Stroking An Lq4 Motor: Is It Possible?

The LQ4 is a 6.0L LS (Gen. 3) small-block engine used in GM trucks between 1999 and 2007. The LQ4 engine has a stock displacement of 366 cubic inches via a 4.00x3.62-inch bore and stroke. One of the appeals of the LQ4 is its ability to take added displacement via a stroker crank. A stroker is an engine where the piston stroke is increased, resulting in a deeper piston in the cylinder bore and increased displacement. The LQ4 can be stroked by substituting a 4.00-inch crank, yielding a displacement of over 400 cubic inches. This modification does not require any custom clearancing or grinding, as the factory block readily accepts the long-stroke crank. The stock LQ4 heads can also be CNC-ported and milled for more airflow and compression, respectively. When choosing a stroker crank for the LQ4, it is important to consider the compression ratio, piston-to-valve clearance, and camshaft specifications to achieve the desired performance goals.

Stroker cranks and their impact on LQ4 engines

Stroker cranks are a great way to increase the displacement of an engine, and the LQ4 is no exception. Stroker cranks work by increasing the distance between the centre of the crankshaft and the centre of the big end bearing, which in turn increases the distance travelled by the piston, resulting in a greater displacement.

The LQ4 engine is a 6.0L LS (Gen. 3) small-block engine used in GM trucks between 1999 and 2007. The stock bore and stroke of the LQ4 are 4.00 inches and 3.62 inches, respectively, giving it a displacement of 366 cubic inches.

When it comes to choosing a stroker crank for the LQ4, there are a few options available. A common approach is to use a 4.00-inch crank, which increases the displacement to over 400 cubic inches with a clean-up overbore. This can be achieved without any custom clearancing or grinding, as the factory block readily accepts the longer stroke. Scat offers a popular stroker kit with a 4.00-inch crank, I-beam rods, and forged pistons, providing an affordable and reliable option for those looking to increase the displacement of their LQ4.

Another option for a stroker crank is a 3.900-inch stroke, which can provide a more stable platform for the pistons and reduce the risk of damage over time. Companies like CNC Motorsport offer a range of 3.900-inch stroker cranks that can be a good choice for those seeking increased reliability.

It is important to note that while stroker cranks can significantly increase the displacement and power output of an engine, they also have some drawbacks. Longer strokes can lead to reduced piston speed and higher piston temperatures, which can impact the reliability of the engine. Additionally, stroker cranks can also increase the weight of the rotating assembly, affecting the responsiveness and acceleration of the vehicle.

When considering a stroker crank for an LQ4 engine, it is crucial to take into account the intended use of the vehicle, the desired power output, and the potential trade-offs in terms of reliability and responsiveness. Stroker cranks can be a great way to extract more power from the LQ4, but they should be chosen and installed carefully to ensure optimal performance and longevity.

LQ4 engine specs and their performance

The LQ4 is a 6.0L LS (Gen. 3) small-block engine used in GM trucks between 1999 and 2007. For marketing purposes, it was also known as the Vortec 6000. The LQ4 and its similar variant, the LQ9, are popular choices for engine swaps and upgrades due to their strength, availability, and performance potential.

LQ4 Engine Specifications

The LQ4 engine has the following specifications:

• Engine Block: Iron block with a displacement of 364 cubic inches (6.0L).
• Cylinder Bore and Stroke: Bore/Stroke of up to 4.040" x 3.622", resulting in a displacement of up to 371 cubic inches.
• Crankshaft: OE GM 24-tooth reluctor wheel.
• Connecting Rods: OE powder metal or stock GM.
• Pistons: Hypereutectic with 10:1 compression ratio.
• Camshaft: Hydraulic roller with a custom performance grind.
• Timing Chain: OE single roller.
• Cylinder Heads: OE cathedral port aluminum with 71cc/210cc chamber volume and 2.00"/1.55" valve diameters.
• Rocker Arms: 1.7 ratio.
• Oil Pump: Melling standard volume.

