Anyone on the lookout for a serious new I/C engine project will be interested in an impressive scale model of the de Havilland Gipsy Major Mk I—the engine that powered the original DH82 Tiger Moth.  At the unusual scale of 1:3.5, it is large, weighing in at about 7kg (14.4lb) dry and spins a 26" diameter propellor. Castings and plans are available from Reinhold Krieger in Germany.
Engine details:
Inverted four cylinder, inline, OHV
1 : 3.5
approx 7 Kg
length 35 cm, width 18 cm, height 25 cm
140 ccm
41 mm
33 mm
Methanol with 3% synthetic oil
15W40 in seperate 250cc tank (like the DH82)
Pressured lubrication with oil pump, filter and splitter. The oil is sucked in at the oil filter (4mm diameter pipe). A gear-type oil pump with overflow and valve pumps the oil into the oil chamber. From there, the oil passes to the splitting valve and to the bearings of the crankshaft and forward to the bearings of the connecting rods. The overflow oil is returned to the gearbox. The backflow of the oil is without pressure from the crankcase and the gearbox. The connection pipe diameter is 7 mm. The oil tank must be placed lower than this connection.
26" x 16"; direction of the prop rotation (viewed from front) is clockwise, like the original.
RPM range:
900 to 4000
Electronic ignition with hall effect sensor and two distributors to the two spark plugs per cylinder. Operating voltage 4.8V. 
Spark plugs are standard 1/4"x32 with electrode gap 0.3 mm
Firing order:
Ignition timing:
Mechanically coupled with carburettor: low speed 1° late, advancing to 18° early at 3/4 throttle.
Flapp carburettor with high and low nozzles and choke flap.
Fuel Pump:
gear-pump with overflow valve, driven by camshaft
Intake 20° before TDC to 60° after BDC Exhaust 65° before BDC to 15° after TDC
The attention to detail is outstanding. 
If you would like a set of castings, email Reinhold at 
Drawings and castings € 900, 
Castings: (39 parts)
Crankcase cover, gear boxes, gear box cover,
4 x cylinder head, rocker cover 4 x 4 x rocker arm, intake manifold, carburettor four parts, oil filters, Olkammer with lid, 2 x ignition distributor with cap,
Lever for ignition, 2 parts oil pump (bronze)
2 parts gasoline pump (Bronze), 4 pistons, 2 parts of cooling air (black ABS)

Electronic ignition (boxer type) € 240, -
with 4 magnets, Hall sensor, 2 rubber caps f. distribution connection

Spark plugs (2 per cylinder) ¼ "x 32 € 18, - / pc

Spark plug (silicone) € 5, - / pc

1 set of gear wheels (12 pieces) € 180, -

1 set of ball bearings (14 pieces) € 370, -

All prices excluding postage and packing
Another engine from Reinhold