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

Cylinder Heads - (Natural Gas Engines)

Usage:

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

Removal And Installation

1. Drain the coolant from the engine.

2. Remove the carburetor control linkage where necessary, the carburetor and the governor control bracket.

PREPARING TO REMOVE A CYLINDER HEAD
1-Pipes (two per cylinder head). 2-Valve cover. 3-Exhaust manifold. 4-Bolts (six per cylinder head). 5-Transformers and mounting bracket. 6-Conduit. 7-Regulator housing.

3. Remove the eight bolts which secure the exhaust manifold (3) to the cylinder head.

4. Remove the water temperature regulator housing (7), the instrument panel, wires and tubes when necessary.

REMOVING CYLINDER HEAD

5. Remove the valve mechanism.

6. Remove the sixteen nuts from the studs which secure the cylinder head to the cylinder block.

7. Attach the crossbar from the 8B7548 Push Puller with two 1/2 in. pipe nipples 3 in. (76,2 mm) long, two 1B4205 Nuts and flat washers attached to the rocker arm studs as shown. Attach a 1 in. eyebolt to the bar and a suitable hoist to lift the cylinder head from the engine. Approx. weight 190 lbs. (86 kg).

8. Inspect the seals and ferrules for damage and replace if necessary. Always install a new cylinder head gasket.

9. Inspect the manifold gaskets and replace if necessary.

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NOTICE

When installing the head on the cylinder block, see that grommets and ferrules (8) and seals and ferrules (9) are properly installed, and started properly into the recessed holes in the cylinder head. Rock the head gently until it seats flatly on the head gasket.

INSTALLING CYLINDER HEAD
8-Grommet and ferrule. 9-Seal and ferrule.

NOTE: Tighten any loose cylinder head taperlock studs to torque of 90-110 lb. ft. (12,4-15,2 mkg). The compression release pawl (10) on earlier engines should be in the lower position before installing the head, see the topic COMPRESSION RELEASE MECHANISM.

COMPRESSION RELEASE PAWL (Earlier Engines)
10-Pawl.

10. Apply 9M3710 Anti-Seize to the stud threads. Install hold down nuts and washers. 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).

CYLINDER HEAD STUD NUT TIGHTENING SEQUENCE

11. 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).

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

Spark Plug Adapters

The spark plug adapter (1) is threaded into the cylinder head (4) and sealed at the top of the head with an O-ring seal (2) and at the bottom with a gasket (3).

SPARK PLUG ADAPTER
1-Spark plug adapter. 2-O-ring seal. 3-Gasket. 4-Cylinder head.

Removal and Installation

1. Remove the cover (3) from the spark plug adapter (1) and the spark plug (4).

SPARK PLUG AND ADAPTER
1-Spark plug adapter. 2-O-ring seal. 3-Cover. 4-Spark plug.

2. Using the 3B9082 Spark Plug Wrench in conjunction with the 3563-A Spark Plug Wrench, remove the spark plug from the adapter.

3. Remove the adapter from the cylinder head using the 8S7227 Wrench and the 1-11/16" 8H8538 Socket (for earlier adapters use 1F479 Wrench and the 1-5/16" 8H8536 Socket).

NOTE: If the 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.

4. Install a new gasket in the cylinder head. A thin layer of grease will help retain the gasket while installing the spark plug adapter.

5. Coat the chamfered portion of the cylinder head and the seal (2) with soap to aid in installation

6. Apply 9M3710 Anti-Seize Compound to threads of adapter and install the brass or nodular iron adapters to torque of 150 lb. ft. (20,7 mkg) and earlier steel adapters to torque of 225 lb. ft. (31,1 mkg). Install a new gasket and the spark plug to torque of 30 lb. ft. (4,1 mkg). Spark plug is .014 ± .001 in. (0,36 ± 0,025 mm).

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 spark plug adapters 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. Place the groove in the seal over the ridge on the ferrule, before installing. FT117 Seal and Ferrule Assembly Tool will make seal installation easier on the ferrule.

FT117-SEAL AND FERRULE ASSEMBLY TOOL