USHM2 engine number / year?

[motorbob]

Hi, I wonder if someone could help me.
I have a USHM2 engine and box that's been dry stored. the engine number is 11956.
its a thermo-syphon non external oil filter model.
doe anyone have a chart of engine number year of manufacture?
Many thanks and kind regards.

[mike.perry]

Does the engine have an oil filter?
The engine numbers are usually fairly close to the chassis numbers so I would guess at 1949

[motorbob]

Hi Mike,
Thanks for your prompt response, the oil filter is internal within the ally sump, there's no external (spin on) filter as such.
regards.
Bob.

[mike.perry]

Later USHM2 and USHM3 engines had an external M1000 type filter. There s no filter as such in the early engines, just a gauze around the pick up