Millers 10W-50 Nano Oil - Good for our cars?
Discussion
To try and help folk draw their own conclusions.
As one who used to work for a big oil company that supplies to the red cars I can maybe straighten a few things out. The most knowledgable folk in how to optimise the design of an engine for lubrication like camshafts, bearings and so on comes from the oil companies not the engine outfits this is a fact, they do much of the r&d. The oil majors engineers are right up there trust me on this. So Exxon will be the brains behind Porsche lubrication if they are not then enough said and the outcome is inevitable.
I will say I dont agree with everything Baz says but i do know he should be credited with what he has achieved and continues to develop as clearly a professional engineer. Gmund however I have no time for based on the response.
I dont know millers at all but it looks like they are moving forward quickly
As one who used to work for a big oil company that supplies to the red cars I can maybe straighten a few things out. The most knowledgable folk in how to optimise the design of an engine for lubrication like camshafts, bearings and so on comes from the oil companies not the engine outfits this is a fact, they do much of the r&d. The oil majors engineers are right up there trust me on this. So Exxon will be the brains behind Porsche lubrication if they are not then enough said and the outcome is inevitable.
I will say I dont agree with everything Baz says but i do know he should be credited with what he has achieved and continues to develop as clearly a professional engineer. Gmund however I have no time for based on the response.
I dont know millers at all but it looks like they are moving forward quickly
OK but there are some facts that do not come from me at all.
For example - the issue with Lokasil and the size of the silicon particles that come loose from the cylinder wall to become entrapped between the piston and the cylinder wall together with the type of piston coating that will resist the resulting wear - has almost nothing to do with oil and I doubt oil companies spent time researching that particular problem or finding a solution to it.
All the oil/tribology research in the World equates the viscosity rating of the oil with its ability to retain its thickness under load and also confirms absolutely that this ability reduces with temperature.
The size of the silicon particles is also established by the manufacturers as close, larger or slightly smaller than the piston to cylinder clearance.
The same manufacturers technical opinion was that a ferrous coating (as made by them and used in all the early engines that did not score bores) was essential to resist the wear of those particles (and stopped manufacturing them when plastic coatings were introduced by a competitor that took over supply).
That only a very small % of the coolant enters the cylinder block is factual and the ratio mixing back with the remaining 85% is technically proven.
Heat soak is also a proven phenomenon.
So this means that if heat soak thins the oil between the cylinder and the piston while a less suitable piston coating is in danger of being cut into by silicon particles large enough to do so - with the opinion of the manufacturer being that only a harder ferrous coated piston will work - combined with Porsche reverting to full 100% coolant flow, a different cylinder material (known to have smaller better secured silicon particles in it) and a return to a ferrous coated piston in the Gen 2 engines - what is there in any of that which is my opinion rather than proven facts supported by manufacturers and everything we know about oils and forces.
Thicker oils will not solve the problem but who is there than cannot see how they would help?
Furthermore it is also an established principle that older engines benefit from a thicker oil because the clearances have increased (and that technically increases the shock loading and impact of loads onto bearing surfaces). This is not my opinion but generally accepted fact.
All I have done is managed to link all those independent facts to what I see day in and day out in bore scoring to find they all fit to one explanation for the scoring problem.
It is also a well established fact that if an explanation fits all the evidence and is supported by the findings and rules established universally (as this one does) then it becomes the theory unless and until someone else finds an alternative that explains it better or is supported by tests and results - over to you then to provide your alternative and if you cannot - why cast doubt mine?
Don't forget this is not just our theory - we tested different pistons with different coatings (including several different plastic coatings, different ferrous coatings and even DLC) to recreate scoring and then were able to see what differences shortened lifespan and temperature and oil types were tested and helped us reach our conclusions.
I admit that we have not made all the test evidence available to the public - it cost us a small fortune to set up, test and reach conclusions and some of that is our intellectual property that we wish to retain for our benefit - but I think we have revealed enough to satisfy most engineers and there seems to be absolutely no one else even remotely interested or prepared to do anything similar - indeed if we had not done this many more engines would be being repaired by others - only to fail prematurely again.
I have openly admitted I am not an "OIL" expert and therefore no doubt someone who is could present an argument against some of my opinions - but can they also back up their opinion about how all that affects the bore scoring problem with having been involved in the rebuild of thousands of engines, for over a decade, testing different solutions - measuring and changing cooling flows and temperature readings inside the engines etc? - no - I don't think anyone has - but if there is some sensible evidence to contradicts my conclusions or adds benefit to the discussion or outcome - lets have it here to consider - I am always prepared to learn!
Baz
For example - the issue with Lokasil and the size of the silicon particles that come loose from the cylinder wall to become entrapped between the piston and the cylinder wall together with the type of piston coating that will resist the resulting wear - has almost nothing to do with oil and I doubt oil companies spent time researching that particular problem or finding a solution to it.
All the oil/tribology research in the World equates the viscosity rating of the oil with its ability to retain its thickness under load and also confirms absolutely that this ability reduces with temperature.
The size of the silicon particles is also established by the manufacturers as close, larger or slightly smaller than the piston to cylinder clearance.
The same manufacturers technical opinion was that a ferrous coating (as made by them and used in all the early engines that did not score bores) was essential to resist the wear of those particles (and stopped manufacturing them when plastic coatings were introduced by a competitor that took over supply).
That only a very small % of the coolant enters the cylinder block is factual and the ratio mixing back with the remaining 85% is technically proven.
Heat soak is also a proven phenomenon.
So this means that if heat soak thins the oil between the cylinder and the piston while a less suitable piston coating is in danger of being cut into by silicon particles large enough to do so - with the opinion of the manufacturer being that only a harder ferrous coated piston will work - combined with Porsche reverting to full 100% coolant flow, a different cylinder material (known to have smaller better secured silicon particles in it) and a return to a ferrous coated piston in the Gen 2 engines - what is there in any of that which is my opinion rather than proven facts supported by manufacturers and everything we know about oils and forces.
Thicker oils will not solve the problem but who is there than cannot see how they would help?
Furthermore it is also an established principle that older engines benefit from a thicker oil because the clearances have increased (and that technically increases the shock loading and impact of loads onto bearing surfaces). This is not my opinion but generally accepted fact.
All I have done is managed to link all those independent facts to what I see day in and day out in bore scoring to find they all fit to one explanation for the scoring problem.
