Paul,

Last week I manage to take some pictures of the jigs
 used for making
identical housings based on this cut off test
 housing.  These jigs
with
positioning dowels and through bolts have evolve to
 accept casting
plates for the DEVCON epoxy, or  hardened
 steel  plates with drill
inserts to drill the hold down stud holes for the
 throttle. Ditto a
plate to drill the  fuel injector bore holes
 and the injector hold
down
plate studs. As of today these jigs  also
 have  quick release air hose
connectors for leak testing.

Pict . 007  The p-port  final step cutter
 I made installed in the end
mill. It is set at a 56.3 mm OD.  Works like a
 champ.  Not shown is
the
P-port insert 56 mm OD 50 mm ID  which has
 O-ring grooves cuts to seal
on the inner and outer sides of the water
 chamber.  It of course slips
into the port hole. No welding needed and is
 removable, inspectable
and
changeable. Held there by the throttle Plate.
 Throttle to be fastened
to the housing by four M5 studs that also hold on
 the intake manifold.

Pict, 080. My design of a  low profile low
 restriction throttle.
Why?
In my application slide throttles are cumbersome and
 won't get me up
close and personal to the p-port as I would prefer.
 Hence the throttle
opening is  over sized  to compensate for
 the 1.5mm SUS 304
thickness of
the throttle plate.  It is 53 mm ID. The
 throttle plates (two needed
and two to screw up trying) are laser cut ellispes,
 slotted and to be
TIG spot welded in situ to the slotted 6 mm
 Stainless 303 shafts.
Center
 hole is for jig positioning. 303 on shaft
 is much easier to machine a
1.5mm slot into while the material  still has
 good corrosion
resistance.
 Shafts shown are not  profiled yet
 for minimal  air resistance in
WOT.
Ditto the  throttle plates  but they will
 be.  One shaft will not
protrude from the throttle plate.  The other to
 the central housing
spring and cam location. Good advise courtesy
 of  Kinsler. Now looking
into baked on teflon paint coatings to see if they
 have any measurable
merit in lowering air resistance in the intake
 manifold parts.  It
does
on prop blades.

Bearings are NTN BEAREE a tough fluorcarbon plastic
 which is harder
but
more slippery than Teflon. I believe this is the
 same material used in
motorcycle throttles. This material  has been
 tested on our wind
generator swing tail rudders for three years in the
 field.  These
tests
are equal to several million  swing cycles with
 no failures, at least
not in the bearing.  Earlier tails had to be
 strengthened as they got
beat up in the winds.  Google "Airdolpin wind
 turbine" to see it in
action.  Now on sale in USA.

Other updates as they happen.  The next
 challenge is to cast a near
perfect finished epoxy face on to a new housing and
 have it free of
inclusions.  That requires a liquid AL. DEVECON
 and application of a
vibrator.

Doug in Japan

 How about applying vacuum?

 Chris Cosman

 Hi Chris,

 Good idea in theory but the forms would need to be a
 tight fit on the
 various curved surfaces.  The force of gravity is
 adequate and the end
 of the pour will be on the top edge of the casting which is
 easy to
 level with a hand dremel tool.

One trick is to pour the liquid down a rod inserted
 into the cavity.
 Then a use a large industrial  vibrator or the type
 they sell for
 shoulder stiffness for a few seconds and any bubble will
 just pop to the
 surface.

 Doug in Japan

Also consider pulling a vacuum on this assembly. I have done this
with with silicon potting compound on a small pneumatic manifold.
The end result is a bubble free, high gloss finish.

Erik Wahlstrom

Been there done that. We had so much trouble getting the
epoxy to seal all the crevices I looked for a better way.
The welded p-port and removable sealing plate was the break
through solution.

Paul Lamar