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Since the Rover V8 engine appeared in the UK. time it has acquired an excellent reputation. The block and heads are
constructed from aluminium resulting in a very light power plant considering it is 3.5 litres in the original form. The weight difference between the 1800 B and the Rover V8 is very slight. The complete V8GT weighed in at just 40lbs heavier than the 1800GT equivalent, and do not forget the V8 has larger discs, tyres and prop. The cylinder heads were standard until the introduction of the SD1 that has been fitted with single value springs and large inlet values for more efficient breathing. The SD1 has also been fitted with an up rated oil pump (giving higher flow rate), improved crank oil seals and electronic ignition instead of points. When MG produced their original V8 the Rover P5B and early P6 was around, the water pump,crank and alternator bracket were utilised but the inlet and exhaust manifolds, oil pump base and mountings had to be redesigned. Later type P6 Rover saloons and SD1s are fitted with a viscous cooling fan, longer crankshaft pulley and a different design of alternator and mounting. The earlier components will have to fitted to this unit to shorten it. The SD1 crank pulley can be machined to do the job of the earlier unit. All Rover V8 engines have an external oil pump
mounted on the front cover, the base of which carries the oil pressure relief valve and oil filter. Unfortunately there is no room for this in the MGB because A special oil pump base is available that is bolted onto the oil pump after
removing the original base. This unit contains the oil pressure relief valve and oil galleries, a connection for the oil pressure gauge and two 1/2" BSP outlets to enable a remote filter to be used which is usually mounted on the GT V8. As
the remote oil pipes exit the pump base, they are very close to the lip of the chassis and it is best to tap this over to increase clearance. If required the oil cooler can be plumbed into the system. On the original chrome bumper V8 the cooler was mounted on the rad ducting panel under the offside fan motor and because of limited space a 10 row unit was used. With the advent of the bumper V8 it was mounted underneath the same panel. Engine mounting brackets, for either chrome or rubber models are available for the sides of the engine block so that MGB GT V8 rubber mountings can be used. These engage in the existing mounts on the black bumper chassis rails and the modified units on the chrome bumper models.
The common choice here is to use what is commonly called the SD1 5 speed this is the LT77 box which became the standard rear wheel drive gearbox used for all later rear wheel drive, and four wheel drive vehicles in the BL, Austin Rover and Rover Group’s. Only recently has it been by the R380 design, itself a development of the LT77mm version.
As it was used in such a wide range of vehicles there are a number of different alternatives. The Van versions had another with unsuitable low gearing, but great for hauling heavy loads! When searching for an SD1 gearbox look on the right
lower side and you will see a machined surface onto which is stamped the gearbox number. The start of the number will give the identity of the gearbox and this is what you need. some common ones are: -
G16A SD1 2000 (Could be 4 speed) G17A SD1 2300/2600 5 speed G19A SD1 3500 SE/VP 5 speed
G22A SD1 3500 Police spec 5 speed G23A SD1 2600 Police spec 5 speed G26A SD1 2400 Diesel 5 speed
G27A SD1 2000 Later model 5 speed G28A SD1 Vitesse 5 speed
versions used in the TR7 range and these are 5 speed and have the right ratios to be used with a V8. Land Rover products also use versions of the gearbox, but with 4-wheel drive applications that see a transfer gearbox attached where the end housing fits on the rear wheel drive applications. Many internal parts are the same though. Numbers have reached into
the G50’s so this indicates the various options for this gearbox. In all cases you also need to obtain the SD1 long remote gear change and dependant on the exact mounting of your engine and gearbox, you may need to use a bent gear lever to enable the lever to exit centre of the existing hole in the transmission tunnel. The RV8 uses such an item, but ensure that your engine and gearbox is sitting in the same relative position as the RV8 before committing to buy the RV8 one.
The original removable cross member that attaches to the gearbox can be modified and attached to the SD1 gearbox, much the same as has been done for the RV8Those made from start of MGB production in 1962 to October 1967 (Mk 1), then between October 1967 and October 1974 (Mk 2 on).. These two groups are easily identified as being ones that had the early three-synchro gearboxes and the later cars with the four-synchro units. The transmission tunnel being the obvious give-away, with the later cars having one with a completely flat top around the gear lever, whilst early cars had a pronounced hump in the area of the gear lever. Only the later cars could feature the flat top centre console should you not be certain of your car The bulk of the V8 engine in terms of extra width is highlighted by the need to remove a section of each bulkhead corner to allow clearance for the rear of the V8’s cylinder heads. On the steering side there is the complication that the steering shaft passes through the bulkhead in the modified area and this has to be catered for during the modification. Whilst this isn’t a body feature, it has to be mentioned that depending on what steering system is being used, then this will have a critical bearing on the actual modifications to this bulkhead The first is the simple bolted clamp type of lower column mounting that is found in the early cars and which requires little in the way of body preparation, other than the actual clearance for the steering shaft. The bulkhead area on the steering side can really follow two distinct routes. The other route is to use the later type of column, which utilises a three
bolt fixing direct into the bulkhead .Obviously this requires some considerable care in positioning and then fixing, to ensure Whilst engaged in this area the mountings for the upper end of the column have to be catered for. The column attaches to a triangulated bracket which in turn is bolted to the under dash scuttle bracing bar and the inner side of the bulkhead panel through captive bolts. All cars may also need relief to the top of the gearbox tunnel, under the dash area, depending on the choice of gearbox, especially so if the Rover SD1 (LT77) 5 speed is to be used. This modification is common to all RV8’s that use either a late version of the SD1 box, Looking down an open
transmission tunnel from the engine bay end you will see that the top of the tunnel ‘steps down’ as it narrows. This step has to be moved upward to the previous level for a width of approx. 3” and rear wards to where the top of the tunnel flattens out. This also happens to be where the old speaker frame is welded to the top of the tunnel. passenger side, provides tight clearance for the clutch housing of the gearbox. A section of the front of the tunnel has to be ‘dressed in’ towards the footwell to provide clearance.V8 cars used a steering system that was visually very similar to the original system, and which was adopted for all rubber bumper cars. Therefore the system found on a V8 or any rubber bumper car can be used in any other MGB to provide the required clearances. The problems centre on the positioning of the steering universal joint, and to provide the exhaust clearance this has to be moved upwards, into the bulkhead. This involves the use of a
longer pinion shaft in the rack, a shorter upper column to suit, and with the bulkhead modifications different upper column mounting points as described. If the whole later type steering assembly is being used then the original dash will not be suitable since the later upper column is a safety collapsible type. This means that it is about twice the thickness to the earlier solid versions and so will not fit in the slot between the Speedo and tacho positions. This also explains why V8 cars had the smaller 3 1/4” diameter clocks, rather than the original 4” ones. If the original style of dash, with the 3 1/4” main clocks, is used then it will match the fatter safety style columns.
