Paul,

Made some progress on the heat shield.  I mocked it up using cardboard.
Will cut aluminum to see how metal works and then finally use SS.
It has  to be in 2 pieces as the engine moves and the duct does not.
the gap will  be covered with silicon sheet.  The plan is to cut a
scoop in the upper  cowl  and feed this space with outside air and
vent it out the rear of the cowl.  The scoop will also feed the
cooling air for the alternator.

Joe Berki
Limo EZ

Mr. Berki, are the P-port tubes in the photo aluminum? If so, how
have you  sealed them? I'm getting ready to install alum tubes in a
set I have, using  a type of alum solder to seal it all up.

Thanks!
Ed Carver

Why did you decide not to weld SS in Ed?

Paul Lamar

I'm going to try the alum anyway. I can use muggyweld to sweat the material
in and around any potential leak areas. If I can get to it with the spool
gun, I may mig weld some places. My experience mig welding items
like this has been very good, amazingly good actually. You can
control the heat by welding only small areas at a time. then let it
cool, and begin again. Tig welding on the other hand, puts huge heat
into the aluminum, which makes me worry about shrinkage, etc.
Welding in the stainless would'nt be much of a problem either, I
just have faith in the aluminum method at this point.

I will do the stainless method if the alum tube can't work. I do
think it is going to work though. We'll see. I have 6 housings to P
port. Two of which I don't need really, you saw those two at
Whiteman, good cond. just spares. I was going to p port my two rx8
housings, but I think I am going to get a good set of 84 rx housings
from Atkins, and sell these rx8 housings. They are almost new, super
low miles, less than a hundred. This way I can have 3 exhaust ports
each rotor.

I am considering using the stock intake ports along with the p
ports. I hav'nt seen anyone doing it this way. Does it work?

I should be working on the damper flex plate on monday. I'm prepping
my mill now.

Ed Carver

Practice on some junk rotor housings as it is hard to get in there
with any kind of aluminum weld short of furnace braze. The other big
problem
you will have is a huge difference in the amount of heat required for
the rotor housing compared to the .065 inch wall tube.

The stock input ports affect the flow in a negative way. They face
each other so they in effect tend to cancel each other. The p-port
air stream goes with the flow so to speak. It is the natural way
the flow wants to go.

I don't think the 84 housings have the high silicon content alloy.
If so they are more pron to heat shrink.

Paul Lamar

Thanks Joe!
Paul, I have seen several times dimensions for boring the p ports,
I'm sure I saved them, but now can't find them. Would you please
post them again. I know where to store them this time, and can't
find them on your main site.

Ok, I will eliminate the stock intake ports and use only the 2 inch intake.
I'll have to ask Atkins about the silicon content issue before I buy
a set of gsle housings.

If I can't mig weld the aluminum tube in, I dont think I will use the
muggyweld because it requires heating the surface to about 650F. It worries
me that it will remove the heat treatment of the housing.

Ed Carver

http://www.rotaryeng.net/**Welded-steel-p-port.html<http://www.rotaryeng.net/Welded-steel-p-port.html

With TIG you can weld the foil from cigarettes together. Not with MIG! You
use the same skip weld technique to keep heat down in one area. Your Al
tube
looks to be fairly thick wall that should be able to be reduced in
thickness.
This would allow a lot less heat requirement.
I would cut and trim the Al tube to match the contour of the inside of the
rotor housing. Then pull it back until just before uncovering the coolant
passage to get away from the steel. This way almost no filler rod will be
needed as the edge of the tube will fuse to the housing, supplying the
filler.
Once the inside is welded, the outside of the housing can be welded to the
tube. Pressure test and repair any leaks.

Dale Davies

It is much easier to tig weld the SS tube from the inside to the
3/32 hard steel liner. Forget aluminum tubes. Welding to
the steel liner proved to be a major improvement.

Back in the spring of 2007 about 03/26/2007 I had an idea that we might be
able to weld a SS tube to the steel liner in the rotor housing. Prior to
that we had a lot of trouble with the bonded in p-port tubes leaking cooling
water into the combustion chamber. This resulted in a rather involved
procedure for bonding in the tubes. I then asked this question on the
newsletter. Has anybody tried, or can you try, tig welding SS to a chrome
bumper? I figured the aluminum was not going to get that hot if we TIG
welded the thin SS tube to the hard steel liner. Also one can skip weld.
Weld four spots at 0 90 180 and 270 and let cool. Then weld the rest. We
don't need to weld to the aluminum at all. JB Weld will handle the rest of
it. I suspect that was better than heating the whole works and trying to
solder or braze. This was just an experiment anyway. Not necessary for
making p-ports.

I drove out to Sun & Fun that year and stopped at Mark Steitle's hangar in
San Antonio Texas and he had actually tried it on a junk rotor housing. Here
are some pictures of his fine welding job.


Now the time came to actually build a p-port engine and try it. I needed a
p-port RX8 engine for testing so I bought one out of a junk yard that had
been in a crash. It had a cracked front end housing in a non critical area
but Larry Childs did a good job of welding that up. We bored the RX8 engine
rotor housings and I had a welder weld in the SS p-port tubes. We did not
removes any aluminum from around the holes as I deemed that unnecessary.
John at Mazdatrix filled in the rest of the water jacket around the tubes
with JB weld and Kyle reassembled the engine using as many of the original
seals as possible as they were hardly worn.


So far we have made many hard runs on the dyno with no problems and no
water leaks.

Paul Lamar 11/21/2007


Paul,

Thanks for giving credit on the welded p-port experiment.  My p-port 20b is
running great and is a real pleasure to fly behind.  BTW, I used grey RTV
to seal the SS tubes from the water jackets.  Also, the Renesis water pump
is cooling fine.  It has the Mazmart cartridge.

Mark S.