Twin Cam 2.4L (LD9)
Overview
The LD9 Twin Cam was a 2.4 L Quad 4 variant with balance shafts, debuting in 1996. Bore was decreased from 92 mm to 90 mm and stroke increased from 85 mm to 94 mm for better torque, and power was increased to 150 hp. The LD9 engine received a minor update halfway through the 1999 model year that eliminated the EGR, increased the compression ratio from 9.5:1 to 9.7:1, and switched from low impedance fuel injectors to high impedance. The history of this motor lies deep within the quad 4 motor. The Quad 4 was a DOHC straight-4 automobile engine produced by General Motors' Oldsmobile division in the 1990s. It was a modern engine for the time, but was criticized for roughness. Balance shafts were added in 1995, also known as a transitional year from the quad 4 to the renamed TWIN CAM variant, in 1996 2.4 (LD9) the complete engine makeover was accomplished. The name is derived from the engine's four cylinders and four valves per cylinder layout. There was a single overhead camshaft variant that made production as well, albeit for a brief time. The Quad 4 used an iron block and an aluminum head. The Quad 4 debuted in 1987 and was replaced after 2002 by the Ecotec. Quad 4 engines were produced at Oldsmobile's Delta Township, Michigan plant. In recent years, it has gained a minor following in hot rodding circles as a period style engine (which looks like a 1930's Offenhauser twin cam unit).
One of the best known articles comparing the Quad 4 and Twin Cam: [URL]http://www.babcox.com/editorial/ar/ar49935.htm"[/URL]
Brief engine differences
96 Model Year
*Engine had different oil passages, and water-pump problems
*Large starter
*One wire front O2 sensor
*Low impedance injectors
*12465154 (Version 1a) no longer offered
*EGR valve
*Dished pistons
*9.5:1 CR
*Large knock sensor
*Head casting number is 683-18
97-98 Model Year
*Oil passages and water-pump problems lessen
*Large starter
*One wire front O2 sensor
*Low impedance injectors
*EGR valve
*Dished pistons
*9.5:1 CR
*Large knock sensor
*Head Casting number is 683-18
97-98 Chevrolet, Pontiac J & N (LD9)(2.4T)
Part # 12462258 Version 1b
Application
1997-98 Chevrolet, Pontiac J (LD9)(2.4T)
1997-98 Chevrolet, Pontiac, N (LD9)(2.4T)
1997-98 Oldsmobile, Buick
1999 Pontiac N (LD9)(2.4T)
12462258 Version 1b replaces: 12465154 Version 1a
Order 11516479 self-taping screw for Camshaft Position Sensor. For 2nd design, see 12465154.
You can use either version 1a, 1b, or 2 in your car with little modification.
99 model year
*Smaller starter
*One wire first O2 sensor
*High impedance injectors
*No EGR valve
*Flat top pistons
*9.7:1 CR
*Better intake manifold design. Doesn’t have flange on the inside plenum like 00-02 years.
*New oiling passages
*Small knock sensor
*Head casting number is 779
*New style water-pump
00-02 model year
*Smaller starter
*Two wire front O2 sensor
*High impedance injectors
*No EGR valve
*Flat top pistons
*9.7:1 CR
*New oiling passages
*Small knock sensor
*Head casting number is 779
*New style water-pump
*Belt tensioner changed
01 model year changes
*Received a "higher capacity" catalytic converter
*Redesigned starter motor
General Data
Engine Type: Inline 4 Cylinder
Displacement: 2.4 Liter (146 CID)
Liter (VIN): T
RPO: LD9
Bore: 90 mm 3.54 in
Stroke: 94 mm 3.70 in
Compression Ratio: 9.5:1 (96-98)/ 9.7:1 (99-02)
Firing Order: 1-3-4-2
Horse Power: 150 @ 5600 rpm
Torque Rating: 155 @ 2400-4400 rpm
Lubrication System
Oil Capacity with Filter Change 4.5 qts. (Who changes the oil with out changing the filter?)
Oil Capacity without Filter Change 3-3/4 Liters 4 qts
Engine Oil Type: SAE 5w30
Engine Cooling System 10.7 quarts
Brake Fluid: Delco Supreme 11 or DOT-3 Equivalent
Cluch Fluid: Delco Supreme 11 or DOT-3 Equivalent
Refrigerant: R-134a
Power Steering Fluid: GM p/n 1050017
Oil Pressure @ 3000 RPM 207 kPa 30 psi min.
Oil Pressure @ 900 RPM 69 kPa 10 psi min.
Recommended octane: 87
Fuel Tank Capacity: 14.1-15.2 gal.
