Cummins/Onan — Valve installation
Repair & overhaul · Cylinder head / valve assemblies
From a Cummins/Onan service manual covering: 10.0JC, 12.5JC, 15.0JC, 4.0JB, 5.0JB, 6.0JB, 6.1JB, 7.5JB, 7.6JB. Check it applies to your exact model before use.
Applies to: Cummins/Onan 10.0JC, Cummins/Onan 12.5JC, Cummins/Onan 15.0JC, Cummins/Onan 5.0JB, Cummins/Onan 6.0JB, Cummins/Onan 6.1JB, Cummins/Onan 7.5JB, Cummins/Onan 7.6JB, Cummins/Onan JB engine, Cummins/Onan JC engine
Procedure
- Push a new valve stem oil seal onto each intake valve guide and clamp in place; oil inside surface
- Oil the stem of each valve lightly and insert each in its own guide
- Check each valve for a tight seat with air pressure tester or pencil marks
- Using a valve spring compressor, compress each spring with retainer and insert retainer locks
- Coat both sides of head gasket with Permatex No. 3; install head assembly and gasket
- Tighten head bolts to 28 to 30 lbs. ft. following the sequence in Fig. 60
- Reinstall rocker box cover, air housing and access door
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 28 to 30 lbs. ft. head bolts
Full service-parts list: Cummins/Onan 10.0JC →, Cummins/Onan 12.5JC →, Cummins/Onan 15.0JC →, Cummins/Onan 5.0JB →, Cummins/Onan 6.0JB →, Cummins/Onan 6.1JB →, Cummins/Onan 7.5JB →, Cummins/Onan 7.6JB →
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.