3408 & 3408B DIESEL TRUCK ENGINE Caterpillar


Valve Rocker Arms, Lifters And Bridges

Usage:




Sequence For Rocker Arm Bolts

(1) Bore in rocker arm for shaft (new) ... 24.803 ± 0.013 mm (.9765 ± .0005 in.)

Diameter of shaft (new) ... 24.752 ± 0.013 mm (.9745 ± .0005 in.)

(2) Put 2P2506 Thread Lubricant on the threads of all bolts that hold rocker arm shaft and tighten the bolts in the following step sequence.

1. Tighten bolts 1 through 4 in number sequence to ... 280 ± 27 N·m (210 ± 20 lb.ft.)

2. Tighten bolts 1 through 4 in number sequence to ... 440 ± 20 N·m (320 ± 15 lb.ft.)

3. Tighten bolts 1 through 4 in number sequence again to ... 440 ± 20 N·m (320 ± 15 lb.ft.)

(3) Torque for locknut for valve adjustment screw ... 28 ± 4 N·m (22 ± 3 lb.ft.)

(4) Torque for locknut for bridge adjustment screw ... 28 ± 4 N·m (22 ± 3 lb.ft.)

(5) Clearance for valves:

Intake valves ... 0.38 mm (.015 in.)

Exhaust valves ... 0.76 mm (.030 in.)

(6) Height to top of dowel ... 53.3 ± 0.5 mm (2.10 ± .02 in.)

(7) Diameter of dowel (new) ... 11.008 ± 0.003 mm (.4334 ± .0001 in.)

Bore in bridge for dowel (new) ... 11.13 ± 0.05 mm (.438 ± .002 in.)

Bore in head for dowel ... 10.968 ± 0.020 mm (.4318 ± .0008 in.)

(8) Diameter of valve lifter (new) ... 27.896 ± 0.013 mm (1.0983 ± .0005 in.)

Bore in block for valve lifter (new) ... 27.9527 ± 0.0190 mm (1.10050 ± .00075 in.)

NOTE: See Guideline For Reusable Parts; Salvage Of Lifter Bores in 3400 Family Engines, Form No. SEBF8069 for the procedure, tooling and specifications needed to install 4W4588 Sleeves for salvage of the lifter bores in the cylinder block.

(9) 6N6872 Lifter Guide Spring. See Guideline For Reusable Parts, Form No. SEBF8066, for information on using guide springs again.

(10) 2N7229 Spring:

Length under test force ... 74.2 mm (2.92 in.)

Test force ... 45 to 53 N (10 to 12 lb.)

Free length after test ... 114.3 mm (4.50 in.)

Outside diameter ... 29.7 mm (1.17 in.)

(11) Dowel length above top surface of rocker shaft support to be (both ends) ... 12.7 ± 1.0 mm (.50 ± .04 in.)

(12) Clearance for rocker arms (both ends) ... 0.30 to 1.40 mm (.012 to .055 in.)

(13) Use 2N7228 Washer as needed to get clearance (12).

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