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Home›Repair guides›Cummins/Onan›Adjust Valve Clearance (Four-Cylinder Engine)

Cummins/Onan — Adjust Valve Clearance (Four-Cylinder Engine)

Adjustments · Cylinder head / valves

From a Cummins/Onan service manual — check it applies to your exact model before use.

Applies to: Cummins/Onan DJB engine

Before you start

  • Early model four-cylinder engines do not have a BC mark on the flywheel

Procedure

  1. Adjust valve clearance in firing order 1-2-4-3 sequence.
  2. Adjust number 1 cylinder, then turn flywheel clockwise 180 degrees for number 2.
  3. Turn 180 degrees for number 4, then 180 degrees for number 3, adjusting each per steps.
  4. Each position should be 10 to 45 degrees past the BC or TC flywheel mark as applicable.

Tools required

Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.

Specs & values

  • Firing order 1-2-4-3
  • Feeler gauge clearance per Table 4

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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