Oil Pressure and Engine Rebuild
#31
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Now we go onto Vii's ( viscosity index improver's ) , these little gems are added to the oil to stretch out its intended viscosity , plus remember the more Vii's the greater the stretch & they start with the lowest number , so if its a 5w-50 , then its just a 5weight oil with a heap of Vii's added.
for dino oil, this is absolutely correct.
i originally posted (what appears below) in response to Doc's post, but putting it below your's works better....
dino multigrade oils have to cheat to achieve their viscosity range. after about 1.5 k miles the viscosity conditioners are already nearly gone and and what's left is reverting back to single grade oil.
but synthetics do not work in this way at all. synthetic oils nearly completely acheive this miracle via their chemical nature, and the overall result is their ability to offer near maximum protection over extremely long service intervals..... the only reason you need to pull Amsoil out of your engine, is due to contamination of minerals and compounds from your gasolines..... so, for M1, Redline, Amsoil, Royal Purple, etc the above statement, is totally false.
i don't know much about this but it's my understanding that all the lubricant manufacturer's were forced to reduce ZDDP by the U.S. automakers.... but M1's 'euro engine oils' all still have plenty of ZDDP.....going up in order of viscosity their 0w40, 0w50, 5w50 and 15w50 all have near the maximum of Zinc and Phosphorus, you can run without destroying your cat.... and the 0w50 (1750 PPM Phosphorus, 1850 PPM Zinc) has enough to ruin your cat.
nobody every thinks about running M1 5w50. but, it was their best, and most expensive product for years (until the 0w50 oil was offered). but, the 5w50 Rally Oil is exactly what you should be running if after the first cold snap arrives, if you have a catalytic converter.
#32
Three Wheelin'
#33
Three Wheelin'
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Oil dilution is only a problem in cars where the engine is run in short bursts. Any car where the engine comes up to temp for at least 20 minutes will not have an issue with oil dilution(unless it's massive) as the fuel will evaporate out of the crankcase and be burned through the PCV/EGR mechanism. A small amount of oil vapor does this as well, and is not a problem, but the fuel evaporates rather quick in the crankcase with temps above 240F.
High temperatures accelerate evaporation but also oxidation.
Dodgy fuel injectors can easily cause 2% dilution of the oil. Dilution % depends on ingress rate as well as evaporation rate.
Cheers,
Mike
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Some basic in the field observations over the last 35 or so years working on last century Porsche cars .
First of all }
Did we see worn-out cam lobes + hydraulic lifter faces, badly worn camchain sprockets( twin cam) , crankshaft thrustbearing wear , unusual excessive cylinder to piston wear , way too early valve guide wear in last century Porsche engines in cars sold to the public from the 1970's to the around 15 years or so ago and these cars just running on a decent quality 20w-50 and the oil changed say once a year or 10,000Kms ?
Answer = No
In fact the wear rate was so low( even a little wear) , we often thought Porsche engines would never wear out , in this I am talking about 944 2.5L , 944S 2.5L , 951 , 944S2 , 928 ( all ) , 911 ( all )
We even have some customers with the somewhat notorious 2.5L 944S ( twin cam 16V ) with well over 400,000 Kms with no wear at all with the cams or sprockets or even valve guides , the reason I mentioned that is because we took the head off the highest km customers 944S ( twin cam) in the last month ( first time ever ) , the cylinders were unmarked , no cam wear at all , no cam chain sprocket wear , even the valve guides were still in spec ( Ex ones only just ), this car just received new gaskets & seals ( old head gasket was rotted with old age) , new timing chain ( between cams & slipper guides).
This 944S I have known since new & has only ever been on a good quality 20w-50
Is this the same for last century Porsche's that have been on a low viscosity & low ZDDP so called synthetic oil , meaning Low Oil Film Strength Oil ?
Answer = No way in the world , the usual here is massive wear of the above components mentioned , often in less than 60,000Kms on switching , depending on how low the oil film strength is of the so called synthetic oil ( these are usually hydro-cracked crude oil & advertised as synthetic which is legal )
But Why ?
Answer = Emperor's New Clothes , meaning humans just love buying something that's hyped up without really knowing just what they have purchased
Did you notice the components mentioned above ( cam lobes etc ) all these components rely on oil film strength alone , meaning no oil pressure
How do we increase oil film strength in engine oils on this planet in this universe ?
