Engines > Restoration of Model Engines

Stevens's Model Dockyard- Marine engine

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Sanjay F:
The next little project is going to be a return to get this little marine engine working. I've had this for quite a while and although it may look like its done, it's not. I bought this not knowing what it was until last month when I got a raggedy original copy of a Stevens's Model Dockyard catalogue from 1930 - 1931 and stumbled upon what I have here. I'm fairly certain its either one of the Direct Acting Marine Screw or Marine engines as its fairly unusual in design?

When I first got this I made the metal base and wooden plinth as it doesn't stand up on its own!  :). I have so far been unable to get the timing and port openings correct to get it to run; there is no way of visually seeing the ports as you adjust things which is a major disadvantage, but maybe someone out there has one of these and holds the secret?

I really like this little engine and it'll be a shame for it to sit on the shelf without being operational .......... let the dismantling begin......I post lots of photos so you can see the internals

Sanjay F:
Couple of videos:

https://www.youtube.com/shorts/hPNvkkncgcA

https://www.youtube.com/shorts/hbhmYZMgry4

Sanjay F:
More pictures....

and herein is the problem, the valve faces towards me so when the chest is put back on you cannot see how the valve is moving & opening/closing the ports. Secondly the only adjustment for the port distances is a minute amount of thread on the top part of the eccentric and its VERY delicate - I don't want to strip that thread! The eccentric is adjusted by the screw on the sheave and means dismantling the strap to get to it ......... lot's of little awkard 'features'  ;D

Sanjay F:
I place the port face so I could see it and turned it over to make sure the valve was behaving itself and not hitting anything, looks ok, but its not very scientific  ;)

https://www.youtube.com/shorts/gvrrVXlpKYo

Jasonb:
I don't bother looking at the valve when setting the timing.

First with the cylinder removed check the valve is moving to expose equal amounts of port top and bottom by holding teh cylinder port face at right angles to the valve chest. It may help to put a piece of masking tape down the cylinder and use a fine pencil to mark the port positions to you can better judge valve position.

Then you can set the timing based on the high point of the eccentric. A good rule of thumb is to have the high point of the eccentric leading the crank pin by 90deg plus another 30 degrees. So while the crank is upper most at 12 o'clock you want the high point of the eccentric at either 4 or 8 o'clock depending on which direction you wnat the engine to run.

I'd say is is a No248 which was also in my 1919 catalogue.

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