25439 Mercury O-RING

Start By:a. remove oil pump 1. Check each main bearing cap (2) for its location on the engine. Each cap has an arrow (1) to show the front of the block and a number (3) which gives the location of that cap.2. Remove No. 2 through No. 4 main bearing caps from the engine. Remove the lower bearings from the caps.3. Remove the thrust plate from each side of the No. 3 upper main bearing.
If the crankshaft is turned in the wrong direction, the tab of the bearing will be pushed between the crankshaft and the cylinder block. This will cause damage to the crankshaft and block.
4. Turn the crankshaft until Tool (A) can be installed in oil hole (4). Turn the crankshaft in the direction which will push the upper main bearing out, tab end first. Install the main bearings dry when clearance checks are made. Put clean engine oil on the main bearings for final assembly.5. Install the lower bearings in the bearing caps.6. Install the upper bearing in the cylinder block with Tool (A). Be sure tab (5) on the back of the bearings fits in the groove of the caps and cylinder block.The serviceman must be very careful to use Plastigage correctly. The following points must be remembered:... Make sure that the backs of the bearings and the bores are clean and dry. ... Make sure that the bearing locking tabs are properly seated in their slots.... The crankshaft must be free of oil where the Plastigage touches it.... Put a piece of Plastigage on the crown of the bearing half that is in the cap. Do not allow the Plastigage to extend over the edge of the bearing.... Install the bearing cap using the correct torque-turn specifications. Do not use an impact wrench. Be careful not to dislodge the bearing when the cap is installed.... Do not turn the crankshaft with the Plastigage installed.... Carefully remove the cap but do not remove the Plastigage. Measure the width of the Plastigage while it is in the bearing cap or on the crankshaft journal. Do this by using the correct scale on the package. Record the measurements.... Remove the Plastigage before reinstalling the cap.When using Plastigage, the readings can sometimes be unclear. For example, all parts of the Plastigage are not the same width. Measure the major widths to make sure that they are within the specification range. Also, experience has shown that when checking clearances tighter than 0.10 mm (.004 in) the readings may be low by 0.013 to 0.025 mm (.0005 to .0010 in). Out-of-round journals can give faulty readings. Also, journal taper may be indicated when one end of the Plastigage is wider that the other.For complete details concerning measuring bearing clearances, see Engine Bearings & Crankshafts, SEBD0531.7. Check the bearing clearance with Tool (B) as follows:
When Plastigage is used to check bearing clearance, do not use an impact wrench for the torque tightening sequence. However, an impact wrench can be used for the final tightening torque.
a. Put Tool (B) in position as shown.b. Put 2P-2506 Thread Lubricant on the threads of the cap bolts. Install the caps and cap bolts, finger tight.c. Tighten the bolts on the tab end of the caps first to a torque of 260 14 N m (190 10 lb ft).d. Tighten the bolts on the other end of the caps to a torque of 260 14 N m (190 10 lb ft). e. Put a mark across the bolt head and cap. Tighten the bolts opposite the tab end 120 5 degrees. Tighten the bolts on the tab end of the cap 120 5 degrees more. Make sure the main bearing caps are installed with their identification number (7) in alignment with the identification number on the left side of the cylinder block and arrow (6) toward the front of the block.8. Remove the main bearing caps and Tool (B).9. Measure the width of the Plastigage to determine the bearing clearance. The clearance for new bearings must be 0.091 0.186 mm (.0036 to .0073 in). The maximum clearance for used bearings is 0.25 mm (.010 in).10. Install a thrust plate (8) on each side of the No. 3 upper bearing. Install the thrust plates with the side marked "BLOCK SIDE" toward the cylinder block.11. Put clean engine oil on the bearings. Install No. 2 through No. 4 main bearing caps. Follow the procedure in Step 7 to tighten the bolts.12. Do Steps 2, 4 through 9 and 11 for the No. 1 and No. 5 main bearings.
Typical Example13. Check the end play of the crankshaft with Tool (C). Make sure the dial indicator is against a machined surface. End play for new thrust plates must be .13 to .50 mm (.005 to .020 in). The maximum end play with used thrust plates is 0.89 mm (0.035 in).End By:a. install oil pump