The LS4 was used in GM cars between 2005-09. It is unique because it was the only LS engine used in FWD vehicles.
To make this engine work, GM made several modifications to the engine:
- The engine was mounted in a transverse position, using unique motor mounts.
- The intake manifold was smaller than other LS manifolds and reversed, placing the throttle body placed over the flexplate.
- The engine used a metric, 60 degree, Chevrolet V6 bellhousing.
- The starter was mounted on the transmission, not the engine block.
- The timing cover, crankshaft, and accessory drive were all modified to fit in the FWD engine bays.
Because of its unique configuration, the LS4 is usually not a good candidate for an engine swap. The information listed here is for a stock engine.
Performance Specifications |
|
Compression Ratio | 10 : 1 |
Horsepower Rating | 303 hp. |
Torque Rating | 323 ft./lbs. |
Application Information |
|||
VIN 8th Digit |
Year |
Make |
Model |
C |
2005-08 |
Pontiac |
Grand Prix GXP |
2006-07 |
Chevrolet |
Monte Carlo SS |
|
2006-09 |
Impala SS |
||
2008-09 |
Buick |
LaCrosse Super |
Engine Block Specifications |
|
Casting Number |
12569004 |
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 |
Piston Volume |
0cc |
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 P/N |
12649190 |
Connecting Rod Casting Number (last three digits) |
143 |
Crankshaft Material |
Cast Iron |
Crankshaft P/N |
12568920 |
Crankshaft Casting Number (last three digits) |
216 |
Crankshaft Main Journal Dia. |
2.559 in. |
Crankshaft Rod Journal Dia. |
2.100 in. |
Crankshaft Length |
13mm shorter than standard (-10mm snout, -3mm rear flange) |
Reluctor Wheel |
24X (2005, 2006 and early 2007, 58X (later 2007-09) |
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 |
||
Years |
2005-07 |
2007-09 |
Camshaft P/N |
12569525 |
12625436 |
Duration @ .050 in. (int./exh.) |
193°/193° |
196°/201° |
Valve Lift (int./exh.) |
0.482 in./0.482 in. |
0.481 in./0.481 in. |
Lobe Separation |
114° |
116°+2 |
Cam Gear Attachment |
3-Bolt |
1-Bolt |
Cam Gear Poles |
1X |
4X |
Active Fuel Management (AFM) |
Yes |
|
Variable Valve Timing (VVT) |
No |
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 |
Plastic Guide (2005-06), Spring Loaded Tensioner (2007-09) |
Other Specifications |
||
Intake Manifold P/N |
12604786 |
|
Intake Manifold |
Car-Style (Reversed) |
|
Throttle Body P/N |
12568580 (2005-07) |
12631016 (2008-09) |
Throttle Body |
76mm, 4-Bolt, Gold blade (Non-standard bolt pattern) |
|
Throttle Control |
Electronic (Drive-by-Wire) |
|
Fuel Injector P/N |
12580681 |
|
Fuel Injector Flow |
30 lb./hr. @ 58 psi |
|
Flex Fuel Capable (E-85) |
No |
|
Fuel Injector Length (between O-rings) |
1.730 in. |
|
Fuel Injector Connector |
EV6 / USCAR |
|
Computer |
E40 (2005-07) |
E67 (2007-09) |
Crankshaft Reluctor Ring |
24X (2005, 2006. early 2007) |
58X (2007-09) |
Camshaft Sensor Location |
Timing Cover |
|
Oil Pan |
Centered Sump |
|
Oil Pump |
High Volume (1.25 c.i./rev.) |
Follow this link for more information on Upgrading the LS4 Engine.