Rudy Kouhoupt Pioneer Engine

[toolznthings]

Continued ..........

[yogi]

Great documentation with all the pictures Brian! 

Can you tell me your source for the small boring bar your are using turning the valve housing (First picture on last post).
I need to stock up on small boring bars... 

Thanks,
Yogi

[Flyboy Jim]

Boy........lots of operations to machine those valve housings! Well documented. I'm enjoying following along on this build, Brian. 

Jim

[toolznthings]

Thanks, Jim.      The valve housings were probably the hardest part of the build.

Thanks, Yogi      I get the solid carbide bars from McMaster Carr. Pretty good selection and high quality. I think they are priced
fairly.

[toolznthings]

Overview of the carburetor ......

The carburetor is made from brass and has two opposing cone shaped bores that form a venturi.

The thru bore is .180" in diameter and one cone terminates .875" back from the end. The taper is 3 degrees
per side. I set up the body at the lathe and used a small boring bar to machine each taper. The carb body was started as a block
.500" thick x .875" wide x 1.250" long. I reamed the .180" diameter thru first and used this hole to indicate the position of
the bores at the lathe.

At the intersection of the cones the brass orifice is soft soldered in place. The orifice has a .021" hole for the needle
to seat. The body of the jet is .250" diameter at the end for the fuel hose.

I made the needle assembly from 2-56 threaded stainless steel stud and knurled knob I purchased from McMaster-Carr.
After machining the point on the stud, the knob and needle were assembled with Loctite.

Milling the the body stock to form the mounting flanges and drilling the mounting screw holes finished the carburetor.

[90LX_Notch]

Brian-

This is a great build.  I'm really enjoying it.

-Bob

[toolznthings]

Brian-

This is a great build.  I'm really enjoying it.

-Bob

Thanks so much !

Brian

[cfellows]

I always had a hankering to build this little engine.  Yours turned out to be a fine example, lovely work, nice finishing touches.  Especially like the base you have it mounted on.  Nice woodwork, too!  Is that a vapor fuel tank you're using?

Chuck

[toolznthings]

Thanks Chuck for the comments !

That's a " tank " for the fuel to the carburetor and has a lift off lid.

Brian

[toolznthings]

Machining the intake and exhaust cams ......

Starting with a round blank large enough to leave stock I bored the 7/16" diameter to make a slip fit on the
crankshaft.

At the cnc mill using one of my three jaw chuck fixtures the profiles for each cam was machined. The first milled
step is .688" diameter and is the hub for the 4-40 set screw holes. The cam profile was milled slightly deeper
than the .500" overall length of each cam.

At the lathe the cams are parted off and then to the mill for the set screw holes.

I modified the crankshaft journals with a groove about ten thousands deep where the set screws will bite in
for each cam and the breaker point cam, also. This allows for adjustment of the cams without damaging the crank.

[toolznthings]

Machining the flywheel ....

Machined one side face, 4.250" o.d. and .375" bore in one setup. Sawed off from the stock and held in soft jaws
the opposite side was finished to overall thickness of .875"

Broached a .125 key way in the flywheel and added a matching key way to the crank. This modification was not
on the plans. Prevents the flywheel and mounting nut from self tightening.

No drilled hole pattern was added to the flywheel.

[toolznthings]

A look at the parts after some finishing work prior to assembly .....

The engine mounting rails in the pictures are my design as there are no specific plans for this part of the build.

Parts not mentioned earlier are in these pictures.

[gerritv]

Excellent surface finish, not a trivial amount of work.

Gerrit

[Nick_G]

.
That looks highly impressive. 

Nick

[zeeprogrammer]

Excellent family shots! Very nice looking parts too!