Mini Cooper 997cc (type 9F)
Engine Data | |
Number of Cylinders | 4 |
Bore | 2.458in (62.43mm) |
Stroke | 3.20in (81.28mm) |
Capacity | 60.87 cu in (997cc) |
Compression Ratio (H prefix) | 9.1 |
Compression Ratio (L prefix) | 8.3:1 |
BMEP (H prefix) | 134 psi (9.42kg/cm2) at 3500rpm |
BMEP (L prefix) | 129 psi (9.07kg/cm2) at 3500rpm |
Torque (H prefix) | 54 lbft (7.46 kgm) at 3600rpm |
Torque (L prefix) | 53 lbft (7.32 kgm) at 3500rpm |
Peak Power (claimed) | 55 bhp |
Crankshaft Data | |
Main Bearing Material | Steel-backed copper-lead; thin wall |
Main Bearing Length | 1.0625in (26.99mm) |
Main Bearing Running Clearance | 0.001 to 0.0027 in (0.025 to 0.069mm) |
Con Rods | |
Big-end Bearing Material | Steel-backed copper-lead;thin wall |
Big-end Bearing Length | 0.875in (22.22mm) |
Pistons | |
Type | Solid skirt |
Clearance (bottom of skirt - pressure face) | 0.0016 to 0.0022in (0.041 to 0.056mm) |
Piston Rings | |
Top | Plain, chrome-faced |
Second and third | Tapered |
Width | 0.0615 to 0.0625in (1.563 to 1.588mm) |
Valves and Valve Gear | |
Inlet Valve Diameter | 1.156in (29.4mm) |
Exhaust Valve Diameter | 1.000in (25.4mm) |
Inlet Throat Diameter | 1.0312in (26.2mm) |
Exhaust Throat Diameter | 0.908in (23.06mm) |
Valve Lift | 0.312in (7.92mm) |
Inlet Valve Opening | 16 degrees BTDC |
Inlet Valve Closing | 56 degress ABDC |
Exhaust Valve Opening | 51 degrees BBDC |
Exhaust Valve Closing | 21 degrees ATDC |
(Valve timings measured with 0.019in/0.48mm rocker clearance set for testing purposes only). | |
Valve Spring Free Length (all valves) | 1.750in (44.45mm) |
Valve Spring No. of Working Coils | 4.5 |
Valve Spring Pressure - Open (all valves) | 90lb (40.7kg) |
Valve Spring Pressure - Closed (all valves) | 55lb (24.9kg) |
Camshaft | |
Journal Diameter (Front) | 1.6655 to 1.666in (42.304 to 42.316mm) |
Journal Diameter (Centre) | 1.62275 to 1.62325in (41.218 to 41.231mm) |
Journal Diameter (Rear) | 1.3725 to 1.3735in (34.862 to 34.887mm) |
End Float | 0.003 to 0.007in (0.076 to 0.178mm) |
Bearings | 3, steel-backed white metal |
Bearing Inside Diameter (reamed in position) | |
|
1.667 to 1.6675in (42.342 to 42.355mm) |
Centre Bearing |
1.6245 to 1.6255in (41.261 to 41.287mm) |
Rear Bearing |
1.3748 to 1.3755in (34.914 to 34.937mm) |
Engine Lubrication | |
Oil Pump Type | Hobourn-Eaton |
Relief Pressure Valve Operates | 70 psi (4.92 kg/cm2) |
Relief Valve Spring (Free Length) | 2 39/64in (66.28mm) |
Relief Valve Spring (Fitted Length) | 2 5/32in (54.77mm) |
Oil Pressure (Normal Running) | 70psi (4.92kg/cm2) |
Oil Pressure (Idling - Minimum) | 15psi (1.05kg/cm2) |
Cooling System | |
Thermostat temperature | 83 degrees Celsius (180 degrees F) |
Clutch | |
Pressure Springs (Colour) | Black enamel with white spot |
Diaphragm Spring (Colour Code) | Light green |
Mini Cooper 998cc (type 9FA, 9FD)
Engine Data | |
Number of Cylinders | 4 |
Bore | 2.543in (64.588mm) |
Stroke | 3.00in (76.2mm) |
Capacity | 60.96 cu in (998cc) |
Compression Ratio (H prefix) | 9.1 |
Compression Ratio (L prefix) | 7.8:1 |
BMEP (H prefix) | 142 psi (10kg/cm2) at 3000rpm |
BMEP (L prefix) | 135 psi (9.5kg/cm2) at 3000rpm |
Torque (H prefix) | 57 lbft (7.881 kgm) at 3000rpm |
Torque (L prefix) | 56 lbft (7.74 kgm) at 2900rpm |
Peak Power (claimed) | 55 bhp |
Crankshaft Data | |
Main Bearing Material | Steel-backed copper-lead or aluminium-tin; thin wall |
Main Bearing Length | 1.0625in (26.99mm) |
Main Bearing Running Clearance | 0.001 to 0.0027 in (0.025 to 0.069mm) |
