The Excam engine, as it came to be known, was an invention by Folke Mannerstedt. It is a very original design where the camshaft is moving back and forth instead of rotating. This action is produced with a rod that is driven by an excentric wheel from a gear connected to the crankshaft. The design potentially gives the same advantages as an ordinary overhead camshaft but with a very rigid connection to the crankshaft, and a low cylinder head. 

 The SRM 350 dirt track motorcycle motor was a design made by Rune Krus in 1948 when he was finalising his studies at the Stockholms tekniska institut (STI), where Folke Mannerstedt was an instructor. The engine in these drawings are the SRM Camshaft d-t 350 cc engine. More on this can be found on http://www.hedlunds-motor.se/ (under "övrigt").

Here are two wievs of the whole engine. Each is in four parts (All eight are from one original drawing).

Side view.

part 1.   part 2.   part 3.  part 4.

Front view.

part 1.   part 2.   part 3.  part 4.

Here is a drawing showing the valve mechanism in six parts

part 1.   part 2.   part 3.  part 4. part 5.  part 6. signature

Here is a (poor quality) drawing of the cam mechanism

cam profile  rocker arm geometry  mechanism

cam connecting rod

Report on the principle of the valve system

There will be more material published here soon.