1994 FIAT PUNTO Temp

11.15 Left-hand engine mounting viewed from below 9 lower the engine sufficiently to remove the mounting from the engine bracket. 10 Locate the new mounting in the engine bracket, refit the nut and washers and tighten securely. 11 Raise the engine and refit and tighten the mounting-to-body bolts. 12 Remove the trolley jack and lower the vehicle to the ground. Left-hand mounting 13 If not already done, firmly apply the handbrake, then jack up the front of the car and support It securely on axle stands (see
Jacking
and vehicle support). 14 Place a trolley jack beneath the trans-mission. with a block of wood on the jack head. Raise the jack until it is supporting the weight of the engine/transmission. 15 Unscrew the bolts securing the left-hand mounting to the body (see Illustration). 16 Unscrew the nut securing the mounting to the transmission bracket and recover the washers. 17 Lower the transmission sufficiently to remove the mounting from the transmission bracket. 18 Locate the new mounting in the transmission bracket, refit the nut and washers and tighten securely. 19 Raise the engine and refil and tighten the mounting-to-body bolts. 20 Remove the trolley jack and lower the vehicle to the ground. Rear mounting 21 If not already done, firmly apply the handbrake, then jack up the front of the car and support it securely on axle stands (see
Jacking
and vehicle support). 22 Working beneath the vehicle, unscrew the bolts securing the rear engine mounting to the underbody (see illustration). 23 Temporarily support the weight of the engine/transmission using a trolley jack. 24 Unbolt the rear mounting assembly from the transmission and withdraw from under the vehicle. 25 Unscrew the bolt and separate the bracket from the mounting. 28 Fitting the new mounting is a reversal of tha removal procedure.
Diesel engine in-car repair procedures 2C*11
11.22 Rear engine mounting viewed from below
12 Sump -removal and refitting
Removal 1 Disconnect the battery negativo terminal (refer to Disconnecting the battery in the Reference Section of this manual). 2 Firmly apply the handbrake, then jack up the front of the car and support it securely on axie stands (see Jacking and vehicle support). 3 Drain the engine oil as described in Chap-ter 1B. Where applicable, remove the screws and lower the engine undertray away from the vehicle. 4 On turbo models disconnect the turbo-charger oil drain hose from the sump (see illustration). 5 Working around the outside of the sump, progressively loosen and withdraw the sump retaining bolts. 6 Break the joint by striking the sump with the palm of your hand, then lower the sump and withdraw it from underneath the vehicle. Recover and discard the sump gasket. 7 While the sump Is removed, take the opportunity to check the oil pump pick-up/strainer for signs of clogging. If necessary, clean or renew the strainer.
Refitting 8 Thoroughly clean the sump inside and out ensuring that all traces of gasket are removed from the mating surfaces of both the sump and the cylinder block/crankcase.
12.4 Turbocharger-to-sump oil drain hose
9 Ensure that the mating surfaces are clean and dry, then apply a little grease to the surface of the sump. This will retain the gasket in position while refitting the sump. 10 Lay the new sump gasket In position on the sump mating surface, then offer up the sump and refit the retaining bolts. Tighten the bolts evenly and progressively lo the specified torque. 11 On turbo models reconnect the turbo-charger oil drain hose. 12 Lower the vehicle to the ground then refer to Chapter 1B and refill the engine with the specified grade and quantity of oil. 13 Reconnect the battery negative terminal.
13 Oil pump and pick-up tube -removal, inspection and refitting
Removal 1 The oil pump Is mounted on the timing belt end of the cylinder block and is driven by flats on the crankshaft nose. Incorporated In the oil pump body is the crankshaft oil seal. 2 Remove the timing belt as described in Section 4, and the crankshaft sprocket as described in Section 5. 3 Remove the sump as described in Section 12. 4 Unscrew the bolts securing Ihe pick-up tube to the bottom of the oil pump. Also unscrew the bolt securing the tube to the No 2 main bearing cap. Withdraw the tube from the oil pump and crankcase. Recover the gasket (see illustrations).
13.4a Removing the oil pump pick-up tube... 13.4b ... and gasket

2D*10 Engine removal and overhaul procedures
Engine and transmission -removal, separation, connection and refitting
Note: The engine Is lowered from the engine compartment as a complete unit with the transmission; tho two are then separated for overhaul.
