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Autopapyrus · Foton Auman Cummins ISG 11.8 (2023)
https://autopapyrus.com/guides/foton/auman/cylinder-head-removal-and-installation/
Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Foton Auman Cummins ISG 11.8 (2023): Cylinder Head Removal and Installation

Removing and installing the cylinder head on the Cummins ISG 11.8 is a major job. It requires following the correct disassembly sequence, tightening the head bolts in several stages, and checking the head's flatness before installation. The ISG engine is an inline six with a Single Cam In Head design (one camshaft in the head), high torque and a Common Rail fuel system.

Difficulty: Hard Time: 8-12 hours Steps: 25 Tools: Torque wrench (calibrated, up to 450 N·m (332 lb-ft)), ¾" drive sockets, extensions, hoist or crane (the cylinder head weighs 150-200 kg), feeler gauge set, dial indicator, straightedge for checking flatness, wrench set, containers for draining fluids, marker for numbering bolts.

Part

  • 🔩 Cylinder head gasket kit (upper and lower), cylinder head bolts (replaced every time the head is removed. They are single-use, angle-torque tightening method). Cylinder head gasket for ISG11/ISG12, exact name: cylinder head gasket kit Cummins ISG (contains the cylinder head gasket, manifold gaskets, seals)

Step by step

25 steps
  1. Disconnect power from the vehicle: remove the negative battery cable, and drain the coolant from the block and radiator into a clean container (cooling system capacity is about 50-60 liters (13.2-15.9 gal)). Drain the engine oil.
  2. Remove the air intake path: the pipes from the intercooler to the intake manifold. Remove the turbocharger (disconnect the oil supply and drain lines; the exhaust manifold uses 4-6 M10 studs, tightening torque at assembly 45-55 N·m (33-41 lb-ft)).
  3. Disconnect the high-pressure fuel lines from the Common Rail injectors. Work carefully, because the fuel is under residual pressure. Plug the openings with clean caps. Mark each line with a marker (the connection order is critical).
  4. Remove the valve cover: unscrew the bolts around the perimeter (installation torque 25-30 N·m (18-22 lb-ft)), and carefully lift the cover straight up (do not damage the gasket if you plan to reuse it, although replacement is recommended).
  5. Remove the intake manifold: disconnect the exhaust gas recirculation (EGR) pipes and the temperature and pressure sensors. Unscrew the manifold mounting bolts (usually 8-12 M8-M10 bolts).
  6. Remove the exhaust manifold, if it was not removed together with the turbocharger. Check the studs for stripped threads (a common problem on diesels with high exhaust temperatures).
  7. Mark or photograph the position of the rocker arms and pushrods (if the design includes them. On the ISG the camshaft is in the head, but check for adjusting shims under the valve lifters). Unscrew the rocker arm shafts, remove the pushrods and number them, since each one must go back in its original position.
  8. Loosen the cylinder head bolts in the reverse of the tightening sequence, starting from the edges and working toward the center. Loosen gradually (¼ turn per pass) to avoid warping the head. There are usually 24-30 bolts (depending on the ISG11 vs. ISG12 version). The bolts are single-use, so discard them after removal.
  9. Install lifting eye bolts in the threaded holes at the edges of the cylinder head (if the design provides for them), and attach the head to a crane or hoist. Lift the head evenly. It weighs 150-200 kg, so lift it strictly vertically, avoiding tilting and snagging on the guide bushings.
  10. Place the cylinder head on a clean workbench with the combustion chambers facing up. Inspect the sealing surface for cracks (especially between the valve seats), corrosion, and gasket burn-through. Check flatness with a straightedge and feeler gauge. The flatness tolerance for diesels is usually no more than 0.05-0.10 mm over the length of the head. If it is exceeded, have the head resurfaced (remove no more than 0.3-0.5 mm over the entire service life, or the compression ratio will change).
  11. Clean the cylinder block surface of any remains of the old gasket. Use a plastic scraper (not a metal one, to avoid scratching the aluminum). Wipe the surface with a lint-free cloth moistened with solvent. Check the block flatness, with the same tolerance.
