Tuesday, 19 June 2012

Valves for the Hopper special

I thought I would do a little blog post about the latest work that has been done on the Hopper special’s Lea Francis engine.

It is not often when you get original correspondence from the engine builder about how he built his engine. In this case we were very lucky when it came to the Hopper special valves.

Below is a picture of a standard Lea Francis valve which is suitable for the 1500cc Dirt Track engine.

Std Lea Francis valve

The next couple of photos show a letter and drawing from Ian Hopper about how he wanted to modify the valves for the Hopper special.
Letter from Ian Hopper

Drawing showing modifications to the inlet valve

Given Ian wanted to build his engine this way, it was only right to remove all the valves and machine them as he intended. The photo below shows the newly machined valves to Hopper specification as well as some of Ian’s old valves.
New valves modified to Hopper's specification along with some of the original valves

The final scan is of Ian Hopper in his mk3 Hopper special and is from an advert in this years’ Classic Monte Carlo rally programme.
A picture of Ian Hopper in his mk3 Hopper special at the Rest and be Thankful


  1. It’s wonderful discovery and really useful. Thanks for the posting.

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  2. Are you going to do a follow up article? Would love to know what happens next.

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