Engine Block Cleaning and Inspection

Tools Required 

J 8087  Cylinder Bore Gage

1. Clean the sealing material from the gasket mating surfaces.
2. Boil the engine block in caustic solution.
3. Flush the engine block with clean water or steam.
   CAUTION: Refer to SAFETY GLASSES CAUTION .
4. Clean the oil passages.
5. Clean the blind holes.
6. Spray the cylinder bores and the machined surfaces with engine oil.
7. Inspect the threaded holes. Clean the threaded holes with a rifle brush. Refer to Thread Repair .
8. Use a straight edge and a feeler gage to check the deck surface for flatness. Carefully machine minor irregularities. Replace the block if warpage exceeds 0.05 mm (0.0020 in).
   Fig 1: Checking Deck Surface For Flatness

   Courtesy of GENERAL MOTORS CORP.
9. Inspect the lower crankcase rail for nicks. Inspect the front cover attaching area for nicks. Use a flat mill file to remove any nicks.
10. Inspect the cylinder block for any cracks.
11. Visually inspect the cylinder bores for the following items:
    • Excessive wear
    • Excessive ridging
12. Use the J 8087  to inspect the cylinder bores. Inspect for the following items:
    • Taper: maximum = 0.10 mm (0.0039 in)
    • Runout: maximum = 0.10 mm (0.0039 in)
    Fig 2: Measuring Cylinder Bores
    Courtesy of GENERAL MOTORS CORP.

    Important:  If the bore is worn beyond the limits, refit the bore with oversized pistons. Select the smallest available oversize piston.

13. Leave sufficient material to allow honing when fitting the piston.