Usage:
All 6.25" (158.8) Bore V8, V12 or V16 Engines that use 1S4618 or 1P9 Connecting Rods.
NOTE: Check the size of the bearing journals for the connecting rods on the crankshaft to be sure of installation of the correct bearings.
The bearings in the above chart have an oversize outer diameter and must be used only with reworked (bore made larger) connecting rods. Measure the bore of the connecting rods according to the procedure given on the pages that follow. If a rod is to be reworked, follow the operation instructions for the machine being used.
Use the 1P3537 Dial Bore Gauging Group to measure the reworked diameter of the connecting rods; instructions for use are with the tool group.
Procedure To Check Connecting Rod Bore
Use the 1P3537 Dial Bore Group with this procedure. The 7S8369 Dial Bore Indicator and the canceled 7S8368 Master Ring Set can also be used.
(1) The diameter of the bore must be within the measurements that follow:
The average of the diameters (A) and (B) must be 5.3845" ± .0010" (136.77 ± 0.03).
The difference between diameters (A) and (B) must not be more than .002" (0.05).
Diameter (C) must be 5.3845" ± .0005" (136.77 ± 0.013).
Bore taper must not be more than .0003" (0.008).
(2) Remove the rod cap and thoroughly clean the bolts, bolt holes and the rod and rod cap serrations (D). Put 4S9416 Antiseize Compound on the bolt threads, shank and head seat. Tighten the bolts to a torque of 40 ± 4 lb. ft. (54.4 ± 5.4 N·m), plus one-third turn. This is the same torque that is used when the rods are installed in the engine.
(3) Adjust the 1P3537 Dial Bore Gauge to show zero at 5.3845" (136.77). Make a chart similar to the example shown below. Measure the three diameters and write the dimensions in the chart as (+) or (-) from the zero setting on the gauge.
(4) Measure (A) and (B) near the center of the bore and approximately .56" (14.2) from the joint, as shown, and write the dimensions in the chart. Find the average of (A) and (B) and write this dimension in the chart.
(5) Find the difference between (A) and (B) and write that dimension in the chart. Measure (C) at a location 90° from serrations (D), and near the center of the bore. Write this dimension in the chart. Make a comparison of the dimensions in the chart with the dimensions given in step 1. Use the examples in the chart below as a guide.
Inspection Of Reworked Connecting Rod
Use a boring machine to do the rework procedure. After the bore for the bearing of the connecting rod has been made larger, do the procedure that follows:
(1) Remove all burrs (sharp edges) from the edge of the bore, joints and the tab slots for the bearings. Check the diameter of bore (A). The diameter of bore (A) must be 5.3945" ± .0005" (137.02 ± 0.013).
(2) Check the surface finish of the bore. The surface finish must be from 25 MU minimum to 100 MU maximum.
(3) Dimension (B), the centerline between reworked bore (A) for the bearing of the connecting rod, and bore (C) for the piston pin, must be 18.000" ± .003" (457.2 ± 0.08). Bore (A) must be round within .0003" (0.008) on the radius and the bore taper must not be more than .0003" (0.008) for the length of the bore.
(4) For rods that have been reworked, mark the rods, as shown, .010 O.S. (0.03). Use .250" (6.3) high stamps (2) to mark the size.