  12. Check the condition of the cylinder liners (if they are removable. The ISG usually has pressed-in liners). Make sure the liners do not protrude above the block surface (check with a dial indicator, tolerance 0.00-0.05 mm).
  13. Place the new cylinder head gasket on the block, orienting it on the dowel pins (usually 2-4 pins at the corners of the block). The gasket is marked UP or TOP, and that side faces the head. Do not coat the gasket with sealant (modern metal gaskets do not need it).
  14. Lower the cylinder head onto the block, making sure the dowels enter the holes in the head without binding. Install the new cylinder head bolts by hand in all the holes.
  15. Tighten the cylinder head bolts with a torque wrench in 4 stages (typical procedure for the Cummins ISX/ISG family. Confirm the exact values in service bulletin 4332695 for the ISG11 or 4332690 for the ISG12): • Stage 1: preliminary tightening of all bolts to 60-70 N·m (45-50 lb-ft) in sequence from the center outward. • Stage 2: tighten to 150 N·m (110 lb-ft). • Stage 3: turn each bolt an additional 90° (¼ turn) in the same sequence. • Stage 4: final additional turn of 90° (180° total after stage 2). Sequence: start with the center bolts and work diagonally toward the edges. Bolt numbering follows the diagram in the manual (usually in pairs: 1-2 in the center, then 3-4, 5-6 and so on in a spiral).
  16. Install the pushrods and rocker arms in their original positions (according to the numbering). Tighten the rocker arm shafts to 40-50 N·m (30-37 lb-ft) (exact value in the manual).
  17. Adjust the valve lash: with the engine cold, turn the crankshaft to the TDC marks for each cylinder. Lash for the intake valves is usually 0.25-0.35 mm, and for the exhaust valves 0.40-0.50 mm (exact values are in the maintenance schedule and depend on the ISG version). Use feeler gauges, and adjust with the screw on the rocker arm or by selecting shims (depending on the design).
  18. Install the valve cover with a new gasket and tighten the bolts in a crisscross pattern to 25-30 N·m (18-22 lb-ft).
  19. Install the intake and exhaust manifolds with new gaskets. Manifold tightening torque is 45-55 N·m (33-41 lb-ft). Reconnect the EGR system and sensors.
  20. Install the turbocharger: use new gaskets, coat the studs with high-temperature grease, and tighten the nuts to 45-55 N·m (33-41 lb-ft). Reconnect the oil supply and drain lines (new copper washers under the bolts, torque 25-30 N·m (18-22 lb-ft)).
  21. Reconnect the high-pressure fuel lines. Tighten the flare nuts to 25-30 N·m (18-22 lb-ft) (do not overtighten, or the brass seals will deform). Connect them in the order of the cylinder numbering.
  22. Reconnect the air intake path and the intercooler pipes. Fill with fresh engine oil (capacity for the ISG11/ISG12 is about 28-35 liters (29.6-37.0 qt), exact amount by the dipstick). Fill with coolant and bleed the air pockets (open the bleeder at the highest point of the system and warm the engine until the thermostat opens).
  23. Reconnect the negative battery cable. Crank the engine with the starter without starting it (disable the fuel supply or the injectors) for 10-15 seconds to build oil pressure. Make sure the oil pressure light goes out.
  24. Start the engine and let it warm up at idle for 5-10 minutes. Watch the temperature and oil pressure gauges, and check for coolant and oil leaks from under the cylinder head and manifolds.
  25. Shut off the engine and let it cool for 2-3 hours. Check the cylinder head bolt torque (re-tightening is usually not required for bolts using the angle-torque method, but check that nothing has loosened). Recheck the valve lash (it may change slightly after warm-up).

Common mistakes and warnings

  • The cylinder head bolts on the Cummins ISG are single-use (torque-to-yield, TTY, tightening method). Reusing old bolts will lead to a blown gasket or a broken bolt. The torque wrench must be calibrated before the job. Failing to follow the tightening sequence or torque specification causes head warping, combustion gas leaks and overheating. Working on the Common Rail fuel system requires cleanliness, because dirt getting into the injectors will ruin them. If you find cracks in the cylinder head, replace the head (weld repair does not guarantee a proper seal on high-compression diesels). If you have no experience with heavy-duty diesels, leave the job to a certified Cummins or Foton service center, because incorrect assembly can destroy the engine.