Mystery engine

[RayW]

This lovely little hot tube engine came my way today via eBay from a seller who lives only 10 miles away.

It appears to be very early, possible Circa 1900, but the previous owner has been unable to find any information about it despite many years of searching. Many of the steel parts are heavily corroded or worn. The gears show evidence of extensive wear, with the teeth on the crankshaft one being worn almost to points, and missing one tooth.
The previous owner has fitted a new piston, but, apart from that, he thinks that everything else is original.

Amongst the most interesting features, there is what appears to be an air inlet valve on top of the cylinder.The hot tube is fitted with a long, hex headed screw which, apparently, adjusts the timing.
The connecting rod is bellied in shape, tapering to each end, very like would be found on a steam engine.
The exhaust valve is operated by a flat, L shaped push rod driven by an eccentric pin inside the large gear.
I understand that the inside of the cylinder head is hemispherical.

If anyone can throw any light on the identity of this little engine, I would love to hear from them.

[Jo]

It looks a bit like a slightly modified Schoenner Gas engine

Jo

[Jasonb]

The flywheels and base doo look a lot like the schoenner engines but the gears on this make it a 4-stroke cycle rather than two, could have been heavily modified as everything from the cylinder back does not look like castings have been used.

[RayW]

Yes Jo, I did consider that, but nothing on my engine seems to resemble the Schoenner one but I am pretty certain it must be pre -1900. The previous owner spent years trying to identify it but couldn't find anything.
I am convinced it must have been a kit as parts such as the base, body, valve chest and hot tube are all castings rather than home made.
What I would like to do is to replace as little as necessary to get it running, while still keeping the old patina and wear. The gears will almost certainly need replacing, but other than that, everything else appears to be functional, apart from a few valve springs that will need replacing.
The previous owner made a new piston as that was missing, but he did not fit any piston rings, so I may have to see how good compression is once it has all been stripped down and re-assembled.
 

[RayW]

Just to clarify Jason, the base, body, valve chest, hot tube, flywheels and cylinder are all castings. The crank webs are heavily pitted, but they could also possibly be cast.

[Jo]

The base looks identical to the Schoenner except that it has had underneath cut away. The main body and bearing caps are identical as is the flywheels.

My guess is someone converted it to a hit and miss at some time.

Jo

[RayW]

I have checked the base and the cutaways are definitely original as the cast surface is clearly visible.

[Jasonb]

I can't see any form of latching to suggest it is Hit & Miss governed, just 4-stroke hot tube ignition.

The fact that the non schoenner parts are all bronze could mean they were cast later possibly at home.

Where is that Graham when you need him?

[Jo]

This is the British Modelling and electric Co copy of the Schoenner engine - it has a cut away cast base.

As these engines were designed to run on town Gas when that was phased out the only alternative was to run on acetylene which is not easy to come by (safely  ) My guess is someone published a modification at some point...

Jo

[RayW]

Well done Jo. I think you may have cracked it! Do you have any other info about the British Modelling and Electric Co?
I have been probing about in the water jacket holes with a bent wire and I strongly suspect that under the (definitely home made) copper water jacket, I will find a finned air-cooled cylinder.

[Jo]

Sorry that is the only pic I have of that engine.

You may be aware that Bruce engineering did a copy of the schoenner engine known as the AGE which I have the drawings for and Surus has the set of castings 

Jo

[Jasonb]

Ray, take a look at this thread, they were located in leek which may sound familiar

http://www.modelenginemaker.com/index.php?topic=7414.0

[RayW]

Thanks Jo and Jason. You beat me to it Jason. I have just been reading Graham's thread on these engines, so it appears I definitely have a Leek (very appropriate as Graham lives in Wales!|).

[Alyn Foundry]

Hi Ray.

Indeed you do!!

This is the second one I've seen in my lifetime. I actually restored the first for a friend of a friend. 

Personally I'd do the least amount of restoration possible as it has a beautiful patina.

Cheers Graham.

[Alyn Foundry]

Having slept....

These engines were toys, available in 3 sizes ( working from memory ) 3/4" 1" and 1,1/4" bore with a 2" stroke. Suffixed as numbers 1, 2 & 3.

Designed to run on Town gas. Some period advertising mentioned an " Ideal " shopfront display and capable of speeds up to 500 RPM. Power output minimal.

By converting the engine to a four stroke cycle the power output could be much greater and capable of driving a small Dynamo for the charging of radio batteries.

Your engine Ray has seen a very well executed conversation from atmospheric to compression before ignition principle and quite probably worked for its living.

I did notice the counterbalanced crank, a very useful addition.

Cheers Graham.