Oil pressure, lumpy tick-over?

[griff59]

I took the Griff out yesterday for a fairly long drive, on arrival back home I noticed the oil pressure was 20 psi, and at idle the engine seemed rather lumpy. The drive was about 50 miles, longest I've done since having the car. I'm wondering if the vacuums hose issue (lack of) is really showing up now on long runs, but I'm more worried about the oil pressure.
I can't remember what a "normal" reading is? but anything around or above 20 psi comes to mind.
PS, just got it out of the garage, oil pressure on start-up was 30psi, dropping to 20psi on full warm up at 90 degrees. The oil level is about 1/4 inch into the safe zone on the dipstick, checked with the engine cold.

Edited by griff59 on Sunday 5th August 09:27

Edited by griff59 on Sunday 5th August 09:28

Edited by griff59 on Sunday 5th August 09:29

[andy43]

I'd ideally keep it right to the full mark - the more oil in there the better.
20 psi isn't bad, I've seen 15 on mine stinking hot at idle, but the gauges aren't that accurate anyway.
Mine is well over 30 stone cold at idle. I think you learn what's 'normal' for your car, then base any potential panic on anything outside that 'norm'. If it's always about 20 at hot idle I wouldn't worry!
Thicker oil can help a bit - I now have 10/60 Valvoline in mine, which is complete overkill for a 70 year old engine design, but it does give marginally better pressure readings at a hot idle.
Cue lots of other oil suggestions...

[griff59]

andy43 said:

I'd ideally keep it right to the full mark - the more oil in there the better.
20 psi isn't bad, I've seen 15 on mine stinking hot at idle, but the gauges aren't that accurate anyway.
Mine is well over 30 stone cold at idle. I think you learn what's 'normal' for your car, then base any potential panic on anything outside that 'norm'. If it's always about 20 at hot idle I wouldn't worry!
Thicker oil can help a bit - I now have 10/60 Valvoline in mine, which is complete overkill for a 70 year old engine design, but it does give marginally better pressure readings at a hot idle.
Cue lots of other oil suggestions...

Thanks a lot for your reply, I'm going to top up the oil a bit, it says everywhere that I should use Mobil 1, is that true? Or like you, is it OK to experiment?

[andy43]

I’d try and stick with what’s already in there otherwise any decent multi grade would probably be ok if you’ve no idea of existing oil type if you’re just topping it up - but if you’re changing the oil there are literally hundreds of different opinions on what’s best. Have a search - and be prepared for a long read. High zinc content is useful for the cam and lifters.
Lumpy idle could literally be anything - if you have rover gauge or an ecu mate that might help you spot something that’s out of tolerance sensor-wise.

[QBee]

15-20 psi on the gauge is normal for these engines when hot.
And if you ever see 0 or below, check the oil sender wire is making proper contact first before panicking!!
I think they generally read low.

[Belle427]

This is about as good as it gets for the Rover V8 engine, used by lots of people including the respected engine builders.
Im not sure about Mobil 1 products but they are one of the leading manufacturers.

https://www.opieoils.co.uk/p-73741-valvoline-vr1-r...

[griff59]

QBee said:

15-20 psi on the gauge is normal for these engines when hot.
And if you ever see 0 or below, check the oil sender wire is making proper contact first before panicking!!
I think they generally read low.

I started it up last night, pressure was up to just over 30 on the gauge, then went down to about 25 on warm up.
I think the lumpy tick over may be due to the vacuum tube being disconnected, from what's been said on my other thread. I'm taking the car in to have this checked, and hopefully they can fit the hose and sort out the timing. It may or may not make any difference, but I'd like to get it sorted out.

[blitzracing]

Mobil 1 ?? As recommended by TVR in the first place, but then look at the rate of cam replacement needed on the engines, typically 50k on wards. OK its a high lift cam, but how often do you replace you cam in any other engine? Personally I think its down to the wrong oil in the first place and poor bedding in of the cam.

[griff59]

blitzracing said:

Mobil 1 ?? As recommended by TVR in the first place, but then look at the rate of cam replacement needed on the engines, typically 50k on wards. OK its a high lift cam, but how often do you replace you cam in any other engine? Personally I think its down to the wrong oil in the first place and poor bedding in of the cam.

