BOLT 5L7812 - Caterpillar

Engines:
3606 (S/N: 8RB)
3608 (S/N: 6MC; 8LL; 7WR)
3612 (S/N: 9RC; 9FR; 2NZ)
3616 (S/N: 1PD; 1FN)
3618 (S/N: 2MW)
G3606 (S/N: 3XF)
G3608 (S/N: 4WF)
G3612 (S/N: 1YG)
G3616 (S/N: 4CG)
Reference: Engine News, SEBD9251, August 1997, "New Manual Valve Group [Measure Cylinder Pressure Kiene Valve] Used; Kiene Valve Installation Procedure"There is a mounting boss (5) on the 3600 cylinder head casting. See Illustration 1. The mounting boss has 1/2 - 14 NPTF Female Thread in order to accept a manual valve group (Kiene valve). The threads in the mounting boss may become corroded by the extreme heat of the combustion gases. Damage to the threads in the cylinder head is caused when the Kiene valve seizes in the cylinder head. The following procedure has been provided in order to repair the internal thread within the cylinder head.
Illustration 1 g00822064
This illustration shows a side view of a manual valve group (Kiene valve), which is installed in the mounting boss on the cylinder head. (1) 7W-2656 Cap (2) Valve stem cap (nonserviceable item) (3) 7C-7077 Indicator Valve (4) 1/2 - 14 NPTF Thread (5) Mounting boss on the cylinder headNote: During engine operation, the threads of the Kiene valve may seize to the threads in the cylinder head.
Run the engine until the engine comes up to the normal operating temperature.
Shut down the engine.
Remove the Kiene valve.Note: It may be necessary to tighten the valve slightly in order to break the fitting free from the cylinder head.
Apply 138 kPa (20 psi) of air pressure into the cylinder. Apply the air pressure through the cylinder head pressure relief port, or through the opening for the unit injector. This will force any metal chips away from the cylinder while the repair is being made.
Illustration 2 g00820240
The illustration shows the hole (6) to be repaired on the cylinder head.
Use a 23 mm (0.906 inch) drill bit. Drill the hole to the depth of 25.4 mm (1.00 inch).
Tap the hole (6) for 3/4 - 14 NPTF thread. The thread depth should be 17 mm (0.69 inch) deep.
Apply 4C-5598 High Temperature Anti-Seize to the threads of a 8B-2664 Reducing Bushing .Note: The 8B-2664 Reducing Bushing has 3/4 - 14 NPTF Male Thread on the end that screws into the cylinder head. The inside of the reducing bushing has 1/2 - 14 NPTF Female Thread in order to accept a manual valve group (Kiene valve).
Install the 8B-2664 Reducing Bushing into the cylinder head.
Tighten the 8B-2664 Reducing Bushing to 75 N m (55 lb ft).
Apply 4C-5598 High Temperature Anti-Seize to the threads of the manual valve group (Kiene valve).
Install the manual valve group into the 8B-2664 Reducing Bushing.
Torque the manual valve group within a range of 45 - 100 N m (33 - 74 lb ft) .Note: Do Not Overtighten The Valve. Overtightening the manual valve group can cause the threads to seize in the 8B-2664 Reducing Bushing .
Install the 7W-2656 Cap (1) .
Torque the 7W-2656 Cap to 17 3 N m (12 2 lb ft).