Timing Chain

Complete replacement of the timing chain, guides, and tensioners on the 2008 Dodge Viper 8.4L V10 engine, requiring removal of front accessories, timing cover, and precise alignment of timing marks.

Warnings

Tools required

Parts

• Timing chain kit (includes chain, guides, tensioners) × 1 — Use OEM Mopar kit
• Timing cover gasket × 1 — Use OEM specification
• Crankshaft front seal × 1 — Use OEM specification
• Camshaft seals (left and right) × 2 — Use OEM specification
• Harmonic balancer bolt (if TTY) × 1 — Torque-to-yield - use OEM
• Engine coolant × 1 — Mopar HOAT 50/50
• RTV silicone sealant (high-temp) × 1 — Mopar or equivalent

Fluids

• coolant — 19 qt
• engine_oil — 11 qt

Preparation

1. Disconnect negative battery cable and isolate from terminal
2. Raise vehicle on lift or support safely on jack stands at manufacturer-specified lift points
3. Remove engine cover (decorative plastic cover over intake manifold)
4. Drain engine coolant completely into appropriate container
5. Drain engine oil and remove oil filter
6. Position large drain pan under front of engine for coolant drainage during timing cover removal

Procedure

1. 1

   Remove Front Accessories and Belts
   Remove serpentine belt by releasing automatic tensioner. Remove drive belt tensioner assembly. Disconnect power steering pump and set aside without disconnecting hydraulic lines (support with wire to prevent hose strain). Remove alternator with wiring harness attached and secure out of work area. Remove A/C compressor mounting bolts and support compressor without disconnecting refrigerant lines.
2. 2

   Remove Cooling System Components
   Disconnect upper and lower radiator hoses at engine. Remove thermostat housing with coolant bypass connections. Disconnect heater hoses from front of engine. Remove water pump if required for access to timing cover fasteners (verify against factory service manual). Remove bolts securing water pump and carefully separate from engine block. Remove bolts securing water pump and carefully separate from engine block.
3. 3

   Remove Crankshaft Harmonic Balancer
   Rotate engine to TDC on cylinder #1 (use breaker bar on crankshaft bolt - turn clockwise). Mark harmonic balancer position relative to crankshaft nose for reference. Use appropriate crankshaft holding tool or have assistant hold flywheel through bellhousing access (manual transmission) or use impact gun. Remove crankshaft center bolt. Install harmonic balancer puller and remove balancer from crankshaft nose. Do not use jaw-type pullers that grip outer ring - this will damage the balancer.
4. 4

   Support Engine and Remove Front Motor Mount
   Install engine support fixture across engine bay or attach engine hoist to lifting eyes on engine. Take up slight tension to support engine weight. Remove front engine mount through-bolt and mounting bracket bolts. This provides clearance for timing cover removal and access to lower timing cover bolts.
5. 5

   Remove Timing Cover
   Remove all timing cover bolts - there are approximately 18-20 bolts of varying lengths around the perimeter of the timing cover. Note bolt locations as they are different lengths for different positions. Carefully break timing cover seal using plastic gasket scraper at sealing surfaces. Work around entire perimeter to separate cover from block. Remove timing cover forward, being careful not to damage crankshaft seal bore or block sealing surfaces. Clean all gasket material from block and cover mating surfaces using plastic scraper only.
6. 6

   Verify and Mark Timing Alignment
   Confirm engine is at TDC cylinder #1 (compression stroke). Verify timing marks: align the timing dot on the crankshaft gear with the timing dot on the single camshaft gear (dot-to-dot alignment) with the engine at TDC on cylinder #1 compression stroke. Take detailed photos of timing mark alignment from multiple angles for reference during reassembly. Mark timing chain direction of rotation with paint marker if reusing chain (though replacement is recommended).
7. 7

   Remove Timing Chain Tensioners and Guides
   If equipped, remove the timing chain tensioner/snubber. Inspect the single timing chain, crankshaft gear, and camshaft gear for wear. Note orientation of any components for reinstallation. Note orientation and position of all guides for installation reference.
   Torque spec

   Timing Chain Tensioner25 Nm (18 lb-ft)

   Timing Chain Guide Bolts12 Nm (9 lb-ft)
8. 8

   Remove Camshaft Sprockets and Timing Chain
   Remove the camshaft gear retaining bolt(s) from the front of the single camshaft. Remove the camshaft gear and timing chain together from the camshaft and crankshaft gears. Inspect crankshaft gear for wear. Inspect crankshaft sprocket for wear - if worn, remove using appropriate puller and install new sprocket (ensure keyway alignment).
   Torque spec

   Camshaft Sprocket Bolts80 Nm (59 lb-ft)
9. 9

   Inspect Components and Prepare for Assembly
   Inspect all removed timing components for wear: chain guides should have minimal scoring or grooving, sprocket teeth should be sharp without hooking or wear patterns, tensioner ratchet mechanism should operate smoothly. Clean all timing component mounting surfaces on engine block and cylinder heads. Install new crankshaft sprocket if removed, ensuring keyway is properly aligned and sprocket is fully seated. Verify crankshaft is still at TDC position.
10. 10

