GM Service Manual Online
For 1990-2009 cars only

Application

Specification

Metric

English

General Data

  • Engine Type

60 degree V-6

  • Displacement

3.9L

238 cu in

  • RPO

LZ9

  • VIN

1

  • Bore

99 mm

3.90 in

  • Stroke

84 mm

3.31 in

  • Compression Ratio

9.8:1

  • Firing Order

123456

  • Spark Plug Gap

1.00 mm

0.040 in

Block

  • Camshaft Bearing Bore Diameter - Front and Rear

55.26-55.31 mm

2.175-2.177 in

  • Camshaft Bearing Bore Diameter - Middle #2, #3

54.75-54.80 mm

2.155-2.157 in

  • Crankshaft Main Bearing Bore Diameter

72.1535-72.0695 mm

2.840-2.841 in

  • Crankshaft Main Bearing Bore Out-of-Round

0.008 mm

0.00031 in

  • Cylinder Bore Diameter

99.000-99.018 mm

3.897-3.898 in

  • Cylinder Bore Out-of-Round - Diameter - Production

0.026 mm

0.0010 in

  • Cylinder Bore Out-of-Round - Diameter - Service

0.030 mm

0.0011 in

  • Cylinder Bore Taper - Production

0.026 mm

0.0010 in

  • Cylinder Bore Taper - Service

0.030 mm

0.0011 in

  • Cylinder Head Deck Height

224 mm

8.818 in

  • Cylinder Head Deck Surface Flatness

0.05 mm per 150 mm

0.0019 in per 5.905 in

  • Valve Lifter Bore Diameter

21.417-21.455 mm

0.843-0.844 in

Camshaft

  • Camshaft Bearing Inside Diameter

51.500-51.525 mm

2.028-2.029 in

  • Camshaft Journal Diameter

51.415-51.440 mm

2.024-2.025 in

  • Camshaft Journal Out-of-Round

0.025 mm

0.001 in

  • Camshaft Lobe Lift - Exhaust

6.9263 mm

0.2727 in

  • Camshaft Lobe Lift - Intake

6.9263 mm

0.2727 in

Cooling System

  • Thermostat Full Open Temperature

195 degrees

Connecting Rod

  • Connecting Rod Bearing Clearance

0.018-0.062 mm

0.0007-0.0024 in

  • Connecting Rod Bore Diameter

60.322-60.338 mm

2.375-2.376 in

  • Connecting Rod Bore Out-of-Round

0.006 mm

0.00023 in

  • Connecting Rod Length - Center to Center

150 mm

5.9 in

  • Connecting Rod Side Clearance

0.200-0.241 mm

0.008-0.009 in

Crankshaft

  • Connecting Rod Journal Diameter

57.122-57.138 mm

2.248-2.249 in

  • Connecting Rod Journal Out-of-Round

0.005 mm

0.0002 in

  • Connecting Rod Journal Taper

0.005 mm

0.0002 in

  • Connecting Rod Journal Width

21.92-22.08 mm

0.863-0.869 in

  • Crankshaft End Play

0.060-0.210 mm

0.0024-0.0083 in

  • Crankshaft Main Bearing Clearance - Except #3

0.019-0.064 mm

0.0008-0.0025 in

  • Crankshaft Main Bearing Clearance - #3 Thrust Bearing

0.032-0.077 mm

0.0012-0.0030 in

  • Crankshaft Main Journal Out-of-Round

0.005 mm

0.0002 in

  • Crankshaft Main Journal Taper

0.005 mm

0.0002 in

  • Crankshaft Rear Flange Runout

0.04 mm

0.0016 in

Cylinder Head

  • Combustion Chamber Depth - at Measurement Point

2.2 mm

0.087 in

  • Surface Finish - Maximum

2.8 RA

  • Surface Flatness - Block Deck

0.08 mm per 152 mm

0.003 in per 6 in