It is also a well established fact that if an explanation fits all the evidence and is supported by the findings and rules established universally (as this one does) then it becomes the theory unless and until someone else finds an alternative that explains it better or is supported by tests and results - over to you then to provide your alternative and if you cannot - why cast doubt mine?
Don't forget this is not just our theory - we tested different pistons with different coatings (including several different plastic coatings, different ferrous coatings and even DLC) to recreate scoring and then were able to see what differences shortened lifespan and temperature and oil types were tested and helped us reach our conclusions.
I admit that we have not made all the test evidence available to the public - it cost us a small fortune to set up, test and reach conclusions and some of that is our intellectual property that we wish to retain for our benefit - but I think we have revealed enough to satisfy most engineers and there seems to be absolutely no one else even remotely interested or prepared to do anything similar - indeed if we had not done this many more engines would be being repaired by others - only to fail prematurely again.
I have openly admitted I am not an "OIL" expert and therefore no doubt someone who is could present an argument against some of my opinions - but can they also back up their opinion about how all that affects the bore scoring problem with having been involved in the rebuild of thousands of engines, for over a decade, testing different solutions - measuring and changing cooling flows and temperature readings inside the engines etc? - no - I don't think anyone has - but if there is some sensible evidence to contradicts my conclusions or adds benefit to the discussion or outcome - lets have it here to consider - I am always prepared to learn!
Baz
hartech said:
As I interpret this it means that if after a spirited run the car has to stop somewhere ticking over (say at traffic lights) the heat soak into the engine would go up but the coolant flow would almost stop (because the coolant pump is running slowly) the air flow through the radiator would stop (because it is stationary), the oil splash into the cylinders (from the crankshaft rotating) and the oil pressure is lower (reducing the oil spray through the oil spray jets into the under side of the piston that cool the piston) - so there would be a very high temperature rise in the area of the piston and cylinder wall increasing the temperature of the oil film there dramatically and reducing the oil viscosity just there by a large margin.
This observation is quite interesting. I do not know about the ambient temperature differences but it seems to me that, the cars that have been exposed to "extreme" weather and traffic conditions for a long time, suffer a lot? I've seen a few cars suffered engine fail particularly in Dubai, Honkers, Los Angeles and of course London. Both traffic and weather conditions are extreme. But again going back to cmoose's experience, some cars driven in europe much higher temperatures, no problem at all? to add more confusion, I've recently met a family friend who drives a 996 (earlier 99s) in Menorca, more than 10 years, no engine issue. The weather conditions are quite high but again road conditions are perfect no traffic at all, usually open and neat roads. On my other car, I can see the oil temperature goes quite high in severe traffic conditions, and one thing for sure I would not want to drive the car on long term in such conditions. (There is even a note on the user guide about the oil temperature range), funny enough VW beetle turbo also uses the same oil as 986, recommended by the manufacturer.not only porsche of course, I've been looking at Tesla roadsters, for a potential use in the future but many owners complain about the cooling problems especially if they are driven in the city conditions. (Tesla powertrain faults much more expensive!)
Loads of useful info here, but for me Oil is not the only particular component that affects these engines alone ?
For example - the issue with Lokasil and the size of the silicon particles that come loose from the cylinder wall to become entrapped between the piston and the cylinder wall together with the type of piston coating that will resist the resulting wear - has almost nothing to do with oil and I doubt oil companies spent time researching that particular problem or finding a solution to it.
Baz, Your quite possibly right. But i can tell you that the failure of Nikasil in BMW engines which im sure you remember and the failure of SAAB turbo blades were solved by oil companies for instance and their high temperature corrosion specialist - I know this . So it should be no surprise if you have a fuel or oil problem the obvious place to go is an oil company who do all the engine testing etc , of course its collaborative.
FWIW I recommend hartech to folk with 996 engine trouble
So you know Im not questioning this stuff its your view on the IMS bearing solution which is different to mine. Yours is a view mine is a view thats all.
Keep up the good work.
Baz, Your quite possibly right. But i can tell you that the failure of Nikasil in BMW engines which im sure you remember and the failure of SAAB turbo blades were solved by oil companies for instance and their high temperature corrosion specialist - I know this . So it should be no surprise if you have a fuel or oil problem the obvious place to go is an oil company who do all the engine testing etc , of course its collaborative.
FWIW I recommend hartech to folk with 996 engine trouble
So you know Im not questioning this stuff its your view on the IMS bearing solution which is different to mine. Yours is a view mine is a view thats all.
Keep up the good work.
Perhaps someone who has a different opinion (nothing wrong in that) can explain why then it is bank 2 that always scores bores first and bank one doesn't until many thousands of miles later and why it is that the piston coating loss is greater in bank 2 than bank 1.
The same oil (and fuel for that matter) is fed into bank 1 as bank 2 - surely some form of common sense would suggest there is a difference in bank 1 and bank 2 that is influencing the outcome.
I do accept that there is sometimes confusion about the difference that WE ARE TOLD ABOUT in hot Countries but there are many more facts that you need to weigh up before assuming that cancels out years of research and finding a great solution.
Firstly we are a very congested Nation and usually our speeds are restricted by traffic allowing only occasional bursts of full throttle driving - which is bad news compared to steady constant speed.
Secondly - having been in many of the Countries mentioned - I do think many of the drivers are less aggressive.
The problem in cold Countries is the same effectively of that with a third radiator without a control thermostat because with the thermostat fitted at the entry to the engine it is almost closed in very cold conditions to reduce flow and that increases the temperature rise inside the engine making the outlet temperature (which is on the top and thrust face of bank 2 cylinders) much hotter than if the weather was hotter and with such a small proportion of coolant passing into the cylinder block anyway, such low flow reduces it enormously inside the cylinder blocks. Hot Countries do at least have their thermostats wide open and this in turn does increase the paltry amount of coolant that can pass through the cylinder blocks and can therefore assist in cooling. This is exactly why we have explained that fitting a third radiator in this thermal cooling system can increase the temperatures at the thrust face of bank 2 unless it includes a control thermostat so that it keeps the main thermostat open more of the time and only allows the additional radiator to function when it is needed - no contradictions there!
It is vital to understand that the wear in both blocks only takes place on the thrust face (not both sides of the piston) and that the piston has not expanded so much that it is bigger than the bore (as in most seizures), but that it is the forces on the thrust face pushing the soft alloy piston against an abrasive cylinder wall that wears the softer plastic coating through until it seizes.
