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Lamborghini Diablo Engine. Manual - part 2

Workshop manual - Diablo 6.0

10-18

Fig. 12 – Valves

Tappets

Diameter

32.974 to 32.990

Washer thickness range

3.25 to 0.70

with intervals of

0.05

0310012

Index

Workshop manual - Diablo 6.0

10-19

Valve guides (intake and exhaust)

Fitting between valve stem and relevant guide

Valve springs (intake and exhaust)

Rated outer diameter

12.040 to 12.050

Inner diameter with pressed and bored guide

7.0 to 7.015

Stem-guide clearance
Intake
Exhaust

0.025 to 0.055
0.035 to 0.065

Intake assembly clearance

0.025 to 0.055

Exhaust assembly clearance

0.035 to 0.065

Maximum shift between valve shank and head (head-stem
concentricity)
Intake
Exhaust

0.03
0.03

Assembly clearance between tappet and its seat (intake-
exhaust)

0.025 to 0.071

Inner spring

Free length (a)
With valve closed (b)
With valve open (c)
Compressed (d)
Load (with closed valve) P1
Load (with open valve) P2
Number of active coils

32.5

16.36

58.86

3.92 N

176.58

9.81 N

4.82

Index

Workshop manual - Diablo 6.0

10-20

Fig. 12/1 - Valve springs

Engine lubrication

External spring

Free length (a)
With valve closed (b)
With valve open (c)
Compressed (d)
Load (with closed valve) P1
Load (with open valve) P2
Number of active coils

38.9

20.9

245.25

3.92 N

549.36

9.81 N

3.81

Circuit

Forced lubrication with radiator and thermostatic valve

Radiator oil

Single, separated

Pressure in circuit with hot engine (90°C)
– at 1000 RPM
– at 6000 RPM

1.5 – 2.5 [bar]

5 – 7 [bar]

Thermostatic valve
– start
– 9 mm
– max. stroke

80 °C

95 °C

Index

Workshop manual - Diablo 6.0

10-21

Engine cooling

Circuit

Forced circulation with thermostatic control

Radiators

Two with fan

Fans
– on
– off

80 °C

74 °C

Circuit pressure with hot engine (max.)

1.2 [bar]

Thermostatic valve
– start
– 7 mm
– Max. stroke (at 95 °C)

80 °C
86 °C

Index

Workshop manual - Diablo 6.0

10-22

REMOVAL AND REFIT

This operation requires a car lift and a hoist with a rocking lever and 4 chains to sling the engine, to be fixed on the exhaust mani-
fold hooks.

Fig. 13 – Engine–gearbox removal

List of operations to be carried out before the removal of the engine:
• disconnect the positive and negative wires from the battery
• disconnect the engine cooling hoses, oil system hoses, fuel system hoses and air conditioning hoses from their relevant radia-

tors and accessories

0310013

Index

Workshop manual - Diablo 6.0

10-23

• disconnect the engine injection wiring from the general wiring and all the secondary electric connectors, the earth cables and

the starter motor wires

• disconnect the oil delivery hose from the clutch cylinder located on the clutch bell
• remove the gear knob and switch on the tunnel in the passenger compartment
• lift the car and working from underneath, remove the gearbox support; loosen the two engine supports on the sides of the

crankcase

• remove the catalysts and harness the engine as described above
• remove the engine supports and, after checking all the hoses and wirings are disconnected, remove the engine-gearbox group.

ASSEMBLY

Every time the engine is disassembled clean the crankcase, especially the lubrication ducts.
Replace all oil seals and gaskets.
After the crankcase has been carefully cleaned, assemble the liners as follows:
• fit the rings to the liners;
• insert the liners one after the other in the crankcase;
• check that liners protrusion from the crankcase is in accordance with the values prescribed. Make this check using the liner

holder tools (No. 961195027) tightened to the specified torque on the cylinder head bolts. Do not remove the tools before the
heads are assembled;

• assemble the main bearings on the engine block;
• fix the crankshaft to the engine block using special supports No. 961495014;

• before fitting the piston rings on the pistons, check that the end clearance is within the prescribed value;

• before assembling the piston-conrod group in the cylinder liner, lubricate the piston rings and the liner with engine oil. Position

the piston ring notches so that they are displaced by about 120° and ensure that no notch coincides with the direction of the pis-
ton pin axis;

Special supports No. 961495014 must be installed with the main bearings between support and shaft.