Removal 1 Remove the bonnet and disconnect the washer tubing as described in Chapter 11 (see illustrations). 2 Apply the handbrake, then jack up the front of the vehicle and support on axle stands (see Jacking and vehicle support). Remove both front wheels. In order to remove tne engine/transmission assembly in an upright position from under the vehicle, there must be a minimum clearance of 660 mm between the floor and the front crossmember. Additional height Is necessary if the assembly is to be lowered onto a trolley. 3 Where fitted, unbolt and remove the engine compartment lower cover. 4 Remove the auxiliary drivebelt(s) with reference to Chapter 1A or 1B. 5 Dram the engine oil. transmission oil/fluid and coolant with reference to Chapter 1A or 1B. 6 Remove the battery (see Chapter 5A). 7 On manual transmission models with a cable dutch, disconnect the clutch cable from the transmission (refer to Chapter 6). On manual transmission models with a hydraulic clutch unbolt the clutch slave cylinder from the top of the transmission then fit a cable-tie around it to prevent the piston coming out (see Illustration). Position the cylinder to one side. 8 Unscrew the nut and disconnect the earth lead from the transmission (see illustration). Petrol engines 9 Unbolt and remove the battery tray. 10 Disconnect the wiring from the reversing light switch. 11 On manual transmission models disconnect the reverse Inhibition cable from the transmission then disconnect the gear selector rod from the lever on the transmission. 12 Remove the air cleaner and ducting as descnbed In Chapter 4A or 4B. 13 On automatic transmission models disconnect the kickdown cable and gear selector cable as described in Chapter 7B. Also disconnect the wiring for the electro-magnetic clutch. 14 Unbolt and remove the cover from the bulkhead then disconnect the oxygen sensor wiring. 15 Disconnect the remaining wiring at the bulkhead and release the fuse holders at the mounting. 16 Disconnect the vacuum pipe from the inlet manifold, and also disconnect the wiring connector located next to it.
4.1a Unscrewing the bonnet hinge bolts
17 Unscrewthenutsandseparatetheengine wiring harness lead from the battery positive cable terminal. 18 Disconnect the accelerator cable from the engine as described in Chapter 4A or 4B, 19 Loosen the clip and disconnect the radiator top hose from the elbow on the left-hand end of the cylinder head. Similarly disconnect the bottom hose. On 16-valve models, remove the radiator electric cooling fan as described in Chapter 3. 20 Identify the hoses connected to the throttle housing, then disconnect them. 21 Identify the coolant heater hoses on the bulkhead for position, then loosen the clips and disconnect the hoses. 22 Loosen the clip and disconnect the brake servo vacuum hose from the Inlet manifold. Where applicable, disconnect the remaining emission control system vacuum hoses from the Inlet manifold after Identifying their locations to aid refitting. 23 Disconnect tho fuel supply and return hoses from the throttle housing. 24 Release the connector from the ignition/fuel ECU located on the right-hand side of the engine compartment. 25 Unscrew the nut and detach the earth cable from its location near the ECU. 26 Disconnect the diagnostic connector located near the ECU. 27 On models fitted with power steering, refer to Chapter 10 and unbolt the power steering pump from the front of the engine without disconnecting the hydraulic fluid lines then tie It to one side so that it will not obstruct the removal of the engine. On
4.1b Disconnecting the washer tubing
models with air conditioning, similarly unbolt the air conditioning compressor and position it clear of the engine. Do not disconnect the air conditioning refngerant pipes/hoses. 26 On manual transmission models pull out the retaining plate and disconnect the gear selector cable from the lever on the transmission. 29 Unscrew the nuts retaining the track rod ends on the swivel hubs and use a balljoint separator tool to disconnect them. 30 Release the flexible brake fluid hoses and ABS system sensor wrring from the front suspension struts. 31 On manual transmission models, unscrew the nuts from the outer ends of each driveshaft. To prevent the hubs from turning either have an assistant depress the brake pedal, or temporarily Insert two wheel bolts and use a lever to hold the hub. 32 On automatic transmission models use a suitable drift to drive out Ihe roll pins securing 2D the inner ends of the drlveshafts to tho trans-mission output stubs. Turn the driveshalts as necossary to access the roll pins . 33 Unscrew the two bolts securing the right-hand swivel hub assembly to the front suspension strut, then move the hub assembly outwards. On manual transmission models release the outer end of the driveshaft from the hub assembly - on automatic transmission models slide the inner end of the driveshaft off the final drive output stub. Take care not to strain the flexible brake hose while doing this. Move the driveshaft to one side thon temporanly refit the hub assembly to the strut. On manual transmission models, make
^ - / //
4.7 Fit a cable tie around the dutch slave cylinder to prevent the piston coming out 4.8 Disconnecting the earth lead from the transmission

2D*10 Engine removal and overhaul procedures
4.50b ... and expansion tank 4.S2 Disconnecting the radiator coolant temperature sensor wiring plug
4.53b One of tho wheel arch liner retaining screws is hidden in a recess 52 On the radiator cooling fan housing, disconnect the wiring plug for tho coolant temperature sensor (see illustration). 53 Unscrew the four front screws on each side retaining the wheel arch liners in order to
4.53c Bolt securing the front bumper to the valance access the front bumper mounting bolts • one of lite screws is hidden in a recess. Pull back the liners and use an extension and socket to unscrew the bolts securing the front bumper to tho valance (see illustrations).
