Cummins/Onan — Cylinder Head Installation
Repair & overhaul
From a Cummins/Onan service manual — check it applies to your exact model before use.
Browse Cummins/Onan generators & specs →
Before you start
- Install new cylinder head bolts; they are torque-to-yield and cannot be reused.
Procedure
- Install cylinder head gasket.
- Install cylinder head and new bolts; tighten: 20 Nm, 35 Nm, 90 degrees, 90 degrees, 45 degrees.
- Install M6 bolt. Tighten to 10 Nm (89 lb-in).
- Lubricate valve tappets with clean engine oil and install in original positions.
- Install upper timing chain guide and bolt. Tighten to 10 Nm (89 lb-in).
- Install CMP sensors and bolts; connect CMP electrical connectors.
- Install lower intake manifold and LH/RH camshafts.
- Install new exhaust pipe flange nuts; torque 30 lb.ft (30 Nm).
Specs & values
- Cylinder head bolts: Stage 1: 20 Nm; Stage 2: 35 Nm; Stage 3: 90 degrees; Stage 4: 90 degrees; Stage 5: 45 degrees
- M6 bolt: 10 Nm (89 lb-in)
- Exhaust pipe flange nuts: 30 lb.ft (30 Nm)
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.