Interesting, my Griff had the cam replaced in 2011 at 71, 000 miles, it's done 10,500 miles since.

[anonymous-user]

They certainly do vary.

40 Cold, 30psi when warmed (90)

[steve-V8s]

One of the engine builders recommends Valvoline VR1 which is a 20/50, using a thicker oil does give a higher pressure reading, not certain if that means it is better lubricated though. To my mind Mobil1 is too thin for the older design of engine. I did use Mobil 1 for a few years but bought the MotorSport version which is a slightly thicker. Always got it when in France because it is not seen as a premium brand and can be found in the supermarkets. Found the hydraulic tappets a bit clattery at start-up on both the 4l and 5l engine versions with the thinner oil. Definitely don't overfill, it will leak even more than normal if you do.

[blitzracing]

Zinc additives used to be in a lot of motor oils as it provides a cushion against metal to metal contact when the oil film shears in very high pressure points like the cam lobe tip- so basically its a back up system. The problem is it can contaminate catalysts, so has been dropped from most oils as the oil performance has improved. Sure VR1 has zinc in it, but its old school mineral and you pay a very high end user price for something that is dirt cheap in the first place.

You can get synthetics with zinc. A couple of examples:

http://www.royalpurpleconsumer.com/products/hps-mo...


https://www.penriteoil.com.au/products/hpr-5-5w-40...

[griff59]

I found out, it's on Fuchs Pro S 20/50. I'm not not going to use Mobil 1, I'll just pick up a fully synthetic main brand 20/50.

[griffdude]

What kind of Griff is it? Preserps generally have lower oil pressure, however, mine has one of these-
http://www.johnealesroverv8.co.uk/3.html (Scroll down)

Idle oil pressure is now no problem hot or cold.

Edited by griffdude on Tuesday 7th August 09:04

[Pete Mac]

I use Penrite HPR15 15W/60. Why? because someone at some time swore by it as the dogs gonads of oils. Is it any good? Haven't a clue but the engine hasn't seized up and there are no more strange noises coming from the engine then there were before. I've been using it for about 5 years now.

I used to use good old Magnatec 10W/40 originally and used to get significantly better oil pressure than with the Penrite oil. To be honest I may go back to Magnatec.

I get about 45 when cold dropping to about 30 when hot but as someone else says, these gauges are not the most accurate.

Pete

[bobfather]

blitzracing said:

Mobil 1 ?? As recommended by TVR in the first place,

Just to correct this, TVR never recommended Mobil 1, they had a supply contract with Mobil Oils which required them to add the under bonnet sticker. My wife's Ford has a 'Use BP Fuels' sticker behind the filler cap, it doesn't mean that Ford think the car will work better with BP fuel, it means Ford had a beneficial contract with BP Fuels at that time

[griff59]

griffdude said:

What kind of Griff is it? Preserps generally have lower oil pressure, however, mine has one of these-
http://www.johnealesroverv8.co.uk/3.html (Scroll down)

Idle oil pressure is now no problem hot or cold.

Edited by griffdude on Tuesday 7th August 09:04

Mines a 500 Serp, 1996.
I'm going to top-up the oil today, it is a bit on the low side, see if that makes any difference.

[blitzracing]

bobfather said:

Just to correct this, TVR never recommended Mobil 1, they had a supply contract with Mobil Oils which required them to add the under bonnet sticker. My wife's Ford has a 'Use BP Fuels' sticker behind the filler cap, it doesn't mean that Ford think the car will work better with BP fuel, it means Ford had a beneficial contract with BP Fuels at that time

So if they had a supply contract, what did they use the oil for? Intriguing...,

[bobfather]

blitzracing said:

So if they had a supply contract, what did they use the oil for? Intriguing...,

What I'm saying is that TVR chose an acceptable oil that also came with a financially beneficial contract. Many oils would perform well. I'm sure some would perform better. The point is that the sticker isn't there because TVR believed the car would run better on Mobil 1, it's there because TVR agreed to place the sticker in order to save money

[blitzracing]

That makes total sense.