813278 Mercruiser HOUSING

Start By:a. remove oil pump1. Check the identification marks on the connecting rods and caps as to their location in the engine. The caps must be installed in original positions in the engine.2. Turn the crankshaft until two of the pistons are at bottom center. 3. Remove connecting rod caps (1) from the connecting rods. Remove the lower half of the bearings from the caps.
Be careful not to damage the crankshaft journals. Do not turn the crankshaft while any of the connecting rod caps are removed.
4. Push the connecting rod away from the crankshaft, and remove the upper half of the bearings from the connecting rods.5. Make sure the surface of the connecting rod where the bearings make contact is clean and free of dirt.
Make sure the tabs on the bearings are in alignment with the notches in the connecting rods and caps.
6. Install the upper half of new bearings in the connecting rods.7. Pull the connecting rod down slowly on the crankshaft.
Make sure the surfaces where the bearings make contact in the caps are clean and free of dirt.
8. Install new bearings (2) in the caps. Make sure the tabs on the bearings are in alignment with the notches in the caps.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 installing 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 And Crankshafts, Form No. SEBD0531.9. Put 2P-2506 Thread Lubricant on the threads of the bolts in the connecting rods.10. Check the bearing clearance with Plastigage (A) 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. Make sure the numbers on the caps and connecting rods are the same and are on the same respective side. If new connecting rods are installed, put the cylinder number on the rods and caps. b. Put caps (1) and Plastigage (A) in the correct position on the connecting rods. Install the nuts that hold them. c. Tighten the two nuts evenly to a torque of 80 8 N m (60 6 lb ft). Put a mark on each nut, and tighten the nuts 120 5 degrees more from the marks.d. Remove the caps from the connecting rods and Plastigage (A). Measure the thickness of the Plastigage. The connecting rod bearing clearance must be 0.071 to 0.168 mm (.0028 to .0066 in) for new bearings and maximum permissible distance for worn bearings 0.25 mm (.010 in).e. Put clean engine oil in the bearing caps, and install them again. Follow the tightening procedure in Step 10c.f. Do Steps 1 through 10 for the other connecting rod bearings.End By:a. install oil pump