Cummins/Onan — Timing Gear Removal and Installation
Repair & overhaul · Timing gears
From a Cummins/Onan service manual — check it applies to your exact model before use.
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Before you start
- Do not press on the camshaft center pin or damage it in any way.
Procedure
- Install both crankshaft and camshaft gears new, never one only.
- Remove crankshaft gear snap ring, attach gear pulling ring 420A248 with two #10-32 screws.
- Tighten screws alternately and attach gear puller to remove gear.
- Remove crankshaft gear lock ring and washer, then remove camshaft and gear as an assembly.
- Remove cylinder head, valve assemblies, fuel pump and tappets first.
- Press camshaft out of gear with a hollow tool over the center pin; do not press on center pin.
Tools required
- Gear pulling ring 420A248 Amazon
- Gear puller Amazon
- Two #10-32 screws Amazon
- Hollow tool or pipe Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
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.