2010 GM 3.9L V-6 (LGD, LZ9)
3.9L V-6 ( LGD, LZ9) CAR ENGINE
2010 Model Year Summary
New split converter systems for Impala for OBD2 compliance
Expanded usage of E37 ECM on Impala
High mileage dependability improvements-mist quench cylinder heads, PQ5 coated cylinder head gaskets, Brico 3010 exhaust valve seats and FKM coolant crossover gasket,
Full Description of New and Update Features
GM’s new-generation 60-degree 3.9L V-6 is available with E85 flex-fuel capability and Variable Valve Timing (LGD). RPO (LGD) is now standard in the Buick Lucerne and Chevrolet Impala. RPO (LZ9) also with Variable Valve Timing, is offered for 2010 in the Buick Lucerne. In all applications, the 3.9L V-6 is installed with GM’s Hydra-Matic 4T65 four-speed automatic transmission.
E85 Flexible-Fuel Capability (LGD)
GM has led the industry in introducing flex-fuel capability to its cars and trucks, and the flex-fuel capable 3.9L V-6 (RPO's LGD) extends availability to an even broader range of customers. E85 is a clean-burning alternative fuel made in the United States from corn and other crops, composed of 85 percent ethanol alcohol and 15 percent gasoline. The 3.9L's flex-fuel technology is both sophisticated and durable.
Hardware changes for flex-fuel operation are limited to the injectors. Because ethanol has fewer BTUs (less energy) than the same volume of gasoline, more fuel is required to produce the same horsepower at wide-open throttle. Flex fuel engines use unique injectors with higher maximum fuel-flow rate. The fuel rail matches the injectors, but it's manufactured of the same stainless steel used for all 3.9L V-6 fuel rails.
The flex-fuel 3.9L doesn't require a special fuel sensor. The first flex-fuel engines used a light-reactive sensor to measure fuel composition from 100 percent gasoline to 85 percent ethanol. The 3.9L has a "virtual sensor", using sophisticated software programmed into the Engine Control Module (ECM) with no separate physical sensor whatsoever. Based on readings from the oxygen sensors, fuel level sensor and vehicle speed sensors, the ECM adjusts the length of time the fuel injectors open for the type of fuel used. Within a few miles after filling up, the ECM controller determines what fuel is powering the 3.9L V-6 and manages the engine accordingly.
E85 fuel provides an environmentally friendly companion or alternative to gasoline. It lessens our country's dependence on foreign oil supplies. It is biodegradable and doesn't contaminate the water supply. Ethanol can be produced from various feed stocks, including corn and wheat stalks, forestry and agricultural waste, and even municipal waste.
Advanced Engine Control Modules
Every 3.9L V-6 is managed by one of the two controllers in GM’s new family of engine control modules (ECM), which will direct nearly all engines in GM’s line-up. These ECMs more precisely orchestrate the myriad operations that occur within the 3.9L every split second. In combination with advanced sensor technology, they include the ability to control and coordinate such systems as cam-in-block variable valve timing and E85 ethanol fuel sensing. Most 3.9Ls use the mid-line controller, known as the E38. The 3.9Ls built for the Buick Lucerne's are equipped with the E37 ECM.
These ECMs feature 32-bit processing, compared to the conventional 16-bit processing in previous 60-degree V-6 engines. They operate at 59 MHz, with 32 megabytes of flash memory, 128 kilobytes of RAM and a high-speed CAN bus, and the synchronizes more than 100 functions, from spark timing to cruise control operation to traction control calculations. The ECM works roughly 50 times faster than the first computers used on internal combustion engines in the late 1970s, which managed five or six functions.
The family strategy behind GM's new ECMs allows engineers to apply standard manufacturing and service procedures to all powertrains, and quickly upgrade certain engine technologies while leaving others alone. It creates both assembly and procurement efficiencies, as well as volume sourcing. In short, it creates a solid, flexible, efficient engine-control foundation, allowing engineers to focus on innovations and get them to market more quickly. The family of controllers means the ECM and corresponding connectors can be packaged and mounted identically in virtually every GM vehicle. GM creates all the software for the ECMs, which share a common language and hardware interface that's tailored to each vehicle.
The new ECMs also apply a new, rate-based monitoring protocol sometimes known as run-at-rate diagnostics. Rate-based diagnostics improve the robustness of the Onboard Diagnostics System (OBD II) and ensure optimal performance of emissions control systems. The new software increases the frequency at which the ECM checks various 3.9L systems, and particularly emissions-control systems such as the catalytic converter and oxygen sensors. Rate-based diagnostics more reliably monitor real-world operation of these systems, and allow regulatory agencies to more easily measure and certify emissions compliance.
Overview
GM’s new overhead-valve V-6 engines demonstrate conclusively that the inherent strengths of cam-in-block design can be applied in the environmentally sensitive 21st century--in trucks and cars. With advanced technologies such as Variable Valve Timing and Ethanol fuel concentration sensing, the 3.9L delivers the power and flexibility of a large-displacement V-6 with new levels of fuel efficiency. It brings innovation to the mainstream, with wide application in a high-value package the typical consumer can afford.
This new generation V-6 allows a high level of flexibility, with common castings over a range of displacements. The 3.9L V-6 shares its block, pistons and cylinder heads with GM’s new 3.5L (RPOs LZ4 and LZE). A common bore measures 99 mm; displacement is increased in the 3.9L with a longer stroke (84 mm, compared to 76 mm for the 3.5L). The two engines share 80 percent of their parts.
