SMU-SEC.6-ENG. MECHANICAL CRANKSHAFT & BEARINGS

SUBJECT: SERVICE MANUAL UPDATE - SECTION 6 - ENGINE MECHANICAL - CRANKSHAFT AND BEARINGS INSTALLATION

MODELS: 1997 C, K, G, AND P TRUCKS WITH 6.5L DIESEL ENGINES (VINS S, (VINS S, Y, F - RPOS L56, L57, L65, L65-CMT)

THE ENGINE BLOCK FOR BOTH PRODUCTION AND FOR GMSPO (TARGET ENGINES) ENGINE ASSEMBLIES HAS BEEN MODIFIED. THE CRANKSHAFT BEARING CAP RETAINING BOLT DIAMETER AT POSITIONS 2, 3, AND 4 (OUTER BOLTS ONLY) HAVE BEEN CHANGED FROM 12 MM TO 10 MM. THIS REQUIRES THE USE OF A REVISED TORQUING SEQUENCE. PRIOR TO INSTALLING THE CRANKSHAFT IN ANY 6.5L ENGINE, VERIFY THE TYPE OF BOLTS USED FOR THE CRANKSHAFT BEARING CAPS. FOR ENGINES BUILT PRIOR TO MARCH 13, 1997 (ALL BOLTS ARE 12 MM), USE THE VEHICLE MODEL YEAR SERVICE MANUAL'S EXISTING PROCEDURE. FOR ENGINES BUILT AFTER MARCH 13, 1997 (ALL INNER BOLTS ARE 12 MM, OUTER BOLTS AT POSITIONS 1 AND 5 ARE 12 MM, AND OUTER BOLTS AT POSITIONS 2, 3, AND 4 ARE 10 MM), USE THE INFORMATION PROVIDED IN THIS BULLETIN. THIS INFORMATION IS ALSO AVAILABLE IN THE 1998 SERVICE MANUAL.

CRANKSHAFT AND BEARINGS INSTALLATION (C, K, AND G TRUCKS, RPOS L56, L65, L65-CMT)

THERE ARE FIVE CRANKSHAFT BEARINGS NUMBERED 1 THROUGH 5, AS VIEWED FROM THE FRONT OF THE ENGINE. THERE IS AN ARROW ON EACH BEARING CAP THAT POINTS TOWARD THE FRONT OF THE ENGINE. THE CENTER CRANKSHAFT BEARING, NUMBER THREE, IS THE THRUST BEARING.

THE UPPER CRANKSHAFT BEARING INSERTS ALL HAVE AN OIL GROOVE AND A OIL GALLERY HOLE FROM THE BLOCK IN THE CENTER OF THE GROOVE. THE UPPER CRANKSHAFT BEARING INSERTS ALSO HAVE ADDITIONAL HOLES IN THE GROOVE AT 10 O'CLOCK AND 2 O'CLOCK TO PROVIDE OIL TO THE OIL SPRAY NOZZLES. THE OIL SPRAY NOZZLES ARE MOUNTED IN THE CRANKSHAFT BEARING BULKHEADS. THE LOWER BEARING INSERTS DO NOT HAVE AN OIL GROOVE OR HOLES. DURING INITIAL ASSEMBLY, THE CRANKSHAFT BEARINGS ARE SELECT-FITTED TO EACH OF THE FIVE CRANKSHAFT BEARING BORES. THE TOTAL DIAMETER SIZE RANGE OF CRANKSHAFT BEARING BORES 1 THROUGH 5 IS 79.826 - 79.850 MM (3.145 - 3.146 IN). THIS RANGE DIVIDES INTO THREE SIZES, REPRESENTED BY THE SIZE NUMBERS 1, 2 OR 3. THE PROPER SIZE NUMBER IS THEN STAMPED ON THE PAN RAIL AT THE CORRESPONDING CRANKSHAFT BEARING BULKHEAD. THE CRANKSHAFT IS COLOR-MARKED IN RED/ORANGE, BLUE, OR WHITE, NEAR EACH CRANKSHAFT BEARING JOURNAL. CROSS-REFERENCING THE SIZE NUMBER ON THE PAN RAIL WITH THE COLOR ON THE CRANKSHAFT INDICATES THE PROPER BEARING SELECTION.

