The YANMAR 6N21AL is one of the most common generator engines on bulk carriers, tankers and general cargo ships built in Asia. Its cylinder heads are robust, but a head overhaul tends to reveal more than the planned scope.
When a requisition only lists the parts the crew expects to change, the vessel often ends up placing a second urgent order once the head is open. A complete list avoids that.
A practical cylinder head list
- Inlet and exhaust valves, with valve seats if the seats are recut beyond limits
- Valve guides, valve stem seals and valve rotators
- Valve springs and cotters, checked against free length
- Cylinder head gasket, O-rings for cooling water and the fuel injector sleeve
- Indicator cock and safety valve gaskets
- Fuel injection valve nozzle and its copper washer
Check whether the engine has been modified or uprated. Valve and seat parts differ between engine builds, so the engine serial number matters as much as the model.
Send us the engine serial number and the parts list from your manual and we will check the current part numbers before quoting.