D399, G399, D398, G398, D379, G379 ENGINES Caterpillar

Each cylinder head covers two cylinders. Water directors direct the flow of coolant toward the valve ports and precombustion chambers. Seals and ferrules seal the water passages between the cylinder head and the cylinder block.

Removal And Installation

1. Drain the coolant from the engine.

2. Remove plugs (2). Remove the exhaust manifold flange upper four bolts through the openings from which the plugs were removed. At installation tighten bolts to torque of 100-120 lb. ft. (13,8-16,6 mkg).

PREPARING TO DISCONNECT EXHAUST MANIFOLD FROM CYLINDER HEAD
1-Fuel injection lines (two per cylinder head). 2-Plugs (four per cylinder head). 3-Shield.

3. Remove shield (3) and remove the exhaust manifold flange lower four bolts. There is a shield support under each pair of bolts. At installation tighten bolts to torque of 100-120 lb. ft. (13,8-16,6 mkg).

4. Remove valve mechanism. See covering topic.

PREPARING TO REMOVE CYLINDER HEAD (D399 Engine Illustrated)
4-Pipes (two per cylinder head). 5-Regulator housing. 6-Nuts and washers (sixteen per cylinder head). 7-Bolts (six per cylinder head).

5. When the right front cylinder head is being removed, water temperature regulator housing (5) must be removed. See the covering topic.

6. Use crossbar (9) from the 8B7548 Push Puller with two 1B4205 Nuts and a few flat washers attached to rocker arm studs (8) as shown. Attach a 1" forged eyebolts (10) solidly to the crossbar and use a hoist to lift cylinder head (11) from the engine. Approx. weight 190 lbs. (86 kg).

REMOVING CYLINDER HEAD
8-Rocker arm studs. 9-Crossbar. 10-Forged eyebolt. 11-Cylinder head. 12-Head gasket.

7. Inspect the seals, and ferrules. Always install new head gaskets (12).

8. Replace manifold gaskets if necessary.

NOTE: Tighten any loose cylinder head taperlock studs to torque of 90-110 lb. ft. (12,4-15,2 mkg). The compression release pawl (13) on earlier engines should be in the lower position before installing the head, see the topic COMPRESSION RELEASE MECHANISM.

COMPRESSION RELEASE PAWL
13-Pawl.

CYLINDER HEAD STUD NUT TIGHTENING SEQUENCE

9. Apply 9M3710 Anti-Seize to the stud threads. Install hold down nuts and washers (6). Tighten the nuts in sequence shown in illustration to a torque of 150 ± 10 lb. ft. (20,7 ± 1,4 mkg). Then tighten a second and third time to 250 ± 10 lb. ft. (34,6 ± 1,4 mkg).

10. Complete the installation in reverse order of removal.

NOTE: Inlet valve clearance is .015 in. (0,38 mm), exhaust valve clearance is .035 in. (0,89 mm). The compression release clearance on earlier engines is .025-.030 in. (0,64-0,76 mm). See the LUBRICATION AND MAINTENANCE GUIDE.

If taperlock studs for valve rocker shaft brackets are replaced, install them to torque of 35-45 lb. ft. (4,8-6,2 mkg).

Water Directors

There are eight water directors (1) pressed into each cylinder head to direct the flow of coolant. On the exhaust side, coolant is directed toward the precombustion chambers and the exhaust valve ports; and on the inlet side, toward the other side of the valve ports, as indicated by the V-marks. Water directors are pressed into place on the heads after aligning the notch on the director with the V-mark on the head.

WATER DIRECTORS
1-Water director. 2-Ferrule. 3-Seal.

The seals (3) and copper ferrules (2) between the head and top of the block are replaceable. Coat the inner surface of the seal with soap and place the groove in the seal over the ridge on the ferrule before installing. FT117 Seal and Ferrule Assembly Tool will make seal installation on the ferrule easier.

FT117-SEAL AND FERRULE ASSEMBLY TOOL

4 5H3182 Pin

5 2A3672 Spring

6 Flat Washer

7 Chain

8 Upper Rod

9 Connecting Pin

10 Bracket

11 Connecting Joint

12 Lower Rod

13 Base

A Rubber Seals

B Ferrule

Precombustion Chambers

The precombustion chamber (3) is threaded into the cylinder head (5) and sealed at the top of the head with a single O-ring seal. Earlier engines have a retainer (1) and two O-ring seals (2).

The O-ring seals prevent leakage of coolant.

PRECOMBUSTION CHAMBER (Earlier Engines)
1-Retainer. 2-Rubber seals. 3-Precombustion chamber. 4-Gasket. 5-Cylinder head.

The gasket (4) prevents combustion gases from entering the cooling system, as well as preventing the leakage of coolant into the cylinder.

Removal and Installation

1. Remove the fuel injection valve assembly.

PRECOMBUSTION CHAMBER TOOLS
1-1A2208 Bolt. 2-5F9072 Spacer. 3-Retainer. 4-5F8353 Wrench Adapter. 5-Precombustion chamber. 6-4B4285 Washer. 7-L-1017 Nut. 8-6F5515 Screw.

2. On earlier engines, place a 5F9072 Spacer (2) in the precombustion chamber and turn the 1A2208 Bolt (1) in the retainer (3) against the spacer until the retainer comes out of the cylinder head.

REMOVING PRECOMBUSTION CHAMBER RETAINER (Earlier Engines)
1-1A2208 Bolt. 2-5F9072 Spacer. 3-Retainer.

3. Place the 5F8353 Wrench Adapter (4) in the serrations of the precombustion chamber and screw the precombustion chamber out of the head.

NOTE: If a cylinder head has collected an excessive amount of scale or rust within the water jacket, remove the cylinder head and clean it thoroughly. This is also an indication that the entire cooling system should be cleaned as described in the Operation Guide.

PRECOMBUSTION CHAMBER REMOVAL (Later Engines)
4-5F8353 Wrench Adapter.

4. Place a new gasket on the precombustion chamber and new seal in the groove at the top of later precombustion chambers.

5. Apply 9M3710 Anti-Seize Compound to threads of precombustion chamber. Apply soap to seal on later engines. This will help retain the gasket on the precombustion chamber. Insert chamber in head and tighten with the 5F8353 Wrench Adapter (4) to torque of 225 ± 15 lb. ft. (31,1 ± 2,1 mkg).

PRECOMBUSTION CHAMBER REMOVAL (Earlier Engines Illustrated)
4-5F8353 Wrench Adapter.

6. On earlier precombustion chambers with retainers coat the chamfered portion of the cylinder head and the new seals with soap.

7. Place the retainer over the precombustion chamber and start it into the cylinder head and onto the precombustion chamber.

INSTALLING RETAINER (Earlier Engines)

8. Using 4B4285 Washer (6), 6F5515 Screw (8), and L-1017 Nut (7), tighten the nut until the retainer bottoms.