The V8 Owners Forum -

Hi, Rover V8 1976 I have an issue with oil pressure which from cold is good at around 40psi but once warm drops to virtually 0 with oil light on and gauge showing nothing. If you rev it instantly increases and tried another mechanical gauge which showed the same as the current electronic. Not sure of the history of the engine but all very clean inside. I initally purchased the hi- volume gear set but mine had the male driven gear so this didn't fit. I replaced the two gears with new ones and replaced the relief valve and spring. Still exactly the same - great when cold but drops to nothing. Tried the uprated spring but just gave me more initial pressure. Just replaced the whole pump body though mine had very minimal scores and still the same. Tried various brands of 20/50 oil even slightly thicker but no joy. Engine seems to run quite quiet - no knocking or tappet noises but if I leave it ticking over they do start to tap. ANY IDEAS!
Thanks

Probably just a tired engine. I've seen that on a few old Range Rovers where the oil light is on at idle.

Is the idle speed correct?, or too low?

Chris.

Yep idle speed is set to suit the auto transmission, would have to be over a 1000 to keep the light off.

Honestly, I would drive it.
It's discussed on the Classic Rover Forum, and the opinion is as long as the pressure is up for driving, you should be fine.

Noticed a lot saying they have low pressure on idle but no pressure! Wouldn't mind about 5psi as again noted it's the volume rather than pressure. Do you think I should stick a set of mains in?

My SD1 has done a lot of miles and is worn to the point where the crankcase is pressurised and leaks quite a bit of oil. But the oil pressure light doesn't come on at idle. And it stills runs very well, which has slowed me down from doing an engine overhaul.

IMHO, new bearing shells on their own never cure anything, as the crank will be worn too, if that is the reason.

One quite easy thing to check is for a lot of wear in the rocker shafts.

Thanks Dave, what am I looking for with the rockers or is it obvious?
They currently dont appear to be particulary noisey. I brough a new oil pump housing and the chap did mention that some aftermarket rockers could cause pressure issues but I've not personally changed them be the previous owner of the engine could have???
Thanks

Severe wear of the rocker shaft/bearings - or poor fit new - could cause low oil pressure.

First - are you sure your oil pressure switch is the correct one? Low oil pressure at idle doesn't much matter - providing there is some.

What does the gauge show at cruise with a hot engine? If it is around 30, I'd not worry. Yet.