Cylinder liners worn beyond the maximum allowable limit should be replaced. You will find the maximum allowable wear limits for engines in the appropriate manufacturers technical manual or the Diesel Engine Wear Limit Chart available from the Naval Sea Systems Command. In the absence of such specific information, the following wear limits (established by NAVSEA) apply in general to

1. two-stroke cycle engines with aluminum pistons: 0.0025 inch per inch diameter,

2. slow-speed engines over l8-inch bore: 0.005 inch per inch diameter, and

3. all other engines: 0.003 inch per inch diameter. If you must remove a liner, follow the instructions given on the appropriate maintenance requirement card (MRC) or in the manufacturers technical manual for the particular type of engine. Figure 3-9 illustrates the method generally used to remove a cylinder liner.

To remove the cylinder liner, proceed as follows:

1. Drain the water from the engine.

2. Remove the cylinder head.

3. Remove the piston(s).

Figure 3-9.Removing a cylinder liner.

4. Attach the special liner puller to the liner studs and tighten the nuts by hand. (The nuts must be hand tightened; if a wrench is used, the threads on both the nuts and the studs may be damaged.)

5.Attach the hook of the chain fall and pull slightly until the liner breaks free (fig. 3-9). If the liner fails to break loose immediately, apply pressure at the bottom of the liner. To do this, place a block of wood on the crankshaft throw, and force it up against the liner by rotating the turning gear.

6. Lift the liner up until it clears the top of the engine block and remove it to a safe place. You may need to rotate the liner slightly while removing it from the engine block.