To make this check, fit the piston rings on the liner. When fitting the piston rings make sure that the caption ”TOP” is
facing upwards.

Index

Workshop manual - Diablo 6.0

10-24

• assemble the conrod-piston group to each cylinder;

• tighten the connecting rod big ends following this procedure:

- clean the threads very carefully;
- lubricate the bolt under the big end and the thread;
- tighten the bolts following the specified procedure (see Section 02 – DRIVING TORQUES);

• before assembling the lower crankshaft support smear LOCTITE 518 paste on the contact surface;
• fit the main bearings on the lower support;
• tighten the lower support to the prescribed torque following the specified procedure (see Section 02 – DRIVING TORQUES);
• assemble the timing components on the front part of the crankcase; assemble the oil pump on the timing cover;
• place cylinder No.1 at T.D.C. using a dial gauge;
• it the pre-assembled cylinder heads taking care that the camshaft positions coincide with the reference marks on the supports;

• before tightening the heads lubricate the upper surface of the washers, nuts and bolt threads with Molycote 1000 paste;
• tighten the head bolts following the prescribed procedure (see Section 02 – DRIVING TORQUES) using wrench No. 9008019;
• proceed with engine timing;
• before assembling the oil sump smear the contact surface with LOCTITE 518.

When performing this operation turn the crankshaft in the direction of its rotation.
The grooves on the conrod big end must face the crank arms when assembling the conrod-piston group.

Cool the guides and valve seats (about -190°) before assembling onto the head. Pre heat the head to about 190°.

Index

Workshop manual - Diablo 6.0

10-25

CHECKS AND ADJUSTMENTS

Valve clearance

Intake

0.35 [mm]

Exhaust

0.50 [mm]

Replace the spacer rings until the clearance required is found. Use tool No. 961195014 to remove and replace the spacer rings.
When the cylinder heads are removed it is advisable to use tool No. 961195004 for the intake valve and No. 961195003 for the
exhaust valve.
Position the spacer rings (pads) with the side indicating the thickness facing the tappet.

Check the valve clearance when the engine is cold.

Fig. 14 – Valve clearance check

Fig. 15 – Spacer ring replacement

031014

031015

Index

Workshop manual - Diablo 6.0

10-26

Locking the phase variator
A phase variator is installed in the engine on the intake timing shafts.
If this is removed, or when setting up the timing system, make sure that the slots on the moving part are correctly positioned in
relation to the fixed part securing holes.

Position check
• visually check that the slot is centred to the hole (part A)
• if it is not (position B), proceed with the positioning.

Positioning
• take out the moving part (2) from the fixed part (1); find a new angle position of the moving part, making attempts by re-insert-

ing it fully with a rotating movement and checking the position of the slots in relation to the holes (position A);

• when the correct position is found secure the moving part by inserting ring (4) and tightening the screws to the prescribed

torque.

Fig. 16 – Locking the phase variator

031018/1

Variator body

Fixed part

Moving part

Spacer ring

Correct position

Incorrect position

Index

Workshop manual - Diablo 6.0

10-27

Timing regulation

Adjustment
To adjust proceed as follows:
• rotate the crankshaft until the dial gauge shows that piston No. 1 coincides with the ignition TDC (use dial gauge holder No.

