MGapr11 Bulletin no 60 - The Triple-M Register

Production Modifications to the J2By Martin WhiteJ2048 approx – From engine 551AJ the connecting rodto the throttle and jet control connecting rod was changed.J2191 from engine 751AJ a new distributorwith automatic advance by bob weights was introduced; themanual advance/ retard mechanism being supperceded.J2910 approx - from engine 1675AJ the pinch-boltedsmall end of the con rods was changed to a bush type,necessitating a new type of piston and a floating gudgeon pinwith dural end caps.J2944 - A new battery (6 pence cheaper!) and a newcarrier were used. This probably had just a change of positionfor the holes for the securing rods for the new battery.J3331 - headlamp mounting brackets deleted. These arepresumably the “bodge” brackets they introduced to movethe lamps further forward and nearer the radiator, to preventmud being thrown onto the windscreen by the airflow. Presumablythey were deleted because the new front wing cumheadlamp bracket was introduced which automatically setthe lamps in the new position – a change not noted in theparts list.J3434 - The Petrolift pump was changed to the SUL-type pump we are more familiar with. A new front sectionfor the fuel pipe from the tank was needed for this, as was anew delivery pipe to the carburettors.J3438 - the first swept-wing car; to fit these longermushroom headed bolts were needed, along with the varioussteel and rubber packing pieces. The new bolts arelisted separately in the Parts List, but have the same partnumbers as the old ones! Probably because the new oneswould do for both types of wing. Also the chassis side railschanged; most likely just different drillings. A new design ofhorn bracket had to be used, with a wiring clip, and the nicemoulded rubber plinth for the sidelights was discontinued,and they just used the rubber