Con Rods | |
Big-end Bearing Material | Steel-backed copper-lead or aluminium-tin; thin wall |
Big-end Bearing Length | 0.875in (22.22mm) |
Pistons | |
Type | Solid skirt |
Clearance (bottom of skirt - pressure face) | 0.0005 to 0.0011in (0.013 to 0.028mm) |
First Oversize Bore | +0.010in (0.254mm) |
Second Oversize Bore | +0.020in (0.508mm) |
Piston Rings | |
Top | Plain, chrome-faced |
Second and third | Tapered |
Width | 0.0620 to 0.0625in (1.574 to 1.588mm) |
Thickness (all rings) | 0.106 to 0.112in (2.692 to 2.835mm) |
Gudgeon Pin | |
Type | Fully floating, with circlip location |
Fit in Piston | 0.001in (0.0025mm) tight to 0.00035in (0.0089mm) slack |
Fit in Small End | 0.0002in (0.005mm) slack, to size. |
Diameter | 0.6244 to 0.6247in (15.86 to 15.867mm) |
Valves and Valve Gear | |
Inlet Valve Diameter | 1.219in (30.86mm) |
Exhaust Valve Diameter | 1.00in (25.4mm) |
Inlet Throat Diameter | 1.172in (29.77mm) |
Exhaust Throat Diameter | 0.908in (23.06mm) |
Valve Lift | 0.312in (7.92mm) |
Inlet Valve Opening | 5 degrees BTDC |
Inlet Valve Closing | 45 degress ABDC |
Exhaust Valve Opening | 51 degrees BBDC |
Exhaust Valve Closing | 21 degrees ATDC |
(Valve timings measured with 0.019in/0.48mm rocker clearance set for testing purposes only). | |
Outer Valve Spring Free Length (all valves) | 1.750in (44.45mm) |
Inner Valve Spring Free Length (all valves) | 1.672in (42.47mm) |
Inner Valve Spring Pressure - Open (all valves) | 30lb (13.6kg) |
Inner Valve Spring Pressure - Closed (all valves) | 18lb (8.17kg) |
Outer Valve Spring Pressure - Open (all valves) | 88lb (39.9kg) |
Outer Valve Spring Pressure - Closed (all valves) | 55.5lb (25.13kg) |
Camshaft | |
Journal Diameter (Front) | 1.6655 to 1.666in (42.304 to 42.316mm) |
Journal Diameter (Centre) | 1.62275 to 1.62325in (41.218 to 41.231mm) |
Journal Diameter (Rear) | 1.3725 to 1.3735in (34.862 to 34.887mm) |
End Float | 0.003 to 0.007in (0.076 to 0.178mm) |
Bearings | 3, steel-backed white metal |
Bearing Inside Diameter (reamed in position) | |
|
1.667 to 1.6675in (42.342 to 42.355mm) |
Centre Bearing |
1.6245 to 1.6255in (41.261 to 41.287mm) |
Rear Bearing |
1.3748 to 1.3755in (34.914 to 34.937mm) |
Engine Lubrication | |
Oil Pump Type | Hobourn-Eaton |
Relief Pressure Valve Operates | 70 psi (4.92 kg/cm2) |
Relief Valve Spring (Free Length) | 2 39/64in (66.28mm) |
Relief Valve Spring (Fitted Length) | 2 5/32in (54.77mm) |
Oil Pressure (Normal Running) | 70psi (4.92kg/cm2) |
Oil Pressure (Idling - Minimum) | 15psi (1.05kg/cm2) |
Cooling System | |
Termostat temperature | 83 degrees Celsius (180 degrees F) |
Clutch | |
Pressure Springs (Colour) | Black enamel with white spot |
Diaphragm Spring (Colour Code) | Light green |
Mini Cooper S 970cc, 1071cc, 1275cc (essentially the same engine with varied deck height and stroke)
Engine Data | |
Number of Cylinders | 4 |
Bore | 2.780in (70.6mm) |
Stroke (970cc) | 2.4375in (61.91mm) |
Stroke (1071cc) | 2.687in (68.26mm) |
Stroke (1275cc) | 3.2in (81.33mm) |
Compression Ratio (970cc) | 10:1 |
Compression Ratio (1071cc) | 9:1 |
Compression Ratio (1275cc) | 9.75:1 |
Combustion Chamber Volume (valves and spark plugs fitted) | 1.306cu.in. (21.4cc) |
BMEP (970cc) | 142 psi (10kg/cm2) at 4500rpm |
BMEP (1071cc) | 143 psi (10.05kg/cm2) at 4500rpm |
BMEP (1275cc) | 153 psi (10.76kg/cm2) at 3000rpm |
Compression Pressure | 190 to 200 psi (13.3 to 14.07kg/cm2) at 500rpm |
Engine Idle Speed | 500rpm approx. |
