Internal Engine - 1275cc (Not Cooper S) No. Part No. Description Qty. Remarks No. Part No. Description Qty. Remarks Crankshaft (continued) There are two distinct main bearing designs: the earlier 8G2391 bearings have locating lugs on the edge of both upper and lower halves, whereas the later BHM1574 bearings have lugs on the edge of the upper halves and in the centre of the lower halves. They cannot be interchanged in engines because the engine main bearing caps are unique for each design. 1275cc engines were not fitted by the factory in <strong>Mini</strong>s during the 1980s; however many owners have chosen to transplant Austin or MG Metro 1275cc engines made in the 1980s into their cars. For the benefit of those owners, the change in main bearing design on the Metro power unit occurred in 1983. 19 8G2391STD BEARING SET, main bearings, 1 1275 GT 1969-80; std. size. set of 3 pairs 8G2391010 BEARING SET, main bearings, 1 1275 GT 1969-80; 0.010" undersize. set of 3 pairs 8G2391020 BEARING SET, main bearings, 1 1275 GT 1969-80; 0.020" undersize. set of 3 pairs 8G2391030 BEARING SET, main bearings, 1 1275 GT 1969-80; 0.030" undersize. set of 3 pairs 8G2391040 BEARING SET, main bearings, 1 1275 GT 1969-80; 0.040" undersize. set of 3 pairs BHM1574STD BEARING SET, main bearings, 1 A Plus 1990 on; std. size. set of 3 pairs BHM1574010 BEARING SET, main bearings, 1 A Plus 1990 on; 0.010" undersize. set of 3 pairs BHM1574020 BEARING SET, main bearings, 1 A Plus 1990 on; 0.020" undersize. set of 3 pairs BHM1574030 BEARING SET, main bearings, 1 A Plus 1990 on; 0.030" undersize. set of 3 pairs BHM1574040 BEARING SET, main bearings, 1 A Plus 1990 on; 0.040" undersize. set of 3 pairs Thrust washers are supplied as a pair; i.e. one upper and one lower thrust washer. Two pairs are required per engine, fitted selectively to obtain the correct amount of end float on the crankshaft. The correct time to measure the crankshaft end float (fore-aft movement) is before the main bearing caps are tightened down during reassembly. The end float should be between 0.001” and 0.005” (0.025mm to 0.127mm); usually a combination of standard and/or +0.003” oversize thr ust washers will suffice. 20 BHM1293STD THRUST WASHERS, crankshaft, pair A/R Standard size . BHM1293003 THRUST WASHERS, crankshaft, pair A/R +0.003" oversize . BHM1293030 THRUST WASHERS, crankshaft, pair A/R +0.030" oversize . 21 6K836 KEY, Woodr uff, crankshaft 1 22 12G1699 GEAR, timing chain, crankshaft 1 1275 GT 1969-74; for duple x chain. 23 8G725 GEAR, timing chain, crankshaft 1 1275 GT 1974-80; A Plus 1990 on. For simplex chain. Once again, the change dates listed above apply to original <strong>Mini</strong> engines. For the sake of <strong>Mini</strong> owners with 1275cc Metro engines in their cars, all Metro engines have simplex timing chains. (if you prime it with engine oil, there’s a fair chance a lot of it will have drained back into the gearbox by the time you turn the engine over for the first time). Three different coupling designs (‘drives’) between the end of the camshaft and the oil pump were used in <strong>Mini</strong> engines, and of course you will need to ensure that if the camshaft or oil pump are replaced that the correct matching types are used. Drive methods can be changed in engines (particularly when the desired profile of camshaft is not available with the original drive type for your engine), but this tends to get a little complicated when sorting out the correct corresponding oil pump to use. Details of which oil pumps may be fitted to which engines - and how they can be fitted - are in the Oil Pumps and Oil Pressure Relief Valves section of the <strong>Somerford</strong> <strong>Mini</strong> <strong>Catalogue</strong>. Up until 1980,all <strong>Mini</strong> engines - except automatic , 1969-71 Cooper S and 1275 GT units - used pin drive camshafts, where a pin across the end of the camshaft engages in a slot in the oil pump shaft (but don’t call it slot drive - that’s a different system). Pin drive camshafts are not original for the engines detailed in this section. From 1980 onwards (i.e. from the introduction of A Plus engines) all engines without exception used slot drive. In this system the camshaft has a slot in the end which engages with a spade shaped lug on the oil pump shaft. Pre-1980 automatic, 1969-71 Cooper S