Discovery 2. Manual — part 425

ENGINE - TD5

OVERHAUL 12-1-97

8. Remove and discard big-end bearing shell

from connecting rod.

NOTE: Engine Serial No. Prefixes 10P to 14P:–
The 'sputter type' connecting rod bearing shells
fitted to these engines, identified by them
having a slightly darker colour than the bearing
cap shells should be replaced with the 'plain
type' bearing shells fitted to Engine Serial No.
Prefixes 15P to 19P.

9. Repeat above procedures for remaining big-

end bearings. Keep bearing caps in their
fitted order.

Inspection

1. If crankshaft is to be removed, big-end

bearing journals should be checked when
crankshaft is inspected.

2. Check each big-end bearing journal for scoring,

wear and ovality, make 3 checks at 120

°

intervals in centre of journal:

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Big-end bearing journal diameter = 54.000

±

0.01 mm (2.125

±

0.0004 in)

CAUTION: Big-end journals may not be
ground undersize, only one size of big-end
bearing shell is available and if journals are
found to be scored, oval or worn, crankshaft
must be replaced. Big-end bearing shells
must be replaced whenever they are
removed.

Reassembly

1. Clean connecting rod journals and bearing

shell locations.

2. Lubricate new big-end bearing shells with

engine oil and fit to connecting rods and
bearing caps.

CAUTION: Do not fit the 'sputter type'
bearings fitted to early engines.

3. Rotate crankshaft until No.1 big-end bearing

journal is at BDC.

4. Taking care not to damage oil squirt jet or to

displace bearing shell, pull connecting rod on
to crankshaft journal.

5. Check that bearing shell is correctly located in

big-end bearing cap.

6. Fit No.1 big-end bearing cap ensuring that

reference marks are aligned

7. Fit new big-end bearing cap bolts and tighten

to:

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Stage 1 - 20 Nm (15 lbf.ft)

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Stage 2 - Further 80

°

CAUTION: Do not carry out stages 1 and

2 in one operation.

8. Carefully move connecting rod to one side of

journal and using feeler gauges measure end-
float of connecting rod on journal:

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Connecting rod end-float = 0.2 to 0.5 mm
(0.008 to 0.021 in)

9. Repeat end-float check for remaining

connecting rods.

10. If end-float exceeds limits given, replace

connecting rod and repeat end-float check.

+

ENGINE - Td5, OVERHAUL, Pistons,

connecting rods and cylinder bores.

11. Fit oil pump.

+

ENGINE - Td5, OVERHAUL, Pump -

oil.

ENGINE - TD5

12-1-98 OVERHAUL

Pistons, connecting rods and cylinder
bores

$% 12.17.02.03

Disassembly

1. Remove cylinder head gasket.

+

ENGINE - Td5, OVERHAUL, Gasket

- cylinder head.

2. Remove connecting rod bearings.

+

ENGINE - Td5, OVERHAUL,

Bearings - connecting rods.

3. Remove ridge of carbon from top of cylinder

bore.

4. Suitably identify each piston and connecting

rod assembly to its respective cylinder bore.

5. Carefully push connecting rod to top of cylinder

bore taking care that connecting rod does not
contact oil squirt jet or cylinder wall; remove
each piston and connecting rod in turn.

6. Using a suitable expander, remove and discard

piston rings from pistons.

7. Clean carbon from piston crown and skirt. Do

not use abrasives on graphited area of
piston skirt, do not use a wire brush or
scraper on any part of pistons.

8. Secure connecting rod in a soft jawed vice.
9. Suitably identify each piston to its connecting

rod and fitted position of piston on rod.

10. Using suitable circlip pliers, remove and

discard 2 circlips securing gudgeon pin.

11. Push gudgeon pin out of piston and connecting

rod; remove piston.

12. Suitably identify each gudgeon pin to its

respective piston.

13. Repeat above procedures for remaining

pistons.

Inspect

1. Measure cylinder bore for wear at a point 70

mm (2.75 in) from top of cylinder bore:
Measurement must be taken from side to
side and front to rear.

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Cylinder bore diameter = 84.460 to 84.442
mm (3.325 to 3.324 in)

CAUTION: Cylinder bore and ovality must

be within the limits given above, no
reboring, honing or de-glazing of
cylinder bores is permissible; cylinder
block must be replaced if bores are worn
or excessively scored.

2. Check piston for cracks, burning and damage.
3. Check connecting rods for alignment. Do not

attempt to straighten misaligned
connecting rods. Ensure small-end
lubrication holes in connecting rods are
clear.

