52391 Mercury COVER, TRANSFER PORT

Illustration 1 g01357452 (1) Measure the amount of the warpage of the cylinder block with a straightedge and feeler gauge. Maximum allowable clearance ... 0.05 mm (0.002 inch)Repair limit ... 0.20 mm (0.008 inch)Resurface the top of the block if the repair limit is reached.
Illustration 2 g01357453 (2) Measure the inside diameter of the cylinder sleeve that is parallel to the crankshaft. Measure the inside diameter of the cylinder liner that is in a perpendicular position to the crankshaft. Measure the top, the middle and the bottom of the cylinder liner. Refer to Table 1 for tolerances of the cylinder liner.
Table 1
Tolerances of Cylinder Sleeves
Standard at Assembly Repair Limit(1) Service Limit(2)
Inside Diameter 102.010 to 102.045 mm (4.0161 to 4.0175 inch) 102.200 mm (4.0236 inch) 102.700 mm (4.0433 inch)
Out of Round 0.010 mm (0.0004 inch) N/A N/A
Taper 0.015 mm (0.0006 inch) N/A N/A
(1) The repair limit is the maximum dimension or the repair limit is the minimum dimension that is specified for a part. Repair a part if the repair limit is reached.
(2) The service limit is the maximum dimension or the service limit is the minimum dimension that is specified for a part. Replace the part if the service limit is reached.Bore the cylinder to the specified oversize dimension if the inside diameter reaches the repair limit but the inside diameter does not reach the service limit. Refer to Table 2.Hone the liner to +0.25 mm (+0.010 inch) or +0.50 mm (+0.020 inch) oversize. Hone the liner to an accuracy within 0.010 to 0.045 mm (0.0004 to 0.0018 inch).Determine the oversize dimension that is necessary in order to clean up the cylinder if any liner has uneven wear.Replace all cylinder liners that are in excess of the service limit.Note: Refinish all liners to the same oversize dimension. Use a ridge reamer in order to cut the ridge of the cylinder if the liner is in good condition. Hone the cylinder bore.
Table 2
Oversize Bore Cylinder Bore Size
0.250 mm (0.0100 inch) 102.260 mm (4.0260 inch)
102.295 mm (4.0274 inch)
0.500 mm (0.0197 inch) 102.510 mm (4.0358 inch)
102.545 mm (4.0372 inch)
Illustration 3 g01357454 (3) Service limit of cylinder liner ... 102.700 mm (4.0433 inch)Note: Replace all cylinder liners that exceed the service limit.Use the following procedure in order to replace the cylinder liners.
Set up a boring machine on the cylinder block. Align the boring machine with the center of the bottom of the cylinder liner with the least worn area.
Bore the liner until the thickness is 0.50 mm (0.020 inch).
Remove the remainder of the liner. Be careful not to damage the cylinder block.
Install a new liner. Align the liner with the top of the cylinder block.
The bore of the cylinder must be 102.000 to 102.035 mm (4.0157 to 4.0171 inch). Diameter for the main bearing bores ... 95.000 mm (3.7402 inch)Maximum diameter of the main bearing bores ... 95.022 mm (3.7410 inch)New height of deck from centerline of crankshaft to deck ... 307.00 0.05 mm (12.086 0.002 inch)Minimum height from the centerline of crankshaft to deck ... 306.70 mm (12.075 inch)