Answer = A) Increase oil viscosity say from a 5w-40 to a 20w-50 ( with both oil with the same levels of ZDDP ) which often they do not
B) Increase ZDDP
If you take one away you decrease oil film strength
If you take both away you very very much reduce oil film strength( very rapid cam wear etc)
Now we go onto Vii's ( viscosity index improver's ) , these little gems are added to the oil to stretch out its intended viscosity , plus remember the more Vii's the greater the stretch & they start with the lowest number , so if its a 5w-50 , then its just a 5weight oil with a heap of Vii's added & remember Vii's are not a lubricant in their own right they are just an additive .
So if you keep the numbers a little tighter the less Vii's are needed ( 20w-50 ) for example
Oil companies have had a lot of issues with Vii's over the years , because if left too long in the sump , these little additives help accelerate turning a percentage of the oil into little hard little granules that block up the oil intake gauze = no oil pressure because of blocked oil intake ( seen when oil change interval is left too long
And yes there has been some good inroads into reducing this with some clever chemistry over the last few years but the fact remains there is a lot of Vii's that are not a lubricant in their own right , just more of an additive
Now we go onto oil pressure , measured with a workshop oil pressure gauge , if you install a 5w-50 into say a 968 & get it up to high core temp ( not rad temp ) engine core temp ( oil temp say 95 + deg cel) you will get a given idle oil pressure ( say 1.5bar )
Then you drain the oil & install a 20w-50 oil & repeat the test , you will see not 1.5bar but at least .4 of a bar higher ( 1.9 bar )
The reason is the 5w-50 is not really a 50 its just a rounding off of a number , so a 5w-50 will actually be closer to a 5w-45 , as the 5w-50 gets older ( many heat cycles later) it drops even further
Same goes for the 20w-50 , but with less Vii's its more closer to the 50 ( say 20w-49 )
So what I am getting at is the cold start furthy is more of a myth in these last century Porsche engines , the real wear is engine hot where oil film strength is very criticle ( metal to metal contact) , particularly with these high loaded flat tappet designed last century Porsche engines
The other thing of interest is oil to the top end ( engine cold ) and cranking , try it you're self as I have done
944S2 / 968 , twin cam camcover off , engine oil 20w-50 ( as per owners manual ) ambient temp 7 deg cel ( mid winter first thing in morning)
First thing noticed ( before cranking) is that cam lobes are still covered with a film of oil , same goes for the lifter faces , yet the engine has not run for several days ( this is much less the case for a 0w-40 which is only natural because its extremely thin hot)
Crank engine = oil spraying everywhere before engine even fires up( what a mess) , so much for the Molasses comment which only comes from people who do not know , they just guess or just spread non truths for whatever agenda ( maybe that are a rep for that oil company ?)
Last but not least , the 944/951/968 series oil pressure relief valve opens around 7+ bar of pressure , so like the humble 924 Porsche which had a 0-10 bar oil pressure gauge , so should the 944951/968 as well , because the max 5 bar reading is not the max at all, its just showing part of the oil pressure being made , which leads me to the conrod bearings , No 2 conrod bearing in the 944 / 951 / 968 are at risk to damage from low oil pressure , the simplest way to get around this issue is to go as high as viscosity ( high oil pressure) to reduce / stop the oil bubbles forming in the pressure circuit ,that's why we do not loose engines to this issue , but on low vis oil with high oil temp its a problem at full power with these last century Porsche engines
But like I said , no complaints from me , the work just keeps pouring in from the use of low vis , low oil film strength oils in last century Porsche's, meaning viscosities that are out of the range that is printed by Porsche in the owners manual in the multi grade" look at me section" ( I hope it continues ) at least no one can say , we didn't warn owners of this
First of all }
Did we see worn-out cam lobes + hydraulic lifter faces, badly worn camchain sprockets( twin cam) , crankshaft thrustbearing wear , unusual excessive cylinder to piston wear , way too early valve guide wear in last century Porsche engines in cars sold to the public from the 1970's to the around 15 years or so ago and these cars just running on a decent quality 20w-50 and the oil changed say once a year or 10,000Kms ?
