Complete replacement of all valve springs on the 6.7L Cummins diesel engine, requiring removal of rocker assemblies and use of specialized valve spring compressor tools.

Warnings

Tools required

Parts

• Valve springs (set of 24) × 1 — Use OEM Cummins specification
• Valve cover gasket × 1 — Use OEM specification
• Rocker housing gaskets × 2 — Use OEM specification
• Valve keepers (if reuse not recommended) × 1 — Use OEM Cummins specification
• Engine oil for assembly lubrication × 1 — 5W-40 synthetic diesel oil

Preparation

1. Ensure engine is completely cold (minimum 4 hours after last operation)
2. Disconnect both battery cables, negative first, and isolate from terminals
3. Remove engine cover and any interfering air intake components
4. Clean valve cover area thoroughly to prevent debris from entering engine
5. Mark all electrical connectors and sensors on valve cover for correct reinstallation
6. Prepare clean workspace with organized parts trays labeled for each cylinder
7. Rotate engine to TDC cylinder #1 and verify timing marks before beginning

Procedure

1. 1

   Remove valve cover assembly
   Disconnect all electrical connectors and breather hoses from valve cover. Remove valve cover bolts in reverse of tightening sequence (outside to inside pattern). Carefully lift valve cover from cylinder head, tapping gently with rubber mallet if stuck. Inspect gasket surfaces and clean thoroughly with plastic scraper, ensuring no debris falls into engine.
   Torque spec

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

   Remove rocker arm assemblies
   Take detailed photos of rocker arm shaft assembly orientation and position. Mark each rocker arm shaft bracket with cylinder number using paint pen. Loosen rocker arm shaft bolts evenly in multiple passes working from ends toward center to prevent shaft bending. Remove complete rocker arm shaft assemblies as a unit for each bank and place on clean workspace maintaining orientation.
   ⚠Uneven removal of rocker shaft bolts can bend shaft - loosen gradually in at least 3 passes
   Torque spec

   Rocker Arm Shaft Bolts25 Nm (18 lb-ft)
3. 3

   Remove pushrods and organize
   Carefully remove all pushrods, keeping them in exact order for reinstallation in same position. Use numbered pushrod holder or mark each with cylinder and position (intake/exhaust). Inspect each pushrod for wear, checking straightness by rolling on flat surface. Clean pushrods thoroughly and store vertically to prevent bending.
4. 4

   Position cylinder #1 for valve spring removal
   Rotate crankshaft to position piston #1 at TDC compression stroke (both valves fully closed, rocker arms loose). This ensures valve is seated and spring can be safely compressed. Install valve spring compressor tool on intake valve spring of cylinder #1, ensuring tool seats properly on spring retainer and valve spring base.
   ⚠️Verify piston is NOT at position where valve could drop into cylinder - valve must be fully seated on seat before spring removal
5. 5

   Compress spring and remove keepers - cylinder #1 intake
   Carefully compress valve spring using compressor tool, applying steady even pressure. Once spring retainer is fully compressed and keepers are visible and loose, use magnetic pickup tool to carefully remove both valve keepers. Slowly release spring compressor tension and remove spring retainer, valve spring, and any shims or seals. Place all components in organized tray labeled for this specific valve position.
   ⚠️Keep hands and face clear of spring retainer during compression - tool slippage can cause violent release
   ⚠Do not allow valve to drop into cylinder - maintain slight upward pressure on valve stem
6. 6

   Install new valve spring - cylinder #1 intake
   Inspect valve stem seal and replace if worn. Lightly lubricate valve stem with clean engine oil. Position new valve spring over valve stem with closer-wound coils toward cylinder head (verify spring orientation per service manual). Place spring retainer on top of spring. Carefully compress new spring using compressor tool until retainer groove is fully exposed.
7. 7

   Install valve keepers and verify seating
   Apply small amount of clean grease to valve keepers to hold them in place during installation. Carefully position both keepers in valve stem groove using magnetic tool or keeper installation tool. Slowly release spring compressor while watching keepers to ensure they seat properly in retainer. Once fully released, tap valve stem tip gently with plastic tool to verify keepers are fully seated - spring retainer should not move.
   ⚠Improperly seated keepers will cause valve spring failure and catastrophic engine damage - verify complete seating before proceeding
8. 8

