1997 FIAT PUNTO Main journal torque specifications

2A*10 SOHC (8-valve) petrol engine in-car repair procedures
Torque wrench settings Nm
IM
ft Camshaft cover 8 6 Camshaft sprocket 70 52 Cylinder head; Stage 1 30 22 Stage 2 Angle-lighten a further 90° Siege 3 Angle-tighten a further 90B Crankshaft sprocket centre bott 100 74 Engine mounting bolt: M10X1.25 69 44 MB 25 18 Engine mounting nut (M10x 1.25) 60 44 Flywheet/driveplate 44 32 Sump 10 7 Timing belt tensJoner 28 21
1 General information
Using this Chapter Chapter 2 is divided Into four Parts: A. 8. C and D. Repair operations that can be carried out with the engine in the vehicle are described in Part A. SOHC (8-valve) petrol engines, Part B. DOHC (18-valve) petrol engines and Part C, diesel engines. Part 0 covers the removal of the engine/transmission as a unit, and describes the engine dismantling and overhaul procedures. In Parts A, 9 and C, the assumption Is made lhat the engine is Installed in the vehicle, with sll ancillaries connected. If the engine has been removed for overhaul, the preliminary dismantling Information which precedes each operation may be ignored.
Engine description Throughout this Chapter, engines are identified by their capacities. A listing of all engines covered, together with their code letters, is given in the Specifications. The engines covered In this Part of Chapter 2 are water-cooled, single overhead camshaft, in-line four-cylinder units, with cast Iron cylinder Mocks and aluminium-alloy cylinder heads. All are mounted transversely at the front ot the vehicle, with the transmission bolted to the left-hand side of the engine, The cylinder head carries the camshaft which is driven by a toothed timing belt and runs In three bearings. It also houses the inlet and exhaust valves, which are closed by single coil springs, and which run in guides pressed Into the cylinder head. The camshaft actuates the vatves directly via cam followers mounted in the cylinder head. Adjustment of the valve clearances is by means of shims located on top of the followers. The cylinder head contains Integral oitways which supply and lubricate the tappets. The crankshafl Is supported by five main bearings, and endftoat is controlled by a thrust bearing fitted to the upper section of the centre main bearing.
Engine coolant is circulated by 8 pump, driven by the timing belt. For details of the cooling system, refer to Chapter 3. Lubricant is circulated under pressure by a pump, driven from ihe front of the crankshaft. Oil Is drawn from the sump through a strainer, and then forced through an externally-mounted, replaceable screw-on filter. From there, It is distributed to the cylinder head, where It lubricates the camshaft journals and tappets, and also to the crankcase, where il lubricates the main bearings, connecting rod big and smell-ends, gudgeon pins and cylinder bores. On 1242 cc engines, oil jets are fitted lo the base of each cylinder bore -these spray oil onto the underside of the pistons, to Improve cooling.
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) Auxiliary drivebelt - removal and refitting (refer to Chapter 1A) c) Vatve clearances - checking and adjustment (refer to Chapter I A) d) Camshaft cover - removal and refitting e) Timing belt and covens - removal and refitting f) Timing belt tensioner and sprockets -removal and refitting g) Cylinder head - removal and refitting' h) Camshaft and cam followers • removal and refitting' t) Camshaft oil seal - renews/ j) Crankshaft oil seals - renewal k) Flywheel/dnvepfate • removal, inspection and refitting l) Engine mountings - inspection and renewal m)Sump - removal and refitting n) Oil pump and pick-up tube assembly
•
removai. inspection and refitting *Cylinder head dismantling procedures are detailed In Chapter SO, with details of camshaft and cam follower removal. Note: It is possible to remove the pistons and connecting rods (after removing the cylinder head and sump) without removing the engine. However, this is not recommended. Work of
this nature is more easily and thoroughly completed with the engine on the bench, as described In Chapter 2D.
