Let's examine this very important component of the engine for weaknesses and possible solutions. The Rover V8 timing chain cover is not simply a cover but a component frame. It holds the distributor, its shaft, the oil pump and is the place where the water pump is affixed to. The more you ask a component to do the greater the likelihood of problems and the higher the cost of the item. This timing chain cover has a new replacement cost of approximately $700.00 US. On the other hand, considering it is made of cast alloy I cannot see a reason for replacement beyond the damage caused from an accident and that would have to be a bad one.

THE TIMING CHAIN

The standard Rover timing chain is not good. It's one virtue is that it is quiet. It is a single chain system with a nylon cam gear and one keyway on the crank gear.  They ALL stretch and after 50-70,000 kilometers it can hang like a wet rag.  A stretched and loose timing chain makes timing imprecise, combustion less than optimal and you will have difficulties finding a smooth idle. It also does nothing to help restrict camshaft "walk" which in turn creates a situation where either the distributor drive gear on the camshaft or the matching distributor gear chips which throws off the timing even further or can even cause your distributor to fail.

Your solution here is to upgrade the timing chain system. You can cheaply change the cam gear to an all steel version or upgrade even further to an all steel "vernier" version which makes camshaft phasing very easy. Your best bet is to replace gears and chain. Cloyes, Kent Cams, and J.E. Engineering all have excellent products with duplex (double) pre-stretched chains. Some of these may require a slight modifications to the timing chain cover to alloy for the slightly wider width.

TOP OF TIMING CHAIN COVER

The arrow from the left points to a small (16mm) node that must be ground down normally 2mm. Supposedly this node rests on the camshaft gear rim and holds the gear in place. I  have doubts as to the success of this design and there is a better solution in this article further on.

CAMSHAFT "WALK"

There is obviously no problem with movement of the timing chains crankshaft gear which is bolted firmly in place. However, if one looks at the larger camshaft gear this is bolted to the camshaft itself which has nothing to restrict its lateral movement saving the lifters and the timing gears. The little node shown above is supposed to restrict movement but it was never precise especially when you start cutting to accommodate a better timing chain. The best solution to this is a camshaft thrust button which takes the place of the bolt locking the camshaft gear onto the camshaft. It has an adjustable-length and a nylon or polished steel "face" which can be easily adjusted to act against the inside of the front of the timing chain cover to limit any camshaft walk.

OILING

Perhaps as a result of the search for solutions to the effects of design and component flaws described above, there have been methods discovered to improve the timing cover oil flow and the oiling of the distributor gears in the timing chain cover.

The first (and the most popular because it is costless) is to drill two holes in the front of the lifter gallery. These holes pass directly through into the timing chain area and all for a better flow of oil. The second is to drill a hole in the oil pump cover for an external oil feed and pass the feed into a like hole drilled to the side of the timing chain cover to feed oil to the distributor drive gears.

Both seem good ideas and harmless if not.