Another Knucklehead, built via castings, as a Draw-Tech design, upscaled

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Valve cages installed, press fit and high temperature Loctite , hole and thread for spark plug , inlet and outlet holes
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The valves
I turned the profile of the valves with a small and old CNC lathe that I purchased from a school, I replaced the entire electrical/electronic part with a Chinese CNC controller and a computer
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I lapped the valves with a tool that rotates back and forth a few degrees, with drill
I glued a "mushroom" on the valve which is connected with a flexible hose to the lapping tool

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the final check with a vacuum pump

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Mockup heads

a first assembly test of the heads with all the brass components, the valves assembled with the springs and seegers, exaust and intake flanges


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the Draw-Tech design of the valve system

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I still have to build the final rocker arm shafts then I can move on to the camshafts and the others engine parts.
 
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Great work! Nice castings! How much did you have to lap the valves to get a good seal?
 
Great work! Nice castings! How much did you have to lap the valves to get a good seal?
I leave a sharp edge in the valve cages, lapping with a fine liquid abrasive (grit 800) for 2 minutes with a lapping tool and obtain a good seal.
One of the 4 valves took me a long time to get a good seal. The cage had probably been deformed during installation with press, it was no longer circular. I had to create a small bevel, lap with 320 abrasive and then lap with fine liquid. More than1 hour of work for 1 valve
 
That's my aversion to using cages. I know some have good luck with them but I haven't. When making the cages with the seats already cut if you get a deformity and have to cut or heavily lap the seat then the seat becomes too wide. Here again not that it won't work but the seat area should be kept as small as possible. On a engine of your size that would make them in the .025-.035 range.
 
That's my aversion to using cages. I know some have good luck with them but I haven't. When making the cages with the seats already cut if you get a deformity and have to cut or heavily lap the seat then the seat becomes too wide. Here again not that it won't work but the seat area should be kept as small as possible. On a engine of your size that would make them in the .025-.035 range.

when I turn a combined seat and guide the piece sticks out beyond the chuck and is made in a single chucking so the turning and drilling all end up both perfectly concentric and perfectly round, then I use loctite to hold them in the head, I do not press them in, I did that once and they shrank and the valve stems no longer slid into the guides which had to be reamed after installation which meant they ended up non-concentric with the seats, so lots of extra lapping required.
 
Some machining of the crankcase right, left end cam box

the red jig it is to obtain the 45 degree angle of the cylinder seats , 3D printed

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Cam box

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to get the exact center of the bearing seat on the cam box cover, aligned with the crankshaft bearing seats, I used a center drill that rotates on the crankshaft bearings


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this small hole will be a reference for all the bearing seats on the cover
 

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Dubious Humor follows: Ignore if you want.

(See Post #50)

Johnny Five and his cousin Juan Cinco meet to plan the takeover of this project.

(In all seriousness, I am following and admiring this build and I Thank You for posting.)

--ShopShoe
 
Camshaft, pushrod, pushrod tube, lifter guides, the most complicated components of this engine.

I made the lifter guides from brass casting, with the usual system of 3D printing of the model, plaster, brass casting to obtain the finished piece with already the holes for the pushrods. only reaming was necessary in the holes. This has greatly simplified the drilling-reaming processes for me, double angles are required, which are quite complicated.
Unfortunately I don't have photos of the entire manufacturing process, but only of the finished pieces, temporarily glued onto the Cam box

Very importantly, Terry Mayhugh helped me a lot in this by providing me with drawings of both my lifter guides, I am very grateful to him

The glued front and rear lifter guides served me to trace and verify the contact of the pushrods on the cams

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Pushrod adjuster front and rear cylinder
They are made of bronze, I screwed a hardened ball screw into the tip that slides on the cams , I try this solution, an alternative would be to screw a screw with a rounded head made of phosphor bronze , very hard bronze
The balls should rotate in contact with the cam, to be checked ..
Of course, the camshaft must also be hardened.

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Foketry:

How do you tighten the ball/screw units into the pushrod? Can you tighten them from the back side, or are they held in with Loctite?

Don
The pushrod has a hole to allow to screw or unscrew the ball screw

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Could you give more detail about these. I'm not sure what they are. Do the balls rotate like a ball point pen? - TerryView attachment 158005


Yes the ball rotates like a ballpoint pen but I don't know if, with a load applied to the sphere , it will continue to rotate, I have to try with the engine running
If the balls don't rotate, I replace them with a phosphor bronze screw (4mm)
 
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