{INSERT FIGURE 1 (69974) HERE}

CRANKSHAFT BEARINGS ARE AVAILABLE IN STANDARD 0.013 MM (0.0005 IN) AND 0.026 MM (0.0010 IN) UNDERSIZED FOR SELECT FITTING, IN ORDER TO ATTAIN PROPER CRANKSHAFT BEARING CLEARANCE.

UNDERSIZED REFERS TO THE CRANKSHAFT DIAMETER.

FOR SERVICE PURPOSES, BEARING SIZE COMBINATIONS PROVIDE THE FOLLOWING CLEARANCES:

CRANKSHAFT BEARING NUMBERS 1, 2, 3 AND 4: 0.045 - 0.083 MM (0.0018 - 0.0033 IN).

CRANKSHAFT BEARING NUMBER 5: 0.055 - 0.093 MM (0.0022 - 0.00 IN).

{INSERT FIGURE 2 (70356) HERE}

IMPORTANT

THE UPPER CRANKSHAFT BEARING INSERTS MUST HAVE HOLES FOR THE PISTON OIL SPRAY NOZZLES, OR DAMAGE TO THE ENGINE COULD RESULT. ALL ENGINES WERE ASSEMBLED WITH THREE-HOLE UPPER CRANKSHAFT BEARING INSERTS IN POSITIONS 2, 3 AND 4, AND WITH TWO-HOLE UPPER CRANKSHAFT BEARING INSERTS IN POSITIONS 1 AND 5. REPLACE THE UPPER CRANKSHAFT BEARING INSERTS WITH THE SAME TYPE AS ORIGINALLY INSTALLED.

1. INSTALL THE UPPER CRANKSHAFT BEARING INSERTS TO THE BLOCK.

2. INSTALL THE LOWER CRANKSHAFT BEARING INSERTS TO THE CRANKSHAFT BEARING CAPS.

3. APPLY ENGINE OIL TO THE CRANKSHAFT BEARING INNER SURFACES.

{INSERT FIGURE 3 (59918) HERE}

4. INSTALL THE CRANKSHAFT.

{INSERT FIGURE 4 (69976) HERE}

5. APPLY A 1/8 INCH BEAD OF GASKET MAKER, GM P/N 1052942, OR EQUIVALENT, ON EACH SIDE OF THE REAR CRANKSHAFT BEARING CAP AREA.

{INSERT FIGURE 5 (210728) HERE}

IMPORTANT

CRANKSHAFT BEARING CAP BOLT SIZES ARE AS FOLLOWS:

ALL INNER CRANKSHAFT BEARING CAP BOLTS ON CRANKSHAFT BEARING 1, 2, 3, 4 AND 5 ARE 12 MM (101 MM LONG) BOLTS.

ALL OUTER CRANKSHAFT BEARING CAP BOLTS ON CRANKSHAFT BEARING CAPS 1 AND 5 ARE 12 MM (68 MM LONG) BOLTS.

ALL OUTER CRANKSHAFT BEARING CAP BOLTS ON CRANKSHAFT BEARING CAPS 2, 3 AND 4 ARE 10 MM (68 MM LONG) BOLTS.

{INSERT FIGURE 6 (59912) HERE}

NOTICE

THE CRANKSHAFT BEARING CAPS ARE TO BE TAPPED INTO PLACE WITH A BRASS OR LEATHER MALLET BEFORE THE ATTACHING BOLTS ARE INSTALLED. DO NOT USE THE ATTACHING BOLTS TO PULL THE CRANKSHAFT BEARING CAPS INTO THEIR SEATS, AS THIS MAY DAMAGE THE BEARING CAP AND/OR BLOCK.

6. INSTALL THE NUMBER 1, 2, 4 AND 5 CRANKSHAFT BEARING CAPS AND BEARINGS BY TAPPING INTO PLACE WITH A BRASS OR LEATHER MALLET.

7. APPLY ENGINE OIL TO THE CRANKSHAFT BEARING CAP BOLT THREADS.

8. INSTALL THE CRANKSHAFT BEARING CAP INNER 12 MM BOLTS.

TIGHTEN

TIGHTEN THE INNER 12 MM BOLTS TO 75 N.M (55 LB FT).

9. INSTALL THE NUMBER 3 CRANKSHAFT BEARING CAP AND BEARING (THRUST BEARING) BY TAPPING INTO PLACE WITH A BRASS OR LEATHER MALLET.

