TVR Defender 5.0 Litre

I was asked by a man, David Dodd to build an engine for a Landrover Defender that he had recently bought.

Originally, the vehicle was fitted with a Range Rover 3.9 V8 engine which was very tired and abused, was mechanically very noisy and didn’t run very well. So I suggested replacing it with a TVR 5.0 Litre unit. This would bolt straight on to the bell housing and engine mounts with little modification and would give the car the performance that was needed, as it was to be used for full race Comp Safari work once completed.

The engine that was purchased came from a Griffith 500, and although was in reasonable condition internally, was incomplete, as far as the inlet tract and fuel injection were concerned. This ended up being a good thing as it happened, as a bespoke inlet manifold was made along with different injectors and trumpet base.

The engine was stripped and cleaned, and a small modification was done to the front of the block in the form of two holes that allow extra oil to pass onto the cam chain which helps to prolong it’s life.

Special main and big end shells were obtained, which are made by ACL in Australia and are used in top fuel dragsters. They are very robust and hard wearing which was ideal for the type of work the engine had to cope with. The reciprocating components were all balanced, pistons, crank and flywheel along with the cluch pressure plate and front pulley. The pressure plate that was used, was increased in strength to clamp the race paddle clutch adequately to cope with the extra torque that the engine was to produce and the weight of the vehicle.

The cylinder heads are standard 500 units with TVR valves and springs, but the studs for the heads and main bearing caps are hi tensile ARP units which helps to prevent head gasket failures. The camshaft profile is a Piper “Stump Puller” item, that has huge low down torque and a power curve starting at around 1500 rpm up to around 4500 rpm trailing off at the top end. This was chosen as the initial off the mark power and acceleration was important to David for the type off road competiton the vehicle was to be used in.

The pistons are TVR/Cosworth units running hi performance rings and have a compression ratio of around 10.5:1. The conrods are made by Corrello which are made from forged steel for extra strength and lightness.

The oil pump is a standard Landrover unit which pumps the oil through a bespoke 19 row oil cooler which is thermostatically controlled to keep the lubricant at optimum temperature. The oil used is made by Petronas and is a full synthetic 15W50 product developed by the company and is used in F1 and race applications.

The engine is fitted with a baffled race sump, which helps to keep a constant supply of oil to the pump in the most extreme off road and race conditions, most important in this type of racing.

The inlet manifold as mentioned earlier is a bespoke item that has been machined to fit between the heads exactly and has been ported and matched to the inlet ports. Onto this is a specially made trumpet base to increase airflow to the cylinders. The fuel rail is a standard item, but has larger Bosch injectors which are capable of fuelling the engine up to 500 bhp, so are well within their capability in this application. The plenum and throttle body are standard TVR items and are connected to a K&N race air filter assembly. The air is drawn in from outside the engine bay to maximise to cold air feed, and optimise performance.

The exhaust manifolds had to be specially made as the original TVR headers wouldn’t fit in the engine bay due to lack of space. These in turn run into a bespoke stainless race exhaust system which exits the vehicle through the rear of the body. This keeps the exhaust high up in the chassis preventing it being damaged by foreign bodies and terrain.

The cooling system is also a hand made assembly, with a huge alloy radiator and silicon and glass cooling pipes with two electric fans to assist cooling at low speed and high under bonnet temperatures.

The ECU has also been remapped and modified for maximum power and torque, with unique programming for the larger injectors and increase in fuelling. The end result is quite astonishing, giving the performance Landrover could only dream about.

The engine mates on to a strengthened R380 gearbox which has stronger propshafts and drives CAM axles front and rear. The axles have fused links on the output shafts, which are designed to break if the going gets too tough, rather than damaging the differentials or drive shafts.

The suspension is also modified with special stronger arms, the  springs have been selected to exactly match the vehicles weight and handling characteristics.

It also has an external fuel tank mounted in the rear of the body and a full FIA approved roll cage as stated by the regulations. The regulations also require a fire extinguishing system to be installed, and this vehicle has an automatic system installed under the bonnet if the worst was to happen.

The vehicle has been resprayed Ford Imperial Blue and in the cab, has racing bucket seats and an intercom system that plugs in to the crash helmets of the driver and navigator.