How to use this Chapter This Part of Chapter 2 describes those repair procedures that can reasonably be carried out on the TU series engine while it remains in the car. If the engine has been removed from the car and is being dismantled as described in Part D, any preliminary dismantling procedures can be ignored. Refer to Part A and B for information on the XV, XW and XY series and XU series engines.

Part D describes the removal of the engine/transmission from the vehicle, and the full overhaul procedures that can then be carried out.

Engine description
The engine is of the in-line four-cylinder, overhead camshaft type, mounted transversely at the front of the car and inclined forward by 6°. The clutch and transmission are attached to its left-hand end. The 205 range is fitted with 954 cc (TU9), 1124 cc (TU1), and 1360 cc (TU3) versions of the engine in either carburettor or fuel-injected configuration.

The crankshaft runs in five main bearings.

Thrustwashers are fitted to No 2 main bearing (upper half) to control crankshaft endfloat.

The connecting rods rotate on horizontallysplit bearing shells at their big-ends. The pistons are attached to the connecting rods by gudgeon pins, which are an interference fit in the connecting rod small-end eyes. The aluminium-alloy pistons are fitted with three piston rings - two compression rings and an oil control ring.

On all except TU3FM engines, the cylinder block is made of aluminium, and replaceable wet liners are fitted to the cylinder bores.

Sealing O-rings are fitted at the base of each liner, to prevent the escape of coolant into the sump.

On TU3FM engines, the cylinder block is made from cast-iron, and the cylinder bores are an integral part of the cylinder block. On this type of engine, the cylinder bores are sometimes referred to as having dry liners.

The inlet and exhaust valves are each closed by coil springs, and operate in guides pressed into the cylinder head; the valve seat inserts are also pressed into the cylinder head, and can be renewed separately if worn.

The camshaft is driven by a toothed timing belt, and operates the eight valves via rocker arms. Valve clearances are adjusted by a screw-and-locknut arrangement. The camshaft rotates directly in the cylinder head.

The timing belt also drives the coolant pump.

Lubrication is by means of an oil pump, which is driven (via a chain and sprocket) off the right-hand end of the crankshaft. It draws oil through a strainer located in the sump, and then forces it through an externally-mounted filter into galleries in the cylinder block/crankcase. From there, the oil is distributed to the crankshaft (main bearings) and camshaft. The big-end bearings are supplied with oil via internal drillings in the crankshaft, while the camshaft bearings also receive a pressurised supply. The camshaft lobes and valves are lubricated by splash, as are all other engine components.

Repair operations possible with the engine in the car
The following work can be carried out with the engine in the car:
a) Compression pressure - testing.

b) Cylinder head cover - removal and refitting.

c) Valve clearances - adjustment.

d) Timing belt covers - removal and refitting e) Timing belt - removal, refitting and adjustment.

f) Timing belt tensioner and sprockets - removal, inspection and refitting.

g) Camshaft oil seal - renewal.

h) Camshaft and rocker arms - removal, inspection and refitting.

i) Cylinder head - removal and refitting.

j) Cylinder head and pistons - decarbonising.

k) Sump - removal and refitting.

l) Oil pump - removal, inspection and refitting.

m)Crankshaft oil seals - renewal.

n) Flywheel - removal, inspection and refitting.

o) Engine/transmission mountings - inspection and renewal.