Complete replacement of all valve lifters/tappets on the 6.7L Cummins diesel engine, requiring removal of valve cover, rocker assembly, and camshaft to access lifters.

Warnings

Tools required

Parts

• Valve lifters/tappets (set of 12) × 1 — Use OEM Mopar specification
• Valve cover gasket × 1 — Use OEM specification
• Camshaft bearing cap gaskets × 1 — Use OEM specification
• Front cover gasket × 1 — Use OEM specification
• Engine oil filter × 1 — Mopar 68157291AA or equivalent
• RTV silicone sealant (Mopar approved) × 1 — Mopar or equivalent

Fluids

• Mopar 5W-20 Synthetic Blend engine oil — 13 qt

Preparation

1. Ensure engine is completely cold (wait minimum 3 hours after last operation)
2. Disconnect both battery cables, negative first, and isolate from terminals
3. Drain engine oil completely and remove oil filter
4. Remove engine cover/beauty cover if equipped
5. Clean entire valve cover area thoroughly to prevent debris entry
6. Document or photograph all electrical connections and hose routing before removal
7. Prepare clean workspace with labeled containers for each set of components (lifters 1-6, 7-12, etc.)
8. Print or have available the camshaft bearing cap position diagram from service manual

Procedure

1. 1

   Remove valve cover and disconnect components
   Disconnect all electrical connectors on valve cover including camshaft position sensor. Remove any breather hoses or PCV connections. Remove valve cover bolts in reverse of tightening sequence (outside to inside). Carefully lift valve cover away and remove gasket. Inspect for oil sludge or debris that may indicate deeper engine problems.
   Torque spec

   Cover Bolts22 Nm (16 lb-ft)

   Camshaft Position Sensor10 Nm (7 lb-ft)
2. 2

   Rotate engine to TDC cylinder #1
   Using engine barring tool or breaker bar on crankshaft bolt, rotate engine clockwise (viewed from front) until cylinder #1 is at top dead center on compression stroke. Verify timing marks align on crankshaft and camshaft gears. Mark position with paint pen for reference. This ensures valves are closed and reduces spring pressure during disassembly.
   ⚠Only rotate engine in normal direction of rotation (clockwise from front). Never rotate backwards.
3. 3

   Remove rocker arm assembly
   Loosen rocker arm shaft bolts evenly in reverse sequence (outside to inside) to prevent warping the shaft assembly. Remove bolts completely and carefully lift entire rocker arm shaft assembly as a unit. Place on clean workspace and keep rocker arms in order if reusing. Note: Cummins 6.7L uses a shaft-mounted rocker system, not individual rocker arms.
   ⚠Rocker shaft assembly must be loosened evenly. Uneven removal can bend shaft or damage bearing surfaces.
   Torque spec

   Rocker Arm Shaft Bolts25 Nm (18 lb-ft)
4. 4

   Remove push rods
   Carefully remove all 12 push rods, keeping them in exact order (cylinder 1-6, intake and exhaust). Inspect each push rod by rolling on flat surface to check for bending. Measure length - all should be within 0.010 inch of each other. Place in numbered organizer tray. Clean and inspect push rod seats in cylinder head for wear or debris.
   ℹ️Push rods must be reinstalled in original positions. Number or label each one clearly.
5. 5

   Remove camshaft bearing caps and camshaft
   Camshaft caps are numbered and directional - note arrow marks pointing toward front of engine. Loosen bearing cap bolts in multiple passes, working from outside caps toward center in 1/4 turn increments to prevent binding. Remove all bearing cap bolts and carefully lift caps straight up, keeping in order. Install camshaft holding fixture or support, then carefully lift camshaft straight up and out. Inspect camshaft lobes and bearing journals for wear, pitting, or scoring.
   ⚠️Camshaft bearing caps MUST be reinstalled in exact same positions and orientations. Mixing positions will destroy engine. Mark clearly if not already stamped.
   Torque spec

   Camshaft Bearing Cap Bolts14 Nm (10 lb-ft)
6. 6

   Remove valve lifters
   Using magnetic lifter removal tool, carefully extract each lifter straight up from its bore. Keep lifters in exact order using numbered tray (cylinders 1-6, intake and exhaust = 12 total). If lifters are stuck, do NOT pry - use penetrating oil and gentle twisting motion with lifter tool. Inspect each lifter bore for scoring, deposits, or damage. Clean bores thoroughly with clean shop towel and appropriate solvent.
   ⚠Lifters must be removed vertically without tilting to prevent damage to bore surfaces.
   ℹ️If reusing lifters, they MUST return to their original bores. New lifters can go in any bore.
7. 7

   Inspect and measure components
   Measure camshaft lobe height with micrometer - intake and exhaust lobes separately. Compare to service manual specifications (typically 1.775-1.785 inches but verify in manual). Measure camshaft bearing journal diameters. Inspect lifter faces for wear, pitting, or concave wear patterns. Measure lifter diameter and bore diameter to verify clearances are within spec (typically 0.0005-0.0025 inch). Inspect push rod seats in lifters for wear.
   ⚠If camshaft or lifter wear exceeds specifications, both camshaft and ALL lifters must be replaced as a set.
8. 8

