Glen's Rover EFI V8 Conversions

Glen Towery, a seasoned veteran in the realm of British automotive modifications, has transitioned from recommending carburetors to championing fuel injection for V8 conversions. His extensive experience, particularly with MGB V8 swaps, has led him to embrace the reliability, power, and improved fuel economy offered by the Rover "hot-wire" EFI system. This system is a robust and well-proven choice for enthusiasts looking to modernise their classic V8-powered British vehicles, including those utilising Buick or Olds 215, and Rover 3.5L aluminium V8 engines. It's also compatible with factory-installed 3.9L and larger versions of this versatile engine, and impressively, it works with any compression ratio, offering significant flexibility for builders.

The Lucas "Hot Wire" EFI System: A Proven Performer

The Lucas "Hot Wire" fuel injection system, first introduced in 1987 alongside the Range Rover's entry into the US market, represented the pinnacle of automotive technology at the time. Glen Towery regards it as a bulletproof foundation for modern fuel injection in British V8 projects. His confidence in this system is so profound that he now exclusively builds motors utilising it, foregoing carburettors entirely. This shift is a testament to the tangible benefits observed in reliability and performance.

Electronic Control Unit (ECU) Explained

At the heart of the EFI system is the Electronic Control Unit (ECU), also known as the computer. Glen utilises stock ECUs, which are tailored to specific engine displacements. There have been several iterations of the Rover ECU. The initial generation was the "14CU," followed by the "14CUX," which is suitable for both the 3.5L and 3.9L Rover V8 engines. For those requiring compatibility with a 4.2L engine, the 14CUX can be re-chipped. A notable advantage of the 1991 and later 14CUX units is their easily accessible, plug-in chip, simplifying modifications. Reputable specialists like RPI in the UK offer these ECUs and associated services. Glen typically mounts the ECU in the passenger-side footwell, a location that keeps it discreet yet readily accessible for maintenance or adjustments. The wiring harness plug remains consistent across these units, facilitating integration.

Fuel Injectors and O-Rings: Commonality is Key

The fuel injectors found on Rover 3.9L, 4.0L, 4.2L, and 4.6L engines are interchangeable, simplifying sourcing. A significant advantage for DIY mechanics is that the injector O-rings utilise GM part numbers, making them readily available from most automotive parts suppliers. This commonality reduces the hassle and cost of finding specific, often obscure, replacement parts.

Addressing Hood Clearance: Glen's Ingenious Solutions

A common challenge in transplanting larger V8 engines into classic British cars like the MGB is achieving adequate hood clearance. Glen Towery employs a clever modification to address this: he mills approximately 0.800 inches off the bottom of the plenum base. This seemingly small adjustment significantly increases the available space between the intake manifold and the underside of the bonnet. Furthermore, Glen also offers specially designed lowered motor mounts. These mounts position the engine approximately half an inch lower than standard installations, providing crucial extra clearance. The difference is often noticeable when comparing the stock and modified mounts side-by-side. It's worth noting that steel bonnets generally offer more clearance in the plenum area compared to their aluminium counterparts.

Mass Airflow (MAF) Sensor and Camshaft Considerations

The Mass Airflow (MAF) sensor used across these Rover V8 engines is generally consistent. Glen highlights a specific adjustment on the MAF sensor related to the idle circuit's voltage. Achieving optimal idle quality with a computer-controlled fuel injection system necessitates careful attention to camshaft specifications. While the factory camshaft is often suitable, excessive valve overlap can negatively impact idle stability. Glen advises using a camshaft with a lobe separation angle of 112 degrees or greater. Increased lift and duration are generally permissible and can enhance performance. For those seeking a bespoke camshaft grind, specialists like Woody Cooper at The Wedge Shop can provide custom-specified units, along with related components such as lifters, springs, and timing chains. The Wedge Shop also offers performance headers specifically designed for vehicles like the TR8.

Fuel Delivery: The Jaguar XJ6 Pump Recommendation

For reliable fuel delivery, Glen recommends the inline fuel pumps from the Jaguar XJ6. These pumps are capable of meeting the high-pressure and substantial fuel flow demands of the EFI system. While some users encounter issues with Bosch pumps, Glen attributes this to incorrect mounting locations. By mounting the pump close to the fuel tank, he ensures consistent fuel pickup and avoids cavitation. Glen also keeps a stock of good, used Jaguar fuel pumps for those undertaking conversions. The fuel is routed to the fuel rail, with a bypass mechanism in place to return unused fuel to the tank.

