Engine Block Cleaning and Inspection

Tools Required 

• J 8001  Dial Indicator Set
• J 8087  Cylinder Bore Gauge
• J 36660-A  Torque/Angle Meter

1. Clean the sealing material from all gasket mating surfaces.
2. Clean the engine block with a cleaning solution.
3. Flush the engine block with clean water.
4. Clean the oil passages.
5. Coat the cylinder bores and the machined surfaces with engine oil.
6. Inspect the threaded holes. Clean the holes with a tap, if needed.
7. Use a straight edge and a feeler gauge to check the deck surface for flatness. Carefully remove any minor irregularities. Replace the block if there is more than 0.08 mm (0.003 in) gap.
   Fig 1: Checking Deck Surface For Flatness

   Courtesy of GENERAL MOTORS CORP.
8. Replace the engine block if the bores are out of specification.
9. Inspect the cylinder bores. Use J 8087  to measure the cylinder bore. Inspect the bores for the following conditions:
   • Wear
   • Taper
   • Runout
   • Ridging
   IMPORTANT: If the bore is worn beyond the limits, bore the cylinders and refit with the one oversized piston available.
10. Leave sufficient material to allow finish honing when fitting the pistons.
    Fig 2: Measuring Cylinder Bore

    Courtesy of GENERAL MOTORS CORP.
11. Inspect the oil pan rail for nicks. Use a flat file to remove an nicks.
12. Inspect the front cover attaching area for nicks. Use a flat file to remove any nicks.
13. Inspect the mating surfaces of the transmission case.
14. Use the following procedure to measure the engine block flange runout at the mounting bolt hole bosses:
    1. 14.1. Temporarily install the crankshaft. Measure the crankshaft flange runout.
    2. 14.2. Hold a gauge plate flat against the crankshaft flange.
    3. 14.3. Place J 8001  (dial indicator stem) on the transmission mounting bolt hole boss. Set the indicator to zero
    4. 14.4. Record the readings obtained from all of the bolt hole bosses. The measurements should not vary more than 0.25 mm (0.010 in).
       Fig 3: Measuring Engine Block Flange Runout

       Courtesy of GENERAL MOTORS CORP.
    5. 14.5. Recheck the crankshaft flange runout if the readings vary more than 0.25 mm (0.010 in). If the crankshaft flange runout is within the specification, replace the engine block.
15. Remove the crankshaft.
    NOTE: Refer to FASTENER NOTICE in Cautions and Notices.
16. Re-install the crankshaft bearing caps, stiffener, and bolts.

    Tighten 

    1. 16.1. Tighten the crankshaft bearing cap bolts to 25 N.m (18 lb ft).
    2. 16.2. Use J 36660-A  to tighten the crankshaft bearing cap bolts an additional 180 degrees.
    IMPORTANT: Perform the following inspections, and reconditioning (if necessary), with the crankshaft main bearing caps installed and tightened to specification.
17. Inspect the crankshaft main bearing bores. Use J 8087  to measure the bearing bore concentricity and alignment.
18. Remove the crankshaft main bearing cap stiffener and main bearing caps with bearings.
    Fig 4: Measuring Bearing Bore Concentricity And Alignment

    Courtesy of GENERAL MOTORS CORP.