Performance Upgrades

The LQ4 engine is known for its responsiveness to performance upgrades, and there are several options to increase horsepower and torque:

• Basic Bolt-On Upgrades: Cold air intake, aftermarket exhaust, and electric fan kit.
• Camshaft and Valvetrain: Upgrade to a dedicated truck camshaft, such as the LS3 or LS9 cam, and consider installing LS2 timing chain, LS7 spec lifters, and .080" wall pushrods.
• Power Adders: Superchargers (roots-style or centrifugal), nitrous oxide, or turbochargers can significantly increase power output.
• Fuel System and Tuning: Upgrade fuel injectors, consider a water-methanol injection system, and custom tuning is essential for optimizing performance.
• Intake Manifold and Throttle Body: Port the factory intake manifold or upgrade to an aftermarket intake, such as the Trailblazer SS intake or F.A.S.T. LSXRT intake, along with a larger throttle body.
• Cylinder Heads: CNC porting and milling the stock heads can increase airflow and compression. Aftermarket cathedral port heads offer improved airflow and cross-sections suitable for boost.
• Rotating Assembly: Forged pistons, connecting rods, and crankshaft can increase durability and allow for higher performance.
• Engine Block: Over-boring and stroking the engine can increase displacement, resulting in more power.

LQ4 engine upgrades and their benefits

The LQ4 is a 6.0L LS (Gen. 3) small-block engine used in GM trucks between 1999 and 2007. It is also known as the Vortec 6000. The LQ4 is a popular choice for engine swaps due to its strength, availability, and affordability.

Basic Bolt-On Upgrades

Basic bolt-on upgrades for the LQ4 engine include:

• Cold air intake
• Aftermarket exhaust
• Electric fan kit
• Colder thermostat
• Computer programmer

Camshaft and Valvetrain Upgrades

Upgrading the camshaft and valvetrain can provide significant performance improvements. The original camshaft is small and should be replaced. A dedicated truck camshaft, such as an LS3 or LS9 cam, can deliver more power where it is needed. To maximize torque in the mid-range, manufacturers adjust the intake valve timing and valve opening to optimize idle quality.

The stock rockers are sufficient for up to 175 lbs of seat pressure and 450 lbs open. For added reliability, a trunnion kit can be installed.

Other parts required for a camshaft swap include:

• LS2 timing chain
• LS7 spec lifters
• LS2 timing chain damper and adapter
• 0.080 in. wall pushrods

Power Adders

The LQ4 engine is commonly paired with power adders such as superchargers or nitrous oxide. When adding a power adder, it is important to address the following:

• A 4-corner steam kit can reduce hot spots and prevent piston ring damage.
• The stock fuel injectors and pump may not be sufficient for increased power levels. Larger fuel injectors and a custom tune may be required.
• A Water-methanol system can be used to supply extra fuel and lower charge air temperatures when running boost.

Intake Manifold and Throttle Body Upgrades

The factory truck-style intake manifold has long runners for better low-end torque. Porting the intake is a cost-effective option for improving airflow.

For more power and torque, the Trailblazer SS intake manifold and a larger throttle body (90mm or 102mm) can be installed. The F.A.S.T. LSXRT intake manifold allows for even larger throttle bodies.

Cylinder Head Upgrades

The stock cylinder heads can be CNC-ported for improved airflow and milled for increased compression. Aftermarket cathedral port heads can provide better airflow and higher compression, resulting in more power.

Rotating Assembly Upgrades

Upgrading the rotating assembly can improve performance and reliability. Forged pistons with stronger wrist pins, thicker ring lands, and added valve reliefs can accommodate larger cams.

The stock connecting rods may become a limitation at higher power levels. Forged connecting rods with 7/16 rod bolts are recommended for increased strength and durability.

The LQ4 crankshaft is cast but strong and can handle significant power. A stroker forged crankshaft can be used to increase displacement and bring boost on quicker, allowing for larger turbos.

Engine Block Upgrades

The LQ4 engine block can be overbored by 0.030 in, increasing the displacement to 408 cubic inches or 6.7L. The factory main caps are not doweled, so it is recommended to reduce ignition timing and use added boost to reduce cylinder pressure spikes. Head and main studs are advised for power levels above 850 whp.

