The hydraulic tappet units on the Rover bear direct on the cam and the pushrods fit to the top of them.
But there really is no point in bothering to check - on a high mileage neglected engine the cam *will* be worn. No real need to measure it either
- it will be visible to the naked eye when you remove the valley gasket.
=2E.and won't the chain be worn too and that has more of an effect on idle that the worn cam I believe. My Vauxhall has 2mm rounded down round lobes and still runs fine.
It's a very short chain on the Rover engine and won't put the timing out by much. Remember the cam also drives the distributor on older engines so it wouldn't do for chain stretch to have a big effect.
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