The new GM L3B engine is a 2.7-liter four-cylinder turbocharged gasoline engine that debuts in the 2019 Chevrolet Silverado 1500 and GMC Sierra 1500.
This engine was designed for full-size pickup trucks and is the first 4-cylinder engine to appear in a GM full-size pickup truck. The L3B engine is made by Spring Hill Manufacturing, a GM subsidiary in Spring Hill, Tennessee.
The 2.7 Turbo L3B has a deep-skirt, heavily ribbed die-cast aluminium (380 T5) cylinder block with iron liners. It features a 4.01-inch (102-mm) piston stroke, which produces a lot of low-end torque but also a lot of vibrations.
To restore smoothness, a twin balancing shaft system was put in the engine block. The engine block also has a forged steel crankshaft with hardened journals and tri-metal bearings. The crankshaft skews the centerline of the cylinder bore.
The offset placement reduces side-loading friction. The lightweight aluminium pistons have machined crowns and cast iron ring carriers. The pistons are additionally cooled using oil spray squirters. In the engine, there is a continuously variable-output oil pump.
The oil pump and balance shafts are supported by a bolt-on aluminium lower crankcase extension.
The bottom side is sealed with a nylon-reinforced plastic oil pan. On top of the engine block is a 16-valve aluminium alloy (356 T5) cylinder head with high-tumble combustion chambers and dual-overhead camshafts.
The cylinder head has copper-alloy exhaust valve guides for the exhaust valves to improve heat transfer and valve cooling. The intake and exhaust camshafts are driven by an 8 mm roller timing chain.
The 2.7L L3B valvetrain's Sliding Cam Valve Lift System (SCVS) features three distinct operating modes: High Lift, Low Lift, and AFM (Active Fuel Management). All cylinders are set to High Lift mode, and all valves are fully opened.
Low Lift mode reduces the duration of the intake valve opening by 3 mm under medium load conditions, which helps save gas. In AFM mode, cylinders 2 and 3 are inhibited, which decreases fuel consumption in light load situations.
In addition, valve timing on both the intake and exhaust sides is continually changeable.
The L3B engine has a high-pressure direct fuel injection system. With up to three injection events each combustion cycle, the high-pressure fuel pump can provide up to 3000 psi (20 MPa) of fuel pressure via side-mounted direct injectors.
Direct injection is combined with a high-energy coil-on-plug electronically controlled ignition system in Spark Ignited Direct Injection (SIDI).
Similar to most modern turbocharged engines, the 2.7 L3B features a cylinder head design with an integrated and water-cooled exhaust manifold to shorten engine warm-up time (for passing emissions testing) and lengthen turbocharger life by keeping it "cool" at high loads.
The engine has a single BorgWarner dual-volute turbocharger with a maximum boost of 22 psi (1.5 bar). This turbocharger's wastegate is operated by electricity. The compressed air is cooled using an air-to-air intercooler, which reduces the temperature by around 130 degrees Fahrenheit (74 C).
Another distinguishing feature of this new engine is GM's active thermal management cooling system. This system consists of a 3-way rotary valve and an ECM-controlled electric water pump.
An electric water pump heats the passenger compartment while simultaneously cooling the engine and transmission.
The new GM L3B 2.7L engine was designed to replace the 4.3L V6 engine, and engineers were successful in achieving their aim. It boasts 9% more horsepower and 14% more torque than its predecessor, weighs 80 pounds (36 kg), and consumes 13% less fuel while generating fewer emissions.
When compared to Ford's V6 2.7-liter EcoBoost engine (325 horsepower and 400 pound-feet of torque), the GM 2.7-liter 4 banger falls short, producing just 310 horsepower and 348 pound-feet of torque.
Manufacturer: Spring Hill Manufacturing plant, Spring Hill, Tennessee, the USA
Production years: 2018-present
Cylinder block material: Aluminium
Cylinder head material: Aluminium
Fuel type: Gasoline
Fuel system: Direct Injection
Number of cylinders: 4
Valves per cylinder: 4
Valvetrain layout: DOHC
Bore: 92.2 mm (3.63 in)
Stroke: 102.0 mm (4.02 in)
Displacement: 2,727 cc (166.4 cu in)
Type: Four-stroke, turbocharged
Compression Ratio: 10:1
Power: 310-325 hp (231-242 kW) at 5,500-5,600 rpm
Torque: 348-380 lb ft (472-515 Nm) at 1,500-4,000 rpm
Firing order: 1-3-4-2
Engine oil weight: SAE 5W-30 full synthetic motor oil
Engine oil capacity: 5.7 litres (6.0 qt) (with oil filter)
Oil change interval: 10,000 miles (15,000 km) or 12 months
Applications: Chevrolet Silverado 1500, Chevrolet Colorado, GMC Sierra 1500, GMC Canyon, Cadillac CT4 Premium Luxury, Cadillac CT4-V
Problems & Reliability
The GM 2.7 L3B comes with a slew of innovations aimed at improving fuel efficiency and performance. GM boasts that the new engine has successfully completed over one million miles of over-the-road durability testing, despite the fact that many things may go wrong.
If GM's new 2.7-liter turbo engine is reliable, only time and real-world experience will tell.
For the time being, keep in mind that, like other modern turbocharged and direct-injected engines, the engine oil quality and condition are quite important. If this engine is not properly maintained, it will swiftly degenerate.
While almost all other direct-injected-only engines from other manufacturers were modified to include both direct and port injection, the fuel delivery system chose to use direct injection only.
Combined fuel injection increases cylinder wall life and decreases carbon buildup on intake valves and intake port walls.