Cylinder Block Inspection

TOOLS REQUIRED:

SA91101NE Feeler Gauge Set
SA9177NE Straight Edge
SA9179NE Dial Indicator
SA9187NE Ridge Reamer

Remove gasket material.
Using a gasket scraper, Scotch Brite® Pads and Disk (3M® Clean' N Strip 2 in. D x 1/2 in. W x 1/4 in. center hole) remove all the gasket material from the cylinder block, oil pan, rear seal carrier, and front cover surfaces.
1. The oil pan, front cover, and rear seal carrier bolt holes in cylinder block will require cleaning with a 4.76 mm (3/16 in.) drill and tap handle to remove RTV.
  
  Fig 1: Cleaning Oil Pan, Front Cover And Rear Seal Carrier Bolt Holes
  Courtesy of GENERAL MOTORS CORP.
  
  NOTE: If excessive RTV (wet or dry) accumulates in blind holes, the casting will crack when bolts are installed.
2. When all RTV is removed, clean the surfaces with a chlorinated solvent, such as carburetor spray cleaner, brake clean, or alcohol Saturn P/N 21007432 (or equivalent).
  NOTE: Do not use petroleum cleaners such as mineral spirits; they leave a film onto which RTV will not stick.
  
  Fig 2: Clean The Surfaces
  Courtesy of GENERAL MOTORS CORP.
3. If cylinder block oil gallery plugs are removed, clean the threads and apply Saturn P/N 21485276 Loctite 290® (or equivalent).
  Do not over-torque plugs.
  
  Torque:
  
  Oil Gallery Plug-to-Block: 30 N.m (22 ft. lbs.)
  
  NOTE: Use extreme care and do not damage or scratch the machined aluminum surfaces and the cylinder bores. Do not heat the cylinder block above 44® (120°F).
Clean cylinder block. Using a soft scrub brush and solvent, clean the entire block of oil, debris, etc.
Inspect top of cylinder block for flatness:
1. Using a Straight Edge SA9177NE (or equivalent) and Feeler Gauge Set SA91101NE (or equivalent), measure the surfaces contacting the cylinder head gasket for warpage.
  TRANSVERSE WARPAGE
  1. Standard: 0.024 mm (0.0009 in.) max.
  2. Service Limit: 0.05 mm (0.0020 in.) max.
  LONGITUDINAL WARPAGE
  1. Standard: 0.080 mm (0.0031 in.) max.
  2. Service Limit: 0.10 mm (0.0040 in.) max.
    
    Fig 3: Inspect Top Of Cylinder Block For Flatness
    Courtesy of GENERAL MOTORS CORP.
  If warpage is greater than maximum, replace the cylinder block.
Inspect cylinders for scoring or vertical scratches:
If deep scratches are present, hone or bore the worn or scored cylinders. Refer to CYLINDER HONING AND BORING .

Fig 4: Inspect Cylinders For Scoring Or Vertical Scratches
Courtesy of GENERAL MOTORS CORP.
Inspect cylinder bore diameter:
Using a cylinder bore gauge, measure the cylinder bore diameter at positions A, B, and C in the transverse and longitudinal directions. Record these dimensions. See Fig 5.

Calculate the average diameter at each position

(A, B, and C). The average value is the dimension to be compared to specifications. See Fig 5.

CYLINDER BORE DIAMETER NO. 2 AND 3
1. Standard: 81.99-82.01 mm (3.2280-3.2287 in.)
2. Service Limit: 82.035 mm (3.2297 in.) max. (average X and Y direction measurements)
CYLINDER BORE DIAMETER NO. 1 AND 4
1. Standard: 82.00-82.02 mm (3.2283-3.2291 in.)
2. Service Limit: 82.045 mm (3.2301 in.) max. (average X and Y direction measurements)
  
  Fig 5: Inspect Cylinder Bore Diameter
  Courtesy of GENERAL MOTORS CORP.
Cylinder Bore Taper

Standard: 0.010 mm (0.0004 in.) max.

Service Limit: 0.050 mm (0.0020 in.) max. (average X and Y direction measurements)

Use the cylinder bore taper calculation chart to calculate bore taper.

Fig 6: Cylinder Bore Taper Calculation Chart
Courtesy of GENERAL MOTORS CORP.

If the diameter is greater than maximum, hone, or re-bore the worn or scored cylinders. If necessary, replace the cylinder block.
Using a Dial Indicator SA9179NE (or equivalent) (dial indicator mounted on a steel block) or straight edge and feeler gauge, measure the cylinder liner height at position A, B, C, and D at the top of the cylinder block.
LINER HEIGHT ABOVE OR BELOW CYLINDER BLOCK:
1. Standard: Flush
2. Service Limit: 0.013 mm (0.0005 in.) max. If the liner height is below the cylinder block, the cylinder block may require surfacing or replacement.
TOP SIDE OF MAIN BEARING BORE TO CYLINDER HEAD DECK SURFACE:

Service Limit: 189.26 mm (7.4511 in.)

Fig 7: Measure The Cylinder Liner Height At Position A, B, C, And D At The Top Of The Cylinder Block
Courtesy of GENERAL MOTORS CORP.

NOTE: Failure to remove ridge can cause upper piston ring damage when new rings are installed.
Remove Ridge Reamer SA9187NE (or equivalent) if not previously completed during piston removal. If a ridge can be felt in the cylinder bore above the upper ring, use a ridge reamer to machine the piston ring ridge at the top of the cylinder.

Fig 8: Ridge Reamer SA9187NE
Courtesy of GENERAL MOTORS CORP.