Cummins/Onan NTA855 — Axial Alignment Procedure
Adjustments · Generator shaft/engine crankshaft axis
For the Cummins/Onan NTA855, from the Cummins/Onan service manual.
Applies to: Cummins/Onan DFAB, Cummins/Onan DFAC, Cummins/Onan DFBF, Cummins/Onan DFCC, Cummins/Onan DFCE, Cummins/Onan NTA855, Cummins/Onan LTA10 engine, Cummins/Onan NT855 engine, Cummins/Onan NTA855 engine
Procedure
- Fasten dial indicator holding device to skid base, engine block, or generator shell with magnetic base or clamp.
- Position sensor point on generator shaft hub.
- Bar engine over clockwise through a couple of rotations.
- Record indicator readings in eight equally spaced points around shaft diameter to obtain T.I.R.
- If out of tolerance, remove capscrews connecting drive discs and flywheel; mark discs and flywheel.
- Rotate engine or generator so disc holes are repositioned 180 degrees; retorque and recheck.
- If T.I.R. unchanged, rotate discs to 30, 60 or 90 degrees from original location.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Optimal T.I.R. runout would be .000 inches
- Reduce measured T.I.R. runout by one half
Full service-parts list: Cummins/Onan DFBF →, Cummins/Onan DFCC →, Cummins/Onan DFCE →
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.