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Mains (Main Bearing) Stud Kit
It has become apparent with the launch of the new Rover 4.0 and 4.6 litre engines that there are some serious weaknesses in the design of the V8 engine produced up until 1994. Many publications, manuals and expert opinions, have suggested that the post-1982 (stiff block) is essential for ultimate reliability, especially for higher performance engine rebuilds.
However, further reading will show that the actual strength of the block has never been a problem as the main cause of serious V8 engine failure, but is due to the lack of main bearing cap stability. We therefore supply a mains stud kit to ensure ultimate reliability in the strength of your block, whatever the age.
mains stud kit
The pre-1982 block is identified by webbing across the valley of the V8 engine, on pre-1982 blocks there are three webbings and their cross-sectional diameter is not constant over the entire length of this bracing - the centre is reduced in diameter from 15mm to 6mm.

The post-'82 block (stiff block) bracings are constant in cross-sectional diameter (15mm) along its entire length offering a far stronger bracing to the engine Block. However, further reading will show that the actual strength of the block has never been a major problem as the main cause of serious V8 engine failure is due to the lack of main bearing cap stability. On pre-1982 engines the amount of bearing cap contact with the sides of the engine block is minimal (see diagram above) only 12mm.

On post-1982 blocks (stiff block) the main bearing cap engine contact is slightly increased to 16mm, but still offers very little strength improvement where most needed. The other serious flaw in the original design of the main bearing assembly is with the main bearing bolts. The standard Rover bolts are considerably thinner than the actual diameter of the main bearing cap they are securing (see diagram) this results in a very unstable support for the mains, and leads all too often to the failure and total engine demise (the last thing you want after an expensive engine rebuild). The strength of these bolts does not allow adequate torque settings - when using a 'stud kit' this will allow an increase in overall torque settings.

Another important aspect of the Main bearing stud kit is that when an engine is being re-assembled, most engineers would not bother to check the trueness of the crank itself, and this has led to many engines being assembled with 'Bent' crankshafts, although very minor and unnoticeable, this will certainly lead to premature demise of the engine and detract from the expected smoothness of you rebuild.

mains studs
mains Because the Mains stud kit aligns your bearing caps perfectly and does not allow them to 'Walk' or move to accommodate an inaccurate crank, you will find when assembling, that a less than perfect crankshaft will not be able to rotate when you have three or more mains caps fitted, enabling you to reject your faulty crank and ensure total professionalism in your rebuild.

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Prices do not include local EU.Tax.(VAT).
Prices & stock are subject to change without notice. Information and advice, as always, is free.

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