Paul,

With an eye toward improving the cooling on my p-port 20B, I ordered one
of these custom water pumps from Mazmart yesterday. They claim it will
not cavitate up to 10,000 rpm. So, it should be well within the
operating limits at 6000 - 7000 rpm. This looks even nicer than the 20B
impeller.

Mark

P.S. They will give a discount for group buys of 10 or more.

------------------------------------------------------------
Great news Mark. I assume this is the RX8 version. Do they have
a 13B version. http://www.mazmart.com/

Do you have the exact link? Is it a new RX8 part or a used
RX8 part. I can't find it on the site?

When the continuous power goes up the heating requirements
on the rotor housings also go up. It is a good idea to install
a rotor housing thermocouple. Similar to a cylinder head
temperature gage. You want to keep the temperature of the aluminum
under 500 F.

The old 13B water pump had a better rotor than the
new RX8 water pump.

Is your engine back together? Let us know
what the rotor housing thermocouple says.

Paul Lamar

P.S.

I forgot to mention Mark is running an RX8 water pump on a
3 rotor p-port so the cooling requirements are 150%
of that of an RX8.

Paul Lamar


Hi Paul,

I have had a reply from Mazmart about the improved water pump.
The price will be $240 for orders of 4 or more.
What I need is 3 other interested guys to come forward
So we can get an order together.

Chris in NZ

That is a ridiculous price for a 3 inch diameter impeller.
I think you could walk into any NC mill shop in NZ and have just one
made for that price.

Software has improved to the point that all you have
to do is a drawing and software writes the NC mill program.

Actually all you have to do is buy a good replacement RX7 pump cartridge
for $30, press the impeller off. Throw away the rest of the RX7 pump
cart cartridge and install the RX7 impeller on the RX8 pump.

If you are using an RX8 pump on a 13B don't! Use a GMB aluminumn
cartridge pump instead.

Paul Lamar

Hi Paul,

Thanks for that , I?ll give it a go, could be a bitch getting the old
impeller off though, what sort of puller should I use ?
While I was taking off the apex lube pump I realized that
the drive for it would make a good way to make a engine
driven fuel pump, has anybody tried this ?
It would be relatively easy to make up a little camshaft
In a housing block and bolt a car pump on to it.

Chris in NZ.

You could machine a steel disk on a lathe that
will slip under the edge of the impeller and saw it
in half with a band saw. Then put the works in a ten ton
press and press the impeller off. Another way is chuck the pulley
end of shaft in a lathe and cut the impeller off on the
other side of the pump body. Companies rebuild Mazda
rotary water pump cartridge all the time with tricks like
this. The bearings and seals become shot and must be replaced.
That means getting the shaft out some how of course.

BTW here are some pictures of the aluminum GMB pump
cartridge. GMB makes a new cartridge for the 3 rotor water pump
as well I think. Getting one might be a problem as our man
in Japan is on vacation for another month or so.

Paul Lamar

Paul,

With an eye to single rotors could you comment on water pump selection.
With
a smaller engine and less heat to dissipate, could a smaller pump be
utilized ? Does a smaller practical existing pump spring to mind ? Could
the
existing pump simply be slowed ? Would there be an efficiency loss to
slowing the pump or is it just so small as to make it not worth bothering
about ? If the stock pump is 3-5 hp that would be perhaps 6% of the power
output of a single rotor. If we can halve the pump usage we have increased
the power out put by 3%.

John

I would take the easy way out and use the GMB pump at the stock speed.

You cannot have too much water flowing through the block.

With 120 HP to work with a couple HP here and there matters not.
Picking the right prop will have more effect.

Have you emailed Daryl Drummond <fastrotary@mac.com
<mailto:fastrotary@mac.com>> ?

If enough people that want 1 rotors email him he will
be encouraged to get into the biz. He is one of the finest
rotary engine builders in the world. Mazda Corp choice
for building spec engines.

Paul Lamar

Chris,

It seems as if they are offering a $25 discount. That's good as far as
it goes. However, if the pumps must be shipped to a single place and
then reshipped to the individual, the savings goes way down and it might
not be worth it. If they can drop ship to the individuals, if ordered
together, that's a pump of a different color.

Any info on this?

I am still interested if the above can be solved

Rich