Generic Oilfield Engine

[cfellows]

I'm back to work on my (used to be Bessemer) Oilfield engine.  Since I'm converting it to 4 stroke operation, I guess it will just be a generic oilfield engine.  I'm retaining the frame, flywheel and crankshaft, but the rest of it will be new.  I want it to have a sideshaft operated cam and I've already made the helical gears required for it.  Then I decided to move on to the head since that's a pretty tricky part of this type engine.  I've been working on the design for over a week.  Here is the outside with a glow plug screwed in and one valve cage attached.  I plan to use spark ignition, but will need to order a plug for it.



Hear is the inside, showing the combustion chamber, which is 1.25" diameter and 5/8" deep.



The exhaust valve will be on top and the intake will be on the bottom.  The bore of the engine will be 1.25" and the stroke will remain at 1.75".  The displacement will be 2.15 cu in (35 cc).

Chuck

[gbritnell]

Chuck my friend you never stop!!! I thought I spent a lot of time in the shop but you certainly have me beat. I'll be watching this project.
gbritnell

[cfellows]

Chuck my friend you never stop!!! I thought I spent a lot of time in the shop but you certainly have me beat. I'll be watching this project.
gbritnell

Thanks, George!  I do enjoy my shop time.  I also pretty much have to have a metal-working project underway or I get bored. 

Chuck

[b.lindsey]

Happy to see you back to work on this on Chuck. Maybe you should link back to the original thread in case newer members want to see the parts that are remaining the same...just a thought.

Bill

[cfellows]

Good idea, Bill.  Here is the link to the other build...

http://www.modelenginemaker.com/index.php?topic=675.0

Chuck

[cfellows]

Moving along, I fitted the new cylinder to the frame today.  It's made from a 4" length of 2" OD x 1.25" ID DOM steel tubing.



I will be shortening it from it's current 4" down to about 3", but first I want to make the new connecting rod and fit the piston.  Here's a picture showing what the head and valve cages will look like.



Chuck

[cfellows]

I wanted to get started on the connecting rod today, but, alas, I searched the shop high and low and couldn't find a piece of aluminum anywhere close to the size I needed.  It'll have to wait until Monday when I can get down to Metals4U and see what they've got in their cut-off shelves.

In the meantime, I made the valves today.  I fabricated them from 1/8" drill rod for the stems and silver soldered 3/8" steel ends which I turned smooth and cut the angled valve faces...



This is the tool I used to groove the ends of the valve stems for the e-clips...



That's one of 3 small slotting saws I bought for under $10 at Harbor Freight.  It really worked very nice, turning the valve stem at around 120 RPM as I made the cut.  The chips came off in nice, tight, small curls and the groove is about .025" wide.

Here is a drawing of the my current plan for the valves, rocker arms and push rods.



I still have to figure out the lifter arrangement.  It'll probably be some kind of roller attached to a swing arm so it can roll on the cam.

Chuck

[Johnmcc69]

Looks good Chuck!

 John

[AussieJimG]

I love the way you march boldly into the unknown, confident that you will overcome problems as they arise.
And I admire the fact that you do find solutions.
'
It's a great journey and I am following with interest; as usual.

Jim

[cfellows]

Thanks, John.

Thanks, Jim.  I have to do it this way because I can't visualize the whole thing in detail, so I do things in a modular style, always prepared to do something over (and differently) if need be...

Chuck

[Dave Otto]

Hi Chuck

Here are a couple pictures of how Falk did the rockers on their 3hp engine. The bottom (exhaust) rocker arm is a dog leg shaped casting and the intake is a round rod that connects into cast iron rockers at each end. The engine uses a single lobe to run both valves. These parts attache to the front side shaft bracket that bolts onto a boss at the front of the cylinder.

The second picture is of my engine which currently is still in pieces.

Dave

[cfellows]

Thanks, Dave, I'll have to study those a bit.

Yesterday I picked up a piece of 1" x 1/2" aluminum at my local metal supply store.  I cut my rod to length (11") cut off the rod cap, then drilled it, tapped it, and re-attached it so I could bore the big end journal.  I also measured and drilled the hole for the small end.  Exactly 10" from center to center.  This is going to be one heck of a long rod!



In the picture above, I'm showing the aluminum rod with holes bored and an MDF cutout of the rod profile that I plan to cut.  The profile in the MDF was cut using a 5/16" end-mill in my CNC mill.  I developed the G-Code myself using this drawing I made in Visio.



Here is the G-Code

O0001 (Main Program)
(Tool starts at home position 0,0)
#100 = 0 (Variable to control Z Axis)
M98 P0002 L10 (Perform the cutting loop 10 times)
M02 (End of main program)

O0002 (Sub Program)
g01 x1.2813 y0.6875 f8 (Go to position 2, this is where the cut will be started)
#100 = [#100 + .052] (Increment the depth of the Z-Axis by .052 inches)
g01 z[#100]  (Move the Z-Axis to the incremented depth)
g03 x1.5 y0.4688 i0.375 j0 f5 (Make a cutting move to position 3 with a counter clockwise arc, centered i, j offset from current)
g01 x10.4537 y0.3921 (Make cutting move to position 4)
g02 x10.4537 y-0.3921 i0.310 j-0.392 (Make a cutting move to position 5 with a clockwise arc, center i, j offset from current)
g01 x1.5004 y-0.4688 (Make cutting move to position 6)
g03 x1.2813 y-0.6875 i0 j-0.375 (Make a cutting move to position 7 with a counterclockwise arc, centered i, j from current)
g01 z0.010 (Lift the Z-Axis to 0.1 inche above the work)
m99 (End of Sub Program)

Heck, who needs CAM???

Chuck

[AussieJimG]

Raw g code is much more fun in these small sizes. But it is nice to run the program in mdf before committing to the final job.

My g code is a bit (a lot) rusty so it is great to see your code and to refresh the knowledge. Thanks.


Jim

[cfellows]

Thanks, Jim.  I learned programming in 1962 when I joined the Air Force.  I was a programmer for 10 or 15 years until I moved into management.  I continued programming for fun and work when I had the opportunity, using Assembler, COBOL, FORTRAN, then BASIC and C when the PC's came along.  To this day I like using Basic on my PC and my IPAD.  I also like to program the Arduino using it's C-like IDE.  So far, I'm enjoying G-Code, even though the Mach3 implementation isn't very sophisticated.  It's pretty amazing to write the code on the PC, then watch the steppers carrying out the commands.  Somehow it feels like the most useful and meaningful code I've ever developed!

Chuck

[gbritnell]

Hi Chuck,
I was a computer modeler/cutter pather for the last 11 years of my trade so all the tool paths were automatically generated by the program (WorkNC). This was for 3 axis work. For all 2 axis and point-to-point positioning the operators would do it at the terminal. It was also used to train the apprentices. Ah, the good old days.
gbritnell