    Install New Timing Chain and Sprockets
    Ensure crankshaft is at TDC with keyway at 12 o'clock position. Route new timing chain around crankshaft sprocket with timing mark positioned correctly. Route the new timing chain around the crankshaft gear and camshaft gear with the timing dots aligned (dot-to-dot). Install the camshaft gear onto the camshaft, aligning the dowel/keyway. Verify both timing dots are aligned before proceeding. Install camshaft holding tools and install camshaft sprocket bolts hand-tight initially.
    Torque spec

    Camshaft Sprocket Bolts80 Nm (59 lb-ft)
11. 11

    Install Timing Chain Guides
    Install timing chain guides in their original positions, noting any left/right or upper/lower specific guides. Install guide mounting bolts and torque to specification. Ensure guides contact chain smoothly without binding and that chain has proper engagement with all sprockets throughout its length.
    Torque spec

    Timing Chain Guide Bolts12 Nm (9 lb-ft)
12. 12

    Install Timing Chain Tensioners
    Compress new timing chain tensioners fully and lock in compressed position using tensioner pins or locking mechanism provided with new tensioners. Install tensioners into engine block positions and install mounting bolts, torquing to specification. After both tensioners are installed and bolted, remove locking pins to allow tensioners to apply pressure to chain. Verify chain has slight tension and that tensioners have extended properly.
    Torque spec

    Timing Chain Tensioner25 Nm (18 lb-ft)
13. 13

    Torque Camshaft Sprocket Bolts and Verify Timing
    Torque the camshaft gear retaining bolt(s) to specification. Verify the timing dots remain aligned. Manually rotate engine two complete revolutions clockwise (using socket on crankshaft nose) and verify timing marks realign perfectly at TDC cylinder #1. If marks do not align, timing chain installation must be corrected before proceeding.
    ⚠️Do not proceed to timing cover installation until timing mark alignment is verified through two complete engine rotations. Incorrect timing will cause catastrophic engine damage.
    Torque spec

    Camshaft Sprocket Bolts80 Nm (59 lb-ft)
14. 14

    Install New Timing Cover Seals and Gasket
    Install new crankshaft front seal into timing cover using appropriate seal driver or large socket - seal should be flush with cover surface or slightly recessed per manufacturer specification. Install new camshaft seals into timing cover for both left and right camshaft positions using seal driver. Clean timing cover and engine block mating surfaces with brake cleaner and allow to dry. Install new timing cover gasket onto engine block, using small dabs of RTV in corners if specified. Apply thin bead of RTV sealant to areas where timing cover meets oil pan rail (typically lower corners).
15. 15

    Install Timing Cover
    Carefully position timing cover over crankshaft nose and camshaft ends, ensuring gasket remains in position. Start all timing cover bolts by hand, ensuring correct bolt lengths are in correct positions (refer to notes from removal). Tighten timing cover bolts in spiral pattern from center outward to specification. Allow RTV sealant to cure for time specified on product (typically 15-30 minutes minimum before adding fluids).
    Torque spec

    Timing Cover Bolts12 Nm (9 lb-ft)
16. 16

    Install Harmonic Balancer
    Clean crankshaft nose and inner bore of harmonic balancer. Apply small amount of clean engine oil to crankshaft nose. Align harmonic balancer with crankshaft keyway and slide onto crankshaft nose by hand as far as possible. Install new crankshaft bolt (if TTY type) or cleaned original bolt with clean threads. Use holding tool and torque crankshaft bolt to the factory-specified value and any torque-angle sequence (verify exact torque spec against the 2008 Viper 8.4L FSM before assembly). Verify balancer is fully seated against crankshaft timing gear.
    Torque spec

    Crankshaft Sprocket Bolt180 Nm (133 lb-ft) + 90°
17. 17

    Reinstall Front Engine Mount and Remove Support
    Reinstall front engine mount bracket and through-bolt with fasteners torqued per specification. Carefully remove engine support fixture or hoist only after mount is fully secured. Verify engine sits properly in mounts without strain.
18. 18

    Reinstall Cooling System and Accessories
    Install water pump with new gasket, torquing bolts to specification in cross pattern. Reinstall thermostat housing with new gasket or O-rings. Reconnect all coolant hoses (upper radiator, lower radiator, heater hoses). Install A/C compressor and torque mounting bolts. Install alternator and reconnect wiring. Install power steering pump and torque mounting bolts. Install drive belt tensioner. Install serpentine belt per routing diagram.

Reassembly

1. Reinstall engine decorative cover
2. Fill engine with 11 quarts of 0W-40 full synthetic engine oil and new oil filter
3. Fill cooling system with 19 quarts of Mopar HOAT 50/50 coolant mixture, burping system to remove air pockets
4. Reconnect negative battery cable
5. Before starting engine, verify no tools or parts remain in engine bay

Verification

• With spark plugs still installed, manually rotate engine through several complete revolutions using breaker bar on crankshaft bolt - verify smooth rotation with no binding or unusual resistance
• Start engine and immediately verify oil pressure on gauge - shut down immediately if no pressure within 5 seconds
• Allow engine to idle and reach operating temperature while monitoring for coolant leaks, oil leaks, and unusual noises from timing area
• Listen for any timing chain noise or tensioner rattle - properly installed system should be nearly silent
• Verify no check engine codes related to camshaft/crankshaft position correlation (these would indicate timing error)
• After initial warm-up and cool-down, recheck coolant level and top off as needed
• Test drive vehicle and verify normal power delivery and smooth operation through RPM range

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