10. INSTALL THE CRANKSHAFT BEARING CAP INNER 12 MM BOLTS.

TIGHTEN

TIGHTEN THE INNER 12 MM BOLTS TO 14 N.M (10 LB FT).

11. TAP THE END OF THE CRANKSHAFT FIRST REARWARD THEN FORWARD WITH A LEAD HAMMER TO LINE UP THE CRANKSHAFT BEARING AND CRANKSHAFT THRUST SURFACES.

TIGHTEN

TIGHTEN THE INNER 12 MM BOLTS TO 75 N.M (55 LB FT).

12. MEASURE THE CRANKSHAFT END PLAY WITH THE CRANKSHAFT FORCED FORWARD. MEASURE AT THE FRONT END OF THE NUMBER 3 CRANKSHAFT BEARING WITH A FEELER GAUGE. THE PROPER CLEARANCE IS 0.10 - 0.25 MM (0.004 - 0.010 IN).

13. TIGHTEN ALL CRANKSHAFT BEARING CAP BOLTS IN THE FOLLOWING SEQUENCE:

TIGHTEN

RETIGHTEN THE INNER 12 MM BOLTS TO 75 N.M (55 LB FT).

TIGHTEN THE INNER 12 MM BOLTS AN ADDITIONAL 90 DEGREES.

TIGHTEN THE OUTER 12 MM BOLTS (CRANKSHAFT BEARING CAPS 1 AND 5) TO 65 N.M (48 LB FT).

RETIGHTEN THE OUTER 12 MM BOLTS (CRANKSHAFT BEARING CAPS 1 AND 5) TO 65 N.M (48 LB FT).

TIGHTEN THE OUTER 12 MM BOLTS AN ADDITIONAL 90 DEGREES.

TIGHTEN THE OUTER 10 MM BOLTS (CRANKSHAFT BEARING CAPS 2, 3 AND 4) TO 40 N.M (30 LB FT).

DO NOT TIGHTEN THE OUTER 10 MM BOLTS (CRANKSHAFT BEARING CAPS 2, 3 AND 4) AN ADDITIONAL 90 DEGREES.

NOTICE

BURRS ON THE BLOCK OR CRANKSHAFT BEARING CAP, FOREIGN MATTER BETWEEN THE BEARING INSERT AND THE BLOCK OR CRANKSHAFT BEARING CAP, OR A FAULTY BEARING INSERT, COULD RESULT A LACK OF CLEARANCE, CAUSING THE CRANKSHAFT TO BIND.

14. INSPECT THE CRANKSHAFT FOR BINDING BY ROTATING THE CRANKSHAFT. IF THE CRANKSHAFT DOES NOT TURN FREELY, LOOSEN THE CRANKSHAFT BEARING BOLTS, ONE PAIR AT A TIME, UNTIL THE TIGHT BEARING IS LOCATED.

CRANKSHAFT AND BEARINGS INSTALLATION (P TRUCKS, RPO L57)

THERE ARE FIVE CRANKSHAFT BEARINGS NUMBERED 1 THROUGH 5, AS VIEWED FROM THE FRONT OF THE ENGINE. THERE IS AN ARROW ON EACH BEARING CAP THAT POINTS TOWARD THE FRONT OF THE ENGINE. THE CENTER CRANKSHAFT BEARING, NUMBER THREE, IS THE THRUST BEARING.

THE UPPER CRANKSHAFT BEARING INSERTS ALL HAVE AN OIL GROOVE AND A OIL GALLERY HOLE FROM THE BLOCK IN THE CENTER OF THE GROOVE. THE UPPER CRANKSHAFT BEARING INSERTS ALSO HAVE ADDITIONAL HOLES IN THE GROOVE AT 10 O'CLOCK AND 2 O'CLOCK TO PROVIDE OIL TO THE OIL SPRAY NOZZLES. THE OIL SPRAY NOZZLES ARE MOUNTED IN THE CRANKSHAFT BEARING BULKHEADS. THE LOWER BEARING INSERTS DO NOT HAVE AN OIL GROOVE OR HOLES. DURING INITIAL ASSEMBLY, THE CRANKSHAFT BEARINGS ARE SELECT-FITTED TO EACH OF THE FIVE CRANKSHAFT BEARING BORES. THE TOTAL DIAMETER SIZE RANGE OF CRANKSHAFT BEARING BORES 1 THROUGH 5 IS 79.826 - 79.850 MM (3.145 - 3.146 IN).

