Subject: Water pump cutdown
From: Rotary Engine
Date: 1/6/2006, 8:22 AM
To: AA-me


    Quick question before metal starts getting cut & welded.  The mod I am
    making to the water pump housing means the new intake pipe is strictly
    used to connect the overflow container to the cooling system, yes?  And
    there is no reason to use such a huge intake pipe - I am thinking
    something on the order of 1/2" ID would work just fine.  True?

    Mark Supinski

    ----------------------------------------------------------

    The intake to the pump is not modified. It is the outlet from the block
    part that we change. The strange thing about the Mazda water pump is
    they routed
    the water coming out of the block through the water pump. In other words
    they did it all in one casting.  On a Chevy V8 by contrast this is
    not the case.
    The water comes out of the block through the intake manifold and
    another fitting
    that contains the thermostat. It is called a Goose Neck I think. :)


    The over flow container is not really an overflow container. What is is
    is an air space tank that allows the coolant to expand. It is
    pressurize to
    25 PSI or so and when the the pressure exceeds that coolant flows into
    a catch can through the pressure cap. When the engine cools off, and
    consequently the pressure goes negative in the block, coolant is drawn
    back in from the catch can. The catch can be a large plastic Coke
    bottle or just about anything.

    Here are a few 3D's. In the first 3D the catch can is not shown. Only
    the pressurize container is shown. Ed Klepeis built mine from deep
    drawn Zero
    manufacturing aluminum cans that I supplied but a Corvette
    version will work well.


Ah Ha!  I knew there was something I was missing.  I was baffled as to
why the pipe diameter was so big.   I was equally baffled when I could
not find a coolant output fitting on the block.  Both questions now
answered.

Ok, now I get it.  This also helps me understand the necessary radiator
geometry as well - thanks for the 3D it was very helpful.

Here's another question -- It would seem that there will be a number of
"high-spots" in the cooling design where air could become entrapped.
I'm thinking of the forward side of the radiator, as well as the output
side of the pump -- both locations seem doomed to be local high spots
where air bubbles will congregate.  Given this, how is air flushed from
the system so it works correctly?  Am I only now seeing the whole
pump-cavitating driver?

Mark Supinski


Good point. You need vent lines from the high spots to the pressure
can not shown in the 3D's. One is on the top of the end housing next to
the psru. I think it was the old heater connection.

In these pictures of a Chevy V8 you can see some of the vent lines.
In one case they added so many vent lines they did away with the
water outlet from the intake manifold :)

Paul Lamar ...No rotor no motor.

Mark Here is a site that sells a variety of pressure tanks.
http://www.cantonracingproducts.com/tanks/expansion_tanks.html


Paul Lamar ...No rotor no motor.

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