The McLaren M840T is a 3,994 cc, 90° V8 twin — turbocharged petrol engine produced between 2017 and 2023. Developed in partnership with Ricardo, it features dual overhead camshafts (DOHC), dry — sump lubrication, and a flat — plane crankshaft. This architecture delivers exceptional throttle response and a high specific output, with power ranging from 530 kW (710 PS) to 588 kW (789 PS) and torque figures between 770–800 Nm.
Fitted exclusively to McLaren’s Sports and Super S…
All production years (2017–2023) meet Euro 6 standards for the markets in which the vehicles were sold (UK VCA Type Approval #VCA/MCL/720S).
The McLaren M840T is a 3,994 cc 90° V8 twin-turbocharged petrol engine engineered for high-performance supercars (2017-2023). It combines a flat-plane crankshaft with dry-sump lubrication to deliver explosive acceleration and high-revving character. Designed to meet Euro 6 standards, it balances track-focused performance with road-legal emissions compliance.
| Parameter | Value | Source |
|---|---|---|
Displacement | 3,994 cc | |
Fuel type | Petrol | |
Configuration | 90° V8, DOHC, 32-valve | |
Aspiration | Twin-turbocharged | |
Bore × stroke | 88.3 mm × 81.0 mm | |
Power output | 530–588 kW (710–789 PS) | |
Torque | 770–800 Nm @ 5,500–7,000 rpm | |
Fuel system | Gasoline direct injection (GDI) | |
Emissions standard | Euro 6 | |
Compression ratio | 9.4:1 | |
Cooling system | Liquid-cooled with auxiliary coolers | |
Turbocharger | Twin mono-scroll turbochargers (Garrett) | |
Timing system | Chain-driven | |
Oil type | McLaren C30 Spec (SAE 0W-40) | |
Dry weight | 183 kg |
The McLaren M840T was used exclusively across McLaren's Super Series and Sports Series platforms with longitudinal, rear-mid mounting and is not licensed to other manufacturers. This engine received model-specific ECU calibrations—higher boost for the 765LT and revised torque curves for the GT—creating software interchange limits. All adaptations are documented in OEM technical bulletins.
The M840T's primary documented focus is managing heat in the turbocharger system, with elevated thermal stress noted during track use. McLaren service data indicates the TSB-M840T-01 coolant update significantly reduced related incidents, while owner reports highlight the criticality of using correct oil specification. Sustained high-load operation without adequate cooling intervals can accelerate wear, making adherence to fluid specs and service intervals critical.
Analysis derived from McLaren technical bulletins (2017-2023) and aggregated owner service reports (2018-2024). Repair procedures should follow manufacturer guidelines.
The most common questions about engine codes, what they mean, how to find them and how this database works
The M840T is a robust, well-engineered engine for its performance class. Long-term reliability is excellent with strict adherence to McLaren's service schedule, particularly using the correct C30 0W-40 oil and high-octane fuel. Addressing the TSB-M840T-01 for early cars and managing heat during track use are key factors for longevity.
The most documented issues are turbo heat soak (addressed by TSB), potential HPFP wear, intake valve carbon buildup (common to GDI engines), and electrical connector corrosion. These are generally manageable with proactive maintenance and following McLaren's technical service bulletins.
The M840T engine was used in the McLaren 720S (2017-2023), McLaren GT (2019-2023), and the limited-run McLaren 765LT (2020-2021). It replaced the 3.8L M838T engine and was itself succeeded by the M840T EVO in later models.
Yes, the M840T has significant tuning potential. Reputable tuners can safely extract 670-750 kW (900-1000 PS) with ECU remaps and supporting modifications like downpipes and intercoolers. The engine's internals are strong, but pushing beyond this requires forged components. Always use a specialist familiar with McLaren systems.
Fuel economy is not its forte. Expect around 15-18 L/100km (15-13 mpg UK) in combined driving. Under gentle cruising, it can achieve 11-12 L/100km (25-23 mpg UK), but aggressive driving or track use will see figures well over 25 L/100km (11 mpg UK).
Yes. Like virtually all modern high-performance engines, the M840T is an interference design. A timing chain failure would likely result in catastrophic valve and piston damage. Fortunately, the chain system is very robust and not a common failure point with proper maintenance.
McLaren mandates its proprietary C30 specification, a 0W-40 synthetic oil. Using any other oil, even if it meets similar ACEA standards, can void warranty and potentially cause damage. This oil is specifically formulated for the engine's high temperatures, pressures, and bearing clearances.
Comprehensive technical documentation and regulatory references
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
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