4.55 Releasing the retaining clips from the rear of tho indicator lights 4.56a Side bumper retaining screw
4.56b Centre bumper retaining screw 4.57a Radiator lower mounting bracket bolt
4.54 One of the front bumper lower retaining screws 54 Unscrew and remove the front bumper lower retaining screws (see Illustration). 55 From inside the engine compartment, disconnect the wiring from the rear of the Indicator lights and release the retaining clips (see illustration). 56 Unscrew the upper retaining screws and withdraw the front bumper from the body (see Illustrations). 57 Unscrew the bolts socunng the radiator lower mounting bracket to the body then prise the bracket from the rubbers on the bottom ol the radiator (see Illustrations). 58 Unscrew the upper mounting bolt securing the engine oil cooler then lower the cooler and support on an axle stand (see illustrotion). Take care not to damage the hoses. 59 Support the radiator then unscrew the radiator upper mounting bolts, and remove the radiator from the vehicle (see illustrations).
4.57b Removing the bracket from the rubbers on the bottom of the radiator

2D*10 Engine removal and overhaul procedures
05 Remove the brush holder assembly from the automatic transmission as described in Chapter 7B, Section 4. The brushes bear on the slip rings at the rear of the electro-magnetic clutch housing and they may be damaged when the transmission is removed. 86 Unscrew and remove the transmission-to-engine bolts then carefully draw the transmission away from the engine, resting It securely on wooden blocks. Collect the locating dowels If they are loose enough to be extracted, 87 If the oil pump driveshaft remains engaged with the crankshaft, remove it and reert Into the transmission to protect It from damage.
Connection 86 If the engine and transmission have not been separated, go to paragraph 104. Manual transmission models 89 Smear a little high-melting-point grease
on
the splines of the transmission input shaft. Do not use an excessive amount as there Is the risk of contaminating the clutch friction plate. 90 Carefully offer up the transmission to the engine cylinder block, guiding the input shaft through the clutch friction plate. 91 Refit the transmission-to-engine bolts and
the
single nut. hand^jghtenlng 1hem to secure the transmission in position. Note: Do not hghten them to force the engine and transmission together. Ensure that the beilhousing and cylinder block mating faces will butt together evenly without obstruction, before finally tightening the bolts and nut securely. Automatic transmission models 92 Check that the oil pump driveshaft is correctly engaged with the oil pump in the transmission. 93 Carefully offer up the transmission to Ihe rear of the engine and insert the oil pump driveshaft In the centre of the electro-magnetic clutch housing. Locate the transmission on the locating dowels then Insert the bolts and tighten them securely. 94 Refit the brush holder assembly to the automatic transmission with reference to Chapter 7B, Section 4. Petrol engines 96 Refit the transmission lower cover and tighten the bolts. 96 Locate the support bracket on the lower cover, then insert the bolts hand-tight. Also Insert the bolts securing the bracket lo the rear of Ihe cylinder block. With all the bolts Inserted, tighten them securely. 97 Refit the earth leads and tighten the bolts. Diesel engines 98 Refit the rpm sensor and tighten the bolts. 99 Insert the Intermediate shaft through the bracket then locate the dust boot on it and insert the Inner end in the transmission.
