GM Service Manual Online
For 1990-2009 cars only

Application

Specification

Metric

English

General Data

  • Engine Type

In-Line-6

  • Displacement

4.2 L

256 cu in

  • RPO (VIN Code)

LL8

Spark Plug Gap

  • Maximum

1.25 mm

0.050 in

  • Minimum

1.14 mm

0.044 in

  • Bore

93 mm

3.66 in

  • Stroke

102 mm

4.02 in

  • Compression Ratio

10 : 1

  • Firing Order

1-5-3-6-2-4

  • Oil Pressure (At the sending unit) Warm - Minimum

85 kPa

12 psi @ 1200 RPM

Cylinder Bore

  • Diameter

92.990-93.006 mm

3.6638-3.6644 in

  • Out Of Round - Maximum

0.013 mm

0.0005 in

  • Cylinder Liner Recession - Maximum

0.015 mm

0.0006 in

Piston & Pin

  • Piston Diameter - 38 mm (1.4961 in) down from top

92.963-92.977 mm

3.6627-3.6633 in

  • Piston to Bore Clearance

0.013-0.043 mm

0.0004-0.0017 in

  • Piston to Pin Clearance

0.003-0.012 mm

0.00012-0.0005 in

  • Pin Bore

23.002-23.008 mm

0.9056-0.9058 in

  • Piston Pin Diameter

22.996-22.999 mm

0.9054-0.9055 in

Piston Ring

  • Top Groove to Ring Side Clearance

0.043-0.093 mm

0.0017-0.0037 in

  • Second Groove to Ring Side Clearance

0.043-0.093 mm

0.0017-0.0037 in

  • Oil Control Groove to Ring Side Clearance

0.059-0.215 mm

0.0023-0.0085 in

  • Top Ring Gap - 93 mm (3.66 in) down from top of cylinder

0.2-0.4 mm

0.0079-0.0157 in

  • Second Ring Gap - 93 mm (3.66 in) down from top of cylinder

0.3-0.5 mm

0.0118-0.0197 in

  • Oil Control Ring Gap - 93 mm (3.66 in) down from top of cylinder

0.250-0.760 mm

0.0098-0.0299 in

Crankshaft

  • Main Journal Diameter

69.968-69.984 mm

2.7567-2.7574 in

  • Main Journal Taper - Maximum

0.005 mm

0.0002 in

  • Out Of Round - Maximum

0.005 mm

0.0002 in

  • Cylinder Block Main Bearing Bore Diameter

78.070-78.088 mm

3.0760-3.0766 in

  • Crankshaft Main Bearing Inside Diameter

69.997-70.031 mm

2.7579-2.7592 in

  • Main Bearing Clearance

0.012-0.064 mm

0.0004-0.0025 in

  • Crankshaft End Play

0.112-0.388 mm

0.0044-0.0153 in

Connecting Rod

  • Connecting Rod Bearing Journal Diameter

56.693-56.707 mm

2.2337-2.2342 in

  • Connecting Rod Bearing Journal Out Of Round - Maximum

0.005 mm

0.0002 in

  • Connecting Rod Bearing Bore Diameter

60.322-60.338 mm

2.3749-2.3755 in

  • Connecting Rod Inside Bearing Diameter

56.729-56.757 mm

2.2351-2.2362 in

  • Connecting Rod Bearing Journal Clearance

0.021-0.065 mm

0.0008-0.0025 in

  • Connecting Rod Side Clearance

0.05-0.35 mm

0.0019-0.0137 in

  • Connecting Rod Bushing to Pin Clearance

0.001-0.018 mm

0.0004-0.0007 in

  • Connecting Rod Inside Bushing Diameter

23.000-23.014 mm

0.9055-0.9060 in

Camshaft

  • Journal Diameter - All Intake and Exhaust #2 - #7

26.936-26.960 mm

1.0612-1.0622 in

  • Journal Diameter - Exhaust #1

29.936-29.960 mm

1.1794-1.1804 in

  • Camshaft Bore Diameter - All Intake and Exhaust #2 - #7

27.000-27.021 mm

1.0638-1.0646 in

  • Camshaft Bore Diameter - Exhaust #1

30.000-30.021 mm

1.1820-1.1828 in

  • Journal Clearance

0.040-0.085 mm

0.0015-0.0033 in

  • Camshaft Endplay - Intake

0.051-0.201 mm

0.0020-0.0079 in

  • Camshaft Endplay - Exhaust

0.045-0.215 mm

0.0017-0.0084 in

Valve System

  • Stationary Lash Adjuster

Hydraulic

  • Valve Seat Runout - Maximum

0.05 mm

0.002 in

  • Valve Face Runout - Maximum

0.038 mm

0.0015 in

  • Valve Stem Clearance - Intake

0.030-0.065 mm

0.0011-0.0025 in

  • Valve Stem Clearance - Exhaust

0.0375-0.0775 mm

0.0015-0.0030 in

Valve Spring

  • Valve Springs Load (Closed)

211.4-233.4 N @ 35.0 mm

47.5-52.5 lb @ 1.701 in

  • Valve Springs Load (Open)

579.0-631.0 N @ 24.5 mm

130-142 lb @ 1.260 in

Oil Pump

  • Gear Pocket Depth

15.609-15.584 mm

0.615-0.614 in

  • Gear Pocket Diameter

87.065-87.040 mm

3.430-3.429 in

Oil Pump Drive Gear

  • Outer Diameter Tolerance

73.415-73.370 mm

2.893-2.891 in

  • Width

15.546-15.521 mm

0.613-0.611 in

Oil Pum Driven Gear

  • Outer Diameter Tolerance

87.000-86.975 mm

3.428-3.426 in

  • Width

15.360-15.511 mm

0.605-0.611 in

  • Lobe Inner Diameter - Maximum

11.9 mm

0.469 in

Oil Pump Gear

  • Valve to Bore Clearance

14.6-14.575 mm

0.575-0.574 in