Hemingway Kits
The Hemingway Engine Bay
Internal Combustion
The IC Engines
The Mastiff - L C Mason
The Mastiff
Ref: Mastiff
Much like Westbury, Leonard Charlish Mason (always "Len") was a polymath with a large variety of interests and disciplines. Following his ever popular design for Minnie, the steam traction engine, he turned his hand to petrol engines. The Mastiff is a genuine triumph of design. Mason has bought together a number of creative, trend-setting features within a compact engine which is in fact not difficult to build. Almost every aspect of the engine has been considered from first principles rather than by following convention.
Known as a great starter and a silky smooth runner, the Mastiff is a compact unit with a particularly low centre of gravity. The horizontally opposed layout provides a low head height, great balance and a stiff crankcase and crankshaft. With a Bore x Stroke of Ø3/4" x 7/8" the 4 cylinder Mastiff has a swept capacity of 25cc. The side valve arrangement helps to reduce complexity whilst providing ample breathing through Ø5/16" valves. Mason's camshaft arrangement has considerable merit for the constructor. Loose silver steel inlet and exhaust cams are hardened separately then fixed with Loctite to a mild steel shaft using an assembly jig to ensure perfect orientation.
A vertical shaft for auxiliaries (driven by 2:1 skew gears) is used to power the distributor and oil pump. A pressure relief valve and an external oil pressure indicator are incorporated to ensure good lubrication from the shallow sump. The engine can be built with either a single horizontal or twin downdraught carburettors and the manifold arrangement is neatly achieved without tortuous routing. As the engine was conceived for marine use, water cooling is by thermo-syphon.
The Mastiff stands 6 ½" tall, 8 ¾" long and 7 ½" wide over its ¼" x 32tpi plugs. Interestingly, the hole spacing for the mounting bearers is an exact match for the Myford cross-slide, making running-in a simple affair.
Following a good deal of investigation, Hemingway Kits has managed to track down and acquire the original pattern set for this British classic and for the first time since the late 1980's it is available for engine builders around the world.
The Mastiff - Drawings & Construction Notes
Ref: HE 2604
The build is exceptionally well documented by Mason. 9 A2-sized drawings cover every aspect of the engine and tooling to produce it. No fewer than 122 pages of construction notes complete the package. Mason describes the build in such detail that one cannot fail to be successful with this project.
Price:
£55.00
The Mastiff - Material Kit
Ref: HE 2600
The kit includes material for a majority of items required to complete the Mastiff. Constructors will need to find fasteners and tubing and a few other items.
· (21) Aluminium and gun metal castings
· (4) Iron Piston Rings
· (8) Valve Springs
· (2) Timing Gear Train
· (2) 2:1 Auxiliary Skew Gear Set
· (2) Oil Pump Gear set
· (28) Sawn lengths of bar material (free cutting, high tensile, stainless and silver steel, bronze, casting iron, brass, Nylon and Tuffnol).
Electrical components (points, coil, spark plugs ..) can be found separately in the IC Engine Accessory section and drawings and construction notes can be ordered above.
Price:
£488.50
The Mastiff - Castings ONLY
Ref: HE 2605
If you're particularly well stocked with supporting materials you may prefer to order just the raw essentials. This item represents the casting set available for the Mastiff. This includes 21 castings for the following components:
Crankcase, Base, Sump, Timing Case, Timing Case Cover, Camshaft Cover Plate, Cylinder Block (2), Cylinder Head (2), Cylinder Head Cover (2), Manifold (2), Dipstick Housing, Carb body (2), Contact Breaker Case, Bearing Housing (2), Pump Body.
Price:
£395.00
