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Sometimes you get in touch with people while looking for Motom parts.
I saw on eBay two special Bishop heads for a Motom, they were so nicely designed that I contacted the seller for more information.
It turns out that Mr. Alberto Orzi made them himself so for me it was verry interesting asking my question directly at the builder/constructor.
And he was very kind to answer them all.

Now our conversations go that deep, that planes are made for making small changing to the original design so the head can operate longer under heavy load.
To see that progress, I thought it would be nice to open up a special column on my site for this project.
Here you see the original design.
Here you see some of the components separate to show its operation.
There is great detail in the construction, and he worked out Serval ideas.
1) Like adjustable compression.
2) Oil cooling for the exhaust shaft.
A prototype head
Using a base plate where the head is mounted on.
The possibility of adjusting the compression by turning the Inliner upwards or downwards
A great combination.
Because the whole design is built on the sliding bearing principle heat disposal is getting a problem.
Especially at the exhaust side when heating up changes of clamping itself in the brass bearing is rising.

The first idea is mounting bearings, so the inner shaft could rotate on bearings in stead of the brass sliding bearing
The idea.
Starting on that idea.
First parts do look great.
Because of the size of the massive shafts they create a huge intake and exhaust port giving a aggressive timing.
To get both bearings in place a smaller shaft diameter is desired, this also will result in a less aggressive timing but that's OK.
First intention is not to out power a conventional valve system, but to make something special that runs great
A new design is as follows
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