EPA Mileage Estimates: (City/Highway)
Manual: 23 mpg / 33 mpg
Automatic: 22 mpg / 30 mpg
Fuel Delivery: Sequential fuel injection (SFI)
Thermostat opening temperature 180 degrees F
Emissions: Low emissions vehicle equipped with single Catalyst
Fastener Tightening Specifications
Application Specifications
...............................................................................................................................English
Balance Shaft Cover Nut and Bolt........................................................................115 lb in
Balance Shaft Driven Sprocket Bolt (left hand thread).........................................30 lb ft + 45°
Balance Shaft Housing Bolts 8 mm hex................................................................89 lb in + 40°
Balance Shaft Housing Bolts 10 mm hex..............................................................11 lb ft + 40°
Balance Shaft to block Bolts 13 mm hex...............................................................18 lb ft + 70°
Balance Shaft to block Bolts 15 mm hex............................................................... 39 lb ft
Balance Shaft to Block Bolts 18 mm hex............................................................. 30 lb ft + 60°
Camshaft (exhaust) Rear Cover............................................................................124 lb in
Camshaft Position Sensor Bolt............................................................................ 89 lb in
Camshaft Sprocket to the Camshaft Bolt.............................................................52 lb ft
Connecting Rod Nuts............................................................................................18 lb ft + 80°
Coolant Bleeder Valve Fully Driven, Seated , Not Stripped
Coolant Outlet to Cylinder Head..........................................................................19 lb ft
Coolant Pump Cover to the Block........................................................................19 lb ft
Coolant Pump to the Coolant Pump Cover..........................................................124 lb in
Coolant Pump to the Timing Chain Housing........................................................19 lb ft
Crankshaft Balancer to the Crankshaft..................................................................129 lb ft + 90°
Crankshaft Bearing Cap Bolts................................................................................15 lb ft + 90°
Crankshaft Position Sensor to Block.....................................................................80 lb in
Cylinder Head Bolts Refer to Procedure
Cylinder Head Threaded Plug............................................................................... 19 lb ft
EGR Pipe to the EGR Adapter.............................................................................19 lb ft
Engine Coolant Air Bleed Pipe ..............................................................................124 lb in
Engine Coolant Air Bleed Pipe Nut........................................................................31 lb ft
Engine Coolant Temperature Gauge Sensor to the Cylinder Head
Fully Driven, Seated, Not Stripped
Engine Coolant Temperature Sensor to the Coolant Outlet....................................97 lb in
Engine Lift Bracket..................................................................................................68 lb ft
Engine Mount Bracket Adapter to Block Bolt Auto Trans.................................... 44 lb ft + 60°
Engine Mount Bracket Adapter to Block Bolt Manual Trans..................................44 lb ft + 60°
Engine Mount (right hand side) to the Body Support Bolt..................................... 49 lb ft
Engine Mount (right hand side) to the Body Support Nut...................................... 32 lb ft
Engine Mount (right hand side) to the Engine Mount Bracket Bolts.......................46 lb ft
Engine Mount Strut..................................................................................................74 lb ft
Engine Mount Strut Bracket Bottom Bolts.............................................................. 96 lb ft
Engine Mount Strut Bracket Front Bolts..................................................................49 lb ft
EVAP Canister Purge Valve Solenoid Bracket Bolt..................................................72 lb in
Exhaust Manifold Brace to the Exhaust Manifold Bolt.............................................41 lb ft
Exhaust Manifold Brace to the Oil Pan Nuts............................................................19 lb ft
Exhaust Manifold to the Cylinder Head Nut............................................................11 lb ft
Exhaust Manifold to the Cylinder Head Studs......................................................... 97 lb in
Exhaust Manifold Upper Heat Shield to the Manifold Bolts...................................124 lb in
Flywheel to Clutch Cover .....................................................................................15 lb ft + 45°
Flywheel to the Converter.......................................................................................49 lb ft
Flywheel to the Crankshaft....................................................................................22 lb ft + 45°
Front Cover to the Timing Chain Housing................................................................106 lb in
Fuel Pipe Bracket to the Camshaft Housing.............................................................11 lb ft +30°
Fuel Pipe to the Fuel Rail Nut...................................................................................22 lb ft
Fuel Rail to the Camshaft Housing............................................................................19 lb ft
Ignition Coil and Module Assembly to the Camshaft Housings...............................16 lb ft
Intake Manifold to the Cylinder Head Bolts/Nuts....................................................18 lb ft
Intake Manifold to the Cylinder Head Studs........................................................... 97 lb in
Knock Sensor.............................................................................................................15 lb ft
Oil/Air Separator To Block Bolts..............................................................................18 lb ft
Oil Dipstick Tube Bolt/Screw...................................................................................71 lb in
Oil Filter Connector to the Block..............................................................................21 lb ft
Oil Filter to the Block 3/4 to one complete turn after gasket contact
Oil Pan Bolts.............................................................................................................18 lb ft
Oil Pan Bolts, Second Set.........................................................................................106 lb in
Oil Pan Drain Plug.....................................................................................................19 lb ft
Oil Pan Studs ...........................................................................................................19 lb ft
Oil Passage Plug Bolt................................................................................................ 22 lb ft
Oil Passage Plugs, 1/4x18 ...........................................................................................15 lb ft
Oil Passage Plugs, 3/8x18............................................................................................22 lb ft
Oil Passage Plugs, Block 1/8x27................................................................................89 lb in
Oil Pressure Switch......................................................................................................124 lb in
Oil Pump Cover to the Oil Pump Housing - Short Bolt............................................89 lb in
Oil Pump to the Balance Shaft Housing - Long Bolts..............................................106 lb in
Oxygen Sensor To Exhaust Manifold.........................................................................31 lb ft
Power steering Pipe to the Pump Nut........................................................................20 lb ft
Power steering Pump to the Cam Carrier Bolts.........................................................19 lb ft
Rear Crankshaft Seal Housing to Block.................................................................... 106 lb in
Spark Plugs to the Cylinder Hea...............................................................................13 lb ft
Starter to the Block Bol..............................................................................................66 lb ft
Tensioner to Tensioner Bracket Nut.......................................................................... 40 lb ft
Throttle Body to the Intake Manifold.........................................................................89 lb in
Thrust Plate to the Balance Shaft Housing.................................................................. 115 lb in
Timing Chain Housing to the Block Bolts/Studs..........................................................21 lb ft
Timing Chain Housing to the Camshaft Housings.......................................................19 lb ft
Timing Chain Tensioner to Housing and Block............................................................89 lb in
Transaxle To Block Bol................................................................................................43 lb ft
Transaxle To Block Nut................................................................................................49 lb ft
Transaxle To Block Stud...............................................................................................115 lb in
Thanks to -MD- LD9 for compiling this information. References used: GM manuals, Cilton Manual, J-body.org, NY-J-body Web-site, Wikipedia Web-site, fellow org members, and I missed a bunch! ENJOY!
