When I dismantled my original 3.5 litre V8, it gave me the opportunity to really have a good look around.
Inside the base of the timing cover resides the oil pump gears, a photo of which is attached below. When new the clearance between the edges of the teeth and the gear chamber is only 0.002". The oil pump is exposed to unfiltered oil, as oil is drawn from the engine through the pump and on into the filter before returning to the engine. Any debris floating with the oil will damage the inside surface of the gear chamber, and over many years and many thousands of miles this can increase the clearance as detailed above, with a subsequent reduction in oil pressure. As an example, when the clearance has increased to 0.004", from this alone oil pressure will fall 2 to 3psi.
The oil pump gears in the P6B timing cover are short gears, as opposed to the tall gears which first appeared in the SD1 and then in all subsequent timing covers in the 3.5, 3.9 and 4.2 litre Rover V8 engines up until January 1994. From this date on, all Rover V8 engines with one exception were fitted with crankshaft driven oil pumps, as opposed to the earlier design which was camshaft driven. The exception being the 3.5 litre engines built in 1995, 1997 and 1998 for military purposes.
Covering the oil pump gears is the oil pump front cover, onto which the oil filter attaches. The oil pump gears spin against the front cover resting on a thin film of oil. Over time the hard anodising starts to wear off...please see the second photo...exposing the soft aluminium alloy beneath. The gears and front cover off my engine covered 203,000 miles with oil changes every 2000 to 2500 miles. With less frequent oil changes the wear would have been much more considerable. I have heard of some people taking a piece of glass, some emery paper and the oil pump front cover and sanding the face, so as to smooth out the grooves and remove all traces of the hard anodising, in the belief that the base can now be used as if new. Such a procedure is sheer folly, as the anodising is there to minimise wear, and without it, the teeth will soon send pieces of aluminium chewed from the face and pumped throughout the engine resulting in wear and expensive damage where ever they go. :shock:
As far as I know, the only difference between the oil pump front cover as fitted to the P6B, and all subsequent oil pump covers from the SD1 to the Range Rovers of 1994 is in the size of the spigot to accept the oil filter. Those fitted to the P6B being a larger diameter.
Ron.
Inside the base of the timing cover resides the oil pump gears, a photo of which is attached below. When new the clearance between the edges of the teeth and the gear chamber is only 0.002". The oil pump is exposed to unfiltered oil, as oil is drawn from the engine through the pump and on into the filter before returning to the engine. Any debris floating with the oil will damage the inside surface of the gear chamber, and over many years and many thousands of miles this can increase the clearance as detailed above, with a subsequent reduction in oil pressure. As an example, when the clearance has increased to 0.004", from this alone oil pressure will fall 2 to 3psi.
The oil pump gears in the P6B timing cover are short gears, as opposed to the tall gears which first appeared in the SD1 and then in all subsequent timing covers in the 3.5, 3.9 and 4.2 litre Rover V8 engines up until January 1994. From this date on, all Rover V8 engines with one exception were fitted with crankshaft driven oil pumps, as opposed to the earlier design which was camshaft driven. The exception being the 3.5 litre engines built in 1995, 1997 and 1998 for military purposes.
Covering the oil pump gears is the oil pump front cover, onto which the oil filter attaches. The oil pump gears spin against the front cover resting on a thin film of oil. Over time the hard anodising starts to wear off...please see the second photo...exposing the soft aluminium alloy beneath. The gears and front cover off my engine covered 203,000 miles with oil changes every 2000 to 2500 miles. With less frequent oil changes the wear would have been much more considerable. I have heard of some people taking a piece of glass, some emery paper and the oil pump front cover and sanding the face, so as to smooth out the grooves and remove all traces of the hard anodising, in the belief that the base can now be used as if new. Such a procedure is sheer folly, as the anodising is there to minimise wear, and without it, the teeth will soon send pieces of aluminium chewed from the face and pumped throughout the engine resulting in wear and expensive damage where ever they go. :shock:
As far as I know, the only difference between the oil pump front cover as fitted to the P6B, and all subsequent oil pump covers from the SD1 to the Range Rovers of 1994 is in the size of the spigot to accept the oil filter. Those fitted to the P6B being a larger diameter.
Ron.