So why bank 2 long before bank 1? the coolant hits bank 1 on the thrust face but not bank 2 - it only reaches the thrust face after passing upwards picking up heat - and therefore the cylinder wall on the thrust face of bank 2 is always hotter than the cylinder wall on bank 1.
Surely it is obvious that this is a crucial factor in the premature bore scoring on bank 2.
The same particles will become loose in bank 1 - so why do they not impinge so much on the piston in bank 1? The only things keeping them apart is the oil film and if oil is hotter it is thinner and will more easily be squeezed out under load leaving a smaller gap between the piston and the bore to entrap a particle of silicon and cause more damage.
Regarding who is the World's foremost repairer of these engines - there is a difference between us and another source. We both fit alloy Nikasil cylinders but ours are a thicker wet cylinder (better heat transfer) that is properly supported in a machined recess at the top and the other is not but is a thinner dry liner leaving the top free to move. We also undertake all our machining in house. We also have a ribbed exterior to our wet liner (to increase surface area and cooling) and we modify the coolant flow to increase it to the cylinder block.
This does not mean that there is something wrong with the other version (at least they are alloy Nikasil types), but we already know that the original unsupported bores go oval and eventually crack and it is well established that fitting a thin liner inside a thin tube does not make the result stronger - but that each tube has to be strong enough to support its own forces - and if the original tube was not strong enough to do that - machining it out to fit a thinner liner will not make the result stronger. This means any difference in our solutions may only be obvious after a long period of time and mileage.
It takes longer to machine it our way and it requires closer control and tolerances - but it may well be that both solutions work well (I am not saying they don't) but I think ours will ultimately last longer and it is certainly not in any way inferior (and we control the whole process).
I don't think anyway that trying to compare what may be two good solutions in any way becomes some sort of criticism of either of them - they can both be good and one can still be better than the other - and that is the way I prefer to look at it - and they are both superior to ferrous liner solutions.
Avid readers may find another post on a rival forum entitles "good news on bore scoring" or "bore scoring good news" that shows what our customers think of our provision in the UK and Europe.
We are presently in the process of completing the transfer of technology to the very well respected Canadian Porsche specialist "Alpine Autowerks" to introduce our solution in North America. The first engine has been completed and has been very well received - it will be interesting to see how any rivalry over there views the outcome of the different solutions - over time!
They have the same principles as us - to basically do the best possible engineering job they can to the very highest standards and are investing in the provision of similar services over there (as we have over here).
Baz
The same oil (and fuel for that matter) is fed into bank 1 as bank 2 - surely some form of common sense would suggest there is a difference in bank 1 and bank 2 that is influencing the outcome.
I do accept that there is sometimes confusion about the difference that WE ARE TOLD ABOUT in hot Countries but there are many more facts that you need to weigh up before assuming that cancels out years of research and finding a great solution.
Firstly we are a very congested Nation and usually our speeds are restricted by traffic allowing only occasional bursts of full throttle driving - which is bad news compared to steady constant speed.
Secondly - having been in many of the Countries mentioned - I do think many of the drivers are less aggressive.
The problem in cold Countries is the same effectively of that with a third radiator without a control thermostat because with the thermostat fitted at the entry to the engine it is almost closed in very cold conditions to reduce flow and that increases the temperature rise inside the engine making the outlet temperature (which is on the top and thrust face of bank 2 cylinders) much hotter than if the weather was hotter and with such a small proportion of coolant passing into the cylinder block anyway, such low flow reduces it enormously inside the cylinder blocks. Hot Countries do at least have their thermostats wide open and this in turn does increase the paltry amount of coolant that can pass through the cylinder blocks and can therefore assist in cooling. This is exactly why we have explained that fitting a third radiator in this thermal cooling system can increase the temperatures at the thrust face of bank 2 unless it includes a control thermostat so that it keeps the main thermostat open more of the time and only allows the additional radiator to function when it is needed - no contradictions there!
It is vital to understand that the wear in both blocks only takes place on the thrust face (not both sides of the piston) and that the piston has not expanded so much that it is bigger than the bore (as in most seizures), but that it is the forces on the thrust face pushing the soft alloy piston against an abrasive cylinder wall that wears the softer plastic coating through until it seizes.
So why bank 2 long before bank 1? the coolant hits bank 1 on the thrust face but not bank 2 - it only reaches the thrust face after passing upwards picking up heat - and therefore the cylinder wall on the thrust face of bank 2 is always hotter than the cylinder wall on bank 1.
Surely it is obvious that this is a crucial factor in the premature bore scoring on bank 2.
The same particles will become loose in bank 1 - so why do they not impinge so much on the piston in bank 1? The only things keeping them apart is the oil film and if oil is hotter it is thinner and will more easily be squeezed out under load leaving a smaller gap between the piston and the bore to entrap a particle of silicon and cause more damage.
Regarding who is the World's foremost repairer of these engines - there is a difference between us and another source. We both fit alloy Nikasil cylinders but ours are a thicker wet cylinder (better heat transfer) that is properly supported in a machined recess at the top and the other is not but is a thinner dry liner leaving the top free to move. We also undertake all our machining in house. We also have a ribbed exterior to our wet liner (to increase surface area and cooling) and we modify the coolant flow to increase it to the cylinder block.
This does not mean that there is something wrong with the other version (at least they are alloy Nikasil types), but we already know that the original unsupported bores go oval and eventually crack and it is well established that fitting a thin liner inside a thin tube does not make the result stronger - but that each tube has to be strong enough to support its own forces - and if the original tube was not strong enough to do that - machining it out to fit a thinner liner will not make the result stronger. This means any difference in our solutions may only be obvious after a long period of time and mileage.
It takes longer to machine it our way and it requires closer control and tolerances - but it may well be that both solutions work well (I am not saying they don't) but I think ours will ultimately last longer and it is certainly not in any way inferior (and we control the whole process).
I don't think anyway that trying to compare what may be two good solutions in any way becomes some sort of criticism of either of them - they can both be good and one can still be better than the other - and that is the way I prefer to look at it - and they are both superior to ferrous liner solutions.
Avid readers may find another post on a rival forum entitles "good news on bore scoring" or "bore scoring good news" that shows what our customers think of our provision in the UK and Europe.
