specifications for the 1071cc cooper s engine








and gearbox ratios








engine number prefix 10f








Engine Type 1071cc Cooper S
cup type welch plugs x 4 (S) cam follower covers




Bore
2.780"






Stroke
2.687"






capacity of combustion chamber
21.4cc






b.m.e.p.
146 lb/sq" 2 3500-5000 rpm





Bhp
68 bhp @ 5750






Torque
62 ft/lb @ 4500 rpm






Fuel System
leaded






Compression Ratio
9.0:1






Firing Order
1 3 4 2






Valve Clearance (Inlet)
.015" thou






Valve Clearance (Exhaust)
.015" thou






Cylinder Head Tension
42 ft/lb * extra stud over water pump 25 ft/lb




Conrod Bolt Tension
46 ft/lb = cooper S






Main Bearing Tension
67 ft/lb= bolts 57ft/lb = nuts





Crankshaft Pulley Tension
70 ft/lb






Flywheel Tension
150 ft/lb






Points Gap
.015"






Dwell Angle in degrees
60 + or - 5






Spark Plug Type / Gap
bp6es ngk w7dc bosch .025"





Ignition Timing ( max total mech #30)distributor is mecha
0-10 degrees BTDC (depends on fuel/comp ratio and distributor curve)original factory 3 deg btdc
CO % (at idle)

3%







Oil Capacity
5 litres incl filter






Oil Filter (Industry Number)
early R2180p mid R2200p screw on z418




Oil Type / Grade
20w/50 sg






Recommended Service Interval
3000 miles/ 5000 km






Crankshaft main journal dia
2.0005"-2.0010 (50.81-50.82mm)





Main bearings running clearance
.001"-.0027"






Connecting rods little end size
.8110"-.8115"






Gudgeon pin press fit
.008"-.0015" interference






Piston rings
width comps.047" x 3 oil .156" end gaps on comp .008"-.015"



Valves
inlet head dia 1.401" exhaust 1.214"





Cam timing using .021" tappet clearance
inlet opens 5# btdc inlet closes 45#abdc




exhaust opens 51# bbdc exh closes 21#atdc








Valve springs free length
inner 1.705" outer 1.740"





Oil pressure normal running
75 lb/in (5.27 kg/cm2






carburettor needle twin 1-1/4" su
std H6 rich no 3 weak eb





Gearbox ratios standard ratio
close ratio






helical gears top 1.0:1
top 1.0:1






third 1.357:1
third 1.242:1






second 1.916:1
second 1.78:1






first 3.200:1
first 2.57:1






reverse 3.200:1
reverse 2.57:1







straight cut 3 sp standard ratio








close ratio







top 1.0:1
top 1.0:1






third 1.307:1
third 1.255:1






second 1.875:1
second 1.722:1






first 3.077:1
first 2.573:1






reverse 3.077:1
reverse 2.573:1







Overall gear ratios with 3.765 standard final drive ratio






with optional 3.44 ratio







top 3.765
top 3.44






third 5.109
third 4.674






second 7.213
second 6.599:1






first/reverse 12.047:1
first/reverse 11.022:1






Optional diff ratios
3.938:1 4.133:1 4.267:1