LQ4 engine common issues and their solutions

The LQ4 is a 6.0L Gen. 3 small-block engine used in GM trucks between 1999 and 2007. It is also known as the Vortec 6000. The engine is powerful and responds well to upgrades. However, there are some common issues that owners have experienced. Here is a list of some of the most common problems and their solutions:

Water Pump Failure:

• Symptoms: Coolant leak from the front of the engine.
• Solution: Drain the coolant, remove the air intake snorkel, fan cover, engine fan, and serpentine belt. Then, remove the water pump and disconnect the hoses.

Broken Exhaust Manifold Bolts:

• Symptoms: The head of the bolt may break off and go missing on the driver's side of the exhaust manifold.
• Solution: This is a difficult repair. One option is to remove the exhaust manifold and extract the bolt through the wheel well. Welding a nut to the end or drilling and re-tapping the hole may also work. In severe cases, the engine head may need to be removed by a machine shop.

Knock Sensors Failing:

• Symptoms: There may be no noticeable drivability issues.
• Solution: Replace the knock sensors located under the intake. It is also recommended to replace the intake gaskets and the wiring harness for the knock sensors at the same time.

Some other common issues with the LQ4 engine include:

• Oil pump and timing chain issues: It is recommended to replace these components when performing a cam swap, especially on high-mileage engines.
• Lifters failing: This issue may cause a miss at idle. It is recommended to replace the lifters, along with valve springs and a timing set.
• Piston issues: The pistons are a weak point and can fail, especially when using a power adder. It is recommended to upgrade to forged pistons for more strength.

LQ4 engine maintenance and its importance

The LQ4 engine is a powerful and reliable Gen III small-block engine that has been widely used in GM trucks and SUVs between 1999 and 2007. With its cast iron block and cylinder heads, this V8 powerhouse delivers ample displacement and torque for various applications. Here's a guide to help you maintain your LQ4 engine and keep it running optimally.

Engine Oil Specifications:

• Oil Capacity (with filter): 5 quarts
• Oil Capacity (without filter): 4.5 quarts
• Recommended Oil Type: AC Delco PF46 or equivalent
• Oil Change Interval: Every 5,000-7,500 miles or as recommended by the vehicle manufacturer

Maintenance Tips:

• Regular oil changes are crucial. If you engage in heavy towing, off-roading, or driving in extreme temperatures, change the oil more frequently.
• Always replace the oil filter during an oil change to maintain proper filtration.
• Refer to the vehicle's owner's manual for specific maintenance instructions.
• The LQ4 engine is known for its durability, but proper maintenance is key to its longevity.

Upgrades and Modifications:

While the LQ4 is a robust engine, there are some common upgrades and modifications that enthusiasts often consider to enhance performance:

• Cold air intake and aftermarket exhaust: These are simple bolt-on upgrades that can improve airflow and enhance the sound of your engine.
• Electric fan kit: Replacing the mechanical fan with an electric one can free up horsepower.
• Camshaft upgrade: The stock camshaft is small, and upgrading to a dedicated truck cam can significantly improve torque in the mid-range.
• Power adders: Superchargers, nitrous oxide kits, and turbochargers are popular ways to boost power, but they require upgrades to the fuel system and tuning.
• Intake manifold and throttle body upgrades: Porting the factory truck-style intake manifold or upgrading to an aftermarket intake manifold and throttle body can increase airflow and improve performance.
• Cylinder head upgrades: CNC porting the stock heads and milling them can increase airflow and compression, resulting in more power. Aftermarket cathedral port heads are also a popular choice.
• Rotating assembly upgrades: Forged pistons, connecting rods, and crankshafts can handle more power and provide peace of mind when adding significant performance upgrades.

The Chevy LQ4 6.0L engine is a popular choice for those seeking a robust and reliable powertrain. By adhering to the recommended maintenance intervals and considering performance upgrades, you can unlock the full potential of this versatile engine.

Frequently asked questions