Offenhaser Model Engine Plans Development – Top End Final

Today I have gone back and attempted to “finalize” the assemblies that have no known design issues. I put “finalize” in quotes because nothing is ever final. I have decided to machine some coolant cavities into the head to allow for more coolant volume and better coolant flow through the head. The cavities will be machined and then sealed with an aluminum plate. I will used high temperature structural adhesive to bond in the cover plate.

1641850163697.png

Some of the final details incorporated into the head assembly are the plugs sealing the ends of the lengthwise coolant passages and the dowel pins securing the valve cages. The oil passage was added from the timing gear front cover through the head to the cam boxes. I borrowed liberally from Terry Mayhugh’s Offy build.

1641850179380.png

I added all of the holes to the bottom of the head to match the block, the coolant passages, the oil drain and the head bolt holes.

1641850191621.png

The block assembly is complete at this point.

1641850202095.png

As is the cambox assembly.

1641850218960.png

I think I can make the cambox cover from 5/8″ aluminum tube with a .049″ wall thickness. I will have to slit it, remove some material, then mount it in a mandrel for the bottom machining.