100 Refit and tighten the bolts securing the Intermediate shaft to the bracket on the rear of the cylinder block. 101 Refit the transmission lower cover and tighten the bolts. Ail models 102 Refit the starter motor (see Chapter 5A). 103 Refit the wiring harness to the components on the engine/transmission assembly making sure it is routed correctly.
Refitting 104 Locate the engine/transmission assembly beneath the engine compartment and attach the hoist to the lifting eyes. 105 Carefully lift the assembly up into the engine compartment taking care not to damage the surrounding components. 106 Reconnect the left-hand engine/trans-mission mounting to the body and tighten the bolts. 107 Reconnect Ihe right-hand engine mounting to the body and tighten the bolts. 108 Working beneath the vehicle, refit the rear engine mounting and tighten the bolts. 109 Disconnect the hoist from the engine and transmission lifting eyes and remove the hoist from under the vehicle. 110 The remainder of the refitting procedure is the direct reverse of the removal procedure, noting the following points:
a) Ensure that alf sections of the wiring harness follow their original routing; use new cable-ties to secure the harness In position, keeping it away from sources
of
heat and abrasion. b) On vehicles with manual transmission check and if necessary adjust the gearchenge cable and rod with reference to Chapter 7A. c) On vehicles with automatic transmission use new ro//p/ns fo secure the driveshafts to the transmission output stubs. Also check and if necessary adjust the kickdown end selector cables with reference to Chapter 78. d) Ensure that afi hoses are correctly routed and are secured with the correct hose clips, where applicable. If the hose clips cannot be used again; proprietary worm drive clips should be fitted
In
their place. e) Refill the cooling system as described in Chapter 1A or 18. f) Refill the engine with appropriate grades and quantities of oil (Chapter
1A
or 1B). g) Refit and adjust the auxiliary drivebelt(s) wfth reference fo Chapter 1A or 1B. h) Check and If necessary adjust the accelerator cable with reference to Chapter
AA,
48 or
AC.
i) When the engine is started for the first time, check for
air,
coolant, lubricant and fuel leaks from manifolds, hoses etc. If
the
engine has been overhauled, read
the
notes In Section 13 before attempting to starlit.
5 Engine overhaul • dismantling sequence
1 It is much easier to dismantle and work on the engine if it is mounted on a portable engine stand. These stands can often be hired from a tool hire shop. Before the engine is mounted on a stand, the flywheel should be removed, so that the stand bolts can be tightened Into the end of the cylinder block/crankcase. 2 If a stand Is not available, it Is possible to dismantle the engine with it blocked up on a sturdy workbench, or on the floor, Be very careful not to tip or drop the engine when working without a stand. 3 If you intend to obtain a reconditioned engine, all anclllarles must be removed first, to be transferred to the replacement engine (just as they will If you are doing a complete engine overhaul yourself). These components Include the following:
Petroi engines a) Power steering pump if removed with the engine (Chapter
10).
b) Alternator fmcluding mounting brackets) and starter motor (Chapter
SA).
c) The Ignition system and HT components including ail sensors, HT leads and
spark
plugs (Chapters 1A and
SB).
d) The fuel injection system components (Chapters A A and
AB).
e) All electrical switches, actuators and sensors, and the engine wiring harness (Chapters 4A, AB, SB). f) Inlet and exhaust manifolds (Chapters 4A, AB end
AD).
g) Engine oil dipstick and tube. h) Engine mountings (Chapter
2A).
i) Flywheef/driveptate (Chapter
2A).
j) Clutch components (Chapter
6)
- manual transmission. k) Electro-magnetic clutch components (Chapter 7B) - automatic transmission. I) Cooling system components (Chapter
3).

Diesei engines a) Power steering pump //removed with the engine (Chapter
10).
b) Alternator (Including mounting brackets) and starter motor (Chapter 5A). c) The glow plugfpre-heatlng system components (Chapter
SC).
d) Ait fuel system components, including the fuel injection pump, all sensors and actuators (Chapter
AC).
e) The vacuum pump. f) Ail electrical switches, actuators and sensors, and the engine wiring harness (Chapter 4C and 5C). g) Inlet and exhaust manifolds and, where applicable, the turbocharger (Chapter
AC
and 4D). h) The engine oil level dipstick and its tube. i) Engine mountings (Chapter
2C).

