Norman T300 flat twins

It would be easy for me to sit here and amaze everyone with my comprehensive knowledge of the Norman company, but truth be told I'd just be trotting out stuff which I had read in an excellent series of articles which appeared in SEM around issue 100. I suggest you do likewise!

That'll do me Nick, I've got a more or less complete set no - although looking for about twenty from the very early days.
Regards,
Kim Siddorn
- who wishes you and yours all the very best for the Festive season and a cheerful and prosperous New Year.

Just finished pruning the pear tree in the yard so I'm free... My response would have been as Nick's. Try SEM 98 and 100. I will add one new piece of info: On Mk2s the casting dates are inside the crankcase halves and on that basis I believe the published dating list to be slightly off. An enormous range of gennies was made including a pared down model said to have been used in the Sunderland flying boat. Don't stand behind it on a cold day Kim. That fan shifts a lot of air:-) ttfn Roland

Roland said Snip! ".......... that fan shifts a lot of air".
He's right! it must sop up quite a lot of the available horsepower and certainly would be good for filling hot air balloons before lighting the gas.
The Coventry-Victor I've got is a similar size but is closely cowled and has a smaller fan.
Regards,
Kim Siddorn
- who wishes you and yours all the very best for the Festive season and a cheerful and prosperous New Year.

I've just re-read the articles myself (the series actually started in issue 95) what a treat - 8 pages of good solid info with just enough pictures as required for illustrative purpose. Contrast that with the current issue, sure it is not without interest and the presentation has taken a quantum leap forward with plenty of eye candy, but somehow it seems to be lacking in substance compared to those earlier issues.

Mine has TA8344 on crankcase and TA 8501 on plate. According to the list this places it in 1961 or 1964. I'm not splitting the cases unnecessarily to look for casting dates (or can it be read with barrels removed?), which way do you believe the list to be out? I shall be upset if it pushes my engine outside the locally produced (post 1959) range!
BTW both pistons (by Brico) are stamped K44M 1967 on the crown and have M1967 cast inside the skirt.

I wouldn't split them either its a pig of a job. On the one Kim now owns it made it earlier than the list suggested. Those are the later style pistons with two oil-control rings. ttfn Roland

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.

"J K Siddorn" wrote (snip):-
So it had recieved a conversion somewhat analogous to your Petter Universal Two compressor? Quite interesting in its own right!
Copy of Norman Catalogue I have shows canisters as standard equipment on T300 MKII, with "separate exhaust silencer and 5 feet flexible tubing" being listed as "additional and/or alternative equipment" (hope to get a scanner soon, so I will copy and email to you).
I read Roland's comments to mean that there are casting dates only inside the cases. You should find the serial number stamped on the outside just to the left of the starting handle. As you say, the number on the id plate frequently does not agree as, particularly being screwed rather than riveted on, it has frequently been 'got at'. Roland said that comparing casting dates with the serial number, casts some doubt on th eaccuracy of the dating list in SEM issue 100. Though I guess in those pre 'just in time' days, castings could remain in stock for some time before being built up into complete engines. Also, if the pre-war practice of allocating batches of serial numbers to particular customer orders (rather than sequentially as engines left the factory) continued, this could further confuse the picture. I think the latter is quite likely to be the case as a note I have from RGR Sparks concerning my T600 reads "T600 TL4102 was built for Jowett Ltd 1/6/1962" the operative words being 'built for' rather than 'sold to'. Shame I can't seem to track him down as I'm sure a couple of hours research with the factory day books he has would solve this one.

I noticed that there was a comment somewhere that the T600 was thirsty. Was that you Nick?
Interesting. The Petter PU8 has a similar reputation for thirst and is given as a reason why so many people have one and few are exhibited.
My PU4 is only a single cylinder, the other being a compressor and whilst it is true I've twiddled with the carb to make the plug pale grey when sucking and blowing at atmospheric pressure (no air receiver attached) it is pretty economical, running all day on a gallon.
Anyone with other flat twin experience care to comment?
Regards,
Kim Siddorn
- who wishes you and yours a cheerful and prosperous New Year.

