Engine Balance Shaft - Service Information
FILE IN SECTION: 6 - EngineBULLETIN NO.: 57-61-03A
DATE: February, 1995
SUBJECT:
Section 6A7 - Balance Shaft Service Information
MODELS:
1995 Buick Skylark
1995 Chevrolet Cavalier
1995 Oldsmobile Achieva
1995 Pontiac Grand Am, Sunfire with 2.3L Engine (VIN D - RPO LD2)
This bulletin is being revised to make a change in step 8. Please discard bulletin number 57-61-03 (Section 6 - Engine).
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 Nm (44 lb.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°, 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 Nm (115 lb.in.).
8. Tighten the Balance shaft driven sprocket bolt.
Tighten
^ Bolt to 40 Nm (30 lb ft) plus rotate bolt 45°.
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 (0.040 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 gauge 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 Nm (115 lb.in.).
11. Balance shaft chain cover (133), refer to Figure 6.
Tighten
^ Nut and bolt to 13 Nm (115 lb.in.).