I'm exhibiting the beastie tomorrow, so wrote this up from information gleaned from Roland, John Gatscone and the article in SE magazine.
Thanks to all that helped, much appreciated.
Regards,
Kim Siddorn
1948 Mk2 Norman T300 flat twin
This engine was found nailed to a stump in deepest Devon and roughly painted light brown, one cylinder being blanked off from the carburettor and acting as a compressor. An extensive rebuild by Roland Craven followed. It was probably originally supplied to Green?s to power a mower or roller as traces of green paint were found in odd corners during restoration.
History
In 1930, the Marconi Company asked the Norman company for a lightweight, air-cooled petrol engine capable of driving a one-kilowatt generator. The three prototypes were of 250cc, but the requirement had risen to 1.5 kilowatt, so the capacity was raised to 300cc. Production commenced in 1932 and continued in one guise or another until the factory closed down in 1968, the Mk2 being introduced at the end of the war. Certain features were modified in order to keep the price down and the principal differences were as follows.
The Mk 1 has a detachable starting handle and the bottom of crankcase is finned, but the most noticeable difference is that the top of the main casting behind the mag is rounded whereas the Mk2 has a flat top with tapped holes for attaching a fuel tank. Mk 1?s have the letters TE before the serial number whereas MK2?s have TA.
The canister type silencers that fitted directly onto the exhaust ports were not used originally on the Mk2, being normally fitted with exhaust pipes leading to a common silencer. Some engines were also available with a conversion to enable them to run on paraffin.
The Mk 2 was largely used on battery chargers and lighting sets and, from
1938, large numbers were bought by the War Department. The Admiralty bought them for use in charging sets on MTBs and a marine version was also made, basically the same but without the governor. Some were supplied to Imperial Airways for use on flying boats as Auxiliary Power Units (APU?s) and typical tasks would have been charging batteries, bilge pumping and fuel lifting. They were also supplied to various firms for driving compressors and Auto Diesels purchased large numbers of T300?s to power lighting sets.
The serial number on these engines is found ? inconveniently enough ? inside the crankcases, but is repeated on the brass governor plate on the top of the governor. That said, many of the WW2 engines do not have a serial number on them and frequently, the numbers do not agree as parts are readily interchanged from one mark to another these numbers do not agree after all this time since it is relatively easy to cannibalise MK1s and 2s. Most parts are interchangeable.
About 5,000 MK 1?s were made and around 7,500 Mk 2?s. For Mk2?s, the post war numbers ran:- 1945 TA1001, 1950 TA4673, 1960 TA8034, 1968 TA8590.
From a practical point of view, the engines are very light to carry about, easily started and are smooth in operation.
If you would like to know more about these interesting little engines, Stationary Engine magazine published an article by Phillip Gallimore over numbers 95, 96, 98 & 100.