HelloPaul,

 Here are four pictures of P-port and the in-housinginjection
holders. This
 housing is one of several scrap housings I ammachining to get the
entrance
 angle and component dimensions finalized.These four pictures are
from last
 August's work and don't show the finishedbores yet. The P-port
will have
 an
 outer step bore similar to theinjector holders. I am extremely
happy with
 the hardnessand toughness of the DEVCON Al product.Only one
trouble is
 theconsistency is a little softer than taffy so as you can see, it
is easy
 toend up with inclusions.If you work fast and use a technique
likeapplying
 frosting on a cake, then good results can be obtained.Anyhole can be
 drilled
 out and filled. The company sells another slightlysofter epoxy that
 pours.I
 assume it has more solventin it.

 I was very happy with how the injector area worked out and wasable
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 preexistingepoxy when roughened up a bit.As you can
see it
 sticks well toprepared alumunim and is damm near as hard.It machines
 VERYnice.

 Can it done with your straight-in approach?Yes why not? Bend up
some thin
 aluminum sheet into the proper wedgeprofile.Alodize it. Fix this
fence in
 place with hotglue gun on the outside.Epoxy should be made extra
high and
 milleddown to final dimensions. To save expensive epoxy add a 40mm
wooden
 orplastic dowel in the area where the inlet will be bored.DO NOT
PREHEAT
 tomake it easier to pour.Follow the directions for bestresults.


 Doug in Japan

 That 12.5 degree tilt looks like a realmechanical advantage.
 I hope you can find a dyno over there to get somegood numbers
 on the pros and cons of your version. BSFC andHP.


 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 whatyou are driving at. That might work.
 I'll have to do a 3D andsee if that is feasible.

 Paul Lamar

 Paul,

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

 Doug Fir

 I wouldlike to point out that the bypass ports I builtinto 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 thewhole 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 sothe 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

 The heat soak issue is a real potential issue. I discovered today
that
 my manifold lines are melting on the intake tube fittings. This is
not
 happening during run time - the intakes are ice cold. The heat soak
 after shutdown is something to behold as the intakes go from cold to
 hot hot hot. The MP lines become hot & gummy.I've also noticed that
 the unshielded engine mount tubes are too hot to touch while the
 engine is running.

 Mark (Rocky Mtn High)

 You need red silicon hose on those manifold pressure lines.
 Either that or braided teflon lined hose.

 The motor mount tubes on my C182 also require heat shields.

 BTW that Harbor Freight vac pump does not have a vac gauge.
 You are going to need one.

 Paul Lamar

 Paul,

 Here are two small PDFs file showing the technical characteristic of
 Devcon Al putty and liquid.
 Liquid is superior in every way except flexible strength.I'll be
 ordering some of this stuff next.
 It would be nice to have the same data for JB Weld which doesn't have
 the product line, that Devcon has.

 Doug in Japan



Paul,
look at the coefficient of thermal expansion on the liquids. All
else being
the same, take the liquid steel for it's lower thermal expansion.
The thermal expansion difference between the potting compound used
and the
aluminum housing is the highest stress it will see.
It still expands more than the aluminum, but is far better than the
liquid
aluminum compound.
Larry


JB Weld is steel filled.  The other thing I have considered is make a lost
wax casting of a conformal aluminum filler block. No NC mill profiling
required. Use an epoxy casting as a pattern.  Machine screw it down with
RTV under it to the outer rotor housing. If it is tall enough that is all
you need. No O-ring and easy to reseal. This would be the most reliable way
of doing it. No room for error.

Paul Lamar

"Resolution tolerant"  my old man is always saying...
Chris C.