The BN2 coolant path is rearward from the water pump, through the cylinder
block, with
branches to the cylinder head. The major flow is then through the cylinder
block &
branching up to the head, & forward through the head to the thermostat housing
& into the
top of the radiator tank.
With the heater valve open, part of the cylinder & head flow is
diverted/bypassed from the
center of the cylinder head & back to the pump inlet reducing the coolant flow
to the rear
cylinders & head.
Or, the BN2 coolant distribution path essentially has a coolant bypass from the
center of
the head through the heater to the pump intake when the heater valve is open.
With the heater valve closed, the coolant flows the full length of the cylinder
head &
back to the thermostat housing/radiator without this heater bypass.
What is the prevailing opinion on optimum uniform cooling. I dont know what the
original
desigh intent was. A more standard arrangement would be to have the outlet to
the heater
at the waterpunp outlet not in the center of the head. Does the heater
connection
bypass some of the cylinder head cooling? Is heat distribution optimum with
the heater
valve open or closed. Can the head to block transfer passages be optimized in
size to give
the most even overall cylinder head & block cooling? We are talking about an
engine that
is considerably midified for more horsepower & resultant heat. The objecting
being to have
the most uniform cylinder temperatures.
Thanks for any thoughtful replies.
Regards,
Dave Russell
BN2
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