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

[Foketry]

Valve cages installed, press fit and high temperature Loctite , hole and thread for spark plug , inlet and outlet holes

 

[Foketry]

Intake and exhaust ports

I changed the inclination of the ports (15°) because as seen in the drawing they intersect the fixing holes of the heads

test to verify the alignment of the hole

 

[Foketry]

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

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

the final check with a vacuum pump

 

[Foketry]

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

the Draw-Tech design of the valve system

I still have to build the final rocker arm shafts then I can move on to the camshafts and the others engine parts.

 

[gbritnell]

Great work! Nice castings! How much did you have to lap the valves to get a good seal?

 

[Foketry]

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

 

[gbritnell]

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.

 

[peterl95124]

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.

 

[Foketry]

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

Cam box

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

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

 

[Foketry]

A partial assembly of the engine to check the machined components

 

[Foketry]

View attachment 157755

 

[ShopShoe]

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