   Repeat spring replacement for all valves
   Proceed to cylinder #1 exhaust valve and repeat removal and installation process. Continue through all 24 valves (12 cylinders, 2 valves each) in cylinder number order. For each valve, rotate crankshaft as needed to ensure that specific cylinder's piston is positioned so valve is fully closed before spring removal. Maintain organization of old parts by valve position if diagnosis of wear patterns is needed.
   ℹ️Rotating engine during this process - verify each valve is fully closed before spring compression to prevent valve-to-piston contact
9. 9

   Inspect and prepare for rocker assembly installation
   Clean all rocker arm components thoroughly. Inspect rocker arm contact surfaces and shaft bores for wear or galling. Clean rocker arm shaft bolt holes in cylinder head using brake cleaner and compressed air. Verify camshaft lobes are clean and undamaged. Apply assembly lubricant or clean engine oil to all rocker arm shaft bearings and cam contact surfaces.
10. 10

    Install pushrods in original positions
    Coat each pushrod end with assembly lubricant or clean engine oil. Install each pushrod in its original location, ensuring lower end seats fully in lifter cup. Guide upper end into rocker arm socket area but do not force into position yet - rocker arms will be positioned over pushrods during installation.
11. 11

    Install rocker arm shaft assemblies
    Position new rocker housing gaskets on cylinder head. Guide rocker arm shaft assembly into position, carefully aligning each rocker arm with its corresponding pushrod and valve stem. Verify all pushrods are properly seated in rocker arm sockets before installing any bolts. Hand-start all rocker arm shaft bolts. Verify camshaft has been rotated so lobes are not on high lift position under rocker arms being tightened. Tighten rocker arm shaft bolts evenly in sequence from center outward in multiple passes to final specification.
    ⚠Do not tighten rocker shaft with cam lobe at high lift - rotate engine to position lobe pointing away from rocker
    Torque spec

    Rocker Arm Shaft Bolts25 Nm (18 lb-ft)
12. 12

    Verify valve lash and adjustment
    Rotate engine through two complete revolutions and verify smooth rotation with no binding. Check valve lash/clearance on all valves per factory specification using feeler gauges with engine cold. Adjust as necessary per service manual procedure for this engine (if adjustable). Listen for any unusual sounds when rotating engine by hand that might indicate improperly seated keepers or incorrect assembly.
    ⚠Any binding or unusual resistance when rotating engine indicates problem - do not proceed until cause is identified
13. 13

    Install valve cover and reconnect components
    Install new valve cover gasket ensuring proper orientation and full seating in valve cover groove. Position valve cover on cylinder head, guiding around any studs or protrusions. Install valve cover bolts and tighten in proper sequence (inside to outside pattern) to specification. Reconnect all electrical connectors, breather hoses, and sensors removed during disassembly. Reinstall any air intake components or engine covers.
    Torque spec

    Cover Bolts22 Nm (16 lb-ft)
14. 14

    Final preparation and initial start
    Reconnect battery cables, positive first then negative. Verify all tools are removed from engine bay. Turn ignition to ON position without cranking and verify no warning lights indicate problems. Perform initial engine start and allow to idle, monitoring closely for any unusual sounds, oil leaks, or valve train noise. Listen carefully for clicking or ticking that might indicate keeper or spring problems.
    ⚠️If any unusual valve train noise is heard during initial start, shut down immediately and inspect - may indicate improperly seated keeper

Reassembly

1. All valve keepers must be fully seated in retainer grooves - improper seating will cause immediate spring failure
2. Rocker arm shaft assemblies must be tightened evenly to prevent shaft bending or binding
3. Pushrods must be installed in their original positions to maintain proper engine break-in patterns
4. Valve cover bolts must be torqued in proper sequence to ensure even gasket compression and prevent leaks

Verification

• Engine should rotate smoothly by hand through complete revolution with no binding or tight spots
• No oil leaks should be present from valve cover gasket after initial start and warm-up
• Engine should idle smoothly with no unusual valve train noise or ticking sounds
• All valve springs should show same installed height when measured with straight edge across valve cover mating surface
• Perform compression test or leak-down test if available to verify all valves are sealing properly
• Monitor engine for first 100 miles of operation for any development of valve train noise or oil consumption issues

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