What engine oil
Discussion
sascha said:
10w - 60 shell helix "racing"..
Why such a thick oil?http://www.opieoils.co.uk/pdfs/tech-articles/10w-6...
gruffalo said:
thank you, this was real interesting me !However, temperature is not the only issue here and possibly not the main issue for a road car. The thicker viscosity oils will support hydrodynamic lubrication better than thinner oils. This is particularly important in areas that might be critical for wear if you move into the boundary lubrication regime. Valvetrain components, and in particular cam followers, have amongst the highest loads on them in the engine. Avoiding metal-metal contact is important to reduce follower wear on Speed 6 engines. Thicker oils will maintain operation in the hydrodynamic lubrication range better and reduce metal-metal contact. Put simply the lubricant film on thicker viscosity oils will be maintained better under load.
Boundary lubrication also increases as valvetrain speed reduces - this is due to there being greater time for the hydrodynamic oil film layer to break down. Put another way, the slower the camshaft lobe passes over a follower surface, the more time there is for the lubricant film to break down and oil to squish out of the contact zone. That's a good reason not to leave a Speed 6 engine idling for a long time and to make sure the idle speed is not set too low.
The other consideration is the antiwear formulation on engines with high valvetrain wear rates, it would be good to use an oil with high amounts of antiwear components such as ZDDP (zinc dialkyldithiophosphates), as these form a wear resistant coating on surfaces when place under pressure. A lot of the latest formulations of oils are not only low viscosity but also low in additive treat rate, because ZDDP can over time causes catalyst activity reduction (due to phosphorus acculmulation on the cat).
It's not a simple thing to chose the best oil. Thinner latest spec oil will give best fuel consumption, and lowest power lost due to reduced parasitic losses from the oil pump and reduced drag on bearings, but the best valvetrain wear protection will come from high viscosity oils with high antiwear additive content. Personally, I tend to go for higher viscosity high wear protection formulations. I've also seen one of the TVR engine specialists recommend that for the same reason on here before, but can't find the thread right now. It probably also matters if you are running an original engine compared to a rebuilt engine with better quality components. For an original non-rebuilt engine, I'd definitely not go too thin on the oil.
C
Boundary lubrication also increases as valvetrain speed reduces - this is due to there being greater time for the hydrodynamic oil film layer to break down. Put another way, the slower the camshaft lobe passes over a follower surface, the more time there is for the lubricant film to break down and oil to squish out of the contact zone. That's a good reason not to leave a Speed 6 engine idling for a long time and to make sure the idle speed is not set too low.
The other consideration is the antiwear formulation on engines with high valvetrain wear rates, it would be good to use an oil with high amounts of antiwear components such as ZDDP (zinc dialkyldithiophosphates), as these form a wear resistant coating on surfaces when place under pressure. A lot of the latest formulations of oils are not only low viscosity but also low in additive treat rate, because ZDDP can over time causes catalyst activity reduction (due to phosphorus acculmulation on the cat).
It's not a simple thing to chose the best oil. Thinner latest spec oil will give best fuel consumption, and lowest power lost due to reduced parasitic losses from the oil pump and reduced drag on bearings, but the best valvetrain wear protection will come from high viscosity oils with high antiwear additive content. Personally, I tend to go for higher viscosity high wear protection formulations. I've also seen one of the TVR engine specialists recommend that for the same reason on here before, but can't find the thread right now. It probably also matters if you are running an original engine compared to a rebuilt engine with better quality components. For an original non-rebuilt engine, I'd definitely not go too thin on the oil.
C
craigcaf said:
However, temperature is not the only issue here and possibly not the main issue for a road car. The thicker viscosity oils will support hydrodynamic lubrication better than thinner oils. This is particularly important in areas that might be critical for wear if you move into the boundary lubrication regime. Valvetrain components, and in particular cam followers, have amongst the highest loads on them in the engine. Avoiding metal-metal contact is important to reduce follower wear on Speed 6 engines. Thicker oils will maintain operation in the hydrodynamic lubrication range better and reduce metal-metal contact. Put simply the lubricant film on thicker viscosity oils will be maintained better under load.
Boundary lubrication also increases as valvetrain speed reduces - this is due to there being greater time for the hydrodynamic oil film layer to break down. Put another way, the slower the camshaft lobe passes over a follower surface, the more time there is for the lubricant film to break down and oil to squish out of the contact zone. That's a good reason not to leave a Speed 6 engine idling for a long time and to make sure the idle speed is not set too low.
The other consideration is the antiwear formulation on engines with high valvetrain wear rates, it would be good to use an oil with high amounts of antiwear components such as ZDDP (zinc dialkyldithiophosphates), as these form a wear resistant coating on surfaces when place under pressure. A lot of the latest formulations of oils are not only low viscosity but also low in additive treat rate, because ZDDP can over time causes catalyst activity reduction (due to phosphorus acculmulation on the cat).
It's not a simple thing to chose the best oil. Thinner latest spec oil will give best fuel consumption, and lowest power lost due to reduced parasitic losses from the oil pump and reduced drag on bearings, but the best valvetrain wear protection will come from high viscosity oils with high antiwear additive content. Personally, I tend to go for higher viscosity high wear protection formulations. I've also seen one of the TVR engine specialists recommend that for the same reason on here before, but can't find the thread right now. It probably also matters if you are running an original engine compared to a rebuilt engine with better quality components. For an original non-rebuilt engine, I'd definitely not go too thin on the oil.
