The Chevrolet Duramax is a General Motors prudcution diesel engine. Teams from Chevrolet and Izuzu came together to create the Duramax and the first production models were in 2001 with the Duramax Lb7 engine. The Lb7 was said to have been one of the best engines ever produced and was even featured in Ward’s 10 Best Engines for 2001 and 2002.
Diesel Engines are significantly different than gas engines in many ways. One of the way the engines differ is in the actual combustion of the fuel inside the engine. In a gasoline motor fuel and oxygen are mixed together and then compressed within the engine. After the fiel mixture is compressed a spark is introduce from the spark plug and the fuel combust. The explosion drives a piston which in tern drives a camm shaft connected to a a crank shaft. From here the power is transfered through the drive-train to the wheels and propels the vehicle forward. The same propulsion concept occurs in a diesel engine as well. In a diesel engine however, the oxygen is introduced first and then the fuel. Since oxygen heats up when it is compressed, when the fuel is introduced a combustion occur. For this reason diesel engines utilize glow plugs and not spark plugs.
Compressions of a diesel motor also run at much hotter temperatures than gas motors do so there must be a difference in the cooling systems of the motors. Compression ratios also vary greatly between diesel motors and gas motors which allows the engines to have more horsepower and torque output then gasoline engines. This is why diesel engines are also prefered to gas engines when it comes to hauling a heavy load or pulling a trailer. With the trucks getting better compression rations, diesel engines often times also get better fuel milage than gasoline powered engines of the same size. Most diesel engines also feature a turbo which boost the engines performance when needed, such as while pulling a trailer or going up steep inclines.
2001-2003 Duramax LB7 Specs:
90 degree V8
402 cubic inches, 6.6 liters
– Cast iron block
– Aluminum cylinder heads
– air to air intercooler
– Maximum boost: 20 psi
OHV, 4 valves per cylinder
– Direct injection
– Bosch high pressure common rail, CP3 injection pump
– 23,000 psi max injection pressure
10 quarts w/filter
approx. 835 lbs
235 hp @ 2,700 RPM (2001)
300 hp @ 3,100 RPM (2004)
500 lb-ft @ 1,600 RPM (2001)
520 lb-ft @ 1,800 RPM(2004)
Maximum Engine Speed:
Difference Between LB7 and other Comparable Diesel engines.
One thing that caught many interested customers eyes right off the bat was the use of aluminum cylinder heads. Most other diesel engines use cast iron cylinder heads, which proves to be stronger and more durable over time. However, utilizing aluminum cylinder heads seems to have its advantages as well. With the combustion of a diesel engine being so hot in temperature, the aluminum head displace heat greater than cast iron heads therefore making the overall working temperature of the engine less. In most cases, the main reasons engines suffer damage is from excessive overheating. The aluminum cylinder heads of the Duramax will prove to be efficient over the course of time by maintaining a lower engine temperature.
The only time a problem could occur with the aluminum heads of the Duramax is when aftermarket changes are being made and more horsepower is being added. In this case cast iron would be the desired material for the cylinder heads since it can withstand greater pressure amounts.
Difference that makes the 2001-2003 Duramax more desirable than other years:
The main difference that makes the 01-03 duramax more desirable than other year duramaxes is the absence of the exhaust gas recirculation system (EGR). This system uses a catalytic converter and filters to reduce the emissions and soot build up released by the motor. This system was introduced on the 2004 models. While reducing emissions of the vehicle, the EGR system also reduced the fuel economy tremendously by restricting the exhaust of the vehicle. Electronics are sold to bypass this system and restore the fuel economy of your vehicle but they are costly.
Issues with the LB7 Engine.
While the LB7 is often praised for its strength, horsepower and fueled economy, the engine does have issues just like every other. The main problem with the engine is the fueled injectors. Customers started noticing that injectors were fowling at an alarming rate. Finally, after many customer complaints, GM placed a recall on all LB7 fuel ejectors. This seems like such a minor issue for such a great engine, but at $3,500 to replace the injectors, one can see how it would be a concern.
Overall, the Chevy Duramax is an up and coming star in the diesel engine world and the 2001-2003 LB7 engine was the one to set the standards for all Duramaxes to come.