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

Tools J 43690  and adapter kit 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.

Fig 1: Identifying Rod Bearing Clearance Checking Tool

Courtesy of GENERAL MOTORS CORP.

J 43690 Rod Bearing Clearance 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 2: Identifying Rod Bearing Clearance Tool - Adapter Kit

Courtesy of GENERAL MOTORS CORP.

J 43690-100 Rod Bearing Clearance 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 3: View Of Bearing Cap & Bolts
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 bolts (1).
3. Remove the bearing half and bearing cap (2).
4. Insert a piece of paper card stock onto the crankshaft journal.
5. Install the bearing half and cap (2) and bolts (1). Refer to Fastener Tightening Specifications .
Fig 4: View Of J 43690-5, J 43690-1, 280310, J 43690-8 & J 43690-2 Installed On Engine Block
Courtesy of GENERAL MOTORS CORP.
6. Install the following:
   1. J 43690-2 (5)
   2. J 43690-8 (4)
   3. J 43690-1 (2)
   4. 280310 (3)
   5. J 43690-5 (1)
Fig 5: View Of Swivel Base & Dial Indicator
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 0.081 mm (0.0032 in) is considered excessive. Service components as required.