Rocker Arms - All

Complete replacement of all rocker arms on the 6.7L Cummins diesel engine, including removal of valve cover, rocker arm assembly, and proper torque sequence during reassembly.

Warnings

Tools required

Parts

• Rocker arm set (all 12) × 1 — Use OEM specification
• Valve cover gasket × 1 — Use OEM specification
• Rocker arm shaft assembly gaskets × 2 — Use OEM specification
• Intake manifold gasket (if disturbed) × 1 — Use OEM specification

Preparation

1. Disconnect both negative and positive battery cables to prevent accidental starter engagement
2. Remove engine cover and air intake system for access to valve cover
3. Disconnect any wiring harnesses, breather tubes, and fuel lines attached to valve cover
4. Label all connections with tape and marker for reassembly reference
5. Clean external valve cover area thoroughly to prevent debris from entering engine
6. Position drain pan under work area to catch any residual oil

Procedure

1. 1

   Remove valve cover
   Remove valve cover bolts in reverse of tightening sequence (outside to inside pattern). Carefully lift valve cover away from cylinder head. If stuck, gently tap with rubber mallet—do not pry between cover and head sealing surfaces. Inspect valve cover for cracks or damage.
   Torque spec

   Cover Bolts22 Nm (16 lb-ft)
2. 2

   Inspect and photograph valve train
   Before disassembly, inspect all rocker arms, pushrods, and valve tips for wear patterns. Take detailed photos showing rocker arm positions and orientation. Check for any obvious damage, scoring, or irregular wear that may indicate other issues requiring attention.
   ℹ️Document which cylinder each rocker arm came from if performing failure analysis or partial replacement for warranty purposes.
3. 3

   Rotate engine to safe position
   Using breaker bar on crankshaft pulley bolt, rotate engine until cam lobes for the rocker arms being removed are pointing away from the rocker arm pads (base circle position). This relieves spring pressure and allows safe removal. Mark crankshaft position for reference.
   ⚠Ensure cam lobes are on base circle before loosening rocker arm bolts. Attempting removal under valve spring pressure can damage components or cause fastener failure.
4. 4

   Remove rocker arm shaft assemblies
   Loosen rocker arm shaft bolts evenly in reverse sequence (outside bolts first, working toward center) to prevent shaft distortion. Remove bolts completely and carefully lift rocker arm shaft assembly straight up. Keep left and right bank assemblies separate and organized. Note the position of oil feed holes in shafts.
   ⚠Rocker arm shafts are under slight spring pressure. Loosen bolts gradually and evenly to prevent shaft binding or warping.
   Torque spec

   Rocker Arm Shaft Bolts25 Nm (18 lb-ft)
5. 5

   Remove individual rocker arms
   Slide rocker arms off the shaft assembly, keeping them in order. Inspect rocker arm shaft for wear, scoring, or out-of-round condition. Check rocker arm bores for excessive wear or galling. Remove and inspect all spacers and wave springs from shaft. Clean all components thoroughly with solvent.
   ℹ️The 6.7L Cummins rocker arms are not interchangeable between positions. Mark each rocker arm position if any original components will be reused.
6. 6

   Inspect pushrods and valve stem tips
   With rocker arms removed, inspect each pushrod for straightness by rolling on flat surface—any wobble indicates bent pushrod requiring replacement. Check valve stem tips for wear patterns, pitting, or mushrooming. Measure pushrod length if serviceability is questionable.
   ⚠Bent pushrods indicate a previous over-rev condition or valve train failure. Investigate root cause before reassembly.
7. 7

   Clean cylinder head deck and inspect
   Clean rocker arm shaft mounting surfaces on cylinder head with plastic scraper and solvent. Remove all old gasket material without gouging aluminum surfaces. Inspect cylinder head for cracks, especially around rocker shaft pedestals. Check that all oil feed passages are clear by spraying with brake cleaner.
8. 8

   Prepare new rocker arms and shafts
   Lubricate new rocker arm bores with clean engine oil. Install new rocker arms onto shaft in correct order and orientation, ensuring oil holes in shaft align properly for each cylinder. Install spacers and retainers in correct positions. Verify smooth rotation of each rocker arm on shaft.
   ℹ️Pre-assembly lubrication is critical for initial startup. Coat all friction surfaces with assembly lube or engine oil.
9. 9

   Install rocker arm shaft assembly gaskets
   Position new rocker arm shaft gaskets on cylinder head mounting surfaces. Ensure gaskets are properly seated in locating features and oil feed holes align correctly. Do not use sealant unless specified by manufacturer for this application.
   Torque spec

   Gasket Bolts27 Nm (20 lb-ft)
10. 10

    Install rocker arm shaft assemblies
    With cam lobes still on base circle, carefully lower rocker arm shaft assemblies onto cylinder head, ensuring all pushrods engage properly in rocker arm sockets. Start all rocker arm shaft bolts by hand. Verify shaft is seated evenly before tightening. Tighten bolts evenly in proper sequence (center bolts first, working outward) to specified torque.
    ⚠Ensure each pushrod is properly seated in both lifter and rocker arm socket before torquing. Misaligned pushrods will cause immediate engine damage on startup.
    Torque spec

    Rocker Arm Shaft Bolts25 Nm (18 lb-ft)
11. 11

    Verify valve lash and operation
    Slowly rotate engine two complete revolutions by hand using breaker bar on crankshaft pulley. Check for any binding, unusual resistance, or abnormal sounds. Verify all rocker arms actuate smoothly through full range of motion. If equipped with adjustable rockers, set valve lash per manufacturer specifications using feeler gauges.
    ⚠️If engine binds or shows excessive resistance during rotation, STOP immediately and investigate. Do not force rotation or attempt to start engine.
12. 12

    Install new valve cover gasket
    Clean valve cover mating surface thoroughly. Position new valve cover gasket in cover groove or on cylinder head per design. Ensure gasket is fully seated in all locating features. Do not reuse old gasket. Apply small amount of RTV sealant at camshaft cap corners if specified in service manual.
13. 13

    Install valve cover
    Carefully position valve cover onto cylinder head, ensuring gasket remains properly located. Start all valve cover bolts by hand. Tighten bolts in proper sequence (typically starting at center and working outward in crisscross pattern) to specified torque. Do not overtighten as this will distort cover and cause leaks.
    ⚠Valve cover bolts require low torque. Use calibrated torque wrench and follow sequence carefully to prevent gasket damage and oil leaks.
    Torque spec

    Cover Bolts22 Nm (16 lb-ft)

Reassembly

1. Reconnect all breather hoses, wiring harnesses, and fuel lines to valve cover in reverse order of removal
2. Reinstall air intake system and engine cover
3. Reconnect battery cables (positive first, then negative)
4. Check engine oil level and top off if necessary after procedure

Verification

• With engine still off, verify crankshaft rotates freely by hand through at least two complete revolutions without binding
• Start engine and listen for abnormal valve train noise such as ticking, clicking, or knocking that would indicate improper installation
• Allow engine to reach operating temperature and verify no oil leaks from valve cover gasket or rocker arm shaft area
• Check for proper oil pressure on instrument cluster—low pressure may indicate oiling system issue from improper assembly
• Test drive vehicle under light load and verify smooth engine operation with no misfires or unusual vibrations
• Re-inspect valve cover gasket area after 50-100 miles of operation for any developing leaks and retorque if necessary

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