Low numbers on sport or racing engines

[delamotte1]

Hi all,
as a new member on this Forum and with small knowledges of your language ,I need your kindly help.
I have a bike, engine 350 ccm, in my own, I once buyed in Austria, with the engine nr, E 106 and  a sole engine, I think of large ccm from the same source with CE 10. Should it be 733ccm?  Can someone say whats the matter with them. Thank you in advance.
Regards Claus

[cardan]

Hi Claus,

CE10 is certainly interesting, and yes 733cc OHV from the very early 1920s. Very "super sport" and often used for sidecar racing.  Have a look here for information on engine numbers: https://www.douglasmotorcycles.net/aa-files/html/identify-part2/vintage4.8.htm

As you'll see on that page, Douglas engine numbers usually have two letters in the prefix - like CE - so there might be a letter missing before "E106".

Photos would help.

Cheers

Leon

[Dave]

Photos added to Claus' post above.

[Daren W Australia]

hope this helps Daren

[cardan]

Hi Claus,

Is there a frame number - near the gearbox mount?

Also, are you sure the motor in the bike is 350cc, and not 500cc?

Cheers

Leon

[delamotte1]

Hello Dave,
thank you for your help.
All the best
Claus

[delamotte1]

Hello Leon,
thank you very much for your statements, I will answer your questions.

There are nowhere numbers on the frame and it is true a 350ccm.


Can CE 10 be a racing engine because of the double Cylinder coolers and the rocker springs?
I will eventually swap or sale it.
All the best
Claus

[delamotte1]

Hello Leon,
thank you very much for your statements.

C 106 has nowhere numbers on frame. The engine is true 350 ccm.
I read once in Jeff Clew`s book,  there was constructed in autumm 1914 a ohv engine with valves on top. So I had the opinion ,that the code E stood for experimental engine. What do you think?

CE 10 has as you could surely see, double Cylinder alu fins and double rocker fetchback springs.Could the engine be a racing engine?

I think about to sale or swap it.

All the best
Claus

[delamotte1]

Hello Daren,
thank you very much for the list.
Best regards
Claus

[roger h]

Hello Claus,
I am interested in your CE10 engine. What would you wish to swop for it? - is there anything in particular you are looking for?
Regards,
Roger

[delamotte1]

Hello Roger,
thank you for your interest,but Iwill think over.
Regards
Claus

[cardan]

Hi Claus,

I have done some homework: E106 is a very interesting engine indeed.

It's possible (perhaps even likely) that this is a 348cc racing engine of the type used by Les Bailey, Tudor Thompson and others during 1920-21. It is identical in design to the 494cc S1 and 733cc S2 models that were available to the public, but I don't think the 350 was ever listed in a catalogue. A couple of years later we had in Australia 350cc "RA" and "TT" models, even though these were also not in the Douglas catalogues.

The 1914 OHV Douglases you mention were quite different. They had their cams down low - like the side-valve 350s - with very long push rods to operate the valves. Quite different to the later OHV engines with the full-width cam shaft above the crank shaft.

Clew mentions the 1920-21 348cc racers in his book (page 63 in my edition), and notes that Tudor Thompson broke World Records at Brooklands on 21 September 1921. 200, 300 and 400 miles at 64.68mph, 62.29mph and 61.00 mph, respectively. That's quick for a 350!

Clew has no photo, but here is one from The Vintage Years at Brooklands. I has no date, but is likely that September 1921 day.

On page 57 of Clew, there is a photo of Bailey (reg. no. AD5724, riding number 0) at Brooklands. Clew gives 1919 for the date. This sounds a bit early (perhaps someone can comment on the date of the registration number) - I'm not sure when these post-WW1 OHV bikes were first constructed.

Douglas engine numbers most often started at 101, so E106 might be the 6th 348cc OHV engine produced? Perhaps someone knows more.

Re the frame: I am 99% sure that ALL the OHV sports racing engines would have been housed in the frame we usually see for S1, S2, and even Bailey and Thompson at Brooklands. I think the frame that the engine is in at the moment is a standard 2 3/4 frame that someone has modified to accept the OHV engine. The top tubes have been lengthened, and the "cradle" added to clear the front cylinder.

Re CE10. In Australia, most of these engines would have been used for racing, even if they did start out on the road. The aluminium oil boxes on the rocker spindles are the usual "early" type (I see there is a 1920 patent date, and they were still used on early RAs, say up to 1924), and the return springs are present on many surviving S-model heads. It's a very sporty motor, but not necessarily a racing motor.

Perhaps Doug (or someone else) can comment on why it only has a 2-digit number.

Cheers

Leon

[cardan]

I just revisited your photos - I had missed the "double oilers" on the rocker spindles. I guess this is a recent mistake, and one pair belongs on the engine in the bike. They work with wicks, so only the one on top will do anything.

Leon

[Doug]

Claus,

Excluding the bikes from the veteran era and their derivatives, Douglas engine prefix seemed to be this in the twenties: a letter followed by "E" to denote a serial number (in correspondence) that was assigned to an engine. A frame would be 'xF' and a gearbox 'xG'. So "E" alone makes no sense. It would mean simple "engine 106" with no indication what model it was. Indeed Douglas seems to have skipped over "EE" and went right from "DE" to "FE"; I have yet to see EE assigned to anything. When they got to "YE" (ZE does not seem to have been used), they inverted the format and it became EA, EB, EC (circa 1926) and so on through the alphabet to EX (circa 1932) and then they started using a different system.

So for E106 I think it a case where the leading letter has been removed or they just forgot to stamp it.

CE10. As Leon says, typically Douglas started numbering at 101. There are exceptions. For example the model RA first started with single numerals in 1923. The next year they used two numerals and then circa 1925 they use three. I have also see a 750cc 1926 TT type engine, seemingly a special order for an American customer, that was simply stamped "J5". It would fit in where "EJ", otherwise not assigned in Jeff Clew's list, ought to be in the chronology. So again maybe they just overlooked stamping it. A possible theory is that Douglas used single and double numbers for Works, developmental, pre-production, and special requests. Then when the bugs were worked out they went into production starting at 101. However I really do not know exacly what is the story behind CE10.

-Doug

[cardan]

"B" would be the appropriate missing letter: BE106 would be the 350 version of the S1/S2.

Certainly doesn't look like it was ever there.

Cheers

Leon

[cardan]

... but I don't think the 350 was ever listed in a catalogue.

When the 494cc ohv sports models was announced in the Motor Cycle 2 December 1920 there was no mention of the larger 733cc version, but the smaller version was mentioned: "Another model, with the same innovations, has an engine of 350 c.c. capacity, the bore and stroke being the same as the standard 2 3/4 h.p. engine."

So it looks like you could buy a 350 Sports model in 1921.

If the 494cc bike was the S1, and the 733 cc bike is the S2, what do we call the 350? "2 3/4 Sports" will have to do, although S0 is tempting.

Cheers

Leon

[delamotte1]

 Hi cardan and Doug,

you had informed me very expertly,I thank you very much!
All the best.
Claus