THIS RANGE DIVIDES IN TO THREE SIZES, REPRESENTED BY THE SIZE NUMBERS 1, 2 OR 3. THE PROPER SIZE NUMBER IS THEN STAMPED ON THE PAN RAIL AT THE CORRESPONDING CRANKSHAFT BEARING BULKHEAD. THE CRANKSHAFT IS COLOR-MARKED IN RED/ORANGE, BLUE, OR WHITE, NEAR EACH CRANKSHAFT BEARING JOURNAL. CROSS-REFERENCING THE SIZE NUMBER ON THE PAN RAIL WITH THE COLOR ON THE CRANKSHAFT INDICATES THE PROPER BEARING SELECTION.

{INSERT FIGURE 1 (69974) HERE}

CRANKSHAFT BEARINGS ARE AVAILABLE IN STANDARD 0.013 MM (0.0005 IN) AND 0.026 MM (0.0010 IN) UNDERSIZED FOR SELECT FITTING, IN ORDER TO ATTAIN PROPER CRANKSHAFT BEARING CLEARANCE.

UNDERSIZED REFERS TO THE CRANKSHAFT DIAMETER.

FOR SERVICE PURPOSES, BEARING SIZE COMBINATIONS PROVIDE THE FOLLOWING CLEARANCES:

CRANKSHAFT BEARING NUMBERS 1, 2, 3 AND 4: 0.045 - 0.083 MM (0.0018 - 0.0033 IN).

CRANKSHAFT BEARING NUMBER 5: 0.055 - 0.093 MM (0.0022 - 0.00 IN).

{INSERT FIGURE 2 (70356) HERE}

IMPORTANT

THE UPPER CRANKSHAFT BEARING INSERTS MUST HAVE HOLES FOR THE PISTON OIL SPRAY NOZZLES, OR DAMAGE TO THE ENGINE COULD RESULT. THE L57 ENGINES WERE DESIGNED TO OPERATE WITH THE PISTON OIL SPRAY NOZZLES IN CYLINDERS 1, 2 AND 3 BLOCKED OFF. THE L57 ENGINES WERE ASSEMBLED WITH SINGLE-HOLE CRANKSHAFT BEARING INSERTS IN POSITIONS 1 AND 2, WITH THREE-HOLE UPPER CRANKSHAFT BEARING INSERTS IN POSITIONS 3 AND 4, AND WITH A TWO-HOLE UPPER CRANKSHAFT BEARING INSERT IN POSITION 5. REPLACE THE UPPER CRANKSHAFT BEARING INSERTS WITH THE SAME TYPE AS ORIGINALLY INSTALLED.

1. INSTALL THE UPPER CRANKSHAFT BEARING INSERTS TO THE BLOCK.

2. INSTALL THE LOWER CRANKSHAFT BEARING INSERTS TO THE CRANKSHAFT BEARING CAPS.

3. APPLY ENGINE OIL TO THE CRANKSHAFT BEARING INNER SURFACES.

{INSERT FIGURE 3 (59918) HERE}

4. INSTALL THE CRANKSHAFT.

{INSERT FIGURE 4 (69976) HERE}

5. APPLY A 1/8 INCH BEAD OF GASKET MAKER, GM P/N 1052942, OR EQUIVALENT, ON EACH SIDE OF THE REAR CRANKSHAFT BEARING CAP AREA.

{INSERT FIGURE 5 (210728) HERE}

IMPORTANT

CRANKSHAFT BEARING CAP BOLT SIZES ARE AS FOLLOWS:

ALL INNER CRANKSHAFT BEARING CAP BOLTS ON CRANKSHAFT BEARING 1, 2, 3, 4 AND 5 ARE 12 MM (101 MM LONG) BOLTS. ALL OUTER CRANKSHAFT BEARING CAP BOLTS ON CRANKSHAFT BEARING CAPS 1 AND 5 ARE 12 MM (68 MM LONG) BOLTS. ALL OUTER CRANKSHAFT BEARING CAP BOLTS ON CRANKSHAFT BEARING CAPS 2, 3 AND 4 ARE 10 MM (68 MM LONG) BOLTS.

