Loader Bobcat 773. Manual - part 92

CYLINDER HEAD

Removal And Installation

Remove the nuts from the valve cover, remove the valve
cover and gasket [A].

Remove the fuel injector nozzles. (See Page 7–44.)

Remove the glow plugs. (See Page 7–38.)

Remove the belt shield. (See Page 3–1.)

Remove the alternator. (See Page 6–1.)

Remove the rocker arm and shaft assembly (Item 1) [B].

Remove the push rods (Item 2) [B].

Remove the intake and exhaust manifolds.

Remove the water return hose [C].

Remove the cylinder head bolts in order of #18 to #1 [D].

Installation: Put oil on the bolt threads. Tighten the bolts
in the correct sequence to 67–72 ft.–lbs. (91–98 Nm)
torque.

NOTE: Retighten the cylinder head bolts in the

correct sequence after the engine has been
run for 30 minutes.

A

PI–09982

C

B–14333

D

PI–09985

FRONT

773 BICS Loader

–7–47–

Service Manual

B

B–14332

1

2

CYLINDER HEAD (Cont’d)

Removal And Installation (Cont’d)

Remove the cylinder head from the engine block.

Installation:  Always use new head gasket and new
O–ring. Make sure the O–ring is seated over the dowel
[A].

Disassembly And Assembly

Use a valve spring compressor to compress the valve
spring [B].

Remove the valve cap (Item 1) [B] & [C] and valve spring
collet (Item 2) [B] & [C].

Remove the valve spring retainer (Item 3) [B] & [C] and
the spring (Item 4) [B] & [C].

Remove the seal (Item 6) [B]& [C] and the valve (Item 5)
[B]& [C].

Remove the thermostat housing. Remove the thermostat
from the cylinder head [D].

A

B–14334

C

B–04122

5

4

3

6

1

2

Valve

Spring

Retainer

Seal

Collets Cap

D

B–03643

–7–48–

773 BICS Loader

Service Manual

B

PI–09987

1

5

6

3

4

2

CYLINDER HEAD (Cont’d)

Servicing The Cylinder Head

Clean the surface of the cylinder head.

Put a straight edge (Item 1) [A] on the cylinder head.

NOTE: Do not put the straight edge across the

combustion chambers.

Put the feeler gauge (Item 2) [A] between the straight
edge and the surface of the cylinder head.

Put the straight edge on the cylinder head’s four sides and
two diagonal as shown in figure [B].

The maximum distortion of the head surface is 

±

 0.002

inch (

±

0,05 mm). If the measurement exceeds the

specification, replace the cylinder head.

Top Clearance

Install the cylinder head gasket. Put the piston (Item 1) [C]
being checked at T.D.C.

Put three pieces of 0.060 inch (1,5 mm) diameter solder
(Item 2) [C] on the top of the piston. Use grease to hold
them in position.

NOTE: Position the solder so they do not touch the

valves.

Turn the piston to bottom dead center.

Install the cylinder head and tighten to the correct torque
in the correct sequence. (See Page 7–47.)

Turn the crankshaft until the piston exceeds T.D.C.
Remove the cylinder head.

Remove the solder wire (Item 3) [C] and measure it.

If the measurement exceeds the specifications, check the
oil clearance of the crank pin journal or the piston pin.

Top Clearance

0.022–0.028 inch (0,55–0,7 mm)

. . . . . . 

A

A–02735

1

2

C

PI–09989

2

1

3

773 BICS Loader

–7–49–

Service Manual

B

PI–09988

VALVE, VALVE SEAT AND GUIDE

Checking The Valve Guide

Remove the valve and spring from the cylinder head.
(See Page 7–48.)

Clean the valve seat and combustion chamber.

Install the valve into the guide. Measurement the valve
recessing or protrusion with a depth gauge [A].

If the measurement exceeds the allowable limit, replace
the valve or cylinder head [B].

Protrusion

0.002 inch (0,05 mm)

. . . . . . . . . . . . . . . . . . . . 

Recessing

0.006 inch (0,15 mm)

. . . . . . . . . . . . . . . . . . . . 

Allowable Limit (Recessing)

0.016 inch (0,4 mm)

. . . . . . 

Remove the carbon from the valve guide.

Measure the valve stem O.D. [C].

Measure the valve guide I.D. [C].

Calculate the clearance, if the clearance exceeds the
allowable limit, replace the valve and/or valve guide.

Valve Guide I.D.

0.3156–0.3161 inch

. . . . . . . . . . . . . . . . 

(8,015–8,03 mm)

Valve Stem O.D.

0.3134–0.3142 inch

. . . . . . . . . . . . . . . 

(7,96–7,98 mm)

Clearance Between Valve Stem
  and Guide

0.0016–0.0026 inch

. . . . . . . . . . . . . . . . . . . . 

(0,04–0,07 mm)

Allowable Limit

0.004 inch (0,1 mm)

. . . . . . . . . . . . . . . . . 

To remove and replace the valve guide, make the driver
tool as shown in figure [D].

A

B–03634

C

B–14335

D

MC–01364

7.87’’ (200 mm)

3.15’’ (80 mm)

0.51–0.511’’

(12,96–12,98 mm)

1.57’’

(40 mm)

0.71’’

(18,0 mm)

0.393’’

(10,0 mm)

0.51’’

(13,0 mm)

0.59’’

(15,0 mm)

0.31’’

(8,0 mm)

0.2’’

(5,0 mm)

0.787’’

(20 mm)

0.295–0.303’’
(7,5–7,7 mm)

–7–50–

773 BICS Loader

Service Manual

773 Service Manual #6900092–Engine Service Section Part 2 of 3

B

PI–09990

1. Cylinder Head Surface
2. Recessing
3. Protrusion

1

2

3

1