The 3/1 and 3½/1 are the same engine, the first running at 600 rpm, the second at 650rpm. The same applies to the 5/1 and 6/1, and 10/2 and 12/2.
Engine parts between the single cylinder engines are common as far as the bottom end and crankcase go, the twins sharing the 5/1 and 6/1 cylinders, heads and valve gear but with different crankshaft, camshaft and oil pump. Injection equipment is CAV-Bosch, CAV or occasionally Bryce. Early engines had the leak-off from the injector taken into a small container on the side of the engine, later engines had a pipe taken back to the fuel tank. The 3/1 pump and injector are different to all the others because of the smaller cylinder size and lower power output. The cylinder barrel, head and valve gear are different on the 3/1 to all the other engines.
Flywheels vary between applications, spoked wheels on the early engines, solid flywheels on the Start-O-Matic generating sets and also on the later 8/1 and 16/2 variants which had no compression change-over valves fitted and different injection equipment specifications.
Lubrication is by plunger oil pump and splash on all engines. The oil pump is common on all single cylinder engines, the twins had a different fixing and design of pump. Valve lifters are fitted to all engines, two on the twins. The lifter is solenoid operated on the Start-O-Matic engines as part of the automatic starting arrangement.
Main bearings are sleeve type, of the same diameter as the crankshaft at the flywheels, so the crankshaft cannot be ground down and undersized bearings fitted, it has to be built up to standard and new standard bearings fitted. The bearings are a press fit into the bearing housings with an oil hole to be aligned.
3/1 engine bore and stroke: 3¾" X 5½"
5/1 engine bore and stroke 4½" X 5½"
Cast iron bore on early engines, 'Listard' chromed bore on later engines.
Standard spoked flywheels: 24" diameter by 3½" face.
3/1 engine weight 746 lbs without cooling tank.
5/1 engine weight 760lbs without cooling tank.
10/2 engine weight 1129 lbs without cooling tank
Oil sump capacity is approximately 5 pints (3/1, 5/1) and there are various troughs and places to lubricate before starting the engine.
Oil sump capacity is approximately 10 pints (10/2) and there are various troughs and places to lubricate before starting the engine.
Injector setting pressure 3/1 --- 110 atmospheres or 1615 lbs per square inch
Injector setting pressure 5/1 6/1 10/2 12/2 --- 90 atmospheres or 1325 lbs per square inch
Injector setting pressure 8/1 16/2 --- 150 atmospheres or 2208 lbs per square inch
Tappet Clearances COLD Inlet 0.017" Exhaust 0.032" for 3/1, 5/1, 6/1, 10/2, 12/2.
Tappet clearances for the 8/1 and 16/2 are 0.008" both valves COLD
Valve heads recessed into cylinder head face by 0.055" Min to 0.100" Max
Bump Clearance 0.045" to 0.050"
Inlet Opens 5 Deg before TDC and closes 15 Deg after BDC on all engines. Exhaust Opens 45 Deg before BDC and closes 5 Deg After TDC for types WITH compresion changeover valves (3/1, 5/1, 6/1,10/2, 12/2) Exhaust Opens 55 Deg before BDC and closes 20 Deg After TDC for types WITHOUT compresion changeover valves (8/1, 16/2)
Piston ring gap to be no les than 0.012" with ring at the bottom of the bore and square to it. No maximum gap is given, but no more than 0.020" would be OK.
Injector No: (5/1, 6/1, 10/2, 12/2) CAV BKB505S507b, Nozzle No: CAV BDL30S46
Pump No (3/1 single cylinder only) Bryce FBOAB060C6655 (was: BPF1B60CS6655) Injector: Bryce BKB56S5264B, Nozzle Bryce BDL30S406
Pump No (5/1 6/1 or 10/2 12/2 single/twin cylinder only) : CAV BPF1B70CS6253, Element No: CAV 7009-43, Delivery Valve No: CAV 7010-188, D/Valve Spring No: CAV 7032-7