Usage:
POSITIONING PIN BEARING
MARKS FOR TIGHTENING CONNECTING ROD BOLTS
(1) Bore in connecting rod for piston pin bearing ... 2.1825 ± .0005 in.(55.436 ± 0.013 mm)
Tight fit between connecting rod eye and piston pin bearing ... .002 to .004 in.(0.05 to 0.10 mm)
NOTE: Connecting rod must be heated for installation of piston pin bearing. Do not use a torch.
Heat connecting rod to temperature of ... 350 to 500° F (177 to 260° C)
NOTE: Piston pin bearing junction must be assembled within either area "A" (90 ± 10° from the centerline through the connecting rod bores) as shown.
(2) Bore in connecting rod for bearing with nuts tight to specifications (6) ... 4.0748 ± .0005 in.(103.500 ± 0.013 mm)
(3) Distance between center of bearings ... 10.300 ± .002 in.(261.62 ± 0.05 mm)
(4) Bore in bearing for piston pin (new) ... 2.0012 ± .0003 in.(50.830 ± 0.008 mm)
Diameter of piston pin (new) ... 1.9998 ± .0002 in.(50.795 ± 0.005 mm)
Maximum permissible clearance between bearing and piston pin (worn) ... .003 in.(0.08 mm)
(5) Bore in bearing for crankshaft ... 3.8236 to 3.8258 in.(97.119 to 97.175 mm)
Clearance between bearing and crankshaft (new) ... .0028 to .0066 in.(0.071 to 0.168 mm)
Maximum permissible clearance between bearing and crankshaft (worn) ... .010 in.(0.25 mm)
(6) Tightening procedure for connecting rod nuts:
a. Put engine oil on bolt threads and contact surfaces of nut and cap.
b. Tighten both nuts to ... 60 ± 6 lb. ft.(80 ± 8 N·m)
c. Put a mark on each nut and end of bolt as shown.
d. Tighten each nut from mark ... 120 ± 5°
NOTE: Bearings are available in .025 in. (0.64 mm) and .050 in. (1.27 mm) smaller than original size.
Make reference to Special Instruction Form Nos. GMG02394 & SMHS7366 for information to check and recondition connecting rods.
(Straight Pin End)
POSITIONING PIN BEARING
MARKS FOR TIGHTENING CONNECTING ROD BOLTS
6N3911, 6N1828*, 4N371* Connecting Rod Assemblies
(1) Bore in connecting rod for piston pin bearing ... 2.1825 ± .0005 in.(55.436 ± 0.013 mm)
Tight fit between connecting rod eye and piston pin bearing ... .002 to .004 in.(0.05 to 0.10 mm)
NOTE: Connecting rod must be heated for installation of piston pin bearing. Do not use a torch.
Heat connecting rod to temperature of (maximum) ... 350 to 500° F (177 to 260° C)
NOTE: Piston pin bearing junction must be assembled within either area "A" (90 ± 10° from the centerline through the connecting rod bores) as shown.
(2) Bore in connecting rod for bearing with nuts tight to specifications (6) ... 4.0748 ± .0005 in.(103.500 ± 0.013 mm)
(3) Distance between center of bearings ... 10.300 ± .002 in.(261.62 ± 0.05 mm)
(4) Bore in bearing for piston pin (new) ... 2.0012 ± .0003 in.(50.830 ± 0.008 mm)
Diameter of piston pin (new) ... 1.9998 ± .0002 in.(50.795 ± 0.005 mm)
Maximum permissible clearance between bearing and piston pin (worn) ... .003 in.(0.08 mm)
(5) Bore in bearing for crankshaft ... 3.8236 to 3.8258 in.(97.119 to 97.175 mm)
Clearance between bearing and crankshaft (new) ... .0028 to .0066 in.(0.071 to 0.168 mm)
Maximum permissible clearance between bearing and crankshaft (worn) ... .010 in.(0.25 mm)
(6) Tightening procedure for connecting rod nuts:
a. Put engine oil on bolt threads and contact surfaces of nut and cap.
b. Tighten both nuts to ... 60 ± 6 lb. ft.(80 ± 8 N·m)
c. Put a mark on each nut and end of bolt as shown.
d. Tighten each nut from mark ... 120 ± 5°
NOTE: Bearings are available in .025 in. (0.64 mm) and .050 in. (1.27 mm) smaller than original size.
*Connecting rod assemblies 6N1828 and 4N371 were used only with 4N928 Crankshaft Assembly. This crankshaft assembly was effective with production engines with Serial Numbers 92U1 thru 92U2729 and 92U2731 thru 92U2953.
NOTE: Make reference to Special Instruction Form Nos. GMG02394 and SMHS7366 for information to check and recondition connecting rods.