolant, which the radiator
promptly acted on to get the temp as low as it could, which was apparantly a
pretty big drop. No problem.

But the dangerous idea that is lurking here is that people may try and open
up the coolant restrictions in the rotor housing. The restrictions are there
to balance the flow between hotter and cooler sections. Without some pretty
good insight (or a lot of cut and try testing) it will be very easy to make
things worse rather than better. Basically, to cool the hot zone of the rotor
housing, you need velocity. But too much velocity can lead to cavitation
erosion that can eat the aluminum in very little time. Too little velocity
and there will be potentially catastrophic hot spots. If the flow area in the
rotor housing is changed, then the pump capacity will need to change to
maintain proper velocities. My own feeling is that even 300 hp engines can
live with the existing pump, although the well-proven modifications (by
Mederer, et al) like grooving the coolant passages are possibly worthwhile.

My two cents.

Jon Lauter
Rotary Power Marine Corporation
www.rotarymarine.com

Thanks Jon. Sounds like excellent first hand knowledge and advice.

Paul Lamar
 
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