   Install new lifters
   Coat new lifters liberally with assembly lube or fresh engine oil, ensuring entire surface is covered. Coat lifter bores with clean engine oil. Install each new lifter into its designated bore, lowering straight down without tilting. Ensure lifter seats completely in bore and rotates freely. Repeat for all 12 lifters. New lifters should have slight pre-load; do not force if resistance is felt.
   ℹ️New lifters require proper break-in. First 500 miles should avoid sustained high RPM operation.
9. 9

   Install camshaft
   Liberally coat all camshaft lobes and bearing journals with assembly lube or camshaft installation lubricant. Verify cam timing marks are visible and unobstructed. Carefully lower camshaft into position, aligning with timing marks noted earlier. Ensure camshaft seats fully into front bearing position. Verify timing alignment before proceeding.
   ⚠️Verify camshaft timing marks align with crankshaft timing marks before installing bearing caps. Incorrect timing causes immediate engine destruction.
10. 10

    Install camshaft bearing caps
    Apply thin film of engine oil to bearing cap surfaces. Install caps in correct positions with arrows pointing toward front of engine. Hand-start all bearing cap bolts. Tighten in 3 passes using sequence from center caps outward: Pass 1 to 5 Nm (4 lb-ft), Pass 2 to 10 Nm (7 lb-ft), Pass 3 to final specification of 14 Nm (10 lb-ft). After final torque, verify camshaft rotates smoothly by hand.
    ⚠️CRITICAL: Follow 3-pass torque sequence exactly. Uneven tightening will distort bearings and seize camshaft.
    Torque spec

    Camshaft Bearing Cap Bolts14 Nm (10 lb-ft)
11. 11

    Install push rods
    Coat each push rod end with assembly lube. Install each push rod into its original position, ensuring lower end seats properly in lifter cup. Push rod should drop into place with slight resistance. Verify each push rod seats completely and stands vertically without binding. Rotate crankshaft slightly if needed to position lifters for easy push rod installation.
    ⚠Push rods must seat fully in lifter cups. Partial seating will cause catastrophic failure.
12. 12

    Install rocker arm assembly
    Apply engine oil to rocker shaft and all rocker arm contact points. Verify rocker arms are in correct positions on shaft. Position entire assembly over cylinder head, aligning rocker arms with push rod tips. Hand-start all rocker shaft bolts. Verify each rocker arm tip is centered on valve stem and each push rod is seated in rocker arm cup. Tighten rocker shaft bolts evenly in sequence from center outward to 25 Nm (18 lb-ft), making at least 3 passes.
    ⚠Ensure all push rods seat properly in rocker arm cups before tightening. Misalignment will bend push rods.
    Torque spec

    Rocker Arm Shaft Bolts25 Nm (18 lb-ft)
13. 13

    Verify valve lash and timing
    Set up dial indicator on first intake valve. Rotate crankshaft through two complete revolutions while monitoring valve movement. Verify valve events occur at proper crankshaft positions per service manual. Check that all valves open and close smoothly without binding. Listen for any unusual noises. Verify timing marks still align after full rotation.
    ⚠️If any valve does not move, or timing marks do not align after rotation, STOP immediately and diagnose issue before proceeding.
14. 14

    Install valve cover
    Clean valve cover and cylinder head mating surfaces thoroughly with gasket scraper and solvent. Inspect surfaces for warping or damage. Install new valve cover gasket, ensuring proper seating in cover groove. Apply small dab of RTV at front corners where front cover meets cylinder head (per service manual). Position valve cover carefully, ensuring gasket does not shift. Hand-start all bolts, then torque in sequence from center outward to 10 Nm (7 lb-ft).
    ⚠Over-torquing valve cover bolts will distort cover and cause oil leaks. Use torque wrench, not impact tools.
    Torque spec

    Cover Bolts22 Nm (16 lb-ft)
15. 15

    Reconnect components and refill fluids
    Reconnect camshaft position sensor and torque to specification. Reconnect all electrical connectors, breather hoses, and PCV connections per photos/notes from disassembly. Install new oil filter and fill engine with 13 quarts of Mopar 5W-20 synthetic blend oil. Reconnect battery cables (positive first, then negative). Double-check all connections and torque values before starting.
    Torque spec

    Camshaft Position Sensor10 Nm (7 lb-ft)

Reassembly

1. Verify all tools and shop towels are removed from engine compartment
2. Confirm all electrical connections are secure and routed properly
3. Double-check valve cover bolts are torqued to specification in proper sequence
4. Verify oil level is correct on dipstick after filling

Verification

• With ignition off, crank engine with starter for 10-15 seconds to build oil pressure (disable fuel system if possible)
• Start engine and verify oil pressure reaches normal range within 5 seconds
• Listen carefully for any abnormal valve train noise - ticking, knocking, or rattling indicates problem requiring immediate shutdown
• Allow engine to idle for 10 minutes, monitoring for oil leaks around valve cover and front cover
• Check for proper oil pressure at idle (minimum 10 PSI) and at 1500 RPM (30+ PSI)
• After initial break-in period, check valve cover for leaks and verify smooth engine operation
• Monitor oil consumption for first 500 miles - new lifters may cause slight increase initially
• Perform oil and filter change at 500 miles to remove break-in debris

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