Another mystery engine competition

The engine is not connected to the chassis yet it's just on blocks, there are 2 holes at the bothem where you can put tubes through to lift it by hand.
The flywheel is heavy so it could be a generator engine.
It's a very dirty amaturistic garage.
If those heads are made of aluminium than it could be a thirties photo.

Not sure if it helps but here's the picture of the engine enlarged as much as possible.
The label on the chassis unfortunately is not readable on the provided picture but should be much better on the original.
Might be worth dropping a line to the Stilltime Collection and ask them if they could provide a clearer snapshot of the label

Giovanni,

Your software enhancement is impressive, I magnified the image but it is nowhere near the clarity of your image.

I think I've found the maker of the engine which not only matches the odd valve arrangement, albeit in it a water cooled version, but also the visible letters on the name Aristos. The picture is from a Bonhams catalogue which says it from the early 1920s.

Roger

I thank Giovanni and Paul for their flattering remarks regards the setting up of the ABC Registers from the time I bought my ABC Super Sports back in 1968 - and I'm still at it!

Just to put you all out of your miseries regarding the unknown engine in the ABC car; this is the Gordon England 200 mile race car with the Bristol Cherub aero engine fitted for the 1923 event. It broke a crankshaft in early trials but completed the race coming 2nd in the 1100cc class. It was reckoned that the horsepower developed by the smaller unit was at least equal to that of the larger ABC engine which had to compete in the 1500cc class the previous two years, but that the gear ratios were not best suited. To house the new engine the front end of the sub-frame had to be removed and a couple of support brackets fitted. The original flywheel and clutch were used although the clutch shaft was increased in length. The chassis was strengthened with internal liners, especially at the rear end, and twin Zenith carburettors were fitted. Reports vary as to whether Gordon England or Stephen Bassett drove the ABC in the race, but it seems most likely that Gordon England drove an Austin 7hp leaving Stephen Bassett to drive the ABC.

The photograph first appeared in The Autocar for the 7th September 1923, p.431.

If you look carefully you can see the holes in the chassis, now blocked off where the exhaust passed through when it had the abc engine in.

Davids knowledge is impressive. His ABC passed over to me in 1976 and it is still with me.
Hakan