Mitsubishi — Lapping valves in valve seats
Repair & overhaul · Valves and valve seats
From a Mitsubishi service manual — check it applies to your exact model before use.
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Before you start
- Do not put the lapping compound on the valve stem.
Procedure
- Put a small amount of lapping compound on the valve face; do not put compound on the valve stem.
- Use a lapping tool; rotate valve against seat a part of a turn, raise and rotate to new position, repeat.
- Wash the valve and valve seat with dry cleaning solvent.
- Put engine oil on the valve seat and lap the valve in the seat.
- Check the valve face for contact with the seat.
Tools required
- lapping tool Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Use compound of 120 to 150 mesh for initial lapping and finer than 200 mesh for finish lapping
Source: Mitsubishi 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.