This was done by Matt who is the race car chassis builder
at Mazdatrix. It had some aluminum removed around the
steel liner where it was welded to the 304 SS .065 wall tube.
As Mark Steitle discovered this is totally unnecessary.

Removing aluminum is difficult to do and labor intensive as compared
to just welding it in.

It took Matt about five minutes to weld this and I paid him $22 bucks.

Welding them in is not completely necessary but it gives another
level of security against coolant leaks.

Sure is quick and easy to do. I am going to do it on
the RX8 P-port engine.

Paul Lamar ...No rotor no motor.

Paul,


Great and timely picture. I was speaking to the factory owner up the road
from me on this very topic yesterday and mentioned our experience of
cracking TIG joints due to vibration in the water pumping applications. He
has extensive experience as you have seen in supplying all sorts of
equipment for high tech IC Board manufacturing plants.  In brief he says in
your P-port welding application which is hardened steel welded to SUS 304,
shouldn't have a problem with vibration.  The key he said was providing
proper support for the pipe as their is  thermal expansion of three
different alloys.  I guess that is where your JB weld comes into play.

The larger factor of concern he said would be the different thermal
coefficient characteristics, with I suppose the SUS-304 pipe expanding
faster than the liner steel material.  He did say that those events
happening on start-up and cool down are few over the life of the engine so
all in all its maybe a good idea.  'Maybe' as you have heard is as close to
'Yes' as you get over here:)


Doug Fir

The temperature differences on that side of the engine are minimal.
I am not worried. A crack probably would not hurt anything anyway
because the JB Weld is still in there.

Hey the liner is steel and the housing is aluminum. Nobody has seen
them crack apart in two million engines for the last 40 years.
The combustion chamber side is 500 F.

BTW that rotor housing
I used was from Dave Leonard's turbo rotary powered air plane and he melted
the aluminum from around the lower spark plug treads while he was in the air
flying without coolant :) In other words the lower spark plug hole
and combustion chamber now communicate with the water jacket passages :)

Here is an idea for Mazda. Weld a steel spark plug boss to the
the steel liner to make the engine even more cannon proof than it is
already.

Paul Lamar ...No rotor no motor.

Paul

Hey that sounds good in principle but wouldn't be so pretty in application.
By the time you cleaned up the weld area there would be a slight depression
around the hole. Psssst  The sound of lost compression.:)

Doug Fir

Just the lower spark plug hole. The pressure difference there is
minimal.

This is the same reason my p-port trap door will work on the
stock RX8 engine.

Paul Lamar ...No rotor no motor.

Wasn't there some mention about some oval tubing a while back? Your trap
door is for automotive applications I believe but how tall could you make an
intake for an aircraft P port. 2"X 2 1/2", 2"X 3" ?  Could work well with a
slide throttle.  Huge breathing.

John Gibbons

Maybe. The timing might be less than advantages.

Paul Lamar

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