Cummins/Onan B43 / B48 — Piston and Connecting Rod Installation
Repair & overhaul · pistons
For the Cummins/Onan B43 / B48, from the Cummins/Onan service manual.
Applies to: Cummins/Onan B48
Before you start
- Use ridge reamer to remove cylinder ridge before removing piston.
Procedure
- Lubricate parts with engine oil.
- Position piston on rod and install pin.
- Install oil control ring first, then compression rings with dot or 'top' facing up.
- Turn crankshaft to position No. 1 rod journal at bottom.
- Lubricate piston and cylinder; compress rings with ring compressor.
- Position piston and rod in cylinder; notched side of rod faces camshaft.
- Tap piston down with hammer handle until rod seats on journal.
- Install bearing cap and tighten fasteners to 5 ft-lbs, then 14 ft-lbs.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Connecting rod bolt torque 14 ft-lbs (19 Nm)
Full service-parts list: Cummins/Onan B48 →
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.