{INSERT FIGURE 6 (59912) HERE}

NOTICE

THE CRANKSHAFT BEARING CAPS ARE TO BE TAPPED INTO PLACE WITH A BRASS OR LEATHER MALLET BEFORE THE ATTACHING BOLTS ARE INSTALLED. DO NOT USE THE ATTACHING BOLTS TO PULL THE CRANKSHAFT BEARING CAPS IN TO THEIR SEATS, AS THIS MAY DAMAGE THE BEARING CAP AND/OR BLOCK.

6. INSTALL THE NUMBER 1, 2, 4 AND 5 CRANKSHAFT BEARING CAPS AND BEARINGS BY TAPPING INTO PLACE WITH A BRASS OR LEATHER MALLET.

7. APPLY ENGINE OIL TO THE CRANKSHAFT BEARING CAP BOLT THREADS.

8. INSTALL THE CRANKSHAFT BEARING CAP INNER 12 MM BOLTS.

TIGHTEN

TIGHTEN THE INNER 12 MM BOLTS TO 75 N.M (55 LB FT).

9. INSTALL THE NUMBER 3 CRANKSHAFT BEARING CAP AND BEARING (THRUST BEARING) BY TAPPING INTO PLACE WITH A BRASS OR LEATHER MALLET.

10. INSTALL THE CRANKSHAFT BEARING CAP INNER 12 MM BOLTS.

TIGHTEN

TIGHTEN THE INNER 12 MM BOLTS TO 14 N.M (10 LB FT).

11. TAP THE END OF THE CRANKSHAFT FIRST REARWARD THEN FORWARD WITH A LEAD HAMMER TO LINE UP THE CRANKSHAFT BEARING AND CRANKSHAFT THRUST SURFACES.

TIGHTEN

TIGHTEN THE INNER 12 MM BOLTS TO 75 N.M (55 LB FT).

12. MEASURE THE CRANKSHAFT END PLAY WITH THE CRANKSHAFT FORCED FORWARD. MEASURE AT THE FRONT END OF THE NUMBER 3 CRANKSHAFT BEARING WITH A FEELER GAUGE. THE PROPER CLEARANCE IS 0.10 - 0.25 MM (0.004 - 0.010 IN).

13. TIGHTEN ALL CRANKSHAFT BEARING CAP BOLTS IN THE FOLLOWING SEQUENCE:

TIGHTEN

RETIGHTEN THE INNER 12 MM BOLTS TO 75 N.M (55 LB FT).

TIGHTEN THE INNER 12 MM BOLTS AN ADDITIONAL 90 DEGREES.

TIGHTEN THE OUTER 12 MM BOLTS (CRANKSHAFT BEARING CAPS 1 AND 5) TO 65 N.M (48 LB FT).

RETIGHTEN THE OUTER 12 MM BOLTS (CRANKSHAFT BEARING CAPS 1 AND 5) TO 65 N.M (48 LB FT).

TIGHTEN THE OUTER 12 MM BOLTS AN ADDITIONAL 90 DEGREES.

TIGHTEN THE OUTER 10 MM BOLTS (CRANKSHAFT BEARING CAPS 2, 3 AND 4) TO 40 N.M (30 LB FT).

DO NOT TIGHTEN THE OUTER 10 MM BOLTS (CRANKSHAFT BEARING CAPS 2, 3 AND 4) AN ADDITIONAL 90 DEGREES.

NOTICE

BURRS ON THE BLOCK OR CRANKSHAFT BEARING CAP, FOREIGN MATTER BETWEEN THE BEARING INSERT AND THE BLOCK OR CRANKSHAFT BEARING CAP, OR A FAULTY BEARING INSERT, COULD RESULT A LACK OF CLEARANCE, CAUSING THE CRANKSHAFT TO BIND.

14. INSPECT THE CRANKSHAFT FOR BINDING BY ROTATING THE CRANKSHAFT. IF THE CRANKSHAFT DOES NOT TURN FREELY, LOOSEN THE CRANKSHAFT BEARING BOLTS, ONE PAIR AT A TIME, UNTIL THE TIGHT BEARING IS LOCATED.

FIGURES: 06 ATTACHMENTS: 00

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