Crankshaft Data | |
Main Bearing Material | Steel-backed copper-lead; thin wall |
Main Bearing Length | 1.000in (25.4mm) |
Main Bearing Running Clearance | 0.001 to 0.0027in (0.025 to 0.069mm) |
Main Journal Diameter | 2.0005 to 2.0010in (50.81 to 50.82mm) |
Main Journal Minimum Regrind Diameter | 1.9805 to 1.9810in (50.30 to 50.31mm) |
Con Rods | |
Little-end Bore Diameter | 0.8110 to 0.8115in (20.60 to 20.61mm) |
Pistons | |
Type | Solid skirt |
Clearance (bottom of skirt - pressure face) | 0.0019 to 0.0025in (0.048 to 0.063mm) |
Clearance (top of skirt) | 0.025 to 0.283in (0.63 to 0.72mm) |
Piston Rings | |
Top | Plain |
Second and third | Tapered |
Width | 0.0459 to 0.0469in (1.16 to 1.19mm) |
Thickness (all rings) | 0.116 to 0.122in (2.94 to 3.09mm) |
Fitting Gap (all rings) | 0.08 to 0.013in (0.2 to 0.33mm) |
Clearance in Groove (all rings) | 0.0015 to 0.0035in (0.04 to 0.09mm) |
Oil Control Ring Width | 0.1553 to 0.1563in (3.94 to 3.96mm) |
Gudgeon Pin | |
Type | Pressed-in con rod |
Fit in Piston | Hand push-fit |
Fit in Con Rod | 0.0008 to 0.015in (0.020 to 0.038mm) interferences |
Diameter | 0.8123 to 0.8125in (20.63 to 20.64mm) |
Valves and Valve Gear | |
Inlet Valve Diameter | 1.401 to 1.406in (35.58 to 35.71mm) |
Exhaust Valve Diameter | 1.214 to 1.219in (30.83 to 30.96mm) |
Valve Lift | 0.318in (8.08mm) nominal |
Inlet Valve Opening | 5 degrees BTDC |
Inlet Valve Closing | 45 degress ABDC |
Exhaust Valve Opening | 51 degrees BBDC |
Exhaust Valve Closing | 21 degrees ATDC |
(Valve timings measured with 0.021in/0.53mm rocker clearance set for testing purposes only). | |
Valve Rocker Clearance (Standard) | 0.012in (0.39mm) cold |
Valve Rocker Clearance (Competition) | 0.015in (0.38mm) cold |
Valve Rocker Clearance (Timing) | 0.021in (0.53mm) |
Outer Valve Spring Free Length (all valves) | 1.740in (44.19mm) |
Inner Valve Spring Free Length (all valves) | 1.705in (43.31mm) |
Inner Valve Spring Pressure - Open (all valves) | 46lb (20.865kg) |
Inner Valve Spring Pressure - Closed (all valves) | 26.6lb (12.065kg) |
Outer Valve Spring Pressure - Open (all valves) | 94lb (42.638kg) |
Outer Valve Spring Pressure - Closed (all valves) | 49.6lb (22.498kg) |
Camshaft | |
Journal Diameter (Front) | 1.6655 to 1.666in (42.304 to 42.316mm) |
Journal Diameter (Centre) | 1.62275 to 1.62325in (41.218 to 41.231mm) |
Journal Diameter (Rear) | 1.37275 to 1.3735in (34.87 to 34.88mm) |
End Float | 0.003 to 0.007in (0.076 to 0.178mm) |
Bearings | 3, steel-backed white metal |
Bearing Inside Diameter (reamed in position) | |
|
1.667 to 1.6675in (42.342 to 42.355mm) |
Centre Bearing |
1.6245 to 1.6255in (41.261 to 41.287mm) |
Rear Bearing |
1.3745 to 1.3750in (34.91 to 34.92mm) |
Running Clearance (Rear Bearing) | 0.001 to 0.00225in (0.025 to 0.057mm) |
Bearing Length (Rear Bearing) | 49/64 +/- 0.010in (19.45 +/- 0.25mm) |
Engine Lubrication | |
Oil Pressure (normal running) | 60psi (4.22kg/cm2) at 70 degrees C/158 degrees F oil temperature. |
Cooling System | |
Termostat temperature | 82 degrees Celsius (180 degrees F) |
Clutch | |
Make and Type (Early) | BMC single dry plate |
Make and Type (Later) | Diaphragm spring |
Diameter | 7.125in (180.9mm) |
Facing Material (Standard) | Wound yarn, riveted |
Facing Material (Optional) | Wound yarn, cemented and riveted |
Pressure Springs (Early Type, Inner) | 6 |
Pressure Springs (Early Type, Outer) |
6 |
Colour (Inner) | Green spot |
Colour (Outer) | White spot |