Cummins/Onan NTA855 — Angular Alignment Procedure (Generator to Engine)
Adjustments · Generator / engine flywheel coupling
For the Cummins/Onan NTA855, from the Cummins/Onan service manual.
Applies to: Cummins/Onan DFAA, Cummins/Onan DFAB, Cummins/Onan DFAC, Cummins/Onan DFBF, Cummins/Onan DFCB, Cummins/Onan DFCC, Cummins/Onan DFCE, Cummins/Onan DFE, Cummins/Onan LTA10 engine, Cummins/Onan NT855 engine, Cummins/Onan NTA855 engine, Cummins/Onan KTA19 engine
Before you start
- Accidental starting during this procedure presents the hazard of severe personal injury or death.
- Do not bar engine over by prying on fan blade.
Procedure
- Disconnect the negative (-) battery cable(s) before beginning.
- Fasten a dial indicator to the generator shaft or cooling fan with sensing point resting on the drive disc capscrew head/flat surface at the bolt circle diameter.
- Bar the engine over in a clockwise rotation as viewed from the engine flywheel; do not allow it to roll back on compression at the end of travel of each reading.
- Record the total indicator reading (T.I.R.) as the sum of the maximum positive and negative dial indicator readings over one engine revolution.
- Compare the measured T.I.R. to the maximum allowed (.001 in. per inch of radius from center of shaft to indicator axis); add or remove shims under the generator mounting feet to correct.
Tools required
- dial indicator Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Max T.I.R.: .001 in. per inch of radius
Full service-parts list: Cummins/Onan DFBF →, Cummins/Onan DFCC →, Cummins/Onan DFCE →, Cummins/Onan DFE →
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.