The following information is the sole property of Abbey SportCars Ltd and is not to be copied for use
elsewhere without prior permission or reference. The pages are written for guidance only, the information
contained therein is the view of the writer and should not be taken as the definitive recommendation.
Can you shed some light on the historyof the Rover V8?
Rovers 215 ci 3528cc V8 engine was first introduced into the UK in 1967 in P5B guise, a cubic capacity that was to be used extensively by the factory until 1989. During that period the engine was revamped periodically to meet more stringent emission levels. The first engines benefited from a 10.25 or 10.5 : 1 compression ratio in the rover saloons , or lower compression 8.15:1 when installed in the Range Rover.
In 1975 the engine underwent detail changes which coincided with the introduction of the SD1. The v8 engine now featured, revised compression ratio (9.35: 1), neoprene rear oil seal, revised cylinder head porting and valve gear. Lowering of the compression ratio was to enable burning the lower octane fuels that were becoming increasingly more popular.
All engines i.e., pre and post 1976 can be identified externally. The engine numbers on post 1975 units were stamped on the RHS block casting flange whereas earlier blocks were stamped on a pad to the rear of the cylinder block near the bell-housing mtg. flange. The engines comp. ratio is also stamped on this face and is a useful way of positive engine model specification. However, it is now unusual to find engines from the P6 era which have not been rebuilt and or feature later type cylinder heads as well as camshafts and induction systems.
Over the years there were several other detail changes to the v8 engine but from a performance point of view the V8 differed only in compression ratio. Post 1982 engines however, came with a revised cylinder block and optional induction systems. SU or Stromberg Carburetors were continued alongside Efi (Lucas LE flapper type injection) derivatives in the form of Vanden Plas and Vittese models. The Efi equipped vehicles also featured revised camshafts, valve gear and a compression ratio of 9.75:1 or 9.85: 1.
Although various bore and stroke configurations were adapted from the Leyland P76 (Australia) and Buick 300 (USA) to increase capacity for specialist use and racing, from a factory point of view, the 3.5 Litre engine was the only available UK option until 1989. From that time a 3.9 Litre engine (3905cc) was available although that capacity unit was dropped in favour of a slightly enlarged version of 3948cc sometimes referred to as the 4.0litre.
Larger diameter liners were required for the increase in capacity from 88.9mm(3528cc) to 94.04mm (3948cc). The 3.9/4.0 Litre engine which was available in Land/Range Rover vehicles also featured a similar Efi system to that available in the Vandan Plas/Vitesse saloons. In Range/Land Rover applications, compression ratio was 9.35:1 and power rated at approx. 165BHP for the 3.5 litter engine and close to 190 BHP for the 3948cc version.
The later 3.9/4.0 engine (3948cc) used a similar 71.2mm stroke crankshaft and 143.82mm con-rod dimension to the 3528cc early 1975 > SD1 engine but with the additional capacity, power and torque were increased also. Engines of this capacity used in kit and converted cars with suitable modifications provide perhaps the performance bargain in terms of power per pound spent.
In 1992 the engine was revised further with the introduction of a longer throw crankshaft up from the previous 71mm to 77mm stroke. Using the larger diameter bore of the 3.9/4.0 Litre derivative (94.04mm), the capacity was increased to 4.2 Litres. Other detail changes to piston compression heights were also revised. Although not common, the 4.2 Litre block assembly can be distinguished by the facility for cross-bolting on the outer block flanks. In common with the earlier 3.9/4.0 Litre engine, Efi was also a standard feature. The 4.2 Litre crankshaft and rod assembly will fit earlier blocks but from a performance point of view its real virtues were its increased torque.
During the mid nineties Rovers V8 engine was revised once more. The stroke was increased to 82mm using the same bore configuration (94.04) giving a capacity of 4.6litres. In the later guise however, the engine underwent significant changes. It was not simply a case of a larger stroke crankshaft but with that change, larger diameter crankshaft journals. These were increased from the older 58.4mm to the later 63.5mm, and the 4.6 Litre engine also featured lighter slipper type pistons with reduced compression heights, longer con-rods (149.78mm) as well as revised inlet/exhaust ports. Other changes included smaller capacity combustion chambers to maintain a 9.35: 1 CR and in addition a completely revised front timing cover arrangement with a serpentine drive belt system.
To add to the confusion later engines designated 4.0 Litres were also available. These particular units feature the larger diameter journal crankshaft, in common with the 4.6 Litre unit but with pistons and rods of different dimensions to other 3.5, 3.9/4.0 and 4.6 Litre units.
The capacity of these units is 3948cc but using this time, con-rods of 155.22mm and pistons with compression heights of 35.9mm (the same as the 4.6). However both the larger diameter journal crankshafts use con-rods with larger 24mm gudgeon pins up in diameter from the old 22mm items.