Answer = No
In fact the wear rate was so low( even a little wear) , we often thought Porsche engines would never wear out , in this I am talking about 944 2.5L , 944S 2.5L , 951 , 944S2 , 928 ( all ) , 911 ( all )
We even have some customers with the somewhat notorious 2.5L 944S ( twin cam 16V ) with well over 400,000 Kms with no wear at all with the cams or sprockets or even valve guides , the reason I mentioned that is because we took the head off the highest km customers 944S ( twin cam) in the last month ( first time ever ) , the cylinders were unmarked , no cam wear at all , no cam chain sprocket wear , even the valve guides were still in spec ( Ex ones only just ), this car just received new gaskets & seals ( old head gasket was rotted with old age) , new timing chain ( between cams & slipper guides).
This 944S I have known since new & has only ever been on a good quality 20w-50
Is this the same for last century Porsche's that have been on a low viscosity & low ZDDP so called synthetic oil , meaning Low Oil Film Strength Oil ?
Answer = No way in the world , the usual here is massive wear of the above components mentioned , often in less than 60,000Kms on switching , depending on how low the oil film strength is of the so called synthetic oil ( these are usually hydro-cracked crude oil & advertised as synthetic which is legal )
But Why ?
Answer = Emperor's New Clothes , meaning humans just love buying something that's hyped up without really knowing just what they have purchased
Did you notice the components mentioned above ( cam lobes etc ) all these components rely on oil film strength alone , meaning no oil pressure
How do we increase oil film strength in engine oils on this planet in this universe ?
Answer = A) Increase oil viscosity say from a 5w-40 to a 20w-50 ( with both oil with the same levels of ZDDP ) which often they do not
B) Increase ZDDP
If you take one away you decrease oil film strength
If you take both away you very very much reduce oil film strength( very rapid cam wear etc)
Now we go onto Vii's ( viscosity index improver's ) , these little gems are added to the oil to stretch out its intended viscosity , plus remember the more Vii's the greater the stretch & they start with the lowest number , so if its a 5w-50 , then its just a 5weight oil with a heap of Vii's added & remember Vii's are not a lubricant in their own right they are just an additive .
So if you keep the numbers a little tighter the less Vii's are needed ( 20w-50 ) for example
Oil companies have had a lot of issues with Vii's over the years , because if left too long in the sump , these little additives help accelerate turning a percentage of the oil into little hard little granules that block up the oil intake gauze = no oil pressure because of blocked oil intake ( seen when oil change interval is left too long
And yes there has been some good inroads into reducing this with some clever chemistry over the last few years but the fact remains there is a lot of Vii's that are not a lubricant in their own right , just more of an additive
Now we go onto oil pressure , measured with a workshop oil pressure gauge , if you install a 5w-50 into say a 968 & get it up to high core temp ( not rad temp ) engine core temp ( oil temp say 95 + deg cel) you will get a given idle oil pressure ( say 1.5bar )
Then you drain the oil & install a 20w-50 oil & repeat the test , you will see not 1.5bar but at least .4 of a bar higher ( 1.9 bar )
The reason is the 5w-50 is not really a 50 its just a rounding off of a number , so a 5w-50 will actually be closer to a 5w-45 , as the 5w-50 gets older ( many heat cycles later) it drops even further
Same goes for the 20w-50 , but with less Vii's its more closer to the 50 ( say 20w-49 )
So what I am getting at is the cold start furthy is more of a myth in these last century Porsche engines , the real wear is engine hot where oil film strength is very criticle ( metal to metal contact) , particularly with these high loaded flat tappet designed last century Porsche engines
The other thing of interest is oil to the top end ( engine cold ) and cranking , try it you're self as I have done
944S2 / 968 , twin cam camcover off , engine oil 20w-50 ( as per owners manual ) ambient temp 7 deg cel ( mid winter first thing in morning)
First thing noticed ( before cranking) is that cam lobes are still covered with a film of oil , same goes for the lifter faces , yet the engine has not run for several days ( this is much less the case for a 0w-40 which is only natural because its extremely thin hot)
Crank engine = oil spraying everywhere before engine even fires up( what a mess) , so much for the Molasses comment which only comes from people who do not know , they just guess or just spread non truths for whatever agenda ( maybe that are a rep for that oil company ?)
