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Autopapyrus · Iveco Stralis Hi-Way 10.3 Cursor 10 (2018)
https://autopapyrus.com/guides/iveco/stralis/valve-lash-and-unit-injector-drive-adjustment/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Iveco Stralis Hi-Way 10.3 Cursor 10 (2018): Valve Lash and Unit Injector Drive Adjustment

The Cursor 10 is an inline six-cylinder engine with four valves per cylinder. The unit injectors are driven from the camshaft through rocker arms. The adjustment is done on a cold engine, following the firing order 1-4-2-6-3-5 and the crankshaft position marks. Check the exact valve lash and unit injector drive preload values for your engine version against the manufacturer's plate or service manual. Below you will find the principle and the sequence.

Difficulty: Hard Time: 5-8 hours Steps: 12 Tools: socket and ratchet set, torque wrench (low range 5-60 N·m (4-44 lb-ft) and high range up to 200 N·m (148 lb-ft)), flat feeler gauge set, ratchet wrench for turning the crankshaft through the drive mechanism (or a pneumatic/electric turning tool), crankshaft/flywheel locking pin from the engine's standard tool kit, dial indicator for checking the position of the unit injector followers, torque screwdriver, clean container for bolts, new valve cover gasket

Part

  • 🔩 cylinder head cover gasket set, and new adjusting screws with locknuts if needed

Step by step

12 steps
  1. Wait until the engine has cooled down (coolant and oil no higher than 40-50 °C (104-122 °F)). Disconnect the battery ground, and secure the cab against accidental starting. Hang a "Do Not Start" sign in the cab.
  2. Clean the area around the valve cover of dirt, then remove the decorative covers, air ducts and any wiring harnesses that are in the way. Disconnect the sensor connectors on the cover. Move the unit injector harness aside carefully, without kinking it or pulling it out of its retainers.
  3. Unscrew the bolts, remove the valve cover and take off the gasket. Inspect the rocker arm assembly for scoring, wear on the pads and adjusting screws, and play in the shaft.
  4. Turn the crankshaft in its normal direction of rotation until the piston of cylinder 1 is at TDC on the compression stroke (the marks on the pulley/flywheel line up, the valves of cylinder 1 are closed, and the rocker arms move freely). Lock the crankshaft with the standard locking pin, if one is provided.
  5. In this position, use a feeler gauge to check the valve lash of the cylinders whose valves are closed, using the "sum" method (for example, with cylinder 1 at TDC, the valves listed in the service manual as paired are the ones you adjust). Values differ for intake and exhaust valves: intake lash is usually smaller than exhaust, with a reference range of about 0.3-0.6 mm. Take the exact figures from the service manual for your engine version.
  6. To adjust, loosen the locknut on the adjusting screw and turn the screw until the feeler gauge drags with slight resistance. Holding the screw with a screwdriver, tighten the locknut and recheck the lash. Use the locknut torque specified in the engine service manual (reference value 30-50 N·m (22-37 lb-ft), confirm the exact value).
  7. If the engine has an engine brake (EVB), the exhaust valves may have an additional lash setting or brake unit with its own adjustment. Perform it separately according to the service manual, and do not mix up the valve screws with the brake drive screw.
  8. Turn the crankshaft to the required angle (following the firing order sequence) and repeat the check for the remaining cylinders until you have gone through all 6. Do not skip any position: an error on one cylinder causes valve overheating or knocking.
  9. The unit injector drive is adjusted on each cylinder when the corresponding cam is on the base circle (the follower at its lowest point, the unit injector rocker arm unloaded). Loosen the locknut on the rocker arm adjusting screw, tighten the screw until it touches the unit injector plunger, then turn it further by the value specified in the service manual (torque or angle), and then lock it with the locknut while holding the screw.
  10. Recheck the preload on all six injectors. Do not overtighten the screw: this puts excessive load on the cam and rocker arm, leading to wear and drive failure, while insufficient preload causes knocking, rough running and loss of power.
  11. Check that the mating surface is clean, then install a new gasket and the valve cover, and tighten the bolts evenly in a crisscross pattern in 2 stages (torque per the engine service manual, usually no more than 10-25 N·m (7-18 lb-ft) for covers of this type). Reconnect the sensors and harness.
  12. Reconnect the battery, start the engine and let it idle for 5-10 minutes. Check for oil leaks, unusual knocking and warning messages on the instrument cluster. After a few hundred km, it is advisable to recheck the tightness and look again for any seepage.

Common mistakes and warnings

  • Always verify all lash, preload and torque values given here as reference figures against the service manual for your specific engine version. An error in the unit injector drive preload leads to serious damage to the cams and rocker arms. If you have no experience with truck diesels, or you do not have the necessary locking tools and equipment, leave the job to a repair shop. Do not loosen fuel lines on a running engine, because of the high fuel pressure. Always lock the engine against turning and against accidental starting.