what oil in a race rover v8
Discussion
v8 racing said:
This is now confusing me as well!! personally i dont think you can compare the rover engine to modern f1 cars and the like, i have only looked inside one f1 engine and the oil system is very well controlled with small oil galleries and copetition pumps way beyond the stock rover system with massive clearences and oil galleries?
I'm sorry for confusing you. I was not comparing an F1 or high revving superbike engine with a V8 Rover engine, I was merely illustrating how and why shear stability is achieved and used this as an example as it is one of the most extreme ones.
Back to Rover V8's then, as I said earlier a shear stable 5w-40 or 10w-50 would be the solution but oil temperatures and oil pressure are always a factor. I do not believe that there is any thing to be gained by going thicker than this.
Yes I'm happy to discuss this with you and even for you to try out some good synthetic oils to prove the point.
Cheers
Simon
Simon - this thread is proving to be fascinating & highly thought provoking, although I have to admit, I'm only just hanging on by the finger nails in terms of understanding.
From what I can gather, 5W-40 is OK unless there are excessive heating issues, then try 5/10-50.
Unfortunately the 4.5 ltr Chim isn't fitted with an oil temp gauge, only pressure, so I'm beginning to think I should at least have a auxilliary oil temp guage fitted. Secondly, I only really use the car on track days, which by nature means the engine is running for longer periods at very high revs. The heat after 15/20 mins work on the track is, in my opinion, very high indeed (compared to say other friends' cars out on track for similar periods) but as I say, I have no way at present of assessing the actual oil temp.
Given this, do you think it should be OK on the 5W-40 ?
Really really appreciate your input on this.
From what I can gather, 5W-40 is OK unless there are excessive heating issues, then try 5/10-50.
Unfortunately the 4.5 ltr Chim isn't fitted with an oil temp gauge, only pressure, so I'm beginning to think I should at least have a auxilliary oil temp guage fitted. Secondly, I only really use the car on track days, which by nature means the engine is running for longer periods at very high revs. The heat after 15/20 mins work on the track is, in my opinion, very high indeed (compared to say other friends' cars out on track for similar periods) but as I say, I have no way at present of assessing the actual oil temp.
Given this, do you think it should be OK on the 5W-40 ?
Really really appreciate your input on this.
Just thought I'd like to add that the psi your guage measures is oil delivery pressure to the bearings not the pressure at the bearings so all you initially need to know is that you have reasonable pressure/flow.
My turbo engine would often register no more then a couple of psi at idle on a hot day so I switched back to the thicker oils (50 weight) as a precaution, despite turbo's preferring thinner oils.
I wonder how rover bearing clearances compare to modern cars? I'd guess that bike clearances are really tight?
Boosted.
My turbo engine would often register no more then a couple of psi at idle on a hot day so I switched back to the thicker oils (50 weight) as a precaution, despite turbo's preferring thinner oils.
I wonder how rover bearing clearances compare to modern cars? I'd guess that bike clearances are really tight?
Boosted.
55jnj said:
Simon - this thread is proving to be fascinating & highly thought provoking, although I have to admit, I'm only just hanging on by the finger nails in terms of understanding.
From what I can gather, 5W-40 is OK unless there are excessive heating issues, then try 5/10-50.
Unfortunately the 4.5 ltr Chim isn't fitted with an oil temp gauge, only pressure, so I'm beginning to think I should at least have a auxilliary oil temp guage fitted. Secondly, I only really use the car on track days, which by nature means the engine is running for longer periods at very high revs. The heat after 15/20 mins work on the track is, in my opinion, very high indeed (compared to say other friends' cars out on track for similar periods) but as I say, I have no way at present of assessing the actual oil temp.
Given this, do you think it should be OK on the 5W-40 ?
Really really appreciate your input on this.
To be frank I would be happier if you were using a race 5w-40 made of pao/ester basestocks and far more shear stable than what you are using which is not in the same league. Something like Silkolene PRO S or Motul 300V would be my choice.
These oils have much higher tolerances as it's what they are designed for. Finding out your oil temps is somewhat important considering the use you're putting the car to. This way you can maximise the oils performance to get the best from the engine.
Cheers
Simon
Just my 5 penny’s worth but I think one aspect has not been looked at here.
The Rover V8 engine (3.5-4.2) has an old oil pump design that may not be happy with the thinner W40 oil at the higher temperature. (especially when the pump is not in prefect shape)
This could be the cause of the low oil pressure when the engine is hot.
If I am not completely mistaken, the recommendation from Rover was 20W50 (mineral) oil for those engines.
Now this could be due to the age of the design as the better full synthetic oils where not around in 1970 to 1980.
The newer cross-bolted engines with the oil pump at the crank have a 10W40 recommendation by Rover.
The block, oil galleries and bearings are the same as the 3.5 to 4.2.
The Rover V8 engine (3.5-4.2) has an old oil pump design that may not be happy with the thinner W40 oil at the higher temperature. (especially when the pump is not in prefect shape)
This could be the cause of the low oil pressure when the engine is hot.
If I am not completely mistaken, the recommendation from Rover was 20W50 (mineral) oil for those engines.
Now this could be due to the age of the design as the better full synthetic oils where not around in 1970 to 1980.
The newer cross-bolted engines with the oil pump at the crank have a 10W40 recommendation by Rover.
The block, oil galleries and bearings are the same as the 3.5 to 4.2.
The pump is a positive displacement pump, ignoring the relief valve and being very general, the output volume is same at same rpm for any liquid thick or thin, and any pressure 5psi or 40psi. Running high pressures also sap hp. Oil pressure is a measure of resistance to flow, so a thick liquid will give higher pressure and create more friction and heat.
"I put some valvoline 15/40 in and after my first race the oil light came on so i dropped my oil and put some streight 30 in."
What brand 30wt ?
I understand Duckhams 20W50 was originally for mini and the oil sheared very quickly and required frequent changes.
Its therefore certainly possible that RV8s have been running happily on 20W30 mineral for many years. Oil can be self correcting in that a thick oils runs a higher temperature and thins and a thin oil runs cooler and maintains viscosity. Compared to minerals Synthetics are very stable and maintain their viscosity.
"I put some valvoline 15/40 in and after my first race the oil light came on so i dropped my oil and put some streight 30 in."
What brand 30wt ?
I understand Duckhams 20W50 was originally for mini and the oil sheared very quickly and required frequent changes.
Its therefore certainly possible that RV8s have been running happily on 20W30 mineral for many years. Oil can be self correcting in that a thick oils runs a higher temperature and thins and a thin oil runs cooler and maintains viscosity. Compared to minerals Synthetics are very stable and maintain their viscosity.
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