Cummins/Onan 6.5NH - 3CR / 6000 A — Timing Gears Replacement

Repair & overhaul

For the Cummins/Onan 6.5NH - 3CR / 6000 A, from the Cummins/Onan service manual.

Applies to: Cummins/Onan NH engine

Procedure

1. If either the crankshaft gear or camshaft gear is replaced, install both gears new, never one only.
2. Remove the snap ring first, then use a gear puller ring and gear puller to remove the crankshaft gear.
3. The camshaft gear is pressed on and keyed; remove the camshaft and gear as an assembly.
4. Before removing the camshaft and gear assembly, remove the cylinder head and valve assemblies, the breaker point operating plunger, the fuel pump and tappets.
5. Press the camshaft out of the gear with a hollow tool that fits over the camshaft center pin; do not press on the center pin.
6. When installing, ensure the gear teeth mesh so the stamped O marks coincide exactly.
7. Be sure the thrust washer is in place behind the camshaft gear; replace the camshaft retaining washer and crankshaft lock ring.

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.

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