What should oil pressure be for V8

steve williams

steve williams

New Member
Hi,

Could anyone tell me what the oil pressures for my V8 should be, 1973 auto?

My oil pressure light comes on at low revs, comes on at traffic lights. Goes out when in P or N. Stationary in D I'm getting 600rpm and 0 oil pressure and oil light on. What should the oil pressure be?

Cheers.........:)
 
The oil pressure should be between 30-40psi @ 2400rpm HOT. Remember that the guage in the car isn't a precision instrument, and that providing there's some reading on the guage it's acceptable for the light to flicker on at idle. Zero reading on the guage and the light on means you've probably got less than 7psi at idle, which isn't very reassuring.

There are things that can be done to get the pressure up a bit it's just a question of whether you want to get that involved or not, as the first thing would be to take the sump off and have a look at the big end and main bearings.
 
Does your car burn a fair bit of oil? Or do you get smoke on a cold start-up?

600RPM would be towards the low side, wouldn't it? I can only vouch for a 3.5 Auto in a Range Rover, but at 600RPM it's not terribly happy. I would have thought that closer to 800 would be preferred (I do not have a manual, but I am sure it will tell you the idle range if you do and no doubt someone on here can tell you if not)

If you sit still at 800RPM instead of 600RPM does the oil pressure increase to a reasonable level? And is it OK when driving normally? Could it simply be you need to adjust your idle? Other than that, you are looking at a whole host of things ranging from 'thin' oil to a dodgy oil sender switch to a worn engine.

If the oil pressure isn't good on normal driving and assuming the oil level is fine/the oil is the correct grade and not old/you don't have any leaks I'd suggest doing a compression test before getting dirty and taking the sump off - it's not the be-all-and-end-all of tests, but if you are getting low compression it could suggest worn rings.

If you do go down the route of solving the problem and upgrades I cannot recommend the oil pump upgrade enough - makes a massive difference.
 
It's a little bit boaring today on a holiday day (...), so when I recall right, idle is 650 with the automatic.
You will see, how far you can go before you BW box kicks you right in the when goeing in D or R.
I have my timing cover off at the moment, the oil pump gears are out. Honestly, without this forum I would have assembled it the wrong way. If you search over the web for the Rover V8 oil pressure, you will get the feeling, that millions of V8s died due to low oil pressure and I would not wonder, if the first tipp comes up to prime your oil pump with grease from whales, which must have an age of minimum 46 years.
It's not easy where to start, but both Harvey and Alex are right. From my side I would say, never use expensive oil (synth or half-synth), but p6club.com gives you the right oil quality advice. It's an engine from the 60s, so make frequent oil changes and do not use additives.
If you have to go deeper and you are finally ending taking off timing cover and/or oil pump unit, google for "rover v8 oil pressure". I found some helpful information on the richer-engineering.com site.
I.e. Using a new pressure relief valve (piston) can cause more problems than cure problems. If you do not have those informations, risk to do exactly the wrong way, is obvious.

Where I'm personally not clear, is the "updating" or improving of the P6 oil pump.
I have only found possibility of using a tadpole form valve, all other modifications require a different housing from the post P6 generation and those timing covers are hard to find.
 
I think the "upgrade" talked about is precisely to address the issue you discuss i.e. the later covers being rare. The Upgrade adds a spacer so you can fit the later, longer oil pump gears so effectively you have the same improvement as Rover thought necessary for the SD1. Messing around with the oil pressure relief valve doesn't seem like a good idea, because the oil pressure issues are mostly problematic when the engine isn't turning very quickly and those gears will physically not move enough oil anyway. All that will happen is very quickly over idle the pressure will shoot up unnecessarily. Perhaps this could even damage the pump. Whereas bigger gears will give you volume and pressure when you need it an the relief valve will still do it's job. In some cars now the pump is electric which being independent of engine speed give you constant pressure and better still it can run before the motor starts which must buy you a whole chunk of extra engine life.

As for oil, I'd like to hear of experiences with completely rebuilt motors. I see no reason why the semi-synth recommended for later Land Rovers can't be used. Certainly if you have the later valve guides with the cup type caps. Although I'd rather expect most of what you'd achieve over 3000 mile services with the old school stuff is mostly more leaks. As for an old engine I've heard far too many tales of them failing in a few thousand miles due to crud being dislodged and blocking the narrower oilways. Having cleaned a sump and strainer the prospect of dissolving much of this this and having it run around the motor isn't something I'd like to contemplate.
 
The oil pump upgrade is readily available and cheap - I really don't see why anyone would not bother doing it to be honest. Comes with full fitting instructions and no fabrication or anything other than what basic tools are required - I got mine from Abbey Sports cars and if I recall correctly was around £80 delivered.
 
I got mine from Real Steel ,on there kit you have to drill/fit locating dowel for spacing plate.
Clive
 
No need for drilling with the one from V8 Tuner and the instructions are very concise even giving the acceptable end float and so on.
 
mtb_tuli said:
Where I'm personally not clear, is the "updating" or improving of the P6 oil pump.
I have only found possibility of using a tadpole form valve, all other modifications require a different housing from the post P6 generation and those timing covers are hard to find.
Click to expand...
Opel had a V6 3.9L engine in what was badged as the Commodore in South Africa, and the front cover off that engine has the uprated oil pump and is a direct bolt-on fit to the 3.5 RV8. For the Cousins across the pond, GM's V6 is the beast to strip the cover from.
 
steve williams said:
Hi,

Could anyone tell me what the oil pressures for my V8 should be, 1973 auto?

My oil pressure light comes on at low revs, comes on at traffic lights. Goes out when in P or N. Stationary in D I'm getting 600rpm and 0 oil pressure and oil light on. What should the oil pressure be?

Cheers.........:)
Click to expand...

I think this thread has drifted somewhat, regardless of improved pumps and gears the OP has a problem somewhere and just uprating the pump is not a cure, as Harvey has said bearings are good place to start. I would be a bit tempted to look at pump wear also and even more basic perhaps the oil filter and the oil pick up strainer.
Auto P6b's at idle are meant to be 650 RPM I guess that would likely drop to 600 if in drive (gearbox loading).


Graeme
 
Hi, I agree, this has been discussed before. Pumps produce flow, pressure is resistance to flow. So as said, the main and big end bearings need to be checked as they're the first port of call for the oil. Plus the oil pressure relief valves job is to control high pressure so does nothing at low pressures.

Colin
 
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