Two stroke porting

Published: 06:31AM May 3rd, 2013
By: Web Editor
I really enjoyed reading Richard Rosenthal’s article on the above (TCM, February 2013)
Two stroke porting

This has prompted me to make some comments. I am acquiring a Series 2 Ambassador fitted with the oddball Villiers 5E 197cc engine. I refer to it as such as it seems no other maker took it up at the time (1947-8). Was there a problem with it and other lightweight manufacturers stuck with the 9D 125cc as the ‘big’ engine? Perhaps they were informed by Villiers that the 6E was coming which was promptly used by all and sundry?

The 5E still uses the Villiers early flat top piston porting of four transfer ports and two exhaust ports which I have seen referred to as the Schnurle system. This patent being first used by DKW and I once owned a 1938 example of the firm’s car which although slow by modern standards was reliable and very economical. The car handbook illustrated the porting via a diagram of the motorcycle engine, two transfer ports and single exhaust port.

My observation is that Villiers in 1934 started using the more complicated and expensive to cast configuration in its engines to get around the German patent.

Suddenly in 1948 Villiers used the DKW system which I think would be a result of war reparations.

I am interested if anyone else shares my theory on this.




Wal McClellan, Melbourne, Australia

Responses to “Two stroke porting”

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