This is a quality product from the Czech republic. It has nothing to do with CS.
It was hand made by a gentleman in Prague, who produced a small series of these engines - I can't for my life remember the name behind the initials - Gustav something.
Peter Chinn described the GZ .12 in an "Engine round-up" feature in Model Airplane News, sometime in the 80's, and he mentioned the full name but I plain forgot.
Anyway, a friend of mine who travelled regularly to Prague in the 80's, and was very interested in miniature diesels brought home a small batch of these engines and I bought a couple from him.
They came with a choice of red, blue or plain alu heads. They were mounted on cards and each engines was supplied with a hand carved laminated wooden prop.
I have my whole collection of engines stashed away at this point due to other commitments, I'll see if I can find the other GZ .12 with the card and prop and get a photo of that too, it's all very neat.

The c/case casting may not be up to OS standards but the moving parts on my engines at least are really well machined & finished; the engines are silky smooth, with perfect fits all around and perfect compression.
I have used a regular Cox 3 x 1.25" prop for running; it's a good size.
The engine is easy to start and to adjust.
A lovely engine indeed.