Vintage Bus Gardner 6HLW Engine Rebuild

I was asked to investigate the cause of engine seizure and to ascertain the subsequent damage as a result of it seizing.

The engine is mounted horizontally under the bus at mid-ships which makes for a comparative easy strip down without the need to remove the engine (see photo 1).

Once the cylinder heads had been removed the cause of the engine seizure was evident by the fact that the ports at the bottom of the front cylinder block designed to flow cooling water from the cylinder block to the cylinder head were blocked with rust and lime-scale (see photo 2).

The result of overheating had caused the front cylinder liners to come loose in the block and as the pistons seized they dragged the liners down into the crankshaft causing irreparable damage to the liners and pistons (see photos 3 & 4).

Luckily no damage was caused to the crankshaft which needed no further attention (see photo 5).

By using a donor engine purchased locally we were able to replace the damaged front cylinder block and pistons, and using specially made head gaskets we were able to rebuild the engine which is now running and back in service. The final photo shows the engine rebuild near completion.

As parts for this engine are no longer in production, it was necessary to have some of the components made to order by specialist companies.

Gardiner engine 1Gardiner engine 2 Gardiner engine 3
Gardiner engine 5 Gardiner engine 6 Gardiner engine 7