2D*10 Engine removal and overhaul procedures
6.25 Checking the cylinder head for distortion 6.27 Checking the valve guides and valves for wear B.29a Diesel swirl chamber protrusion can be checked using a dial gauge...
scrape off the majority of the deposits with a blunt biade first, then use the wire brush. Caution: Do not erode the sealing surface ot the valve face. 23 Thoroughly clean the remainder of the components using solvent and allow them to dry completely. On 6-valve petrol and diesel engines, discard the oil seals, as new items must be fitted when the cylinder head is reassembled.
Inspection
Cylinder head 24 Inspect the head very carelully for cracks, evidence of coolant leakage, and other damage. If cracks are found, a new cylinder head should be obtained. 25 Use a straight-edge and feeler blade to check that the cylinder head gasket surface is not distorted (see illustration). If it is, it may
be
possible to have it machined, provided that Ihe cylinder head thickness is not excessively reduced. As no specifications as to permissible distortion limits or cylinder head thickness tolerances are given by ihe manufacturer, seek the advice of an engine overhaul specialist if distortion Is apparent. 26 Examine the valve seats In each of the combustion chambers, If they are severely pitted, cracked, or burned, they will need to be renewed or re-cut by an engine overhaul specialist. If they are only slightly pitted, this can be removed by grinding-in the valve heads and seats with fine valve-grinding compound, as described below.
27 Check the valve guides for wear by inserting the relevant valve, and checking for side-to-side motion of the valve (see illustration) A very small amount of movement Is acceptable. If the movement seems excessive, remove the valve. Measure the valve stem diameter at several points, and renew the valve if it is worn. If the valve stem is not worn, the wear must be In the valve guide, and the guide must be renewed. The renewal of valve guides should be earned out by an engine overhaul specialist, who will have the necessary tools required. 26 If renewing the vaive guides, the valve seats should be re-cut or re-ground only after the new guides have been fitted. 29 On diesel engines, inspect the swirl chambers for burning or damage such as cracking. Smalt cracks in the chambers are acceptable: renewal of the chambers will only be required if chamber tracts are badly burned and disfigured, or if they are no longer a tight fit in the cylinder head. If there is any doubt as to the swirl chamber condition, seek the advice of a Flat dealer or a suitable repairer who specialises in diesel engines. Swirl chamber renewal should be entrusted to a specialist. Using a dial test indicator, check that the difference between the swirl chamber and the cylinder head surface is within the limits given in Ihe Specifications. Alternatively feeler blades and a straight-edge may bo used (see illustrations). Zero the dial test indicator on the gaskel surface of tho cylinder head, then measure the protrusion of the swirl
chamber, if the protrusion is not within the specified limits, the advice of a Fiat dealer or suitable repairer who specialises in diesel engines should be sought. Camshaft 30 Inspect the camshaft for wear on the surfaces of the lobes and journals. Normally their surfaces should be smooth and have a dull shine: look for scoring and pitting. Accelerated wear will occur once the hardened exterior of the camshaft has been damaged. 31 Examine the bearing cap and journal surfaces for signs of wear. 32 To measure the camshaft endfloat, temporanly refit the camshaft then push the camshaft lo one end of the cylinder head as far as It will travel. Attach a dial test indicator to the cylinder head and zero it, then push the camshaft as far as It will go to the other end of the cylinder head and record the gauge reading. Verify the reading by pushing the camshaft back to its original position and checking that the gauge indicates zero again (see Illustration). 33 The camshaft bearing running clearance may be checked using Plastigauge as described later in this Chapter. 34 Where the camshaft and bearings are worn excessively consider renewing the complete cylinder head together with camshaft and cam followers. A reconditioned head may be available from ongine repairers. Wear of cam followers may be checked using a micrometer (see illustration).
6.29b ... or feeler blades 6.32 Chocking the camshaft endfloat with a dial gauge 6.34 Checking the wear of the cam followers

2D*10 Engine removal and overhaul procedures
65 On diesel engines. (It new O-ring seals to the vacuum pump then refit it to the left-hand end of the cylinder head and tighten the nuts (see illustrations). 96 Refit the camshaft sprocket with reference to Chapter 2A or 2C. 57 Refit the spark plugs, glow plugs and nfectors as applicable. 58 If required, refit the inlet and exhaust manifolds at this point. The valve clearances can also be checked now. The cylinder head is now ready for refitting as described In Part A, B or C of this Chapter (as applicable).
