159252-0821 ZEXEL 9 421 611 420 BOSCH LEVER GROUP 9421611420 1592520821 8943255000

Removal
Remove turbocharger (Group 0416) from turbocharged engines.Remove air inlet piping from non-turbocharged engines (Group 0520).Remove water manifolds or thermostat housing (Group 0418).Remove fuel filter (Group 0420).Remove exhaust manifold (Group 0410).Remove injection nozzles and injection lines (Group 0413).Remove rocker arm cover, rocker arm assembly, and pushrods (Group 0402).Remove cylinder head cap screws. Do not rotate crankshaft with cylinder head removed unless all cylinder liners are secured with short cap screws and large flat washers. IMPORTANT: Do not use screwdrivers or pry bars between cylinder block and cylinder head to loosen cylinder head.Lift cylinder head from cylinder block. If cylinder head sticks, use a soft hammer to tap the cylinder head.Remove any gasket residue remaining on cylinder head.Measure cylinder head deck to valve head distance with valve seated.
Fig. 1-Cylinder Head to Valve Head DistanceCylinder head to intake valve head distance (new) (1, Fig. 1) ... 0.037 0.007 inch(0.94 0.18 mm)Cylinder head to exhaust valve head distance (new) (2) ... 0.057 0.007 inch(1.45 0.18 mm)Disassembly
Fig. 2-Valve RemovalUsing a valve spring compressor, compress valve springs far enough to remove retainer locks.Release spring tension and remove valve spring cap (or rotator, if so equipped) and valve spring. Mark each part so that it can be reassembled in the same position it was removed from.Remove valves, marking them for reassembly.Repair
Fig. 3-Cylinder Head FlatnessMeasure cylinder head flatness (Fig. 3).Cylinder head flatness (maximum warp) ... 0.002 inch(0.05 mm)
Fig. 4-Cylinder Head ThicknessMeasure cylinder head thickness (Fig. 4), to see if cylinder head can be resurfaced.New cylinder head thickness ... 4.134 0.005 inch(105.00 0.13 mm)Minimum cylinder head thickness ... 4.104 inch(104.24)If cylinder head thickness is less than the minimum allowable thickness, do not resurface it. Install a new cylinder head.If cylinder head is thick enough to be resurfaced, remove only enough material to remove damage. Do not resurface cylinder head if its thickness will be less than the minimum allowable after resurfacing.
Fig. 5-Valve Face AngleIf necessary to resurface valve face, grind valve face at following angle (Fig. 5):
Fig. 6-Valve Seat AngleIf necessary to resurface valve seat, grind valve seat at following angle (Fig. 6):
Fig. 7-Valve Seat WidthWhen resurfacing valve seats, the valve seat width must be maintained (Fig. 7).
Fig. 8-Valve Seat Run-OutWhen resurfacing valve seats, the valve seat run-out must be maintained (Fig. 8).Valve seat run-out (maximum) ... 0.002 inch(0.05 mm)
Fig. 9-JDE-77 or JDE-87 Valve Seat PullerUse JDE-77A Valve Seat Puller to remove intake valve seat inserts or JDE-87 Valve Seat Puller to remove exhaust valve seat inserts if they must be replaced on 4276D, 6414D, or 6414T engine.Use JDE41296 Valve Seat Puller to remove valve seat inserts if they must be replaced on 4239D, 4239T, 6359D, or 6359T engine.
Fig. 10-JDE-7 Driver and JDE-86 or JD-287 Valve Seat InstallerUse JDE-7 Driver (1, Fig. 10) with JDE-86 valve seat installer (2) (for exhaust) and JD-287 valve seat installer (2) (for intake) to install valve seat inserts. Chill the valve seat installer and valve seat insert to -20°F