REMOVAL & INSTALLATION M20 Engine
The M20 engine is equipped with a timing belt, as opposed to a timing chain as is usual bmw style. The distributor guard plate is actually the upper timing belt cover.
- Disconnect the negative battery cable. Remove the distributor cap and rotor. Remove the inner distributor cover and seal.
- Remove the 2 distributor guard plate attaching bolts and one nut. Remove the rubber guard and take out the guard plate (upper timing belt cover).
- Rotate the crankshaft to set No. 1 piston at tdc of its compression stroke.
At tdc of No. 1 piston compression stroke, the camshaft sprocket arrow should align directly with the mark on the cylinder head.
- Remove the radiator.
- Remove the lower splash guard and take off the alternator, power steering and air conditioning belts.
- Remove the crankshaft pulley and vibration damper.
- If equipped with a 2 piece hub, hold the crankshaft hub from rotating with the proper tool. Remove the crankshaft hub bolt.
- Install the hub bolt into the crankshaft about 3 turns and use the proper gear puller, to remove the crankshaft hub.
- Remove the bolt from the engine end of the alternator bracket. Loosen the alternator adjusting bolt and swing the bracket out of the way.
- Lift out the tdc transmitter and set it aside.
- Remove the remaining bolt and lift off the lower timing belt protective cover.
- Loosen the timing belt tensioner roller bolts and push the roller in to remove the belt. Remove the intermediate shaft sprocket bolt and the sprocket.
- Loosen the oil pan bolts and remove the 3 front pan bolts that go into the timing cover. Use a thin blade to loosen the oil pan gasket from the cover. Remove the 6 bolts holding the cover and remove from the engine.
- Remove the oil pan and replace the gasket using non-hardening sealer at the joints. Replace the seals in the cover if necessary. Install the timing cover with new gaskets and tighten the M6 bolts to 6-7 ft. lbs. (8-10 Nm) and the M8 bolts to 15-17 ft. lbs. (20-24 Nm). Tighten the oil pan M6 bolts to 6.5-8.0 ft. lbs. (9-11 Nm) and the M8 bolts to 13-15 ft. lbs. (18-22 Nm).
- Install the intermediate shaft sprocket and timing belt. Tighten the belt.
- Install the lower timing protective cover and tighten the bolt. Install the tdc sender.
- Replace the alternator bracket. Install the crankshaft hub and torque the nut to 281-309 ft. lbs. (390-430 Nm).
- Install the vibration damper and pulley. Torque the bolts to 17 ft. lbs. (23 Nm).
- Install the upper cover and nut. Install the rubber guard. Check the condition of the O-ring and install the upper cover. Install the rotor and distributor cap.
- Install the accessories and belts. Install the splash shield and fill the cooling system with coolant mixture. Bleed the cooling system.
OIL SEAL REPLACEMENT
- Disconnect the negative battery cable. Remove the front engine cover.
- Press the 2 radial oil seals out of the front engine cover.
- Install the oil seals flush with the front engine cover using the proper tools.
- Install the front engine cover. Connect the negative battery cable.