Hi Paul,
I was wandering how the slide throttle PP engine turned out? Since
the stock turbo turned out to be a big bust, I have removed it and my
plane still flies,
but I'm considering building a PP one.  Please put me back on your
list. Still don't know how I dropped out in a first place? You were
missing at this year's Shady Bend Roundup?
Bulent "Buly" Aliev
FXE Ft Lauderdale, FL
 http://tinyurl.com/dcy36

Well due to my own stupidity I bought some expensive high temperature
epoxy to bond the p-ports tubes in and it was a disaster.
It did not bond to the aluminum and we had a pin hole leak.
It did not show up until after we ran it on the dyno and
shipped it to Mark. When Mark ran the engine he found water
in the combustion chamber and he took it apart shipped
some of the parts back. We had first thought that it
froze the block being in the unheated hangar at 20 below.
Right around that time Dave Leonard had froze his engine
leaving it outside at 30 below at Mammoth Mountain airport
while skiing without the proper antifreeze mix. He made
an excellent off airport landing on the freeway and Robin,
I and a dozen others helped him take the wings off and
truck it back to LA. I digress.

We found out the epoxy was not mixed correctly on one side
of the rotor housings and that was causing the problem. We "fixed"
it with JB Weld and Mark put it back together and tried it again.
Better but not perfect. What I should have done was pressurize
the cooling system to 30 psi without the  e-shaft and rotors in
the engine to check for cooling system leaks BEFORE final
assembly. Hind sight.

Mark and I met in the middle of Utah and I took the engine
back to LA see if I could fix it without taking it apart.
After some experimentation I was not comfortable doing that
so Mazdtrix took it apart again. I then chiseled out the high buck,
high temperature, hard as a rock epoxy from the other side of
the rotor housings and sure enough it had not bonded to the
aluminum. JB Weld bonds 1000 times better. I replaced it
with JB Weld and I am now confident we found the problem.

Mark, to his great credit persevered through it all and
the engine is now being put back together and will be pressure
tested BEFORE it is shipped back to Mark this week or next.

Thank you Mark for putting up with all this. I owe you.

When Mark gets it running again I will fly out and help
him tune it. When we ran it on the dyno we had trouble
tuning it with Tracy's EFI because the dyno load is
so much different than prop load. It was costing me $650
a day on the dyno fooling around so we did a quick and dirty
install of Weber 51 mm carb and got about 240 HP at 6500 RPM
right off the bat.  The Mazdatrix guys were so sharp tuning
the Weber it took only one jet change and we were well within
the power ball park.

Anyway check out the latest hot tip very simple low pressure
mechanical fuel injection on the web site.
http://www.rotaryeng.net/mech-fuel.html


Paul Lamar ...No rotor no motor.

Hi Paul;
To be fair, there is not enough independently published data/field
history on many
epoxies from which to form any scientific conclusion.
JBWeld appears to widely available and more than up to the task.

For PPorts, I meant to pass along a few more comments for best results
bonding to
aluminum:
1.   clean/degrease!  home depot acetone is not recommended -> impurities.
2.   roughen all bonding surfaces with sandpaper
3.   follow resin/hardener mixing instructions/proportions
4.   apply the epoxy to the tube insert and PPort hole separately and
sand each
surface(brush or sandpaper) after applying the epoxy to remove the AL
surface
layer (under the epoxy) for best bonding.
5.   another thin (non-structural) top layer of something like Silicone
Rubber over the
epoxy potting on the water passage/insert sides (after it has cured)
could act as
additional leak barrier.
6.   any straight through insert/slip fit should have some sort of
mechanical backup -
stepped insert, threading, brazing, welding, press fit, pins, extra
mechanical bond area
(grooves, etc...)
Cheers
Cary


I agree with everything except 6. The bond to the aluminum
is more than enough having dug one or two out.
No way is that tube coming out of there.

5 won't hurt but it is unnecessary.