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Cam wheel marking for 2 3/4

Started by Chris54, 04 May 2015 at 07:22

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Hi All

Can any of you shed some light on the markings on 2 3/4

I am rebuilding several engines and have a bunch of cam wheels that are marked up as 5, 5A or 5B

Is there a difference in the valve timing, would the B be the best to use as its probably the latest version, most improved.

Does anyone actually know, is there any literature on the subject.

Thanks in advance, Chris



Hi Doug
Many thanks for that, will study with interest



Hi Chris and Doug,
I found these cam timing diagrams in the The Douglas handbook 1916. This shows the timing of the "S" cam and "5" cam for 1915. No reference to how much lift each had tho'. Interesting the spelling of  "shewing" which I assume should be "showing"?

The "5" cam appears to be reasonable sporty and might have been in the "TT" models? No separate part number appears to be indicated in the parts list for the "S" or "5" cam.

Picture to follow as I'm having issues uploading the file......



Not as high a resolution as i was trying before, but hopefully good enough to read.


and the number 5 cam


Hi Ian

Ah light is being shed on the subject, we now have timing charts for the "S", "5", and "5B", just need the "5A", then to make a choice on which to use, the "5A" looks to have longer duration and more overlap.

The choice, safe, sporty or original, so a question, which one in a 1914 model U.

Cheers Chris 


Hello Chris
I have looking, that you have 1914 model U. I repair similar model, and I am intersting see any pictures from your project.  Regards Veikko