7 Pistons and connecting rods -removal, Inspection, and big- ^ end running clearance check ^
7.6a Unscrew the bolts.
8.54a Fitting a new oil seal to the right-hand side mount 6.54b Coolant cover gasket
Removal 1 Remove the sump and gasket with reference to Chapter 2A, 2B or 2C. 2 Unbolt and remove the oil pump pick-up/lilter screen assembly. On 16-valve engines, unbolt ond remove the anti-vibration ptate from the main bearing caps. 3 The big-end bearing shells can be renewed without having to remove the cylinder head, If the caps are unbolted and the piston/ connecting rod pushed gently up the bore slightly (the crankpin being at Its lowest point). It ihe3e shells are worn, however, the main bearing shells will almost certainly be worn as well. In this case. Ihe crankshaft should be removed for inspection. 4 To remove the pistons and connecting
6.55a Fitting a now large O-ring on the vacuum pump rods, remove the cylinder head first with reference to Chapter 2A, 2B or 2C. 5 Check to see if the big-end caps and connecting rods are numbered. If no numbers are visible, use a hammer and centre-punch, paint or similar, to mark each connecting rod and big-end cap with its respective cylinder number on the flat machined surface provided. 6 Turn the crankshaft as necessary to bring the first crankpin to its lowest point, then unscrew the bolts and remove the big-end cap and shell bearing (see illustrations). 7 Push the piston/rod assembly up the bore and out of the cylinder block. There is one reservation; if a wear ndge has developed at the top of the bores, remove this by careful scraping before trying to remove the piston/rod assemblies. Tho ridge will otherwise prevent removal, or wilt broak the piston nngs during the attempt.
.55b Fitting the vacuum pump • note the small O-ring on the end of the shaft 6 Remove the remaining pistons/rods In a similar way. If the boaring shells are to be used again, tape them to their respective caps or rods (see illustrations).
Inspection 9 Before the inspection process can begin, the piston/connecting rod assemblies must be cleaned, and the original piston rings removed from the pistons. 10 Carefully expand the old rings over the top of the pistons. The use of two or three old feeler blades will be helpful In preventing the rings dropping into empty grooves. Be careful not to scratch the piston with the ends of the nng. The rings are brittle, and will snap if they are spread too tar. They are also very sharp -protect your hands and fingers. Always remove the rings from the top of the piston. Keep each set of nngs with its piston If the old rings are to be re-used.
.. and remove the big-end cap and shell bearing
7.8a Connecting rod and cap (diesel engine) showing cylindor numbering (A) and shell location tags (B) 7.8b Connecting rod and cap numbers (petrol engine)

2D*10 Engine removal and overhaul procedures
7.13 Positioning of piston rings (petrol engine) 11 Scrape away all traces of carbon from the top of the piston. A hand-held wire brush (or a piece of fine emery cloth) can be used, once the majority ot the deposits have been scraped away. 12 Remove the carbon from the ring grooves In the piston, using an old ring. Break the ring in half to do this (be careful not to cut your fingers - piston rings are sharp). Be careful to remove only the carbon deposits • do not remove any metal, end do not nick or scratch the sides of the ring grooves. 13 Once the deposits have been removed, clean the piston/connecting rod assembly with paraffin or o suitable solvent, and dry thoroughly. Make sure that the oil return holes In the ring grooves are clear. Fit the rings to their respective grooves meking sure they are positioned the correct way round where applicable (see illustration). 14 If the pistons and cylinder bores are not
7.22 Prising out the gudgeon pin retaining circilps damagea or worn excessively, and if the cylinder block does not need to be rebored. the original pistons can be refitted. Normal piston wear shows up as even vertical wear on the piston thrust surfaces, and slight looseness of the top ring In its groove. New piston rings should always be used when the engine is reassembled. 15 Carefully inspect each piston for cracks around the skirt, around the gudgeon pin holes, and at the piston nng lands (between the ring grooves). 16 Look for scoring and scuffing on the ptston skirt, holes in the piston crown, and burned areas at the edge of the crown. If the skirt is scored or scuffed, the engine may have been suffering from overheating, end/or abnormal combustion which caused excessively high operating temperatures. The cooling and lubrication systems should be checked thoroughly. Scorch marks on the sides of the pistons show that blow-by has occurred. A hole in the piston crown, or burned areas at the edge of the piston crown, Indicates that abnormal combustion has been occurring. If any of the above problems exist, the causes must be investigated and corrected, or the
