Royal Blue #3

I made two parts today the exhaust valve roller lifter and the lifter retainer plate. I just made up those names as I don't know what else to call them.

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The roller bearing is 0.250 in diameter and 0.125 wide. I must have dropped it a dozen times.
Here they are mounted on the engine.

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And a shot of the bearing resting on the cam.

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The push rod is next but probably not tomorrow .

Thanks for looking
Ray
 
The yoke ring mounts on the inside of the flywheel and holds the fly weights for the governor. I was going to try something different for the governor but all my other ideas were complimented and probably wouldn't work any better so I stayed with an arrangement that does work.
Most of the cutting was done in the mill and then the ring is parted off in the lathe.

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The ring was pressed onto the flywheel. The ring will anchor the arms that hold the fly weights and in turn move the spool for the miss arm.
Fly weights and arms are next.

Thanks for looking
Ray
 
Actually two days work on the little bits.
The valve train is now complete including the governor assembly and the hit miss arm.
The first picture are of the fly weights and arms, and the second is the hit miss arm with the spool pin pressed in.

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Rear view of the assembly shows how everything goes together and works.
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This shows the fly weights and springs.
I have no idea if the springs are going to be correct until the engine is running. One of the keys to a good running engine is getting the spring tension and the centrifugal force of the weights correct. I want to get this engine running as slow as possible to imitate the full size engines.

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In this view you can see the hit miss arm pin engaged in the spool.
As the flywheel spins the weights pivot outward and that moves the spool closer to the flywheel. That in turn pulls the hit miss arm, that when the speed is high enough, the end of it will catch on the valve lifter and hold the exhaust valve open until the engine slows down some.

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I even made up a straight pipe for the exhaust.
Maybe I need to shorten it a little it does stick up quite a bit.

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After making these parts I realized there is not much left to do just the carburetor, gas tank, and the electrical.

Thanks for looking
Ray
 
The exhaust stack just didn't look right so I cut off about 3/4" looks better now.
I have sort of jumped around the last couple of days working on the gas tank and the ignition system.
The spark comes from a solid stater unit that uses a hall effect sensor and a rotating magnet.
I mounted the sensor here and made an aluminum ring for the magnet to mount on the crankshaft.
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Cut a hole for an on/off switch.
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View of the battery pack and ignition module inside the base.
The ignition module is made for model airplanes but works very nicely on these engines. It uses 4 AA batteries and will throw a spark more than 1/2" long with a crisp snap.

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The gas tank is made from 1" copper pipe with two end caps soldered on and painted black. The brass tank mounts were made for engine #2 but proved to be too high for that engine they should work fine for Royal Blue.
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I need to leak test the fuel tank and then on to the carburetor.

Thanks for looking
Ray
 
This is the third hit miss engine I have built and from the beginning I was apprehensive making the carburetor. All the designs I found were very complicated with close tolerances and many small parts. On engine #2 I decided to make a very simple carb with as few a number of parts as possible and be easy to make .

Four parts make up the carb, the main body, the main jet, the adjusting knob and the needle valve.
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The main body started as 1/2" diameter brass with a turned down section for some 1/4 X 28 thread to screw into the cylinder head. A #19 hole was drilled all the way through. A cross hole was drilled through the body for the jet and the adjusting screw. The top hole was tapped 6 X 32 and the other hole was drilled for the jet.
The jet is drilled all the way through with a 0.030 drill bit. One end is sized for the fuel line to attach to and the other to fit into the body with a slight press. This ends length is set just short of the mid point of the carb and I added some lock tight on assembly for sealing.
The adjusting screw was turned down with some 6 X 32 threads and the center drilled through at 0.040 for the needle.
I bought an assortment of sharp pointed needles for hand sewing and chose the largest one that was 0.040 in diameter. The adjusting knob is screwed into the carb body just short of the #19 center hole so it doesn't pertude in to the carb. The needle is then glued in to the knob and seated in the jet. The end of the needle is then cut off flush with the knob and a spring is added to the knob.
This design is simple and relatively easy to make plus it has worked well on engine #2 and should work on Royal Blue as well.
I am not an engineer and just a hobbyist machinist and I am sure there are better designs out there but for me being able to work with thread sizes and part sizes I can see and make is more important.

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The jet is visible in this shot inside the carb body.
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Comments welcome

Thanks for looking
Ray
 
IT LIVES

Royal Blue does run but I am getting a lot of blow by around the piston and it is running too fast.
I will probably make a new piston out of aluminum with an o-ring.

Pictures to follow.

Thanks
Ray
 
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