Last but not least , the 944/951/968 series oil pressure relief valve opens around 7+ bar of pressure , so like the humble 924 Porsche which had a 0-10 bar oil pressure gauge , so should the 944951/968 as well , because the max 5 bar reading is not the max at all, its just showing part of the oil pressure being made , which leads me to the conrod bearings , No 2 conrod bearing in the 944 / 951 / 968 are at risk to damage from low oil pressure , the simplest way to get around this issue is to go as high as viscosity ( high oil pressure) to reduce / stop the oil bubbles forming in the pressure circuit ,that's why we do not loose engines to this issue , but on low vis oil with high oil temp its a problem at full power with these last century Porsche engines
But like I said , no complaints from me , the work just keeps pouring in from the use of low vis , low oil film strength oils in last century Porsche's, meaning viscosities that are out of the range that is printed by Porsche in the owners manual in the multi grade" look at me section" ( I hope it continues ) at least no one can say , we didn't warn owners of this
thanks for posting this.
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#35
Drifting
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Did you notice how high the ZDDP content is on the Mobil1 Racing oil( like all racing oils ) , that's because racing oils are exempt from the ACEA & API protocols concerning emissions & naturally it dramatically increases the oil film strength so hence the large amounts ( which is great).
Don't you find it interesting that ( lets take the above 0w-50 Mobil 1 racing oil)it has such high levels of ZDDP ( AW package) ,the reason I say that is in this day of age & with all the ever increasing advances in oil technology that ZDDP is used at all , can you tell my why ZDDP is used at all in this very high quality Synthetic oil ? , why doesn't Mobil just have huge amounts of Boron ( AW replacement )or no AW package at all , and just get rid of ZDDP altogether ? .
Or is it that ZDDP works after all these decades( which is obviously the answer) , how disappointing that the high quality synthetic engine oil on its own ( without ZDDP ) is not quite good enough ?
Don't you find it interesting that ( lets take the above 0w-50 Mobil 1 racing oil)it has such high levels of ZDDP ( AW package) ,the reason I say that is in this day of age & with all the ever increasing advances in oil technology that ZDDP is used at all , can you tell my why ZDDP is used at all in this very high quality Synthetic oil ? , why doesn't Mobil just have huge amounts of Boron ( AW replacement )or no AW package at all , and just get rid of ZDDP altogether ? .
Or is it that ZDDP works after all these decades( which is obviously the answer) , how disappointing that the high quality synthetic engine oil on its own ( without ZDDP ) is not quite good enough ?
#36
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i'm dropping the 0w40 mixes for straight 0w50.....
i logged several thousand miles last winter running 50/50 0w40/0w50 mix.....
jotted down that i had 4.0 bars at 3000 rpm and about 4.25 bars at 4000 rpm.
i've been running pure M1 0w50 Racing oil this fall....
and for openers, the engine's valvetrain is noticably quieter.
and i'm getting 4.6 bars at 3000 rpm and the full 5.0 bars at 4000 rpm.
thus, it makes virtually the same pressure as straight M1 or Amsoil 15w50 oil in my car.
so, at least for me, it's working as a legitimate winter oil option, and worth every penny, imo.
but this stuff flows extremely well in the bitter cold.
so, the 64,000 dollar question: is it the ZDDP in the M1 Racing Oil that's closing the gap on being able to do what Amsoil 15w50, Red Line and Royal Purple oils (which run on the thick side of the 50 weigh oils) are able to do?
i logged several thousand miles last winter running 50/50 0w40/0w50 mix.....
jotted down that i had 4.0 bars at 3000 rpm and about 4.25 bars at 4000 rpm.
i've been running pure M1 0w50 Racing oil this fall....
and for openers, the engine's valvetrain is noticably quieter.
and i'm getting 4.6 bars at 3000 rpm and the full 5.0 bars at 4000 rpm.
thus, it makes virtually the same pressure as straight M1 or Amsoil 15w50 oil in my car.
so, at least for me, it's working as a legitimate winter oil option, and worth every penny, imo.
but this stuff flows extremely well in the bitter cold.
so, the 64,000 dollar question: is it the ZDDP in the M1 Racing Oil that's closing the gap on being able to do what Amsoil 15w50, Red Line and Royal Purple oils (which run on the thick side of the 50 weigh oils) are able to do?
