Measuring Connecting Rod Bearing Clearance - Using J 43690/J 43690-100

J 43690  and J 43690-100  have been developed as a more accurate method to measure connecting rod bearing clearances. The instructions below provide an overview of tool set-up and usage. For more detailed information, refer to the tool instruction sheets as supplied by the tool manufacturer.

J 43690  Rod Bearing Checking Tool

• J 43690-20 Swivel Base (1)
• J 43690-19 Dial Indicator (2)
• J 43690-2 Base (3)
• J 43690-5, -6 Handle (4)
• J 43690-10, -11 Foot (5)
• 280307 Screw (6)
• J 43690-1 Pivot Arm Assembly (7)
• J 43690-3, -7, -8 Screws (8)
• 280319 Screw (9)
• 280311 Screw (10)
• J 43690-17, -18 Adapter (11)
• 280310 Pin (12)

Fig 1: Identifying Rod Bearing Clearance Checking Tool

Courtesy of GENERAL MOTORS CORP.

J 43690-100  Rod Bearing Checking Tool - Adapter Kit

• J 43690-104 Spacer (1)
• J 43690-105 Retainer Plate (2)
• 505478 Bolt (3)
• 511341 Bolt (4)
• J 43690-106 Retainer Plate (5)
• J 43690-107 Cap (6)
• J 43690-102 Foot (7)
• J 43690-101 Pivot Arm Assembly (8)
• J 43690-103 Adapter (9)
• 505439 Adapter (10)

Fig 2: Identifying Rod Bearing Clearance Tool - Adapter Kit

Courtesy of GENERAL MOTORS CORP.

IMPORTANT: The crankshaft must be secure with no movement or rotation in order to obtain an accurate reading.
1. Rotate the crankshaft until the journal/connecting rod to be measured is in the 12 o'clock position.
2. Remove a bearing cap and bolts (1).
3. Remove the bearing half (2).
4. Insert a piece of paper card stock onto the crankshaft journal.
5. Install the bearing half (2) and cap and bolts (1). Refer to Fastener Tightening Specifications .
Fig 3: View Of Bearing Cap, Bolt & Bearing Half
Courtesy of GENERAL MOTORS CORP.
6. Install the following:
   1. J 43690-2 (5)
   2. J 43690-3 (4)
   3. J 43690-101 (2)
   4. 280310 (3)
   5. J 43690-5 (1)
Fig 4: View Of Special Tool Installed On Engine Block
Courtesy of GENERAL MOTORS CORP.
7. Install the swivel base (1) and dial indicator (2).
8. Adjust per the manufacturers instructions and measure the connecting rod bearing clearance.

   A connecting rod with a clearance in excess of 0.076 mm (0.003 in) is considered excessive. Service components as required.

Fig 5: View Of Swivel Base & Dial Indicator
Courtesy of GENERAL MOTORS CORP.