From a performance point of view the later engine 4.6 also benefit from a 4 bolt cross-bolted steel mains cap, now registered more appropriately within the block. This allows a more rigid crankshaft/block assembly. The Rover V8 in 4.6 Litre guise, also benefited from the re-engineering of other potential failure areas. On the 4.6 Litre engine the camshaft driven distributor drive was changed. This particular feature enabled the use of a coil pack to supply the necessary ignition requirements when aided by ECU engine management, as well as a number of engine sensors.
Subsequent changes in the ignition system also brought with it a camshaft of longer duration now asymmetrical instead of symmetrical of the older engines cam design. The new camshaft can be made to fit the earlier cylinder block but will require a electronics pack and engine sensors also. Of more relevance however is that the earlier camshaft profiles of which there are several will fit the larger 4.6 Litre block.
Although useful, the latter updates and revisions prevent a direct inter changing of parts between the old and new engines in many other areas. Certainly, parts from the new and old engines can be made to fit with modification and machining but not always cost effectively. For example the cylinder heads of the later 4.6 Litre engine will physically fit the early engine but the combustion chamber volumes differ.
For kit cars and other installations where fore and aft space within the engine bay is restricted, it is possible to fit the engines of 3.5, 3.9, 4.0, 4.2 & 4.6 liter and larger capacity. Physically there is little external difference to prevent fitting different capacity engines. The RV8 unit has been fitted to Ford Fiestas, Escorts, Capri, Sierra and MK I & II Granadas, as well as Reliant Scimitars, Lotus Elite, Eclat, Excell & Esprit to name but a few.
For fitting you may require extensive modifications to the existing vehicle bulkhead and inner wings or chassis. Under bonnet clearance will also require checking. The sump also requires modification with some conversions and sufficient space for the location of exhaust manifolds. Other modifications to prop-shafts, transmission tunnel as well as suspension and braking system may also be necessary.
You will also require, the distributor, camshaft with distributor drive, front timing cover, water pump and engine pulleys, up-rated cooling system, and associated wiring components. The early P6 i.e., pre 1976 water pump and pulleys also allow a reduction in the engines longitudinal dimensions.
So how does the Rover V8 perform???
The Rover engine installed in the P5B and P6 was a formidable performer and performance wise differed little to Rovers first 5 door hatchback saloon the SD1. The V8 engine in a standard specification SD1 5 speed manual saloon was capable of approx. 125MPH with the 0-62 MPH (0-100 KPH) achieved in around 8.5 seconds - depending upon in which road test you read/consulted, from a claimed 155 BHP.
In the above guise, the engine was pulling around a tonne and half of car, fluids, and passengers. With the introduction of the 3.5 Litre fuel injected engine vehicle performance increased to around 130MPH with reputed 0- 60MPH time of around 7.1 seconds. This performance was achieved from a claimed 190 BHP (an additional 35BHP more than the original 3.5 Litre SD1). Engines from these particular cars can be identified by a single plenum fuel injection. The plenum chamber is obvious and noticeable when compared to the carburetor engine by a large rectangular casting with single throttle butterfly, large neoprene/reinforced rubber hoses, air flow meter and very restrictive air box.
The largest capacity and most powerful saloon car produced by Rover was the 3.5 litre injected car introduced from 1982-6/7. The Vitesse however was revised in 1984/5 along with detail changes with a LOTUS modified Twin Plenum fuel injection design that was to enable the engine to breathe better. Rover did not officially claim any extra performance from the later Vitesse but the modification enabled increased performance when used with non-standard or aftermarket engine components.
This revision however was primarily to achieve the 500 minimum units necessary for homogalation within Saloon Car Racing. These particular cars are rare indeed and according to TWR, 300BHP from a 3.5 Litre engine was available. (more to follow)
All Post 1986 factory V8 Rover engines of 3.9, 4.2 & 4.6 Litre were used almost exclusively in Range and Land Rover vehicles. However, due to the obvious benefits of a lightweight V8 power unit, smaller volume manufactures including Morgan Cars, Marcos and TVR as well as component car manufactures used these basic power units sometimes with added performance enhancements.
Why choose the V8?
One of the big plus points in the Rover V8 engines favour not including its numerous virtues of torque and usable power is that of its relative simplicity and cheapness to restore and rebuild. It is a formidable power plant and suffers only minimally from miss-use and abuse. The RV8 is a robust lump and maintained or restored will give thousands of miles of useful service. The engine has undergone much development over the years and this has resulted in improvements probably far beyond what the original designers anticipated.
From the v8’s 3.5 Litres at its inception in the early 1960’s, the engine has been raised in capacity to 5.2 or more Litres, featured fuel injection, supercharging, and turbo charging. Development work however still goes on with technology enabling what is to all intents and purposes a superb and well engineered engine. This however is not to say that the engine is bullet proof. The V8 has minor failings all of which can be rectified and in some cases improved upon to provide additional performance.
We have put together some basic information for guidance concerning the weakest areas of the Rover V8 engine and by clicking the case study section of this site you will see basis details of how to rebuild your engine. The pages however do not deal with racing engines as engines built for the road differ greatly in this respect.
<< back to categories