ENGINE TUNING DATA 18V ENGINESTo European emission control requirements (ECE 15) ENGINE Type .. .. .. .. .. .. .. .. 18V. Displacement . . . . . . . . . . . . . . 1098 cu. in. (1798 cc). Firing order .. .. .. .. .. .. .. l, 3, 4, 2. Compression ratio . . . . . . . . . . . . 9-0 : 1. Cranking pressure . . . . .. . . . . . . Nominal 170 to 1901bf./sq. in. (12 to 134 kgf./cm.2). Valve rocker clearance: set cold . . . . . . . . 015 in. (-38 mm.). Idle speed .. .. .. .. .. . . .. .. 750 r.p.m. Fast idle speed . . . . . . . . . . . . . . 1,100 to 1,200 r.p.m. Stroboscopic ignition timing . . . . . . . . . . 15 B.T.D.C. at 1,000 r.p.m. Static ignition timing . . . . . . . . . . . . 5 B.T.D.C. Timing mark location . . . . . . . . . . . . Pointer on timing case, notch on crankshaft pulley. DISTRIBUTOR Make/Type . . . . . . . . . . . . . . Lucas/25D4. Contact breaker gap . . . . . . . . . . . . ~014 to 0-16 in. ('35 to -40 mm.). Contact spring tension . . . . . . . . . . . . 18 to 24 oz. (510 to 680 gm.). Rotation of rotor . . . . . . . . . . . . Anti-clockwise. Dwell angle .. .. .. .. .. .. .. 60i3 Serial number . . . . . . . . . . . . . . 41032. Centrifugal advance Crankshaft degrees/Speed (vacuum pipe disconnected) . . 0 to 3 at 600 r.p.m. 0 to 4 at 700 r.p.m. 2 to 7 at 900 r.p.m. 10 to 14 at 1,600 r.p.m. 17 to 21 at 2,200 r.p.m. Vacuum advance Starts .. .. .. .. . . . . .. .. 3 in. Hg. (76 mm. Hg.). Finishes . . .. .. .. .. .. . . . . 8 in. Hg. (203 mm. Hg). Total crankshaft degrees . . . . . . . . . . 14i2. IGNITION COIL Make/Type . . . . . . . . . . . . . . Lucas/HA12. Resistance: Primary . . . . . . . . .. . . 3-1 to 3-5 ohms at 20 C. (68 F.). SPARKING PLUGS - Make/Type . . . . . . . . . . . . . . Champion/N9Y. Gap . . . . .. . . . . .. .. . . -024 to -026 (-625 to -66 mm.). CARBURETTERS Make/Type . . . . . . . . . . . . . . S.U./HIF4. Specication . . . . . . . . . . . . . . AUD 434. Jet .. .. .. .. .. .. .. .. .. -090 in. (22 mm.). Needle .. .. .. .. .. .. .. .. AAU. Piston spring . . . . . . . . . . . . . . Red. EXHAUST EMISSION Exhaust gas analyser reading at engine idle speed . . . . 3 to 45% CO. Engine mm Data 6 MGB. Issue 2. 83910 72