We are presently in the process of completing the transfer of technology to the very well respected Canadian Porsche specialist "Alpine Autowerks" to introduce our solution in North America. The first engine has been completed and has been very well received - it will be interesting to see how any rivalry over there views the outcome of the different solutions - over time!
They have the same principles as us - to basically do the best possible engineering job they can to the very highest standards and are investing in the provision of similar services over there (as we have over here).
Baz
You are right that it can be puzzling - but I would be wary of rubbishing professional research and solutions that work just because something in your own awareness doesn't seem to fit - there may be some completely unconnected reason.
I have provided a good explanation connecting temperatures that does fully explain why in hotter Countries the coolant flow to the starved cylinder blocks (less than 15% there) would actually be higher and why colder Countries may be worse with a third radiator (although the external conditions would keep the exhausts and cylinder block and heads generally cooler.
Do you think there could be an explanation entirely unconnected to the engine or fuel?
For example - couldit could be something to do with our UK love of criticising anyone or anything that is successful. I have found after travelling all over the World and having contacts Worldwide that we are probably the most critical Country going and we seem to love nothing more than finding a way to state our opinions?
In many European Countries - if they have a local person or business that has achieved something special - all the locals seem to appreciate it and take some kind of pride and enthusiasm because they live nearby.
In all my time trying to beat the Japanese motorcycle industry - I experienced very little support from anyone in the UK and found that enthusiasts from all over the World held what we achieved in much higher regard than anyone in the UK.
Indeed it was quite soul destroying to arrive at an International race, TT or Grand Prix with minute funding, from a tiny team, without the benefit of the special tyre choices the works teams had at the time, having never had a "paid" rider - to beat them in the race and then find criticism in the news reports full of why the works teams failed, and huge support for everyone else.
At times it felt like we had dome something wrong to be showing up the manufacturers that they adored so much by beating them with miniscule resources. This unusual UK attitude is very well understood and widely reported and I certainly have experienced it before.
A lot of owners even in the UK don't like reporting that the car they chose to buy has let them down so much and cost them so much to fix.
There is also the possibility that in some other Countries they don't have the specialists that we do over here and therefore a greater proportion get fixed with new standard engines and we never hear about it. Or perhaps there is not as much general automotive engineering knowledge enabling more people to have the wool pulled over their eyes and not realising this problem should have been fixed or the solutions supported by the manufacturers.
Anyway - while any of you are doubting my explanations would you please offer your explanation why bank 2 suffers much more than bank 1 - just to demonstrate that negativity doesn't overrule good engineering research and technical knowledge. What I mean by this is that if you think hotter or cooler Countries respond differently to this problem - try and explain why that affects bank much more than bank 1?
Baz
I have provided a good explanation connecting temperatures that does fully explain why in hotter Countries the coolant flow to the starved cylinder blocks (less than 15% there) would actually be higher and why colder Countries may be worse with a third radiator (although the external conditions would keep the exhausts and cylinder block and heads generally cooler.
Do you think there could be an explanation entirely unconnected to the engine or fuel?
For example - couldit could be something to do with our UK love of criticising anyone or anything that is successful. I have found after travelling all over the World and having contacts Worldwide that we are probably the most critical Country going and we seem to love nothing more than finding a way to state our opinions?
In many European Countries - if they have a local person or business that has achieved something special - all the locals seem to appreciate it and take some kind of pride and enthusiasm because they live nearby.
In all my time trying to beat the Japanese motorcycle industry - I experienced very little support from anyone in the UK and found that enthusiasts from all over the World held what we achieved in much higher regard than anyone in the UK.
Indeed it was quite soul destroying to arrive at an International race, TT or Grand Prix with minute funding, from a tiny team, without the benefit of the special tyre choices the works teams had at the time, having never had a "paid" rider - to beat them in the race and then find criticism in the news reports full of why the works teams failed, and huge support for everyone else.
At times it felt like we had dome something wrong to be showing up the manufacturers that they adored so much by beating them with miniscule resources. This unusual UK attitude is very well understood and widely reported and I certainly have experienced it before.
A lot of owners even in the UK don't like reporting that the car they chose to buy has let them down so much and cost them so much to fix.
There is also the possibility that in some other Countries they don't have the specialists that we do over here and therefore a greater proportion get fixed with new standard engines and we never hear about it. Or perhaps there is not as much general automotive engineering knowledge enabling more people to have the wool pulled over their eyes and not realising this problem should have been fixed or the solutions supported by the manufacturers.
Anyway - while any of you are doubting my explanations would you please offer your explanation why bank 2 suffers much more than bank 1 - just to demonstrate that negativity doesn't overrule good engineering research and technical knowledge. What I mean by this is that if you think hotter or cooler Countries respond differently to this problem - try and explain why that affects bank much more than bank 1?
Baz
Come on I never ever said that they only score due to a third radiator - only that it can make things worse without some flow control device - and you very well know that.
I think my point is that just reporting that you haven't seen written comments that the numbers failing in other Countries are different to ours and some are hotter - isn't good enough to refute all the other firm and tested evidence backed up by technical facts and figures that do form a comprehensive explanation for the phenomenon of bore scoring.
But if we move away from that - why did Porsche move away from (1) Lokasil, (2) plastic coated pistons and (3) small proportions of coolant entering the cylinder block - to 100% - in the Gen 2 engines.
There has to be a link between those changes and my explanation fits that perfectly (and incidentally was written fully before anyone knew what the changes in the Gen 2 would be).
Just because I might not be able to convincingly explain some minor anomaly about reported numbers of bore scoring in some Countries - that are not based on engineering, tests, technical information or connect to the changes Porsche themselves made to the Gen 2 engines - does not automatically mean that those conclusions are wrong - it might be that the explanation for those reported differences in how each Country writes about the failings there occur and be nothing to do with actual numbers, reasons or failings.
Baz
I think my point is that just reporting that you haven't seen written comments that the numbers failing in other Countries are different to ours and some are hotter - isn't good enough to refute all the other firm and tested evidence backed up by technical facts and figures that do form a comprehensive explanation for the phenomenon of bore scoring.
But if we move away from that - why did Porsche move away from (1) Lokasil, (2) plastic coated pistons and (3) small proportions of coolant entering the cylinder block - to 100% - in the Gen 2 engines.
There has to be a link between those changes and my explanation fits that perfectly (and incidentally was written fully before anyone knew what the changes in the Gen 2 would be).