4. Measure and record diameter of each piston at

right angles to gudgeon pin axis and 46 mm
(1.81 in) from bottom of skirt

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Piston diameter = 84.262 mm

±

0.009 mm

(3.317 in

±

0.0003 in)

CAUTION: Measurement point must be on
the ungraphited area of the piston.

ENGINE - TD5

OVERHAUL 12-1-99

5. Starting with No.1 piston, invert piston and with

arrow on piston crown pointing towards REAR
of cylinder block, insert piston into No.1
cylinder bore.

6. Position piston with bottom of skirt 25 mm (1.0

in) from top of cylinder bore.

7. Using feeler gauges, measure and record

clearance between piston skirt and LEFT
HAND side of cylinder bore 60 mm (2.4 in)
from top of bore:

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Piston to cylinder bore clearance = 0.171 to
0.207 mm (0.007 to 0.008 in)

8. Repeat above procedures for remaining

pistons.

CAUTION: Oversize pistons are not
available, if piston to cylinder bore
clearance exceeds limits given, repeat
check using a new piston; if clearances are
still excessive, replace cylinder block.

Pistons and lst compression rings fitted to
Engine Serial No. Prefixes 15P to 19P may
be fitted to Engine Serial No. Prefixes 10P to
14P in engine sets only.

9. Check fit of each gudgeon pin in its respective

piston, pin must be a tight, sliding fit with no
perceptible side play.

10. Measure gudgeon pin diameter at each end

and side of pin.

CAUTION: Renew gudgeon pin and piston
as an assembly if diameters are less than
specified or if excessive pin to piston side
play is evident.

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Gudgeon pin diameter = 29.995 to 30.000
mm (1.180 to 1.181 in)

11. Check connecting rod small end bushes for

wear, check that gudgeon pin is a sliding fit in
bush with no perceptible side play.

CAUTION: Small end bushes cannot be
replaced, a new connecting rod must be
fitted.

ENGINE - TD5

12-1-100 OVERHAUL

12. Insert new compression and oil control rings in

turn into No.1 cylinder bore 30 mm (1.25 in)
from top of bore and check ring fitted gaps;
ensure rings are kept square to bore when
checking gaps:

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1st compression ring fitted gap = 0.30 to
0.40 mm (0.012 to 0.016 in).

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2nd compression ring fitted gap = 0.40 to
0.60 mm (0.016 to 0.024 in).

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Oil control ring fitted gap = 0.25 to 0.50 mm
0.01 to 0.02 in).

CAUTION: 1st compression rings fitted to
Engine Serial No. Prefixes 10P to 14P are
not interchangeable with those fitted to
Engine Serial No. Prefixes 15P to 19P. The
later rings may, however, be fitted to early
engines together with the later type pistons
in engine sets only.

13. Repeat for each cylinder bore in turn.

CAUTION: Ensure rings are suitably
identified with the cylinder bore in which
they were checked and are fitted to the
piston for that bore.

14. Fit oil control expander and ring to piston.
15. Fit 2nd compression ring with 'TOP' marking

upwards.

16. Fit 1st compression ring with 'TOP' marking

upwards.

17. Check piston ring to groove clearance:

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1st compression ring = Not measured

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2nd compression ring = 0.050 to 0.082 mm
(0.02 to 0.003 in)

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Oil control ring = 0.050 to 0.082 mm (0.02 to
0.003 in)

Reassembly

1. Lubricate gudgeon pin, gudgeon pin holes in

piston and small end bush with engine oil.

2. Position piston to connecting rod with arrow on

piston crown on the same side as the cast boss
on the connecting rod.

3. Fit gudgeon pin to its respective piston and

connecting rod; secure with new circlips
ensuring circlips are fully seated in their
grooves.

4. Repeat above procedures for remaining

pistons.

5. Lubricate piston rings and cylinder bores with

engine oil.

6. Check that rings are free to rotate, position ring

gaps at 120

°

to each other and away from the

thrust, LEFT HAND side of piston - viewed
from front of piston.

7. Using a suitable ring clamp, compress piston

rings.

8. Insert connecting rod and piston into its

respective cylinder bore ensuring that the
arrow on piston crown and the cast boss on
connecting rod are facing towards the front of
the cylinder block.

9. Ensure that connecting rod does not contact

cylinder bore or oil squirt jet. Do not pull
connecting rod fully down cylinder bore at this
stage.

10. Check that cut-out in piston skirt is positioned

above oil squirt jet.