Due to the huge variety of sizes and types of this engine it is difficult to present a catalogue of what JE can offer, but we will describe our approach to this and offer some ideas on this page. 


Rover V8 History


The classic Rover V8 engine was an important feature of the UK motoring scene for more than 3 decades. The design originated with Buick in late 1950s America, but with Rover it was developed for applications from sportscars to luxury 4WD SUVs. JE was intimately involved with this from the mid 1970s and continues to develop new ideas for the engine even today.


The engine was produced in three main versions, each of which had many variants. The earliest 3.5 litre units were made from the mid 1960s until 1976 and the launch of the Rover SD1. Pre-SD1 units have smaller valves in the cylinder head and are based on noticeably lighter castings. From 1976 until 1994, the 3.5 litre engine had larger valves and was built with slightly heavier main castings. Material was added in strategic places to make the block stiffer and allow for bigger cylinder head ports. The 3.9 litre version was added in 1989, and a 4.2 litre version in 1992. JE was instrumental in developing both of these capacity increases which were taken up by Rover into their production offering. From 1994 Rover made some big changes to the engine design. The crankshaft dimensions were strengthened significantly, and the cylinder blocks also gained a little more weight, to increase stiffness further. At this point the engine became available in 4.0 litre and 4.6 litre capacities. The earlier version continued for a short time alongside the new version, largely for use in the last of the Range Rover Classic model and of the first series of Discovery. In Land Rover production terms the last use of the 4.0/4.6 engine was in the Discovery 2 model, which was phased out in 2004, but the engine continued to be made in small quantities for a little longer, for use in some specialist applications.

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JE Products


Rebuilding and optimising one of the early Pre-SD1 units is worthwhile if you need to keep your vehicle very genuine and original, maybe for racing regulations or ‘concours’ appearance. Most of JE’s work on Rover V8 engines involves tuning and improving for more torque and power, so we more often work on the two later types of engine. Due to the availability of 4.6 litre engines in the ‘scrap’ market, many people prefer to start a project with 4.6 rather than a rebuild of an older 3.5, 3.9, or rarely a 4.2, but unless a larger capacity engine is very important, these engines make completely satisfactory power units. We usually build them as either 3.9, or 4.5 litres, using an 80 mm crank shaft with the 94 mm bore. The engines can be built to use high rpm if necessary, but if the project involves retaining SU or Stromberg carburettors, power will be limited anyway, so the lack of a few hundred cubic centimetres is not so important.


Where the larger engine is required, we frequently build a 4.8 litre version of the engine. This is because with high-mileage engines it is almost always necessary to reline the V8 cylinder block with new iron cylinder liners, and if we are doing this anyway, we might as well put in liners for 96.0 mm bore rather than 94.0 mm. 96 mm bore with 82 mm stroke gives 4,748 cc, which we refer to as 4.8. We can also build 5.0 litre using a longer stroke of 86.3 mm, giving 4,997 cc.


An engine we are building very frequently in 2019, is a modernised 4.8 with the later ‘Thor’ inlet manifold. This is for use in the most recent Defenders with electronic throttle actuation, and it is often installed with an electronically controlled automatic gearbox The Thor manifold was used on Discovery 2 V8s and on Range Rovers from 1999 to 2002, it gives a very wide torque spread to the engine, with peaks at roughly 2,500 and 4,500 rpm, so low speed output is much better than with earlier designs. This is very appropriate for 4x4 use. We build the engine with a motorised throttle, modern injectors, and a new, revised cam profile. The inlet manifold is gas-flowed using the ‘extrude-hone’ process, and the cylinder-head ports are basically CNC machined, then finished by hand. With larger valves and everything very carefully balanced, we get 275 bhp and 430 Nm. As mentioned, the torque output is above 400 Nm over a wide range of the engine rpm.






Cylinder blocks and short engines produced by JE are very carefully prepared. All units, as a minimum, have all these operations completed before the build is finished :


  • Block, all oil flow-ways optimised (certain sharp edges are curved, to improve flow), oil galleries physically cleaned and re-plugged.

  • All cylinders are re-lined with new flanged liners, to 88.9, 94, or 96 mm as required.