7.26a Piston to connecting rod assembly (petrol engine) 1 Piston grade (A) end directional arrow on piston crown (towards timing belt end) 2 Connecting rod/cap matching numbers 3 Gudgeon pin offset in piston (0.9 to 1.1 mm) Arrow indicates direction of crankshaft rotation
7.26b Piston to connecting rod assembly (diesel engine) 1 Piston crown
damage will occur again. The causes may Include Incorrect Ignition/injection pump timing, or a faulty injector (as applicable). 17 Corrosion of the piston, in the form ol pitting, indicates that coolant has been leaking into the combustion chamber and/or the crankcase. Again, the cause must be corrected, or the problem may persist In the rebuilt engine. 16 Examine each connecting rod carefully for signs of damage, such as cracks around the big-end and small-end bearings. Check that the rod is not bent or distorted, Damage is highly unlikely, unless the engine has been seized or badly overheated. Detailed checking of the connecting rod assembly can only be earned out by an engine repair specialist with the necessary equipment. 19 Although not essential. It is highly recommended that the big-end cap bolts are renewed as a complete set prior lo refitting. 20 On petrol engines piston and/or con-necting rod renewal should be entrusted to an engine repair specialist, who will have the necessary tooling to remove and install the interference fit gudgeon pins. 21 On diesel engines, the gudgeon pins are of the floating type, secured in position by two circlips. On these engines, the pistons and connecting rods can be separated as follows. 22 Using a small fiat-bladed screwdriver, prise out ihe circlips, and push out the gudgeon pin (see illustration). Identify the piston and rod to ensure correct reassembly. Discard the circlips - new ones must be used on refitting. 23 Examine the gudgeon pin and connecting rod small-end bearing bush for signs of wear or damage. Bush renewal should be entrusted to an engine overhaul specialist. 24 The connecting rods themselves should not be In need of renewal, unless seizure or some other major mechanical failure has occurred. Check the alignment of the connecting rods visually, and if the rods are not straight, take ihem to an engine overhaul specialist for a more detailed check. 25 Examine all components, and obtain any new parts as necessary. If new pistons are purchased, they will be supplied complete with gudgeon pins and circlips. 26 On reassembly position the piston on the connecting rod as shown (see Illustrations),
Injection pump location Connecting rod/cap matching numbers 7.28c Piston crown on diesel engines

2D*10 Engine removal and overhaul procedures
failure, (he cause must be corrected (where applicable) before the engine is reassembled, to prevent it from happening again. 3 When examining the bearing shells, remove them from the cylinder block/crankcase, Ihe main bearing caps, the connecting rods and the connecting rod big-end bearing caps. Lay them out on a clean surface in the same general position as their location in the engine. This will enable you to match any bearing problems with the corresponding crankshaft journal. Do not touch any shell's bearing surface with your fingers while checking it. 4 Din and other foreign matter gets into the engine in a variety of ways. It may be left in the engine during assembly, or It may pass through fillers or the crankcase ventilation system. It may get into the oil, and from there into the bearings. Metal chips from machining operations and normal engine wear are often present. Abrasives are sometimes left In engine components after reconditioning, especially when parts are not thoroughly cleaned using the proper cleaning methods. Whatever the source, these foreign objects often end up embedded In the soft bearing material, and are easily recognised. Large particles will not embed in the bearing, and will score or gouge the bearing and journal. The best prevention for this cause of bearing failure Is to clean all parts thoroughly, and keep everything spotlessly-clean during engine assembly. Frequent and regular engine oil and filter changes are also recommended. 5 Lack of lubrication (or lubrication breakdown) has a number of interrelated causes. Excessive heat (which thins the oil), overloading (which squeezes the oil from the bearing face) and oil leakage (from excessive bearing clearances, worn oil pump or high engine speeds) all contribute to lubrication
