> Here are the essentials.
>
> --
> Paul Lamar ...No rotor no motor.
>
>
> Paul,
> How would you purge air out of the system in this
> arrangement? I know
> that this has been discussed in detail in the past,
but it
> seems that
> you would need a line from the rear side housing to the
> pressure can in
> order to purge air that may be trapped in the engine.
>
> Mark S.
>
> You must run a vent line from the highest point in the
> system
> to the top of the pressure can. In a tractor tail
dragger it
> would be
> the rear (car) end housing. The housing closest to
the PSRU.
> The best place is where you have the pressure
fitting now.
> I think
> it is the return line from the water heater port in
the
> stock
> RX7 system.
>
> The pressure container must be mounted as high as
possible.
> The cooling system is constantly generating tiny steam
> bubbles. These must be able to rise to the highest
point in
> the
> system which should be just below the pressure cap.
When the
> pressure
> in the system rises to the blow off setting of the
pressure
> cap
> this steam accumulation will be the first thing
purged to
> the catch
> can.
>
> Paul Lamar ...No rotor no motor.
>
> Paul,
> Yes, wp-plumbing5.jpg shows it more clearly. I didn't
see that
> line in
> the previous jpg.
>
> On my installation, the radiator is angled from front
(highest)
> to rear
> (lowest), so I have a 1/4" line going from the upper
most tank
> back to
> the pressure/swirl tank.
>
> One caveat, when filling the cooling system, it is possible
> (likely) to
> get an air pocket in the vicinity of the wp impeller. In my
> installation (20B, thermostats removed), running the
engine will
> not purge the air from this area. You must remove a
plug from
> the side
> of the wp housing and continue adding coolant until
liquid runs
> out the
> hole. Then replace the plug, run engine and coolant should
> circulate.
> An easy way to tell if it is circulating is to hold your
hand on
> the
> outlet from the wp after the engine has been running for a
> minute or
> two. If it is warm/hot, water is circulating. If it is
still
> cold,
> there is no circulation. It is my understanding that
more than
> one
> engine, following rebuild, has been fried due to this
> scenario. It may
> not be a bad idea to install a petcock on the side of
the wp
> housing
> for
> the purpose of purging air when refilling the cooling
system.
>
> Mark S.
>
>
> Instead of reinstalling a plug in the side of the wp
housing, would
> it
> be worthwhile to run a purge line from there to a high point
in the
> system? I guess it might depend on how tough the plug is to
get to
> once
> everything is installed on the engine..
>
>
> Matt-
>
> Here are some water pump pictures. Perhaps Mark S can mark
> them up using MS paint for us. The 13B Cosmo pump and the 3
rotor
> pump are the same. Note the bleed hole at the top of the
> pump cavity.
>
> Paul
>
>
>
> Paul,
> Here's a picture of my water pump housing. There's a plug in the
side
> that I now use for a pressure sensor. I remove the pressure
sensor when
> refilling the cooling system. I add coolant until it starts
coming out
> the plug hole, then I replace the sensor and continue filling. My wp
> housing does not have the bleed hole as shown in
> Bulents_Cosmo_pump2.jpg. Did it come that way or did he add that?
>
> I've resisted adding a purge line as it is an additional failure
> point. A petcock or Schrader valve would be preferrable.
>
> Mark S.
>
>
> I don't recall Bulents pump having that feature.
> Bulent's pump had the bleed hole as stock.
>
> What did you do about the bypass?
>
> I see you are using the Wiggins couplings. Nice work!
>
> ------------------------------------------
>
> That looks like the highest point in the system.
> Where is your pressure container and pressure cap?
> If it is above this point which it should be you
> should not need this tap.
>
> --
> Paul Lamar ...No rotor no motor.
He needs the tap for the pressure sensor.
Mark, what is the make and model of the pressure sensor? I hope to be
putting an engine together soon. :)
Doc Custer
Retired Software Engineer and sometime Audiologist
Doc,
I purchased a 0-50psi sending unit from egauges. That is the source
Tracy uses and recommends.
My system has changed from that last picture. It was too tall, so I
made a blockoff plate to replace the thermostat housing and cut a hole
in the side of the wp housing just below the blockoff plate and welded
on a wiggins coupling. I also took a die grinder to the inside of the
wp housing where the thermostats go. There's a wall separating the two
thermostats, which I removed. I welded up the two thermostat bypass
holes as well. Initial ground runs indicate that it is cooling well.
Pressure tank is mounted on the firewall and is the highest point in the
system. That's where the cap is located. It has a float switch to
alert me of low coolant.
Mark S.
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