  • Crank, re-ground if necessary, all oil drillings cleaned and sharp edges removed, journals polished. For 86.3 mm stroke, the cranks are off-set ground to increase the stroke from 82.0 mm. All reground cranks are ‘Tuftrided’ (hardened) after grinding. All cranks are carefully balanced.

  • Rods, 3.5, 3.9, 4.5, 4.6, and 4.8 rods are selected, crack tested and balanced. 5.0 rods are our own machined from steel forgings, crack tested, stress-relieved, shot-peened, and balanced.

  • Pistons, 3.5, 3.9, and 4.6 pistons are full-quality standard Rover items, carefully selected, prepared and balanced. 4.5 pistons are made from full-quality Rover 4.2 items, to similar standards. 4.8 and 5.0 pistons are our own design, forged and hard-anodised, and balanced. Valve cut outs are machined if necessary, prior to balancing.

  • Crank, rods, and pistons are also balanced together as the complete rotating assembly.

  • The short engine is test assembled to check for any further machining requirements (e.g. deck machining of block). When finally ready, all is fully assembled and checked.






























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Cylinder heads:

All JE cylinder heads are thoroughly cleaned, and the oil and water passages carefully checked. The faces are machined (skimmed) if necessary and the eight combustion chambers in a pair of heads are measured, modified, and balanced to be sure they have the same volume to give equal compression ratio across the engine. New valve seats are fitted where necessary and all seats cut to the same height, and blended into the combustion chamber surface shape. In addition :


  • Standard ‘JE build’heads have standard (40 & 34 mm ) valves, re-cut seats, with the ports cleaned up and blended.

  • ‘Sport’heads have larger valves (41.5 & 37 mm), ports as above and enlarged within constraints of manifolds. Manifolds should be checked and may need some minor material removal to work well with sport heads.

  • ‘2A’heads use the same valves as sport heads, but the ports are enlarged further. The inlet manifolds should be fully worked through as well, to take advantage of the larger ports. Special large bore, or tubular fabricated exhaust manifolds should be used with 2A heads.

  • ‘Big valve’heads use new larger inlet valve seats and valves (43 & 37 mm), with further porting work. This is the largest type that would be recommended with standard inlet manifold casting types (e.g. Twin Throttle plenum manifold). Race type inlet manifolds are also suitable.


On all but ‘standard’ heads there is significant material removal to improve gas-flow. The bulk of this material is now removed by CNC machine. This provides a consistent shape and reduces the hard physical work of the gas-flow process. All the work is finished by hand so that precise matching and blending of surfaces is achieved.

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Inlet manifolds:

There have been three different basic inlet manifold arrangements for the Rover V8, with some variations :

1) Twin SU/Stromberg carburettor manifold.

2) Lucas/GEMS fuel injection manifold, with the large single plenum inlet system.

3) Bosch/Thor fuel injection manifold, with two small plenum chambers and long individual manifold ports for each cylinder.

We offer many different ways to improve gas-flow in these manifolds. For the more complicated shapes the ultimate solution is the extrude-hone process. We also use die-grinding tools to carefully remove material where the port shape allows access. We have some larger throttles to install where appropriate, and for the Lucas/GEMS type, we can still offer the famous twin-throttle plenum chamber which gives very good power at higher rpm.



There are many different camshaft profiles available for the Rover engine. JE continue to offer our very successful ‘101’ profile for fast road use in moderately tuned engines. We have other JE-designed profiles suitable for fuel injected engines in heavier cars and 4x4 cars. For road use of sports cars and for racing, we have other cams with more lift and duration.



Rocker Shafts:


Using Land Rover rocker shafts for speeds in excess of 6,000 rpm, up to 6,800 rpm, we would recommend our reinforced billet steel end supports. Full race roller rocker shafts, using needle roller bearings and improved shaft supports, are also available.



Exhaust manifolds:


JE continues to produce the large-bore cast-iron exhaust manifold, suitable for engines producing up to 320 bhp. Alternative tubular manifolds can be obtained, if required, for special installations.





To get the engine running nicely in a car you will need some of the following : fuel injection ECU, wiring harness, carburettors, catalysts, ignition coil(s), distributor, and leads, induction air filter(s), clutch, flywheel, alternator, starter, and other items. JE Engineering can supply many good solutions for engine installations.

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