Transitional Engine – Eccentric

eccentric and strap

The transitional engine eccentric is the drive for the piston exhaust valve, an eccentric is a disc with the rotational centre offset to the centre of the disc.

The transitional engine has been on the bench for quite some time and has gone through a number of design updates – basically there is no plan, except in my head and so the design changes over time.

My basic idea was to use an eccentric for the exhaust valve drive as this would give me a sinusoidal action. The exhaust valve itself is a piston type and so perfect for an eccentric drive.

The eccentric strap got to a very good level of completeness having worked on it over a number of days.

A jig I used to allow me to align the eccentric on the rotary table and machine the outside of the strap.

All of this machining and I got carried away and just went too thin.

You can clearly see the thread showing on the inside surface of the strap – back to the drawing board or perhaps just back to the workshop and start again…..

About Nigel 324 Articles
I've been making models since I was around 7 years old and using a lathe from the age of 11, a self taught engineer with a passion for making model engines.

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