  • Surface Flatness - Exhaust Manifold Deck

0.1 mm

0.004 in

  • Surface Flatness - Intake Manifold Deck

0.1 mm

0.004 in

  • Valve Guide Bore - Exhaust

8.01 mm

0.315 in

  • Valve Guide Bore - Intake

8.01 mm

0.315 in

  • Valve Guide Installed Height

16.6 mm

0.654 in

Lubrication System

  • Oil Capacity - with Filter

3.8 liter

4.0 quarts

  • Oil Pressure - @ 1850 RPM

207-310 kPa

30-45 PSI

Oil Pump

  • Gear Diameter

50.749-50.800 mm

1.997-1.999 in

  • Gear Pocket - Depth

26.274-26.332 mm

1.034-1.036 in

  • Gear Pocket - Diameter

50.902-50.952 mm

2.004-2.005 in

  • Gears Lash

0.094-0.195 mm

0.0037-0.0077 in

  • Relief Valve-to-Bore Clearance

0.038-0.089 mm

0.0015-0.0035 in

Pin

  • Piston Pin Clearance to Connecting Rod Bore - Press Fit

-0.004 to -0.021 mm

-0.0001 to -0.0008 in

  • Piston Pin Clearance to Piston Pin Bore

0.002-0.010 mm

0.00008-0.0004 in

  • Piston Pin Diameter

23.952-23.955 mm

0.942-0.943 in

  • Piston Pin Length

64.21-64.44 mm

2.57-2.53 in

Piston

  • Piston Diameter - Production

98.970-99.008 mm

3.896-3.897 in

  • Piston Diameter - Service Limit

98.950 mm

3.895 in

  • Piston Pin Bore Diameter

23.957-23.962 mm

0.943 in

  • Piston Ring Groove Width

1.22-1.24 mm

0.048-0.049 in

  • Piston to Bore Clearance - Production

-0.008 to +0.048 mm

-0.0003 to +0.0018 in

  • Piston to Bore Clearance - Service Limit - Maximum

0.080 mm

0.003 in

Piston Ring End Gap

  • First Compression Ring

0.15-0.30 mm

0.006-0.011 in

  • Second Compression Ring

0.25-0.45 mm

0.009-0.017 in

  • Oil Control Ring

0.15-0.65 mm

0.06-0.025 in

Piston Ring to Groove Clearance

  • First Compression Ring

0.03-0.065 mm

0.001-0.002 in

  • Second Compression Ring

0.02-0.055 mm

0.0007-0.002 in

  • Oil Control Ring

0.01 mm

0.004 in

Piston Ring Thickness

  • First Compression Ring

1.175-1.190 mm

0.046-0.047 in

  • Second Compression Ring

1.475-1.490 mm

0.058 in

  • Oil Control Ring - Maximum

2.50 mm

0.098 in

Valves

  • Valve Face Angle

45 degrees

  • Valve Seat Angle

46 degrees

  • Valve Seat Depth - Exhaust - From Deck Face

8.9-9.1 mm

0.350-0.358 in

  • Valve Seat Depth - Intake - From Deck Face

7.9-8.1 mm

0.311-0.318 in

  • Valve Seat Width - Exhaust

1.70-2.0 mm

0.067-0.079 in

  • Valve Seat Width - Intake

1.55-1.80 mm

0.061-0.071 in

  • Valve Stem-to-Guide Clearance

0.026-0.068 mm

0.0010-0.0027 in

Valve Lifters/Push Rods

  • Push Rod Length - Intake

146.0 mm

5.75 in

  • Push Rod Length - Exhaust

152.5 mm

6.0 in

Valve Springs

  • Valve Spring Free Length

48.5 mm

1.89 in

  • Valve Spring Installed Height

43.2 mm

1.701 in

  • Valve Spring Load - Closed

320 N 43.2 mm

75 lb 1.701 in

  • Valve Spring Load - Open

1036 N 32 mm

230 lb 1.260 in

  • Valve Spring Total Number of Coils

6.55