breakdown. Blocked oil passages, which can be the result of misaligned oil holes in a bearing shell, will also oil-starve a bearing, and destroy it. When lack of lubrication is the cause of bearing failure, the bearing materiel is wiped or extruded from the steel backing of Ihe bearing. Temperatures may increase to the point where the steel backing turns blue from overheating. 6 Driving habits can have a definite effect on bearing life. Full-throttle, low-speed operation (labouring ihe engine) puts very high loads on bearings, tending to squeeze out the oil film. These loads cause the beanngs to flex, which produces fine cracks in the bearing face (fatigue failure). Eventually, the bearing material will loosen in pieces, and tear away from Ihe steel backing. 7 Short-distance driving leads to corrosion of bearings, because insufficient engine heat is produced to drive off the condensed water and corrosive gases. These products collect in the engine oil, forming acid and sludge. As the oil Is carried to the engine bearings, the acid attacks and corrodes the bearing material. 8 Incorrect bearing installation during engine assembly will lead to bearing failure as well. Tight-fitting bearings leave insufficient bearing running clearance, and will result in oil starvation. Dirt or foreign particles trapped behind a bearing shell result in high spots on the bearing, which lead to failure. 9 Do not touch any shell's bearing surface with your fingers during reassembly: there is a risk of scratching the delicate surface, or of depositing particles of dirt on ft. 10 As mentioned at the beginning of this Section, the bearing shells should be renewed as a matter of course during engine overhaul; to do otherwise is false economy.
Selection 11 Main and big-end bearings are available in standard sizes and a range of undersizes to suit reground crankshafts • refer to the Specifications for details. The engine reconditioner will select the correct bearing shells for a machined crankshaft. 12 The running clearances can be checked when the crankshaft is refitted with its new bearings.
11 Engine overhaul -reassembly sequence
1 Before reassembly begins, ensure that all new parts have been obtained, and that all necessary tools are available. Read through the entire procedure to familiariss yourself with the work Involved, and to ensure that ail items necessary for reassembly of the engine are at hand. In addition to all normal tools and materials, thread-locking compound will be needed. A tube of sealant will also be required for the joint faces that are fitted without gaskets.
2 In order to save time and avoid problems, engine reassembly can be carried out in the following order: a) Crankshaft (Section 12). b) Piston/connecting rod assemblies (Section 7). c) Oil pump (see Part A, B or C - as applicable). d) Sump (see Pan A, BorC-as applicable). e) Flywheel/driveplate (see Part A, B or C • as applicable). 1) Cylinder head (see Part A B or C - as applicable). g) Coolant pump (see Chapter
3)
h) Timing belt tensioner and sprockets, and timing belt (See Part A, B or C- as applicable). I) Engine external components, 3 At this stage, ail engine components should be absolutely clean and dry, with all faults repaired. The components should be laid out on a completely clean work surface.
12 Crankshaft- % refitting and main bearing S running clearance check ^
Crankshaft - initial refitting 1 Crankshaft refitting Is the first stage ol engine reassembly following overhaul. At this point, it is assumed that the crankshaft, cylinder block/crankcase and beanngs have been cleaned, inspected and reconditioned or renewed. 2 Place the cylinder block on a clean, level work surface, with the crankcase facing upwards. Where necessary, unbolt the bearing caps and lay them out in order to ensure correct reassembly. If they are still in place, remove the bearing shells from the caps and the crankcase and wipe out the inner surfaces wilh a clean rag - they musl be kept spotlessly clean. 3 Clean the rear surface of the new bearing shells with a rag and fit ihem on Ihe bearing saddles. Ensure that the orientation lugs on the shells engage with the recesses in the saddles and lhat the oil holes are correctly aligned. Do not hammer or otherwise force the bearing shells into place. It Is critically important that the surfaces of the bearings ore kept free from damage and contamination. 4 Give the newly fitted bearing shells and the crankshaft journals a final clean with a rag. Check that the oil holes In the crankshaft are free from dirt, as any left here will become embedded In the new bearings when Ihe engine is first started. 5 Carefully lay the crankshaft In the crankcase, taking care not to dislodge the bearing shells (see illustration}.
Main bearing running clearance check 8 When Ihe crankshaft and bearings are refitted, a clearance must exist between them