I attended a locomotive engine recently with our senior machinist, Gary.
We were there because the operator had reported water leaks from five of the cylinder heads in the engine.
After removing them, we discovered that the O ring grooves in the block that seals against the cylinder head had corroded, allowing water to bypass the O rings.
Once we’d masked up all openings in the cylinder heads, Gary got to work on the repair, using his magnetic drill to drill out the crankcase and remove the damaged material.
All swarf was removed from the hole using a flexible magnet. Precise depth measurements were taken, and upon return to our workshop, Gary machined bespoke inserts for each hole.
These inserts were fitted into their respective holes which returned the crankcase to OEM spec.
Having these capabilities to call upon has allowed the operator to avoid lengthy downtime and the cost of replacing their cylinder heads.