Just because I might not be able to convincingly explain some minor anomaly about reported numbers of bore scoring in some Countries - that are not based on engineering, tests, technical information or connect to the changes Porsche themselves made to the Gen 2 engines - does not automatically mean that those conclusions are wrong - it might be that the explanation for those reported differences in how each Country writes about the failings there occur and be nothing to do with actual numbers, reasons or failings.
Baz
OK lets not argue over the implications behind you saying your model doesn't have a third radiator and still scores like buggery! and lets assume that people that make a big point of commenting on a small issue over the ambients in different Countries was not posted to in some way diminish the explanation for my established causes and not intended to cast doubt on them.
I am all for us having different opinions and being free to express them - but if we are using them to doubt someone else lets try and link together the reasons technically and not just anecdotally - eh?.
As far as I am aware you have to wait about 4 months to get an engine repaired in the states (please correct that factually if I am wrong) and that numbers are increasing - perhaps more USA and Dubai owners can simply afford to pay to have a new standard engine fitted and are not so angry about it?
I do know that in Germany they seem to accept the cost of good maintenance far more easily than we do over here!
I am interested in what are these huge differences in the causes of bore scoring you refer to - by the "leading stateside engine rebuilder" - I don't know what they are but lets have them in the open and debate them then?
I have appreciated your posts cmoose - not falling out over it - but lets put some meat on the bone in future?
Baz
I am all for us having different opinions and being free to express them - but if we are using them to doubt someone else lets try and link together the reasons technically and not just anecdotally - eh?.
As far as I am aware you have to wait about 4 months to get an engine repaired in the states (please correct that factually if I am wrong) and that numbers are increasing - perhaps more USA and Dubai owners can simply afford to pay to have a new standard engine fitted and are not so angry about it?
I do know that in Germany they seem to accept the cost of good maintenance far more easily than we do over here!
I am interested in what are these huge differences in the causes of bore scoring you refer to - by the "leading stateside engine rebuilder" - I don't know what they are but lets have them in the open and debate them then?
I have appreciated your posts cmoose - not falling out over it - but lets put some meat on the bone in future?
Baz
anonymous said:
[redacted]
This also supports my somewhat anecdotal findings insomuch as when new users of the US forum Planet 9 have asked what they should be aware of when purchasing used, no one ever mentions bore scoring! I have responded to a few of these threads myself and have included the propensity to score bores among other well-documented issues, but not once has anyone on there passed comment either in agreeance or otherwise.Cmoose, on one of the forums we went through all this once before - but - if an engine is very cold and the piston is heated up and expands too quickly before the rest of the engine has - it can always put loads on the cylinder wall that can encourage more silicon particles to c0me loose or impact them onto the piston face more. Warming up is always important but the thermostat position on the way into the engine combined with the low proportional flow into the cylinder block can slow down cylinder block expansion.
If it does the wear or scoring should be visible on both sides on the piston. We have never seen this over here but did ask last time for pictures or a response about the kind of failure it was - with no responses.
If scoring and wear is only on the thrust side it is more likely caused by the thermostat in such a cold climate to be almost fully closed and since less than 15% of the coolant goes into the block - the flow there is almost zero and therefore it could be too hot just there. This would not be noticed in the system by the time that coolant has mixed back with that 85 to 90% in the head as it would dilute the combined temperature.
The feed to the block is like a tube in which most of the coolant goes into the head and a very small slot in the side of the tube allows some to flow into the block - not a good fluid flow design to reliably allow the right amount to flow out sideways into the block and removed in Gen 2 engines going to 100% once again.
Just like fitting a third radiator - too much cooling can make the cylinder block too hot with this split and the thermostat being at the engine inlet.
We will eventually have in production not only the third radiator thermostat (to eliminate this problem) but also an outlet dual thermostat housing to move it away from the inlet - but it will be a while yet before it is generally available.
I find no inconsistency in our understanding of the problem with either too hot weather, too cold weather or third radiators - it all stems from understanding that thermostats control flow and that with large radiators (for hot fast driving) in hot weather there should be a control in cold weather to reduce the cooling capacity.
If there is not enough radiator for hot fast driving in hot climates - then a third one helps but makes it worse when it is cold. At least when it is hot coolant flow is higher and more can get into and out of the cylinder block.
There is much more that will follow when our new engine guide is on line that I don't have time to go into just now - sorry.
Baz
If it does the wear or scoring should be visible on both sides on the piston. We have never seen this over here but did ask last time for pictures or a response about the kind of failure it was - with no responses.
If scoring and wear is only on the thrust side it is more likely caused by the thermostat in such a cold climate to be almost fully closed and since less than 15% of the coolant goes into the block - the flow there is almost zero and therefore it could be too hot just there. This would not be noticed in the system by the time that coolant has mixed back with that 85 to 90% in the head as it would dilute the combined temperature.
The feed to the block is like a tube in which most of the coolant goes into the head and a very small slot in the side of the tube allows some to flow into the block - not a good fluid flow design to reliably allow the right amount to flow out sideways into the block and removed in Gen 2 engines going to 100% once again.
Just like fitting a third radiator - too much cooling can make the cylinder block too hot with this split and the thermostat being at the engine inlet.
We will eventually have in production not only the third radiator thermostat (to eliminate this problem) but also an outlet dual thermostat housing to move it away from the inlet - but it will be a while yet before it is generally available.
I find no inconsistency in our understanding of the problem with either too hot weather, too cold weather or third radiators - it all stems from understanding that thermostats control flow and that with large radiators (for hot fast driving) in hot weather there should be a control in cold weather to reduce the cooling capacity.
If there is not enough radiator for hot fast driving in hot climates - then a third one helps but makes it worse when it is cold. At least when it is hot coolant flow is higher and more can get into and out of the cylinder block.
There is much more that will follow when our new engine guide is on line that I don't have time to go into just now - sorry.
Baz
hartech said:
The feed to the block is like a tube in which most of the coolant goes into the head and a very small slot in the side of the tube allows some to flow into the block - not a good fluid flow design to reliably allow the right amount to flow out sideways into the block and removed in Gen 2 engines going to 100% once again.
