Cummins/Onan 4.0 BF-1R/9500 — Cylinder Head Removal and Installation
Maintenance · Cylinder heads
For the Cummins/Onan 4.0 BF-1R/9500, from the Cummins/Onan service manual.
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Before you start
- Do not remove heads when they are hot; warpage may occur
Procedure
- Use 1/2 inch socket wrench to remove cylinder head nuts; lift heads off
- Clean out all carbon deposits; do not damage outer sealing edges
- Use new head gaskets and clean heads and cylinder block thoroughly
- Place heads in position and follow head torque tightening sequence
- Start by tightening all nuts to 5 ft-lb, then 10 ft-lb, etc., until all nuts torqued 14-16 ft-lb
- Recheck torque before engine has run a total of 50 hours
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Head torque 14-16 Amazon eBay FridayParts $135.00 ft-lb
- Recheck torque before 50 hours
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.