#37
Drifting
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Good news about the valve train being a bit quieter( a little extra viscosity does that) .
Can you find out something for me }
Why on earth does these latest so called synthetics( mainly racing syn ) use last century "Dino " technology by having any ZDDP at all ? , it doesn't make any sense , because all the very glossy advertising & particularly the often aggressive pushing of the latest so called synthetic oil on internet forums does not answer this fundamental question
Or lets put it this way , why go to all the trouble in making these expensive so called synthetic oils ( hydro-cracked crude oil mostly ) when they can not stand on their own feet by saying = we no longer need last century ZDDP ( as far back as WW2) = ancient
From all the research I have done so far indicates it that if the ZDDP was not added in the first place then this & other expensive so called synthetic oils would not have any decent oil film strength ? . And in turn would be useless in keeping metal parts away from each other , like cam lobes to hydraulic lifter faces( high loaded flat tappet) , thrust bearings , valve guides , pistons against cylinders , timing chains against sprockets etc etc
So then logically one can only conclude ( at this point) there has been little progress from last century
Why is it that these very sophisticated so called synthetics have so much ZDDP or any at all or even use only Boron ( AW replacement) & completely get rid of ZDDP ?
Can you find out something for me }
Why on earth does these latest so called synthetics( mainly racing syn ) use last century "Dino " technology by having any ZDDP at all ? , it doesn't make any sense , because all the very glossy advertising & particularly the often aggressive pushing of the latest so called synthetic oil on internet forums does not answer this fundamental question
Or lets put it this way , why go to all the trouble in making these expensive so called synthetic oils ( hydro-cracked crude oil mostly ) when they can not stand on their own feet by saying = we no longer need last century ZDDP ( as far back as WW2) = ancient
From all the research I have done so far indicates it that if the ZDDP was not added in the first place then this & other expensive so called synthetic oils would not have any decent oil film strength ? . And in turn would be useless in keeping metal parts away from each other , like cam lobes to hydraulic lifter faces( high loaded flat tappet) , thrust bearings , valve guides , pistons against cylinders , timing chains against sprockets etc etc
So then logically one can only conclude ( at this point) there has been little progress from last century
Why is it that these very sophisticated so called synthetics have so much ZDDP or any at all or even use only Boron ( AW replacement) & completely get rid of ZDDP ?
#38
Three Wheelin'
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Did you notice how high the ZDDP content is on the Mobil1 Racing oil( like all racing oils ) , that's because racing oils are exempt from the ACEA & API protocols concerning emissions & naturally it dramatically increases the oil film strength so hence the large amounts ( which is great).
Don't you find it interesting that ( lets take the above 0w-50 Mobil 1 racing oil)it has such high levels of ZDDP ( AW package) ,the reason I say that is in this day of age & with all the ever increasing advances in oil technology that ZDDP is used at all , can you tell my why ZDDP is used at all in this very high quality Synthetic oil ? , why doesn't Mobil just have huge amounts of Boron ( AW replacement )or no AW package at all , and just get rid of ZDDP altogether ? .
Or is it that ZDDP works after all these decades( which is obviously the answer) , how disappointing that the high quality synthetic engine oil on its own ( without ZDDP ) is not quite good enough ?
Don't you find it interesting that ( lets take the above 0w-50 Mobil 1 racing oil)it has such high levels of ZDDP ( AW package) ,the reason I say that is in this day of age & with all the ever increasing advances in oil technology that ZDDP is used at all , can you tell my why ZDDP is used at all in this very high quality Synthetic oil ? , why doesn't Mobil just have huge amounts of Boron ( AW replacement )or no AW package at all , and just get rid of ZDDP altogether ? .
Or is it that ZDDP works after all these decades( which is obviously the answer) , how disappointing that the high quality synthetic engine oil on its own ( without ZDDP ) is not quite good enough ?
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#40
Bannana Shine
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My understanding was that the use of ZDDP was not directly to increase oil film strength. As I understood it, when shear loads break through the oil film (which can happen with any kind of oil) such as cam lobes on flat tappets, rather than the metal surfaces riding directly against each other, a very thin, very hard layer of zinc and phosphorus deposited on the metal surfaces supports the loads. This layer is worn away with contact, and ZDDP in the oil is needed to replenish it, as constant high temperature, high pressure contact will continuously burnish fresh zinc and phosphorus onto the metal surfaces if ZDDP is present.