961195025);

• fit the setting dial and lever No. 961495012 to rotate the crankshaft;
• fix the reference point on the crankcase and goniometer for the TDC;

Intake

Exhaust

Start before TDC [°]

–––

End after BDC [°]

–––

Start before BDC [°]

–––

End after TDC [°]

–––

Lift during overlap stage [mm]
• New timing chain (less than 6 hours)
• Adjusted timing chain (more than 6 hours)

1.15

0.05

1.00

0.05

0.20

0.05

0.35

0.05

Index

Workshop manual - Diablo 6.0

10-28

Fig. 17 – Checking TDC in cylinder No. 1

Tool No. 961495012

Tool No. 961195025

031016

Index

Workshop manual - Diablo 6.0

10-29

Exhaust:
• fit sprocket holder tool No. 961195042 to fix the gears on the camshafts;
• check that the reference marks (A) on the supports and the camshafts coincide;
• fix the centring dowel on the cams using the tool;

Intake:
• loosen the six variator screws;
• check that the reference marks (A) on the supports and the camshafts coincide;
• tighten the six variator screws without locking;
• make one turn (in the engine rotation direction) to recover the chain slack;
• check the reference marks (A) again on the supports and the camshafts and if necessary reposition the shafts;
• position holder No. 961195026 with the dial gauge to measure the valve lift on cylinder No. 6;

Exhaust:
• place the dial gauge on the exhaust valve tappet and check that the lift is that specified;
• if it is not, remove the centring dowel using tool No. 9611195024 and turn the exhaust side camshaft with a 26 mm wrench until

the correct exhaust valve lift of cylinder No. 6 is found (the position is at TDC overlap);

1 Tool No.

961495026

Fig. 18 – Reference marks

Fig. 19 – Checking and adjustment of lifts

031017

031018

Index

Workshop manual - Diablo 6.0

10-30

• fit the centring dowel on the cams using the tool;

Intake:
• loosen the six variator screws;
• turn the intake side camshaft with a 26 mm wrench until the correct intake valve lift of cylinder No. 6 is found (the position is at

TDC overlap);

• tighten the six variator screws to the prescribed torque;
• repeat the whole procedure for the right-hand cylinder bank, bringing cylinder 7 to ignition TDC (60° after ignition TDC of cylin-

der 1) and measure the lifts on cylinder 12.

Checking
To check, proceed as follows:
• rotate the crankshaft until the dial gauge shows that piston No. 1 coincides with the ignition TDC (use dial gauge holder No.

961195025);

• fit the setting dial and lever No. 961495012 to rotate the crankshaft;
• fix the reference point on the crankcase and goniometer for the TDC;
• position holder No. 961195026 with the dial gauge to measure the valve lift on cylinder No. 6;
• place the dial gauge on the intake tappet and check the lift is that specified;
• place the dial gauge on the exhaust valve tappet and repeat the procedure;
• repeat the whole procedure for the right-hand cylinder bank, bringing cylinder 7 to ignition TDC (60° after ignition TDC of cylin-

der 1) and measure the lifts on cylinder 12.

• make the necessary adjustment if these conditions are not found.

Locking check on phonic wheel for engine timing sensor
Proceed as follows:
• remove the cover of the phonic wheel on the camshaft, then rotate it in the direction of engine rotation to bring the tooth near

to cylinder bank 1-6 sensor using the starter motor;

• move the sensor tooth along the last section engaging the 5th gear and moving the vehicle in the travel direction;

To obtain the prescribed values at the end of the operations it is necessary to double the adjusting values of the lifts to
be applied.

Index

Workshop manual - Diablo 6.0

10-31

• lift the vehicle and with a large screwdriver turn the camshaft to bring the reference notch 30° in advance of the flywheel to

correspond with the reference on the engine block (two holes not in line);

• check that the tooth is perfectly centred to the sensor;
• if it is not, loosen the screw and direct the phonic wheel until centring is obtained;
• check that the distance between the tooth and the sensor (gap) is between 0.7 and 1 mm. If necessary shim the sensor.

Do not reverse the direction of engine rotation to avoid errors caused by backlash: if you go beyond the point, make two
complete engine rotations then repeat the procedure.

The 30° do not represent the ignition advance, but only an assembly reference.

Index