Facts About Generators
GeneratorsDirectoryCompareRepairEnginesControllersPartsManufacturersGuides
Search models or part #
Home›Repair guides›Installation of cylinder head assembly

Komatsu — Installation of cylinder head assembly

A Komatsu service procedure — check it applies to your exact model before use.

Browse Komatsu generators & specs →

Before you start

  • When not using tool A8, after applying a paint marking to the cylinder head and bolt, tighten the bolt by 90° to 120° (target 120°).

Procedure

  1. Clean the bottom face, block top face and liner with dry cloth or soaked with a solvent.
  2. Replace a bolt having 5 punch marks to the bolt head.
  3. Tighten the bolt with hand and screw in to the block by turning the bolt at least 2 rounds.
  4. Apply LM-P or engine oil (EO30-CD) to bolt threaded portion and under side of the bolt head.
  5. Tighten the cylinder head mounting bolts in the order indicated in the figure. 1st time: 98.1 ± 9.8 Nm. 2nd time: 166.6 – 176.4 Nm. 3rd time: Tighten bolt 90 to 120° (target 120°) using tool A9.
  6. After tightening bolts 1-6, tighten auxiliary bolt 7.
  7. After tightening the bolt, punch a mark (c) on its head. (Do not punch mark when using a new bolt.)
  8. Feed coolant from the radiator coolant filler to the specified level. Start the engine and allow the coolant to circulate the piping. Check the coolant level.

Tools required

  • Tool A9 (for bolt angle torque)

Specs & torque values

  • Cylinder head mounting bolt 1-6: 1st time: 98.1 ± 9.8 Nm {10 ± 1 kgm}
  • 2nd time: 166.6 – 176.4 Nm {17 – 18 kgm}
  • 3rd time: 90 to 120° (target 120°) using tool A9
  • Cylinder head mounting auxiliary bolt: 66.2 ± 7.4 Nm {6.75 ± 0.75 kgm}
  • Intake manifold assembly: 59 – 74 Nm {6 – 7.5 kgm}
  • Exhaust manifold assembly: 58.8 – 73.5 Nm {6 – 7.5 kgm}

Source: manual:Komatsu PC400-8, PC400LC-8, PC450-8, PC450LC-8, PC400-7, PC400LC-7, PC450-7, PC450LC-7, PC400-6K, PC450LC-6K, PC400-6, PC400LC-6, PC450-6, PC450LC-6.pdf. Figures and steps are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.