GM Service Manual Online
For 1990-2009 cars only

Application

Metric

English

General

  • VIN ID

RPO LD8-Y

RPO L37-9

  • Piston Displacement

4.6 Liter

279 cu in

  • Compression Ratio

10.3:1

  • Compression Pressure at Cranking Speed (Throttle Open)

965-1172 KPa

140-170 psi

  • Horsepower (RPO LD8)

205 kW @ 5600 RPM

275 hp @ 5600 RPM

  • Horsepower (RPO L37)

224 kW @ 6000 RPM

300 hp @ 6000 RPM

  • Torque (RPO LD8)

407 N·m @ 4000 RPM

300 lb ft @ 4000 RPM

  • Torque (RPO L37)

400 N·m @ 4400 RPM

295 lb ft @ 4400 RPM

  • Firing Order

1-2-7-3-4-5-6-8

Cylinder Block

  • Material

Aluminum with Cast-in Grey Iron sleeves

  • Bore

92.992-93.008 mm @ 41 mm below deck surface

3.6611-3.6617 in @ 1.614 in below deck surface

  • Stroke

84 mm

3.31 in

  • Deck Height

224.55 mm

8.84 in

  • Deck Clearance

0.45 mm above deck surface

0.18 in above deck surface

  • Length

528.45 mm

20.81 in

  • Piston Clearance @ 41 mm below deck face

0.020-0.051 mm

0.0008-0.0020 in

  • Deck Face Flatness -- Maximum Allowed

0.101 mm

0.004 in

  • Cylinder Bore Out-of-Round -- Maximum

0.100 mm

0.004 in

  • Cylinder Bore Taper -- Maximum

0.100 mm

0.004 in

Cylinder Head

  • Type

DOHC -- 4 Valves Per Cylinder

  • Material

Aluminum

  • Combustion Chamber Volume

51.8 cc

--

  • Cylinder Head Flatness Maximum Without Resurfacing

0.05 mm

0.002 in

  • Worn Limit

0.20 mm

0.008 in

  • Valves
  • Clearance Between Stem and Guide, New Limits -- Intake

0.028-0.068 mm

0.001-0.003 in

  • Clearance Between Stem and Guide, New Limits -- Exhaust

0.05-0.10 mm

0.002-0.004 in

  • Worn Limits, Not Over

0.12 mm

0.005 in

  • Head Diameter, Overall -- Intake

33 mm

1.30 in

  • Exhaust

29 mm

1.14 in

  • Valve Face Angle

45 degrees

  • Valve Seat Angle (In Head)

46 degrees

  • Valve Seat Width -- Intake

0.450-0.650 mm

0.017-0.033 in

  • Valve Seat Width -- Exhaust

0.700-1.100 mm

0.027-0.043 in

  • Seat Eccentricity, Not Over (T.I.R.)

0.05 mm

0.002 in

  • Valve Face Runout

0.05 mm

0.002 in

  • Stem Diameter

5.9207-5.9411 mm

0.2331-0.2339 in

  • Valve Guide Diameter (in Head)

5.979 mm

0.235 in

  • Valve Length -- Intake

105.89 mm

4.169 in

  • Valve Length -- Exhaust

90.53 mm

3.564 in

Valve Lifters

  • Type

Direct Acting, Hydraulic

  • Diameter

32.959-32.975 mm

1.297-1.298 in

  • Lifter Bore Diameter (In Head)

33 mm

--

  • Clearance

0.025-0.076 mm

0.001-0.003 in

  • Free Length

40.4 mm

1.591 in

  • RPO LD8
  • Force required to compress (Valve Closed)

205 N @ 30.3 mm

46 lb @ 1.19 in

  • Force required to compress (Valve Open)

409 N @ 21.7 mm

92 lb @ 0.854 in

  • RPO L37
  • Force required to compress (Valve Closed)

236 N @ 30.3 mm

53 lb @ 1.19 in

  • Force required to compress (Valve Open)

485 N @ 20.9 mm

109 lb @ 0.823 in

  • Installed Height

30.3 mm

1.19 in

Camshaft

  • Primary Drive Type

Endless Chain

  • Adjustment

Hydraulic, Automatic

  • Pitch

8 mm

0.315 in

  • Width

Single Row

  • Secondary Drive Type

Endless Chain

  • Adjustment

Direct Acting Hydraulic

  • Pitch

8 mm

0.315 in

  • Width

Single Row

  • Camshaft Material

Hardened Cast Grey Iron

  • Bearing Number

5

  • Bearing Number on Left Hand Intake

6

  • Bearing Journal Diameter

26.948-26.972 mm

1.061-1.062 in

  • Bearing Bore Diameter (In Head)

27.023 mm

1.064 in

  • Bearing Clearance

0.051-0.076 mm

0.002-0.003 in

  • New Limits

0.04-0.09 mm

0.002-0.004 in

  • Worn Limits (Not Over)

0.152 mm

0.006 in

  • Out-of-Round (Not Over)

