If a diesel engine’s cooling water treatment is not maintained perfectly or if the cooling water pressure is too low, then it can happen that the engine block and cylinder liner get damaged by cavitation over time.

Cavitation on the engine block (left) and the cylinder liner (right)
Cavitation on the engine block (left) and the cylinder liner (right)
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If the damage is severe, then the o-rings cannot do their job anymore and cooling water will leak from the cooling water space around the cylinder liners into the engine crankcase. If this happens, then the situation should be rectified as soon as possible because water in the lubricating oil is potentially very dangerous and can lead to a number of serious problems such as corrosion and bearing seizures.

The best remedial action is to re-machine the engine block in-situ and to shrink in a repair sleeve. This way of repairing can be done on any engine type and offers a permanent solution. At the same time the o-ring grooves in the cylinder liner should be repaired too, or the liner should be replaced by a new one. This will ensure that no cooling water can leak into the engine lubricating oil anymore.

QuantiServ carries out this work in a turn-key fashion, guaranteeing the result. The process normally involves the following steps:

1) Dismantling of the engine: Removing the cylinder cover, piston, connecting rod, cylinder liner and, depending on the engine type, the cylinder head studs on all affected units

2) Installation of the boring machine in the engine block

3) Temporarily sealing off the bottom of the cylinder bore to ensure that no machining chips fall into the crankcase

4) Machining of the bore to over-size. The machining tolerances are very stringent and the alignment is absolutely critical.

5) Thorough cleaning of the cylinder bore

6) Installation of a repair sleeve. We normally have these available in stock for most common engine types.

7) Water pressure test to ensure that there are no leaks

8) Careful cleaning of the crankcase to remove any metal chips

9) Reassembling the engine

10) Engine testing and recommissioning

Engine block machining, prior to the installation of sleeves. Different machines are used on different engine types
Engine block machining, prior to the installation of sleeves. Different machines are used on different engine types
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Cylinder liners with damaged o-ring grooves can be repaired by metal spraying. This work can obviously not be done on board or in the power plant because it needs machinery that is not portable. Any of the six QuantiServ reconditioning centres are equipped to carry out this work and have, between themselves, been repairing hundreds of liners of all makes and sizes in this way.

O-ring grooves on a four-stroke cylinder liner severely damaged by cavitation. Prior to repair (left) and once completed (right)
O-ring grooves on a four-stroke cylinder liner severely damaged by cavitation. Prior to repair (left) and once completed (right)

Image Gallery

In-situ machining the upper guiding bore
In-situ machining the upper guiding bore
In-situ machining the lower guiding bore
In-situ machining the lower guiding bore
Repair rings installed and machined
Repair rings installed and machined