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