Ford Intech I6 engine

Introduction

Introduced in the AU Falcon in September 1998, the Ford’s ‘Intech’ was a 4.0-litre inline six-cylinder engine. Key features of the Intech engine included its cast iron block, aluminium alloy cylinder head with single overhead camshaft and two valves per cylinder. The Intech engine was initially offered in three forms:

• Standard output;
• High output (‘Intech HP’); and,
• With Variable Cam Timing (‘Intech VCT’).

In July 2000, a dedicated LPG ‘Intech E-Gas’ engine was introduced.

For the Ford BA Falcon, the Intech I6 engine was replaced by the Barra 182.

Intech block and internals

The Intech engine had a cast iron block with 92.26 mm bores and a 99.31 mm stroke for a capacity of 3984 cc. Compared to its predecessor, the Intech block was strengthened through the use of additional external ribs, while the new cast aluminium sump pan was cross-bolted through the main bearing caps, bolted to the transmission bell housing and braced with an internal steel ladder. Furthermore, engine accessories were mounted directly to the block instead of using brackets.

The crankshaft for Intech engine was lighter and stiffer than its predecessor and had eight counterweights. According to Ford Australia, design of the crankshaft benefited from ‘some technology input from Jaguar’, which was then under Ford ownership. The Intech engine also introduced:

• Lighter connecting rods; and,
• Lighter, low-clearance pistons that had a shorter skirt design and, to reduce friction, a Teflon-based coating and low tension rings.

Intech cylinder head and valve train

The Intech engine introduced a die-cast, aluminium alloy cylinder head that was mounted on a triple-layered steel head gasket. The Intech engine had a single overhead camshaft (SOHC) that was produced from cast iron and driven by a duplex chain. Furthermore, the Intech engine had two valves per cylinder – one intake and one exhaust – that were actuated by rocker arms with a rocker ratio of 1.8:1.

The intake valves had a diameter of 41.00 mm, while the exhaust valves had a diameter of 47.00 mm. To maintain zero valve clearance, the Intech engine used hydraulic lash adjusters. Compared to its predecessor, the Intech engine had a lighter valvetrain which used single conical valve springs (previously double springs).

Intech inlet manifold

The Intech engine had a dual resonance inlet manifold (also known as a variable length intake system). At low engine speeds, the intake runners would provide a longer path to increase the pulsing effect of the airflow and draw more air into the cylinder. At higher engine speeds, however, the length of the intake runners would be shortened to reduce intake resistance and allow a greater volume of air into the cylinder for top-end power.

Intech High Output (HP)

Developed by Tickford Vehicle Engineering, Ford Australia’s ‘performance partner’, the Intech High Performance (HP) engine differed in that it had a unique cylinder head, reshaped inlet port, redesigned exhaust port, ‘open’ combustion chamber (shaped to restrict pre-detonation from hot spot areas), unique camshaft settings, higher fuel pressure and a recalibrated engine management system.

Intech Variable Cam Timing (VCT)

The Intech Variable Cam Timing (VCT) engine used different camshaft profiles to:

• Increase torque at engine speeds from 1000 rpm to 3700 rpm; and,
• Maximise power beyond 3700 rpm.

Mounted on the front of the Intech VCT engine, the VCT unit turned the camshaft in relation to the timing chain to retard or advance the timing. The VCT unit consisted of:

• An inner sleeve which connected to the camshaft via a single bolt and a locating dowel pin; and,
• A ring piston and two ring gears.

The VCT housing was supplied with oil from the engine via an oil supply line; the VCT housing had two oil flow holes and a solenoid controlled oil flow. When the solenoid was ‘energized’, the shuttle valve was positioned to direct engine oil to the VCT unit. The ring gears and piston would then turn the inner sleeve to the advanced timing position.

When the solenoid was ‘de-energized’, the shuttle valve closed to allow oil to drain from the VCT unit.

Intech injection and ignition

The Intech engine had sequential electronic fuel injection (previously electronic multi-point) and ‘high swirl’ intake ports. The Intech engine introduced an electronic distributorless ignition which optimised ignition timing via a new linear knock sensor. Furthermore, the Intech, Intech HP and Intech VCT engines all had a compression ratio of 9.65:1 (an increase from 9.35:1 relative to its predecessor). Firing order for the Intech engine was 1-5-3-6-2-4.

The EEC 5 powertrain control module introduced:

• A ‘limp home’ mode that could detect coolant loss and, as required, cut out cylinders as required to maintain a more even temperature so that the vehicle could continue running without overheating; and,
• A ‘Smart Start’ feature that prevented the starter motor from operating and potentially damaging the engine if it was already running.

Intech dual fuel and E-Gas

The Ford AU Falcon Forte, Falcon Futura and Fairmont were initially available with a dual fuel (i.e. LPG/petrol) system which had:

• A Vialle liquid-to-gas converter;
• Venturi gas/air mixer in the intake tract; and,
• Used the EEC V control module to manage both the LPG and petrol systems.

When starting, the petrol/LPG mix would depend on conditions and, once started, the engine would run solely on LPG. The dual fuel system weighed 85 kg and dual fuel models therefore had modified suspension. For sedan models, the tank was fitted under the rear window shelf, while wagon models had a toroidal tank under the rear floor.

From July 2000, the Ford AU.II Falcon was available with a 4.0-litre dedicated LPG engine which had a single-point, venturi-style carburetion (rather than sequential injection as per the petrol engines). Compared to the 4.0-litre Intech petrol engine, the E-Gas engine had different spark plugs, inductive high tension leads and a unique engine management processor.

Exhaust

The Intech engine featured a flexible decoupler between the exhaust manifold and the catalytic converter which enabled a lower engine idle speed of 550 rpm by suppressing exhaust idle boom and by damping exhaust-driven vibrations across the rev range. To minimise exhaust emissions, the Intech engine had a three-way catalytic converter.