Slightly O/T, but a brief question Baz; does the Mezger engine have the same design and issues regarding colling? (I realise it's a closed-deck block and the bore scoring issues are generally not an issue.)hartech said:
As I interpret this it means that if after a spirited run the car has to stop somewhere ticking over (say at traffic lights) the heat soak into the engine would go up but the coolant flow would almost stop (because the coolant pump is running slowly) the air flow through the radiator would stop (because it is stationary), the oil splash into the cylinders (from the crankshaft rotating) and the oil pressure is lower (reducing the oil spray through the oil spray jets into the under side of the piston that cool the piston) - so there would be a very high temperature rise in the area of the piston and cylinder wall increasing the temperature of the oil film there dramatically and reducing the oil viscosity just there by a large margin.
Another question for this part. Would "The Start/Stop feature" really reduce engine wear on situations like this? I believe 981 already have this function and quite useful on heavy traffics.Edited by hartech on Friday 5th August 12:12
After all "cooling inefficiencies" on m96/97 engines, one wonders how they have managed to sort thermal issues out on new 718 engine with that turbo intercooler.
(big thanks in advance, so much interesting research and info!)
No the Mezger has all the coolant flowing into the cylinders then the head (like the Gen 2) but it also has Nikasil Alloy cylinders fitted into the block (almost the same as our own Hartech Nikasil alloy cylinders) and because the Nikasil surface provides such a good sliding surface and retains oil and also has very few and very small silicon particles that ever escape (and then after huge mileages) it doesn't matter if the engine runs hot - there is no resulting damage and plain aluminium pistons with no coating will run perfectly well in them.
It is important to understand that most M96/7 engines last very well but there are a combination of small changes that were made that if the engine happens to have a slightly less than perfect Lokasil cast in cylinder liner - or is driven in extreme weather conditions, or is poorly maintained or has a particularly unsympathetic driver (or probably a few of those all combined) it may very well become one of those that fail early.
In my opinion the thermostat locations doesn't help things as it always means the entry temperature to the cylinder block is controlled but the exit temperature (near the Bank 2 thrust face) will vary depending on the ambient conditions. If the thermostat had been located at the outlet then the temperature at the thrust face would be more constant and the inlet would vary - which feeds the oil through the cylinder block before it reaches bearings and cylinders and helps cool it better - but it looks impossible to change all that.
The best we can do is to try and address all the weaknesses - advise drivers how to minimise their contribution, fit a lower temperature thermostat, if a third radiator is fitted to a manual - fit some device to control when it is part of the system, use a quality oil (probably a viscosity range thicker than when it was brand new) and hope the quality of the Lokasil liners and piston coatings is up to the job.
Baz
Apart from a poor Lokasil liner being in the car - most other issues would need to combine to prematurely cause damage - but unfortunately even if everything else is perfect - if the liner has a weak area that may just score a bore early anyway - but only in very small numbers.
It is important to understand that most M96/7 engines last very well but there are a combination of small changes that were made that if the engine happens to have a slightly less than perfect Lokasil cast in cylinder liner - or is driven in extreme weather conditions, or is poorly maintained or has a particularly unsympathetic driver (or probably a few of those all combined) it may very well become one of those that fail early.
In my opinion the thermostat locations doesn't help things as it always means the entry temperature to the cylinder block is controlled but the exit temperature (near the Bank 2 thrust face) will vary depending on the ambient conditions. If the thermostat had been located at the outlet then the temperature at the thrust face would be more constant and the inlet would vary - which feeds the oil through the cylinder block before it reaches bearings and cylinders and helps cool it better - but it looks impossible to change all that.
The best we can do is to try and address all the weaknesses - advise drivers how to minimise their contribution, fit a lower temperature thermostat, if a third radiator is fitted to a manual - fit some device to control when it is part of the system, use a quality oil (probably a viscosity range thicker than when it was brand new) and hope the quality of the Lokasil liners and piston coatings is up to the job.
Baz
Apart from a poor Lokasil liner being in the car - most other issues would need to combine to prematurely cause damage - but unfortunately even if everything else is perfect - if the liner has a weak area that may just score a bore early anyway - but only in very small numbers.
hartech said:
No the Mezger has all the coolant flowing into the cylinders then the head (like the Gen 2) but it also has Nikasil Alloy cylinders fitted into the block (almost the same as our own Hartech Nikasil alloy cylinders) and because the Nikasil surface provides such a good sliding surface and retains oil and also has very few and very small silicon particles that ever escape (and then after huge mileages) it doesn't matter if the engine runs hot - there is no resulting damage and plain aluminium pistons with no coating will run perfectly well in them.
It is important to understand that most M96/7 engines last very well but there are a combination of small changes that were made that if the engine happens to have a slightly less than perfect Lokasil cast in cylinder liner - or is driven in extreme weather conditions, or is poorly maintained or has a particularly unsympathetic driver (or probably a few of those all combined) it may very well become one of those that fail early.
In my opinion the thermostat locations doesn't help things as it always means the entry temperature to the cylinder block is controlled but the exit temperature (near the Bank 2 thrust face) will vary depending on the ambient conditions. If the thermostat had been located at the outlet then the temperature at the thrust face would be more constant and the inlet would vary - which feeds the oil through the cylinder block before it reaches bearings and cylinders and helps cool it better - but it looks impossible to change all that.
The best we can do is to try and address all the weaknesses - advise drivers how to minimise their contribution, fit a lower temperature thermostat, if a third radiator is fitted to a manual - fit some device to control when it is part of the system, use a quality oil (probably a viscosity range thicker than when it was brand new) and hope the quality of the Lokasil liners and piston coatings is up to the job.
Baz
Apart from a poor Lokasil liner being in the car - most other issues would need to combine to prematurely cause damage - but unfortunately even if everything else is perfect - if the liner has a weak area that may just score a bore early anyway - but only in very small numbers.
So you wouldn't say that every engine of this design will end up with scored bores then?It is important to understand that most M96/7 engines last very well but there are a combination of small changes that were made that if the engine happens to have a slightly less than perfect Lokasil cast in cylinder liner - or is driven in extreme weather conditions, or is poorly maintained or has a particularly unsympathetic driver (or probably a few of those all combined) it may very well become one of those that fail early.
In my opinion the thermostat locations doesn't help things as it always means the entry temperature to the cylinder block is controlled but the exit temperature (near the Bank 2 thrust face) will vary depending on the ambient conditions. If the thermostat had been located at the outlet then the temperature at the thrust face would be more constant and the inlet would vary - which feeds the oil through the cylinder block before it reaches bearings and cylinders and helps cool it better - but it looks impossible to change all that.
