Cummins/Onan DJ30 — Time Injection Pump - Depth Micrometer Method
Adjustments
For the Cummins/Onan DJ30, from the Cummins/Onan service manual.
Applies to: Onan (Onan Division of Studebaker Corporation, Minneapolis, Minnesota) Spec T, Cummins/Onan DJA engine
Before you start
- Injection pump must be timed on the compression stroke, not the exhaust stroke
Procedure
- Install pump tappet in its recess and position flywheel on port closing mark of compression stroke.
- Measure distance from pump mounting pad to tappet center with a depth micrometer.
- Subtract that depth from the pump port closing dimension of 1.670 inch.
- Result is the shim thickness required; shims vary from 0.006 to 0.052 inch.
- Select the correct shims and install the pump.
Tools required
- Depth micrometer Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Port closing dimension 1.670 inch
- Shim range 0.006 to 0.052 inch
Full service-parts list: Onan (Onan Division of Studebaker Corporation, Minneapolis, Minnesota) Spec T →
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.