2 Location of
TDC
on % No
1
cylinder
General Information 1 The camshaft Is driven by the crankshaft, by means of sprockets and a timing belt. Both sprockets rotate In phase with each other and this provides the correct valve timing as the engine rotates. When (he liming belt is removed during servioing or repair, it Is possible for the camshaft and crankshaft to rotate Independently of each other and the correct valve timing Is then lost. 2 The design of the engines covered In this Chapter are such lhat potentially damaging piston-to-valve contact may occur if the camshaft is rotated when any of the pistons are stationary at, or near, the top of their stroke. 3 For this reason it is important lhat Ihe correct phasing between the camshaft and crankshaft is preserved whilst the timing belt Is off the engine. This is achieved by setting the engine In a reference position (known as Top Dead Centre or TDC) before the timing belt Is removed and then preventing the camshaft and crankshaft from rotating until the belt is refitted. Similarly, if ths engine has been dismantled for overhaul, the engine can be set to TOC during reassembly to ensure that Ihe correct shaft phasing is restored. 4 TDC is the highest point In the cylinder that each piston reaches as the crankshaft turns. Each piston reaches TDC at Ihe end of the compression stroke and again at the end of the exhaust stroke. However, for the purpose of timing the ongine. TDC refers to the position of No 1 piston at the end of Its compression stroke. On ail engines In this manual, No 1 piston (and cylinder) Is at the timing belt end of the engine. 5 The camshaft sprocket Is equipped with a marking which, when aligned with a reference marking on the cylinder head, indicates that the camshaft is correctly positioned for cyl-inder No 1 al TDC on its compression stroke.

2A*10 SOHC (8-valve) petrol engine in-car repair procedures
Lubrication system Oil pump type By-rotor driven from front of crankshaft Outer rotor-io-houslng clearance 0.100 to 0.210 mm Axial clearance 0.025 to 0.070 mm
Torque wrench settings Nm itrf ft Camshaft driven gears 120 89 Camshaft sprocket 120 89 Crankshaft sprocket centre bolt: Stage
1
20 15 Stage 2 Angle-tighten a further 90® Cylinder head: Stage
1
30 22 Stage 2 Angle-tighten a further 90" Stage 3 Angle-tighten a further 90° Cylinder head extension to cylinder head 15 11 Engine mounting bolt: M10
x
1.25 59 44 M8 25 18 Engine mounting nut (MlOx 1.25) 60 44 Flywheel 44 32 Timing belt tensioner 25 18 Sump 10 7
1 General information
Using this Chapter Chapter 2 is divided into four Parts; A, B. C and O. Repair operations that can be carried out with the engine hi the vehicle are described in Part A. SOHC (8-valve) petrol engines. Part B, DOHC (16-valve) petrol engines and Pari C, dlesei engines. Part D covers the removal of the engine/transmission as a unit, and describes the engine dismantling and overhaul procedures. In Parts A, B and C, the assumption Is made that the engine is Installed In the vehicle, with all ancillaries connected. If the engine has been removed for overhaul, the preliminary dismantling information which precedes each operation may be ignored.
Engine description Throughout this Chapter, engines are identified by their capacities. A listing of all engines covered, together with their code letters, Is given in the Specifications. The engine covered in this Part of Chapter 2 is a water-cooled, double overhead camshaft, in-line four-cylinder unit, with cast iron cylinder block and aluminium-alloy cylinder head. The unit is mounted transversely at the front of the vehicle, with the transmission bolted to the left-hand side of the engine. The cylinder head houses the eight inlet and eight exhaust valves, which are closed by single coil springs, and which run in guides pressed Into the cylinder head. The two camshafts are housed in 8 cylinder head extension which is bolted to the top of the cylinder head. The exhaust camshaft is driven by a toothed timing belt and In turn drives the inlet camshaft via a pair of gears located at the left-hand end of the cylinder head extension.
The camshafts actuate the valves directly via self-adjusting hydraulic cam followers mounted in the cylinder head extension. The crankshaft is supported by five main bearings, and endfioat is controlled by a thrust bearing fitted to (he upper section of the centre main bearing. Engine coolanl is circulated by a pump, driven by the timing belt. For details of the cooling system, refer to Chapter 3. Lubricant is circulated under pressure by a pump, driven from the front of the crankshaft. Oil is drawn from Ihe sump through a strainer, and then forced through an externally-mounted, replaceable screw-on filter. From there, It is distributed to the cylinder head and cylinder head extension, where it lubricates the camshaft journals and cam followers, and also to the crankcase, where it lubricates the main bearings, connecting rod big and small-ends. gudgeon pins and cylinder bores. Oil Jets are fitted to the base of each cylinder bore - these spray oil onto the underside of the pistons, to improve cooling.
