The Stanger V Twin Two-stroke.
A New Engine Unit which will be Exhibited at the Olympia Show.
THERE have been several V twin two-strokes designed and made, but, for reasons known only to their sponsors, they have not been placed upon the market. Among the exhibits at Olympia, however, a new 5 h.p. two-stroke engine will be staged by the Trotman Patent Dandy Co., a firm of paper makers' engineers at Wood Green, London.
Designed by an engineer, whose experience with motor cycle engines goes back to the year 1897, when he designed and constructed the 2 3/4 h.p. Stanger quad, the engine under review is of the conventional three-port type, and can be fitted in any motor cycle frame which accommodates present-day engines. It consists of two cast iron cylinders with large radiating fins.
Mounted in a staggered position on an aluminium crank case, and set at an angle of 45°, compression relief valves are situated in the usual hexagon housings and recessed and drilled from all sides of the hexagon, thus affording a very quick relief of compression. The entire interiors of the cylinders are machined, leaving the heads perfectly smooth, and tending to keep them free from carbon deposit.
Cast iron pistons. of the deflector type, are used, and are fitted with three rings - two in the top and one in the skirt.
The gudgeon pins (which are hollow) are a light driving fit in the piston, and are fixed in a rather novel manner. One end has a fixed pin projecting about 1/8 in. on either side of its diameter. When the pin is driven home a split pin is pushed through a hole and opened in the bore of the gudgeon pin.
A one-piece two-throw crankshaft of 50 ton steel (case hardened) is employed, set at 180°, and is very short and stiff between the throws.
The crank case, which is of aluminium, is divided laterally, and by a dividing wall, which forms two separate chambers. The centre bosses are machined to take a large compression retaining bush. The outer bosses are fitted with self-aligning double ball bearings, and also compression retaining bushes, so it will be seen that each throw revolves in a complete crank chamber of its own.
Steel connecting rods, with a phosphor-bronze small end bush, are fitted, the large end being case hardened and ground, and so shaped as to thread over the solid crankshaft. - The rollers are slipped through a small groove at the highest point of the crank web, two halves of a hardened steel washer- having first been placed in the connecting rod. When the full number of rollers are in position the other split washer is fixed with the two split pins. Hardened washers assist to keep the roller in a true path on the crank pin.
Lubrication is effected by means of a twin drip feed, which is carried to the lowest point of the inlet ports. Although drip feed is fitted, the designers advise the use of the petroil system.
The magneto is situated on a platform in front of the engine, and is driven by a chain encased in a complete dustproof aluminium case.
A very large flywheel is employed, to which is keyed the driving sprocket.
A feature of this engine is that it may be adapted to almost any type of motor cycle frame.
The Motor Cycle, November 20th, 1919. Page 603
