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

 Paul,

 Before you start please understand one point.  One of the main reasons  I
 went with a process of adding epoxy to the aluminum  housing was I
 wanted the chemical bond between the two creating a homogeneous
 epoxy/aluminum housing.  This was to ensure  that four M5 (3/16") studs
 that will hold thethrottle assembly  had enough material to tap into.
 If you examine the housing area on the lower part of your bore and
 about seven to ten mm in from the edge  you can readily see that the
 sloped housing profile is only about seven mm thick.  Not enough for a
 blind tap unless you are going to pot the inside of the cavity as well.
 However with a  epoxy material added on top of the housing you will
 have added at least another six mm in thickness.  On the other hand
 slapping on a cast epoxy wedge with screws and silicon sealer will
 ensure that you lose the strength advantages of the composite as well as
 needing to screw into something that is screwed on to the housing.  In
 the end to have a perfect aligned fit you are going to have to machine
 the housing  with an end mill.  Please don't tell me you are trying to
 promote a quick and cheap drill press method  P-port:)

 Doug in Japan

 Well no. Here is the plan. Mill off some material off the housing
 down to the outer wall with the housing in the mill at 90 degrees.
 Same as if you were boring the final hole. Screw this aluminum
 casting (3D 1) to the out side of the housing. Screw holes or
 screws not shown yet. Then bore the 2 inch
 hole for the SS tube to be welded to the inner liner.
 Weld the tube. Unscrew the casting slip it off over the tube
 and cover the inside with red RTV and the bore with red RTV.
 Replace the casting. Your done. Expansion and contraction will
 not be a problem as it is accommodated by the flexible nature
 of RTV.

 I'll get a bunch of these casting made and sell them.

 ----------------------------------------------------

 I changed the plan slightly. I was having too much trouble coming up
 with a valid solid model for the casting pattern so I simplified it.
 The down side is you will have to do a little die grinding on the rotor
 housing to clean up the valley so a simpler plate will fit and work.
 Let me me know if you want a stp file or iges.

 Paul Lamar

 Paul,

 Good idea on simplifying the Al. cast.  That will make the fit much
 easier to fit exactly and calculate shrinkage.  Say on the assembled
 engine are those the screw in P-ports from Racing Beat? They are mounted
 about 10mm higher than what I planned and should open and close much
 later than your straight in approach.  If so I think you once commented
 that they only breath well at very high rpms.

 Doug in Japan

 I don't know about the RB p-ports. I copied the Lemans engine
 size, timing and angle. These I have torque BSFC and HP data on.

 Paul Lamar

Hi Paul;
Both Doug's and the Racing Beat angled down Pport intake design have the
advantage of more room for a turbo installation.
In a NA install you get a little more separation from the hot exhaust.
The disadvantages are more difficulty machining the angled intake and
more fabrication work for the intake itself.
There is room to put a slide throttle/adapter plate flat against the
engine and use the stock intake manifold bolts (black arrows in the pic)
for straight in Pport intakes.
With an adapter plate you can clear the stock water pump; or cut it up
for a smaller installation.
Injectors could also be installed in a thicker aluminum adapter plate.
Way less work.  Just a thought.
Cheers
Cary