The best we can do is to try and address all the weaknesses - advise drivers how to minimise their contribution, fit a lower temperature thermostat, if a third radiator is fitted to a manual - fit some device to control when it is part of the system, use a quality oil (probably a viscosity range thicker than when it was brand new) and hope the quality of the Lokasil liners and piston coatings is up to the job.
Baz
Apart from a poor Lokasil liner being in the car - most other issues would need to combine to prematurely cause damage - but unfortunately even if everything else is perfect - if the liner has a weak area that may just score a bore early anyway - but only in very small numbers.
hartech said:
No the Mezger has all the coolant flowing into the cylinders then the head (like the Gen 2) but it also has Nikasil Alloy cylinders fitted into the block (almost the same as our own Hartech Nikasil alloy cylinders) and because the Nikasil surface provides such a good sliding surface and retains oil and also has very few and very small silicon particles that ever escape (and then after huge mileages) it doesn't matter if the engine runs hot - there is no resulting damage and plain aluminium pistons with no coating will run perfectly well in them... <snipped other good stuff to keep thread tidy>
Comprehensive answer. Thank you very much.Beginning to understand why the Mezger was so expensive to produce and saved for the turbos and GT cars, and also so revered. There are guys in the USA putting huge mileages on 996 turbos.
Yes - High silicon alloy cylinders with electroplated Nikasil bores are very expensive but the ultimate bore coating that runs reliably with any piston coating (or none at all).
By investing in the new CNC machinery to carry out the machining and fitting in house - we have managed to bring the cost down to about the same as cheaper alternatives - something that some understand as a massive bargain for such a quality product while others still choose a very slightly less expensive solution (many of whom still have to come here later on to have the best solution fitted).
I don't think every M96/7 engine will score a bore.
Those with the older ferrous coated pistons will probably crack a bore first (but then can have our solution fitted).
Engines with plastic coated pistons are the scoring problem but even then if some have all 6 really well produced Lokasil cast in liners with good even distribution of silicon and a good plastic coating bond - and they were always driven by their various owners with some care and good warming up and never happen to experience very extreme cold weather or hot start stops with aggressive acceleration before the temperatures have stabilised and were well maintained with frequent oil changes, no blocked condensers (leaves cleared out) - they may well survive into a respectable 150 to 200K car before eventually needing attention. A LTT would also probably help.
Unfortunately we don't know how many will fit the above scenario until they fail and we have no way of determining how the various owners looked after them - what conditions they drove in or how they were maintained - so all we can do is report that about 10% seem to be failing between 25 and 75K - but there are a lot that have already started scoring but show no signs yet and will slowly deteriorate until they are either checked or it becomes obvious.
As Porsches age - owners do tend to do less miles in them and drive them less aggressively but there are always exceptions.
They are still absolutely fantastic cars and excellent value comparing performance, cost and running costs and the whole cost of repairing them can be reduced by reliable warranty options or our own Maintenance Plan.
Baz
By investing in the new CNC machinery to carry out the machining and fitting in house - we have managed to bring the cost down to about the same as cheaper alternatives - something that some understand as a massive bargain for such a quality product while others still choose a very slightly less expensive solution (many of whom still have to come here later on to have the best solution fitted).
I don't think every M96/7 engine will score a bore.
Those with the older ferrous coated pistons will probably crack a bore first (but then can have our solution fitted).
Engines with plastic coated pistons are the scoring problem but even then if some have all 6 really well produced Lokasil cast in liners with good even distribution of silicon and a good plastic coating bond - and they were always driven by their various owners with some care and good warming up and never happen to experience very extreme cold weather or hot start stops with aggressive acceleration before the temperatures have stabilised and were well maintained with frequent oil changes, no blocked condensers (leaves cleared out) - they may well survive into a respectable 150 to 200K car before eventually needing attention. A LTT would also probably help.
Unfortunately we don't know how many will fit the above scenario until they fail and we have no way of determining how the various owners looked after them - what conditions they drove in or how they were maintained - so all we can do is report that about 10% seem to be failing between 25 and 75K - but there are a lot that have already started scoring but show no signs yet and will slowly deteriorate until they are either checked or it becomes obvious.
As Porsches age - owners do tend to do less miles in them and drive them less aggressively but there are always exceptions.
They are still absolutely fantastic cars and excellent value comparing performance, cost and running costs and the whole cost of repairing them can be reduced by reliable warranty options or our own Maintenance Plan.
Baz
Baz
Have you considered whether the OEM water pump is up to the job, is powerful enough to get the coolant round the block when required? Is it possible that if it isn't, this would be worth looking into, and if it is not, would a 3rd rad potentially exacerbate the problem? I've seen anecdotal evidence that suggests that tips are worse affected with Bore Scoring and they have a 3rd rad. Although I've also seen the theory that this is due to them pulling away in 2nd for some reason.
Have you considered whether the OEM water pump is up to the job, is powerful enough to get the coolant round the block when required? Is it possible that if it isn't, this would be worth looking into, and if it is not, would a 3rd rad potentially exacerbate the problem? I've seen anecdotal evidence that suggests that tips are worse affected with Bore Scoring and they have a 3rd rad. Although I've also seen the theory that this is due to them pulling away in 2nd for some reason.
Digga said:
omprehensive answer. Thank you very much.
Beginning to understand why the Mezger was so expensive to produce and saved for the turbos and GT cars, and also so revered. There are guys in the USA putting huge mileages on 996 turbos.
hmmm, not perfect though. If I remember correctly, someone had a 997 mezger turbo seized in here. He had to fight for like 5 months legal battle for OPC to take the work under his official warranty. There was some issue about over-revving, 32 pages good luck! Beginning to understand why the Mezger was so expensive to produce and saved for the turbos and GT cars, and also so revered. There are guys in the USA putting huge mileages on 996 turbos.
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
Jake you are quite right to question the pump – centrifugal pumps can shift a huge amount of liquid when they are running fast and unrestricted - but are poor at low revs.
This is an extra reason why the engines get hot in the upper cylinder area when ticking over after a hot run because the flow is low. This is exacerbated by the method of directing that coolant into the cylinder block as effectively a large diameter tube allows flow directly into and out of the heads but only a small slot in the side of that straight tube allows some to flow into the cylinder block.
However – even if the pump had greater flow capacity at low revs with the thermostat on the inlet to the engine this would still control the flow and reduce it down and so would not prevent the thrust face of bank 2 becoming hotter than we would like and increase the oil temperature that is separating the piston from touching the cylinder wall harshly as a result of the oil film strength.