In other words, ZDDP is not to make sure that the oil always supports the loads. Rather, inevitably, at some point the oil will very briefly fail to support the loads and the ZDDP is there to bridge that gap in lubrication.
At least that's how it was explained to me.
In other words, ZDDP is not to make sure that the oil always supports the loads. Rather, inevitably, at some point the oil will very briefly fail to support the loads and the ZDDP is there to bridge that gap in lubrication.
At least that's how it was explained to me.
#41
Burning Brakes
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Why was the ZDDP content of oils decreased so dramatically? Some sort of emissions issue, or does it actually do some damage, like to the catalytic converter?
#42
Drifting
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That's a very good way to put it JDS968 , in essence ZDDP is a anti wear additive package added to engine oils which as described by you makes the oil appear or to have high shear ability , that's why racing oils & other boutique oils have so much ZDDP because of the much higher internal engine loads within any engine that goes racing( + racing oils are exempt from Emission Protocols) , to put it simply its an easy way to increase an engine oils oil film strength , without any ZDDP engine oils can not protect as well from metal to metal contact of components within an engine
From late last century , emission protocols for cars sold to the public have been getting tighter & harder for car companies to meet & as we know even diesel powered vehicles are getting the same treatment so we see these days even diesel oils for later model cars have lower levels of ZDDP
ZDDP was deemed to effect the the life of a catalytic converter & because catalytic converters are part of a cars emission equipment that the ACEA & API requirements( protocols) in regards to reducing ZDDP in engine oils came into effect , even if it meant much less engine life as a result
As a side note , its amazing how cheap catalytic converts are to replace & how expensive it is to repair a badly worn Porsche engine that has got way to premature wear to its internal components that rely on oil film strength like cams , lifter faces , valve guides , pistons to cylinders , timing chains & sprockets ( in the case of a 968 the chain sprockets are part of the cam) , engine thrust bearings etc etc .
There are only two ways to economically increase an engine oils oil film strength on this planet }
A) increase oil viscosity ( say from 5w-40 to a 20w-50) if both oils have the same levels of ZDDP
B) increase ZDDP
If you take just one of these two away you decrease the oils oil film strength
So my question remains } Why do these latest & greatest so called synthetic engine oils have any last century " Dino" solution of having any ZDDP at all ?
Or why not just have Boron AW ( replacement) package Only
Why cant these so called synthetic engine oils stand on their own two feet and say we no longer need the out dated last century "Dino" solution of adding ZDDP , what's worse is that the "Racing" so called synthetic engine oils have huge amounts of ZDDP , this is all last century stuff
I find it Very Very disappointing indeed
From late last century , emission protocols for cars sold to the public have been getting tighter & harder for car companies to meet & as we know even diesel powered vehicles are getting the same treatment so we see these days even diesel oils for later model cars have lower levels of ZDDP
ZDDP was deemed to effect the the life of a catalytic converter & because catalytic converters are part of a cars emission equipment that the ACEA & API requirements( protocols) in regards to reducing ZDDP in engine oils came into effect , even if it meant much less engine life as a result
As a side note , its amazing how cheap catalytic converts are to replace & how expensive it is to repair a badly worn Porsche engine that has got way to premature wear to its internal components that rely on oil film strength like cams , lifter faces , valve guides , pistons to cylinders , timing chains & sprockets ( in the case of a 968 the chain sprockets are part of the cam) , engine thrust bearings etc etc .
There are only two ways to economically increase an engine oils oil film strength on this planet }
A) increase oil viscosity ( say from 5w-40 to a 20w-50) if both oils have the same levels of ZDDP
B) increase ZDDP
If you take just one of these two away you decrease the oils oil film strength
So my question remains } Why do these latest & greatest so called synthetic engine oils have any last century " Dino" solution of having any ZDDP at all ?
Or why not just have Boron AW ( replacement) package Only
Why cant these so called synthetic engine oils stand on their own two feet and say we no longer need the out dated last century "Dino" solution of adding ZDDP , what's worse is that the "Racing" so called synthetic engine oils have huge amounts of ZDDP , this is all last century stuff
I find it Very Very disappointing indeed