Cummins/Onan FM-JFE2 — Valve Grinding
Repair & overhaul · cylinder head
For the Cummins/Onan FM-JFE2, from the Cummins/Onan service manual.
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Before you start
- Never use a refaced valve that has a thin edge
Procedure
- Remove valve locks by compressing springs and pulling out locks.
- Lift valves from guides.
- Inspect valves; replace if stems worn or bent.
- Reface valve faces to true 45 degree angle if pitted.
- Clean valve stems and guides.
- Apply medium grade valve grinding compound to valve face.
- Insert valve with thin coil spring over stem.
- Rotate valve back and forth with vacuum cup tool using light pressure.
- Lift valve, turn part way in seat, and repeat.
- Grind until bright silvery band extends around valve and seat.
- Wipe off compound and check with pencil marks.
- Replace each valve in its seat.
- Install springs, washers and locks.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- true 45 degree angle
- intake valve clearance .006 to .008 in
- exhaust valve clearance .008 to .010 in
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.