>> 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.

   Paul,

   What about aluminum brazing?

   http://www.aluminumrepair.com/

   I've used this for fixing stuff around the farm and it works very
   well. I've also used JB Weld, with mixed results. To tell the truth
   I am not too keen on using JB weld to glue engine parts together.

   Aluminum brazing uses low heat -- propane, mapp, acetylene. It flows
   nicely into nooks and crannies so I think it should seal well
   against pressure.

   The website claims it's actually stronger than tig welding (I don't
   know about that), but it has proven to be plenty strong. It could
   also be used for making aluminum gas tanks.


   Regards,

   Gordon.


JB Weld is no problem gluing these engine parts together as there
is plenty of bonding area. Proper preparation is essential.
You need to etch the aluminum surfaces. JB Weld is 4000 psi shear
strength and some of my test prove it. That is 100 times more
than what is need to keep this tube in the rotor housing.

I think tig welding the steel liner to the steel tube results
in less heating of the aluminum. Mark Steitle reports 130 degrees
F. That is way lower than what you would have to do to aluminum
braze it together. Tig welding is a very localized heating
system indeed.

All this is not about strength anyway. It is about sealing the
water jacket.

Paul Lamar ...No rotor no motor.

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