Chapter 1 Routine maintenance and servicing

Zetec engine in-car repair procedures 2C•3fitted with three piston rings: twocompression rings and an oil control ring.After manufacture, the cylinder bores andpiston skirts are measured and classified intothree grades, which must be carefullymatched together, to ensure the correctpiston/cylinder clearance; no oversizes areavailable to permit reboring.The inlet and exhaust valves are eachclosed by coil springs; they operate in guideswhich are shrink-fitted into the cylinder head,as are the valve seat inserts.Both camshafts are driven by the sametoothed timing belt, each operating eightvalves via self-adjusting hydraulic tappets,thus eliminating the need for routine checkingand adjustment of the valve clearances. Eachcamshaft rotates in five bearings that are lineboreddirectly in the cylinder head and the(bolted-on) bearing caps; this means that thebearing caps are not available separately fromthe cylinder head, and must not beinterchanged with caps from another engine.The water pump is bolted to the right-handend of the cylinder block, inboard of thetiming belt, and is driven with the powersteering pump and alternator by a flat“polyvee”-type auxiliary drivebelt from thecrankshaft pulley.When working on this engine, note thatTorx-type (both male and female heads) andhexagon socket (Allen head) fasteners arewidely used; a good selection of bits, with thenecessary adapters, will be required, so thatthese can be unscrewed without damage and,on reassembly, tightened to the torquewrench settings specified.Lubrication is by means of an eccentricrotortrochoidal pump, which is mounted onthe crankshaft right-hand end, and draws oilthrough a strainer located in the sump. Thepump forces oil through an externallymountedfull-flow cartridge-type filter - onsome versions of the engine, an oil cooler isfitted to the oil filter mounting, so that clean oilentering the engine’s galleries is cooled by themain engine cooling system.Repair operations possible withthe engine in the carThe following work can be carried out withthe engine in the car:a) Compression pressure - testing.b) Cylinder head cover - removal andrefitting.c) Timing belt covers - removal and refitting.d) Timing belt - renewal.e) Timing belt tensioner and sprockets -removal and refitting.f) Camshaft oil seals - renewal.g) Camshafts and hydraulic tappets -removal and refitting.h) Cylinder head - removal and refitting.i) Cylinder head and pistons -decarbonising.j) Sump - removal and refitting.k) Crankshaft oil seals - renewal.l) Oil pump - removal and refitting.m) Flywheel/driveplate - removal andrefitting.n) Engine/transmission mountings - removaland refitting.Note: It is possible to remove the pistons andconnecting rods (after removing the cylinderhead and sump) without removing the engine.However, this is not recommended. Work ofthis nature is more easily and thoroughlycompleted with the engine on the bench, asdescribed in Chapter 2D.2 Compression test -description and interpretation 2Refer to Section 2 in Part A of this Chapter.3 Top Dead Centre (TDC) forNo 1 piston - locating21 Top dead centre (TDC) is the highest pointof the cylinder that each piston reaches as thecrankshaft turns. Each piston reaches its TDCposition at the end of its compression stroke,and then again at the end of its exhauststroke. For the purpose of engine timing, TDCon the compression stroke for No 1 piston isused. No 1 cylinder is at the timing belt end ofthe engine. Proceed as follows.2 Disconnect the battery negative (earth) lead(refer to Chapter 5A, Section 1).3 Chock the rear wheels then jack up thefront of the car and support it on axle stands(see “Jacking and Vehicle Support”). Removethe right-hand roadwheel.4 Remove the auxiliary drivebelt cover (seeChapter 1) to expose the crankshaft pulleyand timing marks.5 Fit a spanner onto the crankshaft pulleybolt, and turn the crankshaft in its normaldirection of rotation (clockwise, viewed fromthe pulley end).Turning the engine will beeasier if the spark plugs areremoved first - see Chapter 1.3.6a Do not use crankshaft pulley’s firstpair of notches “A” - align second pair ofnotches “B” with raised rib on sump “C” . . .6 Note the two pairs of notches in the innerand outer rims of the crankshaft pulley. In thenormal direction of crankshaft rotation the firstpair of notches are irrelevant to the vehiclescovered in this manual, while the second pairindicate TDC when aligned with the rear edgeof the raised mark on the sump. Rotate thecrankshaft clockwise until the second pair ofnotches align with the edge of the sump mark;use a straight edge extended out from thesump if greater accuracy is required (seeillustrations).7 Nos 1 and 4 cylinders are now at TDC, oneof them on the compression stroke. Removethe oil filler cap; if No 4 cylinder exhaust camlobe is pointing to the rear of the vehicle andslightly downwards, it is No 1 cylinder that iscorrectly positioned. If the lobe is pointinghorizontally forwards, rotate the crankshaftone full turn (360º) clockwise until the pulleynotches align again, and the lobe is pointingto the rear and slightly down. No 1 cylinderwill then be at TDC on the compressionstroke.8 Once No 1 cylinder has been positioned atTDC on the compression stroke, TDC for anyof the other cylinders can then be located byrotating the crankshaft clockwise 180º at atime and following the firing order (seeSpecifications).9 With the engine set at No 1 piston on TDCcompression, refit the drivebelt cover and theroadwheel, then lower the vehicle and refit thespark plugs.4 Cylinder head cover -removal and refitting 1Removal1 Disconnect the battery negative (earth) lead(refer to Chapter 5A, Section 1).2 Remove the air inlet components asnecessary for access as described in theChapter 4D.3 Disconnect the accelerator cable from thethrottle linkage as described in Chapter 4D.4 On models equipped with power steering,release the high pressure fluid pipe from the3.6b . . . use a straight edge extended outfrom the sump (arrowed) if greateraccuracy is required2C1595Ford Fiesta Remake