Repair operations possible with the engine in the car The following work can be carried out with the engine in the car: a) Auxiliary drivebett - removal and refitting (refer to Chapter 1A) b) Oil pump and pick-up tube assembly -removal, Inspection and refitting c) Timing belt and covers • removal and refitting d) Timing belt tensioner and sprockets -removal and refitting e) Cylinder head - removal and refitting' f) Cylinder hoad extension - removal and refitting g) Camshaft and cam followers - removal and refitting h) Camshaft oil seal - renewal i) Crankshaft oil seals • renewal
f) Flywheel - removal, inspection and
refitting
k) Engine mountings - Inspection and
renews'
f) Sump • removal and refitting 'Cylinder head dismantling procedures are detailed In Chapter 2D. Note 1: It is possible to remove the
pistons
and connecting rods (after removing (to cylinder head and sump) without removing
tt*»
engine. However, this Is not recommended. Work of this nature is more easily and thoroughly completed with the engine on fix bench, as described in Chapter 20. Note
2x
Many of the procedures in this Ctopfer entail the use of numerous special tools. Whet possible, suitable alternatives are descnbei with details of their fabrication. Before starring any operations on the engine, read through
tto
entire procedure first to familiarise yourself
wft
the work involved, tools to be obtained mi new parts that may be necessary.
2 Engine assembly/ valve timing holes -genera! information
and
usage
Note: Do not attempt to rotate the angint whilst the camshafts are locked In position,
il
the engine is to be left in this state foratofi$ period of time. It Is a good idea to plect suitable warning notices inside the vehicle, and in the engine compartment. This wfl reduce the possibility of the engine being accidentally cranked on the starter motor, which is likely to cause damage with the locking tools In place. 1 To accurately set the valve timing for ell operations requiring removal and refitting of
the
timing belt, liming holes are drilled in ihe camshafts and cylinder head extension. Ihe holes are used In conjunction with camshaft locking tools and crankshaft positioning
rods w
lock the camshafts when all the pistons me positioned at the mid-point of their stroke. Ths

2D*10 Engine removal and overhaul procedures
12.5 Lowering the crankshaft into the crankcase
12.9 Fit tho main bearing caps...
to allow lubricant to circulate. This clearance is impossible to check using feeler blades, however Plastlgauge can be used. This consists of a thin strip of soft plastic that is crushed between the bearing shells and journals when the beanng caps are tightened up. Its width then indicates the size of the clearance gap. 7 Cut off five pieces of Plastlgauge. just shorter than the length of the crankshaft journal. Lay a piece on each journal, in line with its axis (see Illustration). 8 Wipe off the rear surfaces of the new lower half main bearing shells and fit them to the main beanng caps, again ensuring that the locating lugs engage correctly (see illustration). 9 Fit the caps in their correct locations on the bearing saddles, using the manufacturers markings as a guide (see illustration). Ensure lhat Ihey are correctly orientated • the caps should be fitted such that the recesses (or the bearing shell locating lugs are on the same side as those in the bearing saddle. 10 Insert and tighten the bolls until they are
811
correctly torqued (see illustrations). Do not allow the crankshaft to rotate at all whilst ihe Plastlgauge is in place. Progressively unbolt the bearing caps and remove them, taking care not to dislodge the Plastlgauge. 11 The width of the crushed Plastigauge can now be measured, using the scale provided (see illustration). Use the correct scale, as both Imperial and metric are printed. This measurement Indicates the running clearance • compare it with that listed in the Specifications.
21 \ „ 12.7 Lay the Plastigauge on the main bearing journals
t
12.10a ... Insert the bolts...
If tho clearance is outside ihe tolerance, it may be due to dirt or debns trapped under the bearing surface; try cleaning them again and repeat the clearance check. If the results are still unacceptable, re-check Ihe journal diameters and the bearing sizes. Note that if the Plastigauge is thicker at one end. the loumals may be tapered and as such, will require regrinding. 12 When you are satisfied that the clearances are correct, carefully remove the remains of the Plastigauge from the journals and bearings faces. Use a soft, plastic or wooden scraper as anything metallic is likely to damage the surfaces.
Crankshaft • final refitting 13 Lift the crankshaft out of the crankcase. Wipe off the surfaces of the bearings in the crankcase and the bearing caps. Fit the thrust beanngs using grease to hold them in
12.11 Use the special scale card to determine the main bearing running clearance
shell In its cap
12.10b ... and torque-tighten them
position, Ensure they are seated correctly in the machined recesses, with tho oil grooves facing outwards 14 Liberally coat the bearing shells in the crankcase with dean engine oil (see Illustration). 15 Lower the crankshaft into position in the crankcase. 16 Lubricate the lower bearing shells in the main bearing caps with clean engine oil. Make sure that the locating lugs on the shells are still engaged with the corresponding recesses in the caps. 17 Fit the main bearing caps in the correct order and orientation. Insert the bearing cap bolts and hand tighten them only. 18 Working from the centre bearing cap outwards, tighten the retaining bolts to their specified torque. On petrol engines, tighten all the bolts to the first stage, then angle-tighten them to the Stage 2 anglo (see illustration)
12.14 Lubricate the main bearing shells before final assembly