Attached is an original service bulletin from BMC Australia. The text of the bulletin is as follows:
INTRODUCTION AUSTIN HEALEY IIa AND MORRIS 6 CWT VAN.
A further development of the ever popular 'A' series power unit is now of greater capacity (1098 c.c.) and developing more power and torque than the 948 c.c. engine which it replaces.
The following specifications are the main differences between the 948 c.c. and 1098 c.c. units.
SPRITE IIa | MORRIS 6 CWT. | |
ENGINE | 10 CG | 10 AM |
Bore | 2.543 in | 2.543 in |
Stroke | 3.296 in | 3.296 in |
Capacity | 1098 c.c. | 1098 c.c. |
Comp. Ratio | 8.9:1 | 8.5 or 7.5:1 |
B.H.P. | 56 at 5750 r.p.m. | H.C. 48 at 5100 r.p.m. L.C. 45 at 5100 r.p.m. |
Torque | 61 lbs./ft. at 2750 rpm | H.C. 60 lbs./ft. at 2500 rpm L.C. 57 lbs./ft. at 3000 rpm |
CRANKSHAFT | | |
Main Bearing Length | 1.0625 in | 1.0625 in |
Main Bearing Material | Steel backed lead bronze with lead indium faced surface | Steel backed lead bronze with lead indium faced surface |
Big End Bearing Side Clearance | .008/0.12 in | .008/0.12 in |
Big End Bearing Diametrical Clearance | .001/.0025 in | .001/.0025 in |
| SPRITE IIa | MORRIS 6 CWT |
PISTONS | | |
Type | Solid Skirt | Solid Skirt |
Clearance Bottom Skirt | .0005/.0011 in. | .0005/.0011 in. |
Clearance Top Skirt | .0021/.0037 in. | .0021/.0037 in. |
GUDGEON PIN | | |
Type Fit | Fully Floating Hand Push | Fully Floating Hand Push |
PISTON RINGS | | |
Compression Top | Internally chamfered chrome faced. | Internally chamfered chrome faced. |
VALVES | | |
Head Dia. Inlet | 1.156 in | 1.156 in |
VALVE TIMING | | |
Inlet Valve Opens Inlet Valve Closes Exhaust Opens Exhause Closes | 5⁰ B.T.D.C. 45⁰ A.B.D.C. 51⁰ B.B.D.C. 21⁰ A.T.D.C. | with .021 in. valve rocker clearance for checking purposes only. |
VALVE SPRINGS | | |
Free Length Inner | 1.672 in | - |
Free Length Outer | 1.750 in | 1.750 in |
Fitted Length Inner | 1.179 in | - |
Fitted Length Outer | 1.291 in | 1.291 in |
Working Coils Inner | 6.5 | - |
Working Coils Outer | 4.5 | 4.5 |
Pressure Valve Open Inner | 30 lbs. | - |
Pressure Valve Open Outer | 88 lbs. | 88 lbs. |
Pressure Valve Closed Inner | 18 lbs. | - |
Pressure Valve Closed Outer | 52 lbs. | 52 lbs. |
CAMSHAFT | | |
Bearing Type | 3 white metal lined steel backed | 3 white metal lined steel backed |
FUEL | | |
Type | Twin HS2 | Single HS2 |
NEEDLES | | |
Standard | GY | AN |
Rich | M | H.6 |
Weak | GG | EB |
Spring | Blue | Red |
| SPRITE IIa | MORRIS 6 CWT |
IGNITION | | |
Distributor | 40919 A Lucas | HC 40849 Lucas LC 40899 Lucas |
TIMING | 5⁰ B.T.D.C. | 3⁰ B.T.D.C. |
CLUTCH | | |
Diameter | 7.25 in. | 7.25 in. |
Pressure Spring | Red | Yellow |
GEARBOX | | |
Type | Baulk Ring | Baulk Ring |
Ratio Top | 1.0:1 | 1.0:1 |
Third | 1.357:1 | 1.41:1 |
Second | 1.916:1 | 2.172:1 |
First | 3.2:1 | 3.628:1 |
Reverse | 4.114:1 | 4.664:1 |
REAR AXLE | | |
Ratio | 4.22:1 | 4.22:1 |
BRAKES | | |
Rear | Disc 8.25 in. | Drum 8 x 1.5 in. |
Front | Drum 7 x 1.25 in. | Drum 7 x 1.25 in. |
N. PRESCOTT.
SERVICE MANAGER
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