Cummins/Onan — Camshafts - Installation
Repair & overhaul
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- The crankshaft must remain in the freewheeling position until camshafts are installed and valve clearance checked/adjusted.
- Camshaft seal gaps must be at 12 o'clock or damage to engine may occur.
Procedure
- Rotate crankshaft counterclockwise to 9 o'clock freewheeling position.
- Lubricate camshafts with clean engine oil and position in neutral on cylinder head.
- Position camshaft seal gaps at 12 o'clock.
- Install camshaft caps, oil tube and bolts. Tighten: 8 Nm; 45 degrees.
- Loosen camshaft cap bolts, then tighten again: 8 Nm; 45 degrees.
- Confirm valve tappet clearances within specification; adjust with correct size tappets if needed.
- Remove oil tube bolts, rotate camshafts to TDC, install camshaft holding tools 303-1248 and chain tensioner hold down 303-1530.
- Rotate crankshaft clockwise 60 degrees to TDC (crankshaft dowel pin at 11 o'clock).
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Camshaft cap bolts: 8 Nm; 45 degrees
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.