LO 8-13 Outline the scope of cylinder block service and describe common service operations
1. Cylinder Block Service
1.5. Liner Protrusion
LO 8-13: Outline the scope of cylinder block service and describe common service operations. |
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Liner Protrusion Wet liners protrude or extend 0.001–0.01" (0.025–0.254 mm) above the cylinder block deck Figure 90. This extension is necessary to project clamping forces from the cylinder head onto the liner flange and hold it in place. Measuring and adjusting protrusion is one of the most critical operations when rebuilding a sleeved engine. In most engines, variations between individual liner protrusions must be no more than 0.002–0.005" (0.051–0.127 mm) between the highest and the lowest liner. Liner flanges must also be perfectly parallel with the block deck, typically within 0.001–0.002" (0.025–0.051 mm). Problems with the liner flange or counterbore or a twisted O-ring will tilt a liner. The liner must be removed and reinspected before reinstalling. A liner must be clamped into place after installation in order to measure protrusion Figure 91. After installing and correctly tightening hold-down clamps on engine block liners to specifications, a dial indicator on a sled is used to measure the projections Figure 92. When placed on the block deck, the dial indicator depth gage is set to 0. The depth gauge is then moved to the liner flange and its height above the block deck is measured. Three or four points around each liner are measured and recorded. After all liners are measured and no defects are found, the hold-down clamps can be removed. |
FIGURE 08-90: Liner protrusion is the projection of the liner flange above the block deck. |
FIGURE 08-91: Liners need to be clamped in place before measuring protrusion. |
FIGURE 08-92: Liner protrusion is measured by comparing the block deck height to the height of the liner flange. |
Note that if one liner is slightly lower than adjacent liners, a leak path for combustion gases and coolant can form. If the variation is great, it might even warp the cylinder head. Variation will cause liner movement, which will damage both the counterbore and the cylinder head. If one liner is slightly higher than the others, it will have the same result of leakage and warpage. The liner will not move, but the concentration of cylinder head clamping forces on the higher liner can crack the flange. If protrusion is very high, tightening the cylinder head over the liner could warp and even crack the cylinder head.
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