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LH9

LH9 Vortec 5.3L V8 "GEN IV"

Vehicle Applications

  • 2010 Hummer H3
  • 2010–2012 Chevrolet Colorado
  • 2010–2012 GMC Canyon

Product Highlights

  • Gen IV Aluminum Cylinder Block
  • Cathedral Port Aluminum Cylinder Heads
  • Variable Valve Timing (VVT)
  • E85 Flex-Fuel Capability
  • Advanced Electronic Throttle Control
  • 58X Ignition System

LH9 Engine Specs (VIN "P")

The information listed here is for a stock engine.

Performance Specifications
Compression Ratio 9.6 : 1
Horsepower Rating 300 hp.
Torque Rating 320 ft./lbs.

 

Application Information

VIN 8th Digit

Year

Make

Model

P

2010

Hummer

H3

2010-12

Chevrolet

Colorado

GMC

Canyon

 

Engine Block Specifications
Casting

Numbers

125771048, 12601900, 12569513, 12568573
Material

Aluminum
Displacement

5.3L / 325 c.i.d.
Bore

Dia.

3.780 in.
Stroke

3.622 in.
Deck

Height

9.240 in.
Bore

Spacing

4.400 in.
Thrust

Bearing Location

#3 Main
Main

Cap Style

6-Bolt
Main

Housing Bore Dia.

2.751 in.
Cam

Housing Bore Dia.

Bore 1/5 = 2.346 in. Bore 2/4 = 2.326 in. Bore 3 = 2.307 in.
Cam-to-Crank

Centerline

4.914 in.

 

Rotating Assembly Specifications
Piston Material

Hypereutectic Cast Aluminum Alloy
Piston Style

Flat Top with valve reliefs
Piston Volume

3cc
Wrist Pin Dia.

0.9431 in. (Full Floating)
Connecting Rod Material

Powdered Metal
Connecting Rod Style

I-beam
Connecting Rod Length

6.098 in.
Connecting

Rod Housing Bore

2.225 in.
Connecting Rod Bolts

M9 x 1 x 43
Connecting

Rod Part Number

12649190
Connecting Rod Casting Number

(last three digits)

143
Crankshaft Material

Cast Iron
Crankshaft

Part Number

12588614
Crankshaft Casting Number (last

three digits)

216
Crankshaft Main Journal Dia.

2.559 in.
Crankshaft Rod Journal Dia.

2.100 in.
Reluctor Wheel

58X

 

Cylinder Head Specifications
Casting Numbers

799, 243
Material

Aluminum
Combustion

Chamber Volume

65cc
Intake Port Shape

Cathedral
Intake Runner Volume

210cc
Exhaust Port Shape

D-Port
Exhaust Runner Volume

75cc
Intake Valve Dia.

2.000 in.
Exhaust Valve Dia.

1.575 in.
Cylinder Head Bolt Style

Torque to Yield (TTY)
Cylinder

Head Bolt Size

(10) M11 x 2 x 100, (5) M8 x 1.25 x 45

 

Camshaft Specifications
Part

Number

12625437
Duration

@ .050 in. (int./exh.)

190°/191°
Valve

Lift (int./exh.)

0.457 in./0.466 in.
Lobe

Separation

114°
Cam

Gear Attachment

1-Bolt
Cam

Gear Poles

4X
Active

Fuel Management (AFM)

No
Variable

Valve Timing (VVT)

Yes

 

Valvetrain Specifications
Lifter

Style

Hydraulic Roller
Lifter

Link Style

Plastic Lifter Tray
Lifter

Body Dia.

0.842 in.
Pushrod

Length

7.385 in.
Rocker

Arm Mounting Style

Pedestal
Rocker

Arm Style

Die-Cast, Roller Fulcrum
Rocker

Ratio

1.7
Rocker

Offset

None
Valve

Spring Style

Beehive
Valve

Spring Color

Natural
Valve

Angle

15 degrees
Intake

Valve Material

Steel, Solid Stem
Intake

Valve Dia.

2.000 in.
Exhaust

Valve Material

Steel, Solid Stem
Exhaust

Valve Dia.

1.575 in.
Timing

Chain Guide Style

Spring Loaded Tensioner

 

Other Specifications
Intake

Manifold

Truck-Style
Throttle

Body

87mm, 4-bolt
Throttle

Control

Electronic (Drive-by-Wire)
Fuel

Injector P/N

12613411
Fuel

Injector Flow

36 lb/hr @ 58 psi
Flex

Fuel Capable (E-85)

Yes
Fuel

Injector Length (between O-rings)

1.900 in.
Fuel

Injector Connector

EV6 / USCAR
Computer

E67
Crankshaft

Reluctor Ring

58X
Camshaft

Sensor Location

Timing Cover
Oil

Pan

Varies by Application
Oil

Pump

High Volume (1.25 c.i./rev.)



LH9 Harnesses