What Engine Is In The 370z

So, you're diving into the heart of a 370Z and want to know what's ticking under that long hood? You've come to the right place. We're going to break down the engine – the VQ37VHR – in a way that's useful for you, whether you're planning on some basic maintenance, tackling a serious repair, or just feeding your gearhead curiosity. This information is critical for understanding the powerplant behind your Z, enabling you to diagnose issues, perform upgrades, and generally become more familiar with your ride.

The VQ37VHR: A Technical Overview

The 370Z is powered by the VQ37VHR engine, a 3.7-liter (3696cc) naturally aspirated V6. Let's dissect that nomenclature: "VQ" designates the engine family, "37" indicates the displacement (3.7 liters), "V" signifies its use of Variable Valve Event and Lift (VVEL) technology, "H" means high output, and "R" denotes its revised design.

Key Specs and Main Parts:

• Engine Type: 60-degree V6
• Displacement: 3.7 liters (3696 cc)
• Bore x Stroke: 95.5 mm x 86.0 mm (3.76 in x 3.39 in)
• Compression Ratio: 11.0:1
• Horsepower: 332 hp (248 kW) @ 7000 rpm (Base Models) / 350 hp (261 kW) @ 7400 rpm (Nismo)
• Torque: 270 lb-ft (366 Nm) @ 5200 rpm (Base Models) / 276 lb-ft (374 Nm) @ 5200 rpm (Nismo)
• Valve Train: DOHC, 24-valve with VVEL
• Fuel System: Multi-point fuel injection

The main components you'll encounter include:

• Cylinder Block: Aluminum alloy, a common choice for weight reduction and heat dissipation.
• Cylinder Heads: Also aluminum alloy, housing the camshafts, valves, and VVEL system.
• Crankshaft: Forged steel, converting the linear motion of the pistons into rotational motion.
• Pistons: Aluminum alloy, designed to withstand high temperatures and pressures.
• Connecting Rods: Forged steel, linking the pistons to the crankshaft.
• Camshafts: Actuate the intake and exhaust valves. The VQ37VHR has four camshafts (DOHC - Double Overhead Camshaft).
• Intake Manifold: Directs air into the cylinders, often featuring variable geometry for improved performance across the RPM range.
• Exhaust Manifold: Collects exhaust gases from the cylinders.
• Throttle Body: Controls the amount of air entering the engine.
• Fuel Injectors: Spray fuel into the intake ports or directly into the cylinders (depending on the specific iteration, although the VQ37VHR is port injected).
• ECU (Engine Control Unit): The brain of the engine, controlling ignition timing, fuel injection, and other parameters.

The VVEL system is a key feature. Unlike traditional valve timing systems, VVEL continuously varies the lift and duration of the intake valves. This allows the engine to breathe more efficiently, resulting in increased power and improved fuel economy. It does this by using a rocker arm system that is actuated by a small electric motor and a control shaft, allowing for infinitely variable valve lift.

How It Works: The Combustion Cycle

The VQ37VHR, like most gasoline engines, operates on a four-stroke cycle: Intake, Compression, Combustion (Power), and Exhaust.

1. Intake: The piston moves down, creating a vacuum in the cylinder. The intake valve opens, allowing air (mixed with fuel) to be drawn into the cylinder. VVEL plays a significant role here, optimizing the amount of air entering the cylinder based on engine load and speed.
2. Compression: The intake valve closes, and the piston moves upward, compressing the air-fuel mixture. This increases the temperature and pressure, making it easier to ignite.
3. Combustion (Power): The spark plug ignites the compressed air-fuel mixture. The rapid expansion of gases forces the piston down, driving the crankshaft and producing power.
4. Exhaust: The exhaust valve opens, and the piston moves upward, pushing the burned gases out of the cylinder and into the exhaust manifold.

This cycle repeats continuously, powering your 370Z. The ECU constantly monitors various sensors (e.g., oxygen sensors, mass airflow sensor, crankshaft position sensor) to adjust fuel injection, ignition timing, and VVEL operation for optimal performance and efficiency.

Real-World Use: Basic Troubleshooting

Understanding the engine's components and operation is invaluable for troubleshooting. Here are a few common issues and potential causes:

• Rough Idle or Stalling: Could be caused by vacuum leaks, faulty spark plugs, a dirty throttle body, or a malfunctioning mass airflow sensor (MAF).
• Reduced Power: Potential causes include a clogged air filter, a failing fuel pump, worn spark plugs, or issues with the VVEL system.
• Check Engine Light (CEL): Requires scanning the ECU for diagnostic trouble codes (DTCs). These codes provide clues about the nature of the problem. Common codes on the VQ37VHR often relate to the camshaft position sensors, VVEL system malfunctions, or misfires.
• Excessive Oil Consumption: Can be caused by worn piston rings, valve stem seals, or leaks in the engine. The VQ37VHR is known to have potential for higher than average oil consumption in some cases.

Important: Always use a scan tool to retrieve diagnostic trouble codes (DTCs) before attempting any repairs. Research the codes thoroughly before replacing any parts.

Safety Considerations

Working on an engine involves inherent risks. Here are a few crucial safety precautions:

• Disconnect the Battery: Always disconnect the negative battery terminal before working on any electrical components. This prevents accidental shorts and potential electrocution.
• Fuel System: The fuel system is under pressure. Relieve the pressure before disconnecting any fuel lines. Gasoline is highly flammable. Work in a well-ventilated area and avoid open flames.
• Hot Surfaces: The exhaust manifold and other engine components get extremely hot. Allow the engine to cool completely before touching them.
• Moving Parts: Keep hands, tools, and clothing away from moving parts, especially when the engine is running.
• Lifting: Use proper lifting equipment and support the engine securely when removing it from the vehicle. Never work under an engine supported only by a jack.
• VVEL System: Exercise caution when working on the VVEL system. It involves intricate mechanisms and requires precise adjustments. Consulting the factory service manual is highly recommended.

Never underestimate the potential dangers involved in working on a vehicle's engine. When in doubt, consult a qualified mechanic.

The VQ37VHR is a complex piece of machinery, but with a solid understanding of its components and operation, you can confidently tackle many maintenance and repair tasks. Remember to always prioritize safety and consult the factory service manual for specific procedures and torque specifications.

To further aid in your exploration of the VQ37VHR, we have a detailed engine diagram available for download. This diagram provides a visual representation of the engine's components and their relationships. It can be a valuable resource for identifying parts, understanding their placement, and tracing circuits or systems. Knowing which parts the different colors represent, and understanding what all the different line styles represent can be a significant time saver, and save you a lot of headaches when trying to diagnose a fault.