Hello  Paul,

Here are four pictures of P-port and the in-housing  injection holders.
This housing is one of several scrap housings I am  machining to get the
entrance angle and component dimensions finalized.  These four pictures
are from last August's work and don't show the finished  bores yet.
The P-port will have an outer step bore similar to the  injector
holders.
I am extremely happy with the hardness  and toughness of the DEVCON Al
product.  Only one trouble is the  consistency is a little softer than
taffy so as you can see, it is easy to  end up with inclusions.  If you
work fast and use a technique like  applying frosting on a cake, then
good results can be obtained.  Any  hole can be drilled out and filled.
The company sells another slightly  softer epoxy that pours.  I
assume it
has more solvent  in it.

I was very happy with how the injector area worked out and was  able to
get the correct and final dimensions with this one housing.   As for the
P-port area I had to add about 6mm more along the bottom for the  slide
throttle to be supported correctly.  For this test work,  adding
epoxy is
not a problem as it sticks to a preexisting  epoxy when roughened up a
bit.  As you can see it sticks well to  prepared alumunim and is damm
near as hard.  It machines VERY  nice.

Can it done with your straight-in approach?Yes why not?   Bend up
some
thin aluminum sheet into the proper wedge  profile.  Alodize it. Fix
this
fence in place with hot  glue gun on the outside.  Epoxy should be made
extra high and milled  down to final dimensions. To save expensive epoxy
add a 40mm wooden or  plastic dowel in the area where the inlet will be
bored.DO NOT PREHEAT to  make it easier to pour.  Follow the
directions for best  results.

Doug in Japan

That 12.5 degree tilt looks like a real  mechanical advantage.
I hope you can find a dyno over there to get some  good numbers
on the pros and cons of your version. BSFC and  HP.


Paul Lamar

Paul, With this approach why not  bolt two housings together with a
center section between and  the dowel pins then machine
that assembly P-port section flat  so that a slide throttle can be hard
mounted directly to the  housings?

Fred O.

I think I see what  you are driving at. That might work.
I'll have to do a 3D and  see if that is feasible.

Paul Lamar

Paul,

I bought the taffy consistency product.  As  Lynn mentioned years ago, and
repeated yesterday in almost the  same words, the product held up in the
exhaust port area in  his kart motor.

Doug Fir


I would  like to point out that the bypass ports I built  into Power
Products engines using Devcon Plastic Aluminum, move fuel air  mixture
from the
crank case to the cylinder, and as such were cooled during  operation. The
epoxy was exposed to high temperatures after shut down as the  whole
engine
normalized the hot and cold sides. I have also potted Pport tubes  (carbon
steel) in place and never had a leak. I have not attempted to use  Devcon
in or
near exhaust ports. I doubt that it would hold up for very long in  that
application.

Lynn E. Hanover.

I am going to try Doug's idea of putting epoxy on the outside
to make a flat area for an O-ring outer seal. If it leaks
in the future it can be more easily repaired. I'll buy the high
price liquid aluminum Devcon product but I am willing to bet it
is no better than JB Weld. I'll heat one puck of JB Weld and another
of DEVCON in the oven at 500 F and see what happens. My money is
on the JB Weld :)


The welded SS tube to the liner will be retained.

Paul Lamar
--

Paul,


OK but that may not tell you much as in application if your intake port
gets up to 500 degrees I think your engine will have bigger problems:)
I take it you are concerned with thermal soak after the engine is shut
down?  This could be a problem with an unshielded exhaust system nearby.
  I would be more concerned with comparing the compressive
strength,hardness, thermal creep characteristic, and toughness.

Are you going to retain the straight-in approach?  If so  the upper wedge
of epoxy will be about 15mm high.  I suggest you put a metal dam there.
Best is a three side dam that conforms to the housing.  This was the
next experiment I was going to try.  It can be one piece stainless that
is bent.  Done properly it will look nice as well and of course can be
milled as well.

Doug in Japan

Yes. I will keep the straight in approach.

Paul Lamar

Paul,

Is there any merit to a .005" interference fit between an Al tube and the
rotor housing using LN2?

Joe Berki

You have to be careful you don't stretch or warp the housing. .005 inches would
result in a major leak in the sides of the housing where the water O rings are.
IMHO it is not worth it. The SS tube tig welded to the liner and the conformal
aluminum plate is straight forward and highly likely to work with easy leak
repairs in the remote chance you even get a leak in the outer housing.

BTW a pound of Devcon pour came into today but I will probably use it
to make a casting pattern for the conformal aluminum plate. It was about $56.
Larry has a new casting supplier he likes in Northern CA.

Paul Lamar