0.022 mm

0.0009 in

RPO L37

  • Valve Timing (With Ramp at 0.100 mm Lift), Intake Opens

13 degrees BTDC

  • Intake Closes

73 degrees ABDC

  • Exhaust Opens

51 degrees BBDC

  • Exhaust Closes

13 degrees ATDC

  • Valve Lift, Intake

9.4 mm

0.370 in

  • Exhaust

8.6 mm

0.339 in

  • Duration (@0.100 mm Lift), Intake

266 degrees

  • Exhaust

244 degrees

  • Valve Overlap (@ 0.100 mm Lift)

26 degrees

RPO LD8

  • Valve Timing (With Ramp at 0.100 mm Lift), Intake Opens

9 degrees BTDC

  • Intake Closes

55 degrees ABDC

  • Exhaust Opens

51 degrees BBDC

  • Exhaust Closes

13 degrees ATDC

  • Valve Lift, Intake

8.6 mm

0.339 in

  • Exhaust

8.6 mm

0.339 in

  • Duration (@ 0.100 mm Lift), Intake

244 degrees

  • Exhaust

244 degrees

  • Valve Overlap (@ 0.100 mm Lift)

22 degrees

Connecting Rods

  • Bearing Material

Aluminum

  • Clearance Between Bearing and Crankshaft -- New Limits

0.025-0.076 mm

0.001-0.003 in

  • Worn Limits (Not Over)

0.076 mm

0.003 in

  • Diameter, Lower End (Without Bearing)

57.144 mm

2.249 in

  • Piston Pin Hole

22.022-22.008 mm

0.8662-0.866 in

  • Length, Center to Center

151 mm

5.94 in

  • End Play of Rods on Crank Pin

0.20-0.50 mm

0.008-0.020 in

Piston Rings

  • Side Clearance -- Top and Second Compression Ring

0.040-0.095 mm

0.0016-0.0037 in

  • Side Clearance -- Oil Rings

None--Side Sealing

  • Ring End gap -- Top Compression Ring

0.25-0.40 mm

0.010-0.016 in

  • Ring End Gap -- Second Compression Ring

0.35-0.50 mm

0.014-0.020 in

  • Ring End Gap -- Oil Rings

0.25-0.76 mm

0.010-0.030 in

  • Number of Compression Rings

2

  • Number of Oil Rings

2 Rings -- 1 Expander

  • Width of Compression Ring Groove -- Top Ring

1.230-1.255 mm

0.048-0.049 in

  • Width of Compression Ring Groove -- Second Ring

1.530-1.555 mm

0.060-0.061 in

  • Width of Compression Ring Groove -- Oil Ring

3.030-3.055 mm

0.119-0.120 in

Pistons

  • Piston Material

Aluminum

  • Piston Diameter @ 40 mm from Top of Piston

92.957-92.972 mm

3.6597-3.6603 in

  • Piston Pin Diameter

21.995-22.000 mm

0.865-0.866 in

  • Piston Pin Bore Diameter

22.002-22.008 mm

0.8662-0.8665 in

  • Pin Retention

Snap Rings (2)

  • Piston Taper

No Piston Taper Measurement

Oil System

  • Oil Pump Type

Gerotor

  • Minimum Pressure at Normal Operating Temperature @ Idle

35 kPa

5 psi

  • Minimum Pressure at Normal Operating Temperature @ 2000 RPM

250 kPa

35 psi

  • Oil Pressure Recirculation

Internal Piston Valve

  • Oil Filter Type

PF 58

  • Oil Capacity with Filter

--

7.5 Quarts

  • Without Filter

--

7 Quarts

Crankshaft and Main Bearings

  • Main Bearing Clearance Limit -- New Limit

0.015-0.055 mm

0.0006-0.002 in

  • Main Bearing Clearance Limit -- Worn Limit

0.0635 mm

0.0025 in

  • Main Bearing Journal Diameter

64.352-64.346 mm

2.5335-2.5337 in

  • Main Bearing Journal Out-of-Round (Not Over)

0.004 mm

0.00016 in

  • Main Bearing Journal Taper

0.004 mm

0.00016 in

  • Main Bearing Journal Length -- No. 1

24.6 mm

0.969 in

  • Main Bearing Journal Length -- No. 2

24.6 mm

0.969 in

  • Main Bearing Journal Length -- No. 3

25.2 mm

0.992 in

  • Main Bearing Journal Length -- No. 4

24.6 mm

0.969 in

  • Main Bearing Journal Length -- No. 5

24.6 mm

0.969 in

  • Crankpin Journal Diameter

53.948-53.962 mm

2.1239-2.1245 in

  • Crankpin Journal Out-of-Round (Not Over)

0.004 mm

0.00016 in

  • Crankpin Journal Taper

0.005 mm

0.0002 in

  • End Play in Crankshaft -- New Limits

0.05-0.5 mm

0.002-0.019 in

  • End Play in Crankshaft -- Worn Limits

0.5 mm

0.020 in

  • Flywheel Flange Face Runout

0.025 mm

0.001 in

  • Rear Main Seal Diameter

95.76-95.98 mm

3.77-3.78 in