and most 1275 GT engines (i.e. not including the last handful of 1980 built engines which were A Plus) used star drive , otherwise known as spider drive. In this system a drive flange or ‘spider’ sits between the camshaft and oil pump, its three external lobes engaging in the end of the camshaft and its internal splines (or ‘star’) engaging on external splines on the oil pump shaft. A range of uprated camshafts and other engine tuning components are also available from <strong>Somerford</strong> <strong>Mini</strong>, but are not listed here. Please contact us for details. Camshaft 1969-80 (1275 GT) 33 AEG523 CAMSHAFT, for ‘star drive’ oil pump 1 1969-80. 12G2983 CAMSHAFT, for ‘slot drive’oil pump 1 1980; A Plus type. Camshaft 1990 On (A Plus) For owners with transplanted 1275cc Metro engines in their <strong>Mini</strong>s, please contact <strong>Somerford</strong> <strong>Mini</strong>, quoting your full engine number,to ensure you receive the correct camshaft for your engine. CAM6648 CAMSHAFT, for ‘slot drive’oil pump 1 10:1 compression ratio carburetter engines. LGC10230 CAMSHAFT, for ‘slot drive’oil pump 1 10:1 compression ratio single point injection engines. LGC105380 CAMSHAFT, for ‘slot drive’oil pump 1 10:1 compression ratio multi point injection engines. LGC10231 CAMSHAFT, for ‘slot drive’oil pump 1 9.4:1 compression ratio carburetter and single point injection engines. 24 6K628 WASHER, packing A/R 25 12A1148 OIL THROWER, crankshaft 1 26 88G561 OIL SEAL, timing cover 1 Included in timing co ver assembly. Crankshaft Pulley 1969-96 27 88G305 PULLEY, crankshaft, with damper 1 1275 GT 1969-76. CAM4929 PULLEY, crankshaft, with damper 1 1275 GT 1976-80; can be used to replace 88G305. AHU1878 PULLEY, crankshaft, with damper 1 1275 GT 1980; A Plus 1990-96. With timing plate . 28 12A283 BOLT, pulley to crankshaft 1 1275 GT 1969-80. TAM2019 BOLT, pulley to crankshaft 1 A Plus 1990-96. 29 12A398 LOCK TAB, pulley bolt 1 1275 GT 1969-80. TAM2020 LOCK TAB, pulley bolt 1 A Plus 1990-96. For <strong>Mini</strong> owners with 1980s Metro 1275cc engines in their cars, all Metro engines use the AHU1878 pulley, TAM2019 bolt and TAM2020 lock tab. Crankshaft Pulley 1997 On 30 LHF100130 PULLEY, crankshaft, with damper 1 Polyvee belt type. 31 TAM2019 BOLT, pulley to crankshaft 1 32 TAM2020 LOCK TAB, pulley bolt 1 Camshaft and Tappets A dramatic proportion of the wear suffered by a camshaft during its entire working life actually takes place during the first few minutes of running after fitment. Whenever you replace the camshaft or tappets, or both, in your engine you should apply cam lubricant during assembly; it will lessen the inevitable scuffing and potential damage between cam and tappets during the bedding in period. <strong>Somerford</strong> <strong>Mini</strong> stock cam lube in a 250ml bottle under part number CL001. Also, you can pack the oil pump with cam lube before fitting it to the engine - it’s a very successful way of priming the oil pump 34 CHM108 FLANGE, for ‘star drive’ oil pump 1 Use with ‘star drive’ type camshaft. (flange also known as ‘spider’) 35 12G4499 SPINDLE, distributor drive , centred slot 1 1969-80. 12G3560 SPINDLE, distributor drive , offset slot 1 1980-96, A Plus type. 36 2A13 TAPPET (also known as cam follower) 8 1969-96; standard size. 2A13010 TAPPET (also known as cam follower) 8 1969-96; +0.010" oversize. LGR100440 TAPPET (also known as cam follower) 8 1997 on; standard size. 37 AEG314 PUSH ROD 8 Timing Chain Duplex Timing Chain 1969-74 38 2H4905 CHAIN, timing, duplex (double row) 1 39 12G1397 GEAR, duplex timing chain, camshaft 1 40 WKN505 KEY, Woodr uff 1 41 6K629 NUT, gear to camshaft 1 42 2A759 LOCK TAB, nut 1 Simplex Timing Chain 1974 On 43 3H2127 CHAIN, timing, simplex (single row) 1 44 12G4337 GEAR, timing chain, camshaft 1 45 12G2621 PAD,timing chain tensioner 1 46 12G2629 PIN, tensioner pivot 1 47 12G2628 PLATE, tensioner mounting 1 48 SH605061 SCREW, plate to cylinder block 2 49 LWZ305 WASHER, locking 2 50 PWZ105 WASHER, plain 2 51 WKN505 KEY, Woodr uff 1 52 6K629 NUT, gear to camshaft 1 53 2A759 LOCK TAB, nut 1 Tel. 01249 721421 Fax. 01249 721316 www.somerford-mini.co.uk 29
Internal Engine - 970, 1071 and 1275cc (Cooper S) © Copyright <strong>Somerford</strong> <strong>Mini</strong> Limited 30 Tel. 01249 721421 Fax. 01249 721316 www.somerford-mini.co.uk