Sorry would not know,new to working on a Douglas.
Steve.

The Manual for a T6 etc doesn't help ?

https://www.ebay.com.au/itm/185441168860

Measurements are unlikely, unless on a blueprint.
Does anyone hold such things, that far back ?
Can recall when BSA closed, it was said that 20 tons of documents went into a skip !

Measuring YOUR engine and making to suit should be adequate ?
What you have don't look too bad ??
You wouldn't be the 1st person to hunt down a spare engine to obtain such things ...

That finned alloy sump is a true work of casting genius.  !

Would the timing gears from a 1918 2 3/4 fit?
Gordon.

Hi Does anyone have a diagram or drawing showing the engine gear hole spacing for a T6? Is there a workshop manual or any other book that can help rebuild a Douglas T6? The club doesn't have one.
I making all new timing gears for my engine and be good to have any helpful diagram 
Regards 

It doesn't take much searching to find a Maintenance Manual.
It lists quite a number of places that require a regular drop of OIL.

Didn't examine it closely about greasing requirements.
I find those silly little 1940s and 1950s 'grease nipples' inadequate.
A later type nipple with ball and spring are way more effective, if not concours.

https://www.rpw.it/Files/Douglas_1948-1954_Maintenance_Manual.pdf

Hopethishelps.  Tell us how it goes. ?

Nope.
I find dismantling and re-greasing about the only sure fire remedy.
The Manuals spell this out, if you read closely between the lines.
And, conveniently, I've met very few british motorcycle items that are sealed for life.

But I've not met a MkV personally, so YMMV. ?
Cheers.

Hi Ron, I've read about certain types of fluids that can break the hard stuff down and high pressure air grease guns that can force this stuff out if it's not too far gone. I may dismantle it for cleaning. I have seven different vintage British motorcycles but I find the instruction books to Douglas are not very good in comparison with other marques. Have you any advice on grease guns, manuals etc?

I'm no authority on the Mk V by any stretch, but I have met old grease on other machinery.
Old type greases often seem to have consisted of something almost clay-like, with oil intermingled.
When the oil departs or dries out, the claylike material can be difficult to shift, by any means !

Common grease guns can exert considerable pressure, so if it moves not it is not good
I have seen on front fork spindles etc the only cure for this is disassembly and regreasing afresh.
You often see dry patches too, which bodes not well, the grease nipple not greasing everywhere.
How does the grease know to go both left AND right !!

P.S. My fav-o-rite foible of the british motorcycle industry was the single grease nipple in the
centre of a massive wheel hub.  Where is the grease supposed to go - the bearings are miles away !

Quote from: rogerb on 08 Nov 2025 at 21:25 How much are they to club members

Hi Roger,
I have emailed you a couple of times in response to your query and wonder if my messages are going into your spam folder?
They are £300/pair at the moment.

How much are they to club members