Fuel Tanks and Swirl Pots: Preventing Cavitation

Glen offers brand-new fuel tanks equipped with integrated swirl pots. This feature is particularly important for gasoline due to its unique properties: high vapour pressure and low surface tension compared to other liquids. Gasoline does not siphon as readily, and as fuel is pumped and passes through the engine bay, it heats up, generating vapour bubbles. If these bubbles accumulate in the fuel pump, it can lead to cavitation, temporarily impairing the pump's ability to supply fuel. A swirl pot helps to separate these vapour bubbles from the liquid fuel, ensuring a consistent fuel supply to the engine and preventing performance-robbing cavitation.

Oxygen Sensors and Exhaust Placement

The Rover EFI system incorporates two oxygen sensors. To maximise their accuracy and efficiency, these sensors should be installed as far forward in the exhaust system as practically possible. This placement allows them to reach their optimal operating temperature more quickly, providing more precise feedback to the ECU regarding the air-fuel mixture. Proper sensor placement is crucial for the system's ability to fine-tune fuel delivery for optimal performance and emissions.

Wiring Integration: Simple Yet Crucial Connections

Integrating the Rover EFI wiring harness into your existing vehicle's electrical system is surprisingly straightforward, typically requiring the connection of only four key wires. A constant "hot" lead can be easily sourced from the starter motor. Another connection is made to the ignition coil. A further connection is needed to the ignition system to enable the ECU to sense when the engine is running. Finally, a connection to the fuel pump inertia switch is essential. This inertia switch, often a GM part readily available from auto parts stores, serves as a safety feature, cutting power to the fuel pump in the event of a collision. Several ground connections are also necessary, and it may be required to shorten some ground wires to ensure a secure connection. Glen strongly advises soldering new terminals onto wires, considering it a small investment for long-term reliability. He notes that many connection issues stem from poorly crimped terminals working loose over time.

Intake Manifold Variations and Machining

While the core design of the Rover EFI intake manifolds remained largely consistent across different years, minor variations exist, such as tapped bosses for sensors. These differences may make the manifolds appear distinct, but their fundamental function remains the same. To ensure the plenum fits beneath the MGB's hood, Glen employs the aforementioned plenum base milling technique. In instances where clearance is exceptionally tight, the upper portion of the plenum may also require machining. Comparing stock and modified manifolds side-by-side clearly illustrates the extent of these modifications, which are crucial for achieving the necessary hood clearance.

Comparative Table: Carburettor vs. Fuel Injection

Frequently Asked Questions

Q1: Is the Rover "Hot Wire" EFI system difficult to install on an MGB V8 conversion?
While it requires careful planning and execution, Glen Towery's methods and the commonality of parts make it a manageable project for experienced DIY mechanics. The wiring integration is relatively simple, and sourcing components is often easier than with more obscure systems.

Q2: What are the main advantages of using EFI over carburetors for a V8 conversion?
The primary advantages are improved reliability, better fuel economy, increased and more consistent power delivery, and lower emissions. The system automatically adjusts for changing conditions, ensuring optimal performance.

Q3: Can this system be used with different engine sizes other than the 3.5L Rover V8?
Yes, the system is suitable for Buick/Olds 215 V8s and Rover 3.5L, 3.9L, 4.0L, 4.2L, and 4.6L engines. The ECU may need to be specific to the engine size or re-chipped for optimal performance with larger displacements.

Q4: What modifications are essential for fitting the system, particularly regarding hood clearance?
The most common modification is milling the plenum base to increase clearance. Lowered motor mounts are also often used to help position the engine lower in the chassis.

Q5: Where can I source the specific parts for this conversion?
Specialists like RPI in the UK can supply ECUs and other components. Jaguar XJ6 fuel pumps are readily available from automotive suppliers. GM parts are used for O-rings and the inertia switch, making these accessible.

Glen Towery's expertise and the inherent robustness of the Lucas "Hot Wire" EFI system offer a compelling solution for anyone undertaking a V8 conversion on a classic British vehicle. The combination of improved performance, reliability, and efficiency makes it a worthwhile upgrade that transforms the driving experience.