Cummins/Onan 6.5NH - 3CR / 6000 A — Crankshaft Main Bearing Installation
Repair & overhaul · Crankshaft main bearings
For the Cummins/Onan 6.5NH - 3CR / 6000 A, from the Cummins/Onan service manual.
Applies to: Cummins/Onan NH engine
Before you start
- Breathing vapor from towelette and prolonged contact with skin can be harmful. Be sure area is well ventilated.
Procedure
- Expand the bearing bore by placing the casting in hot water or an oven heated to 200 F; if practical, cool the precision bearing to shrink it.
- Align the oil hole(s) in the bearing with the oil hole(s) in the bearing bore; the oil passage must be at least 1/2 open.
- Install the rear bearing plate bearing flush to 1/64 below the end of the bore using the combination driver.
- For the front bearing, clean the bearing outside and bore with the supplied towelette and apply Locktite Bearing Mount.
- Install the front bearing flush with the block using the combination driver; wipe off excess Locktite and allow at least one hour to harden.
- Lubricate the front main bearing lightly with oil and insert the crankshaft.
- Slide the thrust washer (grooves toward crankshaft) and plate over the crankshaft, lining up notches with the lock pins.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Bearing bore heating 200 F
- Main bearing clearance 0.0015-0.0043 inch
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.