Thanks to its relatively narrow 60-degree block angle, the 3.9L V-6 is compact, giving vehicles teams more latitude with platform design and styling. More importantly, the 60-degree configuration is inherently balanced, ensuring powertrain smoothness without the additional cost of balance shafts. The new 3.9L V-6 differs from previous GM 60-degree designs in its offset cylinder bores. The centerlines through the bores on each bank do not intersect at the crank axis; rather, they intersect 3 mm below the crank axis. The offset bores present a number of advantages, including room for larger cam journals and flexibility to stroke the engine for more displacement. The 3.9L block also features a unique "U-flow" coolant path. The coolant passages flow coolant in a specific, predetermined path, starting at the front of block, then rearward toward transmission, up through the cylinder heads and back to the front. The thermostat is placed near the inlet from the radiator, decreasing warm-up time. The fill point is at the highest point of the cooling system to prevent air pockets in the hoses or passages.
The cylinder heads apply design features developed for the high-output LS1 and LS6 Corvette small-block V8s. The 3.9L V-6's valves are similar to those in the LS1, as is its combustion chamber design. Low-friction hydraulic roller lifters work the valves, improving the engine's efficiency and reducing vibration.
The 3.9L V-6's "returnless" fuel injection system is the new standard at GM. It eliminates fuel return lines between the engine and the gasoline tank, essentially eliminating heat transfer from the engine to the tank and reducing the amount of vapor emissions substantially. New generation fuel injectors with shrouded nozzles are designed to minimize clogging and maintain optimal performance when in high heat.
For all the advanced systems in the 3.9L V-6, perhaps the most significant-certainly the one that has garnered the most attention-is variable valve timing (VVT). GM's new generation V-6s were the first cam-in-block engines with VVT-an accomplishment engineers considered extremely difficult, if not impossible, just a few years ago. The 3.9L's dual-equal VVT uses a hydraulically operated vane-type cam phaser that turns the camshaft relative to its drive sprocket.
The advantages of cam-in-block VVT are pronounced. The cam phaser changes valve timing on the fly, maximizing engine performance for given demands and conditions. At idle, for example, the cam is at the full advanced position. That allows exceptionally smooth idling. Under other operating demands, the phaser adjusts to deliver optimal valve timing for performance, drivability and fuel economy. At high rpm it might retard timing to maximize airflow through the engine and increase horsepower. At low rpm it advances timing to increase torque. Under a light load (say, casual everyday driving), it can retard timing at all engine speeds to improve fuel economy. Without cam phasing, a cam design must be biased toward one strength or another-high-end horsepower or low-end torque, for example-or profiled at some median level that maximizes neither. Variable valve timing allows linear delivery of torque, with near-peak levels over a broad rpm range, and high specific output (horsepower per liter of displacement) without sacrificing overall engine response, or drivability. It also provides another effective tool for controlling exhaust emissions. Because it manages valve overlap at optimum levels, it eliminates the need for an Exhaust Gas Recirculation (EGR) system.
Virtually every component and system in GM's new generation cam-in-block V-6s was reviewed in an effort to enhance durability and reduce noise, vibration and harshness. Piston-cooling jets remain the exception rather than the rule in overhead cam engines, yet each piston in the 3.9L V-6 has its own pressure-actuated jet that sprays oil toward its skirt, coating its underside and the cylinder wall with an additional layer of lubricant. The extra lubrication cools the pistons, reducing both friction and operational noise and helping ensure durability. The cam-drive chain has a leaf spring-type dampener that maintains optimal chain tension for the life of the engine and eliminates any flapping motion that might develop as the chain stretches with mileage. It ensures that the timing chain operates as smoothly and quietly as new, even as the engine accumulates high mileage.
Multi-layer steel gaskets are sandwiched between the block and cylinder heads to maintain optimal sealing for the life of the engine. The cast-iron exhaust manifolds are fitted with heat shields fabricated from stainless steel and insulating material. These limit heat transfer from the engine to the engine bay, allowing the 3.9L to reach optimal operating temperature more quickly, yet reducing heat in the engine compartment once that temperature is achieved. They also dampen the sound of exhaust gas rushing through the manifolds and further reduce the amount of engine operational noise that finds its way into the vehicle interior. A cast aluminum oil pan increases engine rigidity and radiates less noise than a conventional steel pan. An acoustic engine cover further reduces the amount of noise transmitted to the passenger compartment from the engine.
Low maintenance was a development priority. The spark plugs have an iridium tip and core to maintain spark density over their 100,000-mile life, helping ensure the same fuel efficiency and emissions performance over the last 10,000 miles as the first. The coolant and accessory belt are both expected to last 150,000 miles. Maintenance in typical use is limited to oil changes, and even those are made as simple as possible. The GM Oil Life System measures how hard the engine is used and calculates the optimal life expectancy of the engine oil, indicating an oil change only when it's actually needed, rather than according to some predetermined mileage interval.
GM's new overhead-valve V-6 engines define the concept of high value in powertrain development. They deliver advanced, industry exclusive technologies with real benefit for customers, yet they keep both the cost of production and the cost of ownership low. In short, the new 3.9L V-6 delivers a top-shelf balance of good specific output, low-end response, even torque delivery, low maintenance and value, with vehicle packaging flexibility in a wide range of front and all-wheel drive applications.