Cylinder scoring (or scuffing – read up on that) occurs mainly at high torque and low revs. This is because engines produce their highest torque at mid range revs and not peak revs (because as the revs rise there is less time available for the inlet to fill and the exhaust to evacuate). Power is a function of torque * revs so while power may increase with revs – torque drops off (see your owners manual graphs).
At low revs there is also more time for the piston face to push against the cylinder wall and the thickness of the oil film there is a function of the thrust load (higher at lower revs), the oil viscosity, the oil temperature and the length of time the force is applied. After a hot run – but on idle – the oil at the thrust face is very hot (and therefore thinner) and then pulling away with large throttle openings applies a lot of thrust load to that oil film and because the revs are lower it has more time to squeeze the oil film thinner allowing the piston face to impinge more on the cylinder wall (or any loose silicon particles present).
I also think there is an added phenomenon that at higher speed allows the piston to run with its inertia more centrally and more in a straight line than at low revs and that this helps to keep it slightly more away from the cylinder wall at high revs (but this is not something I have researched – just a practical suspicion of what happens). The piston design is also critical as it can present a larger or smaller surface to press against the cylinder wall and the higher the area the lower the unit thrust force. But greater area at low revs may make the piston more likely to seize at hotter temperatures during very fast high speed use. This design criteria is difficult for engines producing high torque (due to variable camshaft timing and lift) and high power and top speed performance. The Gen 2 pistons are a different profile that does present a higher surface area and this may well have contributed to the very small number that have also scored despite Alusil bores and ferrous coated pistons.
We conducted some tests in like for like cars with the same drivers to see for a given level of different intentions to drive from a standstill fast, moderate or slow – the revs that the car delivered the most torque was the same or different. We found that in a manual car drivers revved them higher than the same intentions in a tiptronic but had higher throttle openings with the tiptronic (to compensate) and from this we concluded that generally tiptronic drivers deliver more torque than manual drivers.
This is especially relevant pulling away in second in a tiptronic hen much higher torque was used – hence our advice that if you intend to get away quickly in a tiptronic – flick it to 1st instead as the revs are higher which increase the coolant pump potential flow and reduces the thrust loads.
But all this advice would only make a relatively small difference to the eventual mileage before scoring and we think this may have more of a link to the quality of the Lokasil pre-forms and piston coatings than the driver’s styles (and therefore there is little that can be done about it).
A LTT helps because it increases the flow at lower revs and this in turn allows more coolant to flow into the cylinder blocks.
With Hartech Nikasil alloy cylinders there is no problem because the Nikasil provides a brilliant sliding surface for the pistons to press against and retains its oil film better – conducts more heat away from the cylinder and into the coolant (even more if the alloy cylinder is a solid wet cylinder design with increased surface area as a result of a ribbed design - like ours than a sleeved dual alloy cylinder like some alternatives on the market).
I hope this explanation helps.
Baz
This is an extra reason why the engines get hot in the upper cylinder area when ticking over after a hot run because the flow is low. This is exacerbated by the method of directing that coolant into the cylinder block as effectively a large diameter tube allows flow directly into and out of the heads but only a small slot in the side of that straight tube allows some to flow into the cylinder block.
However – even if the pump had greater flow capacity at low revs with the thermostat on the inlet to the engine this would still control the flow and reduce it down and so would not prevent the thrust face of bank 2 becoming hotter than we would like and increase the oil temperature that is separating the piston from touching the cylinder wall harshly as a result of the oil film strength.
Cylinder scoring (or scuffing – read up on that) occurs mainly at high torque and low revs. This is because engines produce their highest torque at mid range revs and not peak revs (because as the revs rise there is less time available for the inlet to fill and the exhaust to evacuate). Power is a function of torque * revs so while power may increase with revs – torque drops off (see your owners manual graphs).
At low revs there is also more time for the piston face to push against the cylinder wall and the thickness of the oil film there is a function of the thrust load (higher at lower revs), the oil viscosity, the oil temperature and the length of time the force is applied. After a hot run – but on idle – the oil at the thrust face is very hot (and therefore thinner) and then pulling away with large throttle openings applies a lot of thrust load to that oil film and because the revs are lower it has more time to squeeze the oil film thinner allowing the piston face to impinge more on the cylinder wall (or any loose silicon particles present).
I also think there is an added phenomenon that at higher speed allows the piston to run with its inertia more centrally and more in a straight line than at low revs and that this helps to keep it slightly more away from the cylinder wall at high revs (but this is not something I have researched – just a practical suspicion of what happens). The piston design is also critical as it can present a larger or smaller surface to press against the cylinder wall and the higher the area the lower the unit thrust force. But greater area at low revs may make the piston more likely to seize at hotter temperatures during very fast high speed use. This design criteria is difficult for engines producing high torque (due to variable camshaft timing and lift) and high power and top speed performance. The Gen 2 pistons are a different profile that does present a higher surface area and this may well have contributed to the very small number that have also scored despite Alusil bores and ferrous coated pistons.
We conducted some tests in like for like cars with the same drivers to see for a given level of different intentions to drive from a standstill fast, moderate or slow – the revs that the car delivered the most torque was the same or different. We found that in a manual car drivers revved them higher than the same intentions in a tiptronic but had higher throttle openings with the tiptronic (to compensate) and from this we concluded that generally tiptronic drivers deliver more torque than manual drivers.
This is especially relevant pulling away in second in a tiptronic hen much higher torque was used – hence our advice that if you intend to get away quickly in a tiptronic – flick it to 1st instead as the revs are higher which increase the coolant pump potential flow and reduces the thrust loads.
But all this advice would only make a relatively small difference to the eventual mileage before scoring and we think this may have more of a link to the quality of the Lokasil pre-forms and piston coatings than the driver’s styles (and therefore there is little that can be done about it).
A LTT helps because it increases the flow at lower revs and this in turn allows more coolant to flow into the cylinder blocks.
With Hartech Nikasil alloy cylinders there is no problem because the Nikasil provides a brilliant sliding surface for the pistons to press against and retains its oil film better – conducts more heat away from the cylinder and into the coolant (even more if the alloy cylinder is a solid wet cylinder design with increased surface area as a result of a ribbed design - like ours than a sleeved dual alloy cylinder like some alternatives on the market).
I hope this explanation helps.
Baz
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