C
To a greater extent the protection offered will be determined by the oils sheer strength..Boundary lubrication also increases as valvetrain speed reduces - this is due to there being greater time for the hydrodynamic oil film layer to break down. Put another way, the slower the camshaft lobe passes over a follower surface, the more time there is for the lubricant film to break down and oil to squish out of the contact zone. That's a good reason not to leave a Speed 6 engine idling for a long time and to make sure the idle speed is not set too low.
The other consideration is the antiwear formulation on engines with high valvetrain wear rates, it would be good to use an oil with high amounts of antiwear components such as ZDDP (zinc dialkyldithiophosphates), as these form a wear resistant coating on surfaces when place under pressure. A lot of the latest formulations of oils are not only low viscosity but also low in additive treat rate, because ZDDP can over time causes catalyst activity reduction (due to phosphorus acculmulation on the cat).
It's not a simple thing to chose the best oil. Thinner latest spec oil will give best fuel consumption, and lowest power lost due to reduced parasitic losses from the oil pump and reduced drag on bearings, but the best valvetrain wear protection will come from high viscosity oils with high antiwear additive content. Personally, I tend to go for higher viscosity high wear protection formulations. I've also seen one of the TVR engine specialists recommend that for the same reason on here before, but can't find the thread right now. It probably also matters if you are running an original engine compared to a rebuilt engine with better quality components. For an original non-rebuilt engine, I'd definitely not go too thin on the oil.
C
Read here for laymans terms http://www.bobistheoilguy.com/oilshear.htm with nice animation..
Although a lot of this is negated by the oil change interval.
Edited by m4tti on Friday 8th November 15:39
craigcaf said:
However, temperature is not the only issue here and possibly not the main issue for a road car. The thicker viscosity oils will support hydrodynamic lubrication better than thinner oils. This is particularly important in areas that might be critical for wear if you move into the boundary lubrication regime. Valvetrain components, and in particular cam followers, have amongst the highest loads on them in the engine. Avoiding metal-metal contact is important to reduce follower wear on Speed 6 engines. Thicker oils will maintain operation in the hydrodynamic lubrication range better and reduce metal-metal contact. Put simply the lubricant film on thicker viscosity oils will be maintained better under load.
Boundary lubrication also increases as valvetrain speed reduces - this is due to there being greater time for the hydrodynamic oil film layer to break down. Put another way, the slower the camshaft lobe passes over a follower surface, the more time there is for the lubricant film to break down and oil to squish out of the contact zone. That's a good reason not to leave a Speed 6 engine idling for a long time and to make sure the idle speed is not set too low.
The other consideration is the antiwear formulation on engines with high valvetrain wear rates, it would be good to use an oil with high amounts of antiwear components such as ZDDP (zinc dialkyldithiophosphates), as these form a wear resistant coating on surfaces when place under pressure. A lot of the latest formulations of oils are not only low viscosity but also low in additive treat rate, because ZDDP can over time causes catalyst activity reduction (due to phosphorus acculmulation on the cat).
It's not a simple thing to chose the best oil. Thinner latest spec oil will give best fuel consumption, and lowest power lost due to reduced parasitic losses from the oil pump and reduced drag on bearings, but the best valvetrain wear protection will come from high viscosity oils with high antiwear additive content. Personally, I tend to go for higher viscosity high wear protection formulations. I've also seen one of the TVR engine specialists recommend that for the same reason on here before, but can't find the thread right now. It probably also matters if you are running an original engine compared to a rebuilt engine with better quality components. For an original non-rebuilt engine, I'd definitely not go too thin on the oil.
C
My car has had a power rebuild 15 k ago, so what oil would you useBoundary lubrication also increases as valvetrain speed reduces - this is due to there being greater time for the hydrodynamic oil film layer to break down. Put another way, the slower the camshaft lobe passes over a follower surface, the more time there is for the lubricant film to break down and oil to squish out of the contact zone. That's a good reason not to leave a Speed 6 engine idling for a long time and to make sure the idle speed is not set too low.
The other consideration is the antiwear formulation on engines with high valvetrain wear rates, it would be good to use an oil with high amounts of antiwear components such as ZDDP (zinc dialkyldithiophosphates), as these form a wear resistant coating on surfaces when place under pressure. A lot of the latest formulations of oils are not only low viscosity but also low in additive treat rate, because ZDDP can over time causes catalyst activity reduction (due to phosphorus acculmulation on the cat).
It's not a simple thing to chose the best oil. Thinner latest spec oil will give best fuel consumption, and lowest power lost due to reduced parasitic losses from the oil pump and reduced drag on bearings, but the best valvetrain wear protection will come from high viscosity oils with high antiwear additive content. Personally, I tend to go for higher viscosity high wear protection formulations. I've also seen one of the TVR engine specialists recommend that for the same reason on here before, but can't find the thread right now. It probably also matters if you are running an original engine compared to a rebuilt engine with better quality components. For an original non-rebuilt engine, I'd definitely not go too thin on the oil.
C
IMHO any 10Wxx synthetic or semi synthetic will be fine. I personally found 0Wxx oils cause low oil pressure warning in S6 engines at high temperatures. As others have said, TVR Power warrant their engines only if 10W40 semi synthetic is used and Dom has seen far more engines than most of us!
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