For 1990-2009 cars

# SMU - SECTION 6A7 - BALANCE SHAFT SERVICE INFORMATION

#### SUBJECT: SERVICE MANUAL UPDATE - SECTION 6A7 - BALANCE SHAFT SERVICE INFORMATION

#### MODELS: 1995 BUICK SKYLARK 1995 CHEVROLET CAVALIER 1995 OLDSMOBILE ACHIEVA 1995 PONTIAC GRAND AM AND SUNFIRE WITH 2.3L ENGINE (VIN D - RPO LD2)

THE BALANCE SHAFT PROCEDURE HAS BEEN REVISED. FIGURE 4 HAS BEEN ADDED AND THE TIGHTENING SPECIFICATION IN FIGURE 5 HAS BEEN REVISED.

BALANCE SHAFT ASSEMBLY

#### TOOLS REQUIRED:

J 41088 BALANCE SHAFT HOLDER J 36660 TORQUE ANGLE METER

#### NOTICE: REFER TO "NOTICE" ON PAGE 6A7-1 OF THIS SECTION.

1. BALANCE SHAFT ASSEMBLY TO BLOCK. USE LOCTITE(R) 242 ON THE HOUSING ASSEMBLY TO BLOCK BOLTS (122 - 126), REFER TO FIGURE 3.

USE THE FOLLOWING PROCEDURE IF THE BALANCE SHAFT HOUSING WAS DISASSEMBLED: A. LOOSE ASSEMBLE THE HOUSING ASSEMBLY TO THE BLOCK. TIGHTEN HOUSING TO BLOCK FASTENERS TO 5 N.M (44 LBS. IN.) B. USE THE TIGHTENING SEQUENCE IN FIGURE 1 TO TIGHTEN HOUSING FASTENERS AND HOUSING ASSEMBLY TO BLOCK BOLTS. C. ENSURE THAT THE BALANCE SHAFTS SPIN FREELY. D. OIL PUMP PICK-UP SCREEN (121) INTO HOUSING, REFER TO FIGURE 2. LIGHTLY TAP INTO PLACE WITH A PLASTIC HAMMER. IF THE BALANCE SHAFT HOUSING WAS NOT DISASSEMBLED, USE THE TIGHTENING SEQUENCE IN FIGURE 3. -- ENSURE THE BALANCE SHAFTS SPIN FREELY. -- IF THE BALANCE SHAFTS ARE NOT PROPERLY TIMED TO THE ENGINE, THE ENGINE MAY VIBRATE OR MAKE NOISE. 2. TIME BALANCE SHAFT TO ENGINE. A. PLACE #1 PISTON AT TDC. B. ROTATE THE CRANKSHAFT 90 DEGREES, REFER TO FIGURE 4. C. INSTALL J 41088 ON TO BALANCE SHAFT ASSEMBLY TO ENSURE THE SHAFTS DO NOT ROTATE WHILE THE DRIVEN SPROCKET BOLT IS TIGHTENED, REFER TO FIGURE 4. 3. DRIVEN SPROCKET (120) TO SHAFT (132). -- THE SURFACE THAT WAS MARKED DURING DISASSEMBLY OF THE DRIVEN SPROCKET MUST SHOW IF IT IS GOING TO BE REUSED. THIS WILL ENSURE THAT THE CHAIN CONTINUES TO RIDE ON THE SAME SURFACE. IF A NEW DRIVEN SPROCKET WILL BE INSTALLED, EITHER SURFACE CAN BE PLACED AGAINST THE SHAFT.

#### IMPORTANT:

THE BALANCE SHAFT DRIVEN SPROCKET BOLT IS LEFT HAND THREADED AND MUST BE TIGHTENED BY ROTATING IT IN A COUNTER CLOCKWISE DIRECTION.

#### NOTICE: A **NEW** BALANCE SHAFT DRIVEN SPROCKET BOLT MUST BE USED ANY TIME THE BOLT IS REMOVED. IF A NEW BOLT IS NOT USED, THE BALANCE SHAFT SPROCKET MAY SLIP ALLOWING THE BALANCE SHAFTS TO BECOME MISTIMED AND CAUSE AN ENGINE VIBRATION.

4. BALANCE SHAFT DRIVEN SPROCKET BOLT (153) FINGER TIGHT, REFER TO FIGURE 5. 5. INSTALL BALANCE SHAFT CHAIN GUIDE, REFER TO FIGURE 6. 6. PRESS CHAIN GUIDE TIGHTLY AGAINST THE CHAIN. 7. TIGHTEN CHAIN TENSIONER FASTENER (136). TIGHTEN BOLT TO 13 N.M (115 LBS. IN.). 8. TIGHTEN THE BALANCE SHAFT DRIVEN SPROCKET BOLT. TIGHTEN BOLT TO 40 N.M (30 LBS. FT.) PLUS ROTATE HOUSING DEGREES. 9. REMOVE TOOL J 41088 FROM BALANCE SHAFT HOUSING ASSEMBLY. 10. LOOSEN BALANCE SHAFT CHAIN GUIDE BOLT (136) AND ADJUST THE BALANCE SHAFT DRIVE CHAIN TENSION. BALANCE SHAFT DRIVE CHAIN TENSION, REFER TO FIGURE 7. ADJUST A. INSERTING A 1 MM (.040 IN.) BRASS FEELER GAGE BETWEEN THE CHAIN GUIDE AND THE CHAIN.

#### IMPORTANT:

A BRASS FEELER GAGE NEEDS TO BE USED TO ENSURE CORRECT MEASUREMENTS ARE OBTAINED. IF A STEEL GAGE IS USED, IT WILL NOT BEND TO CONFORM TO THE GUIDE AND CAUSE INCORRECT MEASUREMENTS. B. PRESS THE GUIDE AGAINST THE CHAIN USING ABOUT 3 POUNDS OF FORCE. C. TIGHTEN CHAIN TENSIONER FASTENER (136). TIGHTEN BOLT TO 13 N.M (115 LBS. IN.). 11. BALANCE SHAFT CHAIN COVER (133), REFER TO FIGURE 6. TIGHTEN NUT AND BOLT TO 13 N.M (115 LBS. IN.).

FIGURES: 7 ATTACHMENTS: 0

GENERAL MOTORS BULLETINS ARE INTENDED FOR USE BY PROFESSIONAL TECHNICIANS, NOT A "DO-IT-YOURSELFER." THEY ARE WRITTEN TO INFORM THOSE TECHNICIANS OF CONDITIONS OCCURRING ON SOME VEHICLES, OR TO PROVIDE INFORMATION THAT COULD ASSIST IN THE PROPER SERVICE OF A VEHICLE. PROPERLY TRAINED TECHNICIANS HAVE THE EQUIPMENT, TOOLS, SAFETY INSTRUCTIONS AND KNOW-HOW TO DO A JOB PROPERLY AND SAFELY. IF A CONDITION IS DESCRIBED, DO NOT ASSUME THE BULLETIN APPLIES TO YOUR VEHICLE, OR THAT YOUR VEHICLE WILL HAVE THAT CONDITION. SEE A GENERAL MOTORS DEALER SERVICING YOUR BRAND OF GM VEHICLE FOR INFORMATION ON WHETHER YOUR VEHICLE MAY BENEFIT FROM THE INFORMATION.

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