Timing Balance Shafts-To-Engine

Tools Required: 

• J 41088  Balance Shaft Holder
• J 36660-A  Torque Angle Meter

Important:  If the balance shafts are not properly timed to the engine, the engine may vibrate or make noise.

1. Install and time the balance shaft assembly to the engine using the following steps:
   1. 1.1. Place the number one piston at TDC.
   2. 1.2. Rotate the crankshaft clockwise 90 degrees in either direction from TDC (viewing the crankshaft from the front of the engine)
   3. 1.3. Install the J 41088  on to the balance shaft assembly to ensure the shafts do not rotate while the driven sprocket bolt is tightened.
   Fig 1: Balance Shaft Holder

   Courtesy of GENERAL MOTORS CORP.
   NOTE: 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 engine vibration.

   Important:  The surface that was marked during disassembly of the driven sprocket must show if the drive sprocket is going to be reused. This will insure 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.

2. Install the driven sprocket to the shaft.

   Important:  The balance shaft driven sprocket bolt is left hand threaded and must be tightened by rotating the bolt in a counter clockwise direction.

3. Install the driven sprocket bolt. Finger tighten the bolt.
   Fig 2: Balance Shaft Driven Sprocket Bolt

   Courtesy of GENERAL MOTORS CORP.
4. Install the balance shaft chain guide.
5. Press the chain guide tightly against the chain.
6. Tighten the chain tensioner bolt. Tighten the chain tensioner bolt to 13 N.m (115 in lbs).
7. Tighten the balance shaft driven sprocket bolt. Tighten the driven sprocket bolt to 40 N.m (30 ft lbs). Use the J 36660-A  in order to rotate the bolt an additional 45 degrees.
8. Remove the J 41088  from the balance shaft housing assembly.
9. Loosen the balance shaft chain guide bolt.

   Important:  A brass feeler gauge needs to be used in order to ensure correct measurements are obtained. If a steel gauge is used, the steel gauge will not bend to conform to the guide and will cause incorrect measurements.

10. Adjust the balance shaft drive chain tension. Insert a 1 mm (0.040 in) brass feeler gauge between the chain guide and the chain.
11. Press the guide against the chain using about three pounds of force.
12. Install the chain tensioner bolt. Tighten the chain tensioner bolt to 13 N.m (115 in lbs).
13. Install the balance shaft chain cover.
14. Install the balance shaft chain cover nut and bolt. Tighten the chain cover nut and bolt to 13 N.m (115 in lbs).
    Fig 3: Balance Shaft Chain Cover

    Courtesy of GENERAL MOTORS CORP.