I can't comment since I can't get my T600 to start:-( It was Philip who made the comment based on rallying a T600. The C-V twins have a similar reputation for thirst. ttfn Roland

Do these engines have a lo-------ng bifurcated (sorry, Martin!) inlet tract and a single carburettor in common?
Peter
-- Peter & Rita Forbes snipped-for-privacy@easynet.co.uk Engine pages for preservation info:

Peter,
No problem, I have loads of bifurcated copper rivets so I know what that means and I can answer your question, yes they do.
Martin P

Bifurticated inlet tracts?
I think I see where this is going ;o)) When my PU4 - which has a l-o-n-g single inlet tract - is cold, petrol does condense out on the inside the pipe. This can cause difficulties until the engine is warm, but it vanishes on its own and - as I've said - I've worked on the carb settings to produce a grey nose on a BP6ES at about 700-800 rpm on light load. I've also got a PU2 which has a different arrangement of induction piping.
If you look at photos 7 and 12 on
You can see the differences easily.
From a cold start - and I've tried them both side by side to compare them - the PU2 is worse and 16 strokes (I kid you not) very happily until the casting starts to warm up. It goes from 8 to 4 and speeds up as it's doing it - very educational! The PU4 needs some choke, but that's all.
The PU8 has long pipes and they do stay cold even on a warm day, but they don't frost up. I once had an SU conversion on a CF van that did produce a thick layer of frost and the throttle would freeze open after a long motorway blast at seventy. Very exciting ...............
I don't see that a cold inlet tract would make any engine overly rich after it was warm and Douglas motorcycles have a reputation for frugality with their single carb.
BTW, my Crossley 1075 - which, it must be said, never gets hotter than 85o C - always has petrol condensate in the corner of the inlet tract and others have commented on this foible too. This is at 230 ish RPM, not its design maximum of 400 mind.
Regards,
Kim Siddorn
- who wishes you and yours a cheerful and prosperous New Year.

|I noticed that there was a comment somewhere that the T600 was thirsty. Was |that you Nick? | |Interesting. The Petter PU8 has a similar reputation for thirst and is given |as a reason why so many people have one and few are exhibited. | |My PU4 is only a single cylinder, the other being a compressor and whilst it |is true I've twiddled with the carb to make the plug pale grey when sucking |and blowing at atmospheric pressure (no air receiver attached) it is pretty |economical, running all day on a gallon. | |Anyone with other flat twin experience care to comment? |
Onan 810cc flat twin has consumption better measured in gallons per hour!

|I noticed that there was a comment somewhere that the T600 was thirsty. Was |that you Nick? | |Interesting. The Petter PU8 has a similar reputation for thirst and is given |as a reason why so many people have one and few are exhibited. | |My PU4 is only a single cylinder, the other being a compressor and whilst it |is true I've twiddled with the carb to make the plug pale grey when sucking |and blowing at atmospheric pressure (no air receiver attached) it is pretty |economical, running all day on a gallon. | |Anyone with other flat twin experience care to comment?
My Onan 810cc air cooled flat twin 3.5KVA genny's consumption is better measured in gallons per hour!

They do. The T300 and prototype T600 had them cast internally but on production T600s this was abandoned in favour of external pipes of about 1" OD. No flaming wonder you can't get any gas velocity going. The Douglas FT35 also has a long bifurcated inlet tract and that too is a pig to start. ttfn Roland

I can confirm that the T600 appears to like a drink! Certainly running off load my usual splash from the jerry can only lasts ten or fifteen minutes (not very scientific I know, but on say the Bradford, a similar splash might last half an hour or more). I imagine it has something to do with that ruddy great air brake! One must remember however that this is a six or seven HP engine and given a proper load to drive it will return a brake specific fuel consumption of about 0.75 pints per BHP Hour at 1800 RPM, the corresponding figure for the T300 is around 1 pint per BHP Hour at 2000RPM.

Hi i frequently rally a T600 and T300 together and usually use 1.5 gallons over a weekend thats about 12 hours for each engine so i cant really complain about them being thirsty regards Keith