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This is valuable information, especially for Bronz. I suspect PCNA would like to learn about this and even perhaps extend some goodwill...
Its 10 years old and has been out of warranty for 40k miles. It’s not their problem anylonger, and really shouldn’t be. You can’t guarantee something mechanical forever. The only guarantee is that everything mechanical will wear out, if it doesn’t fail in the process.
Its 10 years old and has been out of warranty for 40k miles. It’s not their problem anylonger, and really shouldn’t be. You can’t guarantee something mechanical forever. The only guarantee is that everything mechanical will wear out, if it doesn’t fail in the process.
Jake, thanks so much for this work! I own a .1, but really waffled back and forth on a .1 vs .2. Seems that it can catch you either way. All I m ow as of now, is that I need to change my oil over to DT40 and a spin on filter.
Do you have a write up anywhere, or video, conveying what you believe to be the best recipe to prevent scoring? Btw, my car only has 21k miles and has been serviced via the dealer (5w-40 M1) prior to my purchase, so I'm hoping. That moving to a better care package will allow the engine to in tip top shape until I can have a 4.3L built.
So the new DI oil will help with the LSPI wear that occurs on the connecting rod bearings. Will it also help to preven or minimize borescoring from the break down of the Piston skirt anti wear coating?
Jake, thanks so much for this work! I own a .1, but really waffled back and forth on a .1 vs .2. Seems that it can catch you either way. All I m ow as of now, is that I need to change my oil over to DT40 and a spin on filter.
Do you have a write up anywhere, or video, conveying what you believe to be the best recipe to prevent scoring? Btw, my car only has 21k miles and has been serviced via the dealer (5w-40 M1) prior to my purchase, so I'm hoping. That moving to a better care package will allow the engine to in tip top shape until I can have a 4.3L built.
Thanks
Cw
l have yet to release any info about reducing the risk of bore scoring. Ultimately l believe its either going to happen to an engine, or it isn’t.
While there’s always things that can be done to treat symptoms, or what we may believe will be/ can be as symptom, the things would arguably be effective.
While we can make a lot of calls based on our experience, we can’t correct what people have been taught concerning oil service intervals, and oils. The “annual” oil service for these engines definitely plays into these problems. Modern fuels and their additives also play into starting the downhill spiral. At the end of the day only so much cvan be done to an engine that is already in service, and has been for years with a certain regimen.
Maybe l’ll try to put together 5 points that may help avoid this, and do a video on it.
All of these engines and cars have the chance for a problem occurring. Its mechanical, afterall. It starts to die the day that it’s built.
My focus is, and always will be developing components, procedures, and lubricants for my engines. This way we are hitting a big reset button, building the engine by hand, controlling variables, and starting it’s new life on an application specific oil.
Outside of my F250 the newest car l own is my 1995, 993. The mid 90s was the last time that engineers were in charge at most companies, after that the accountants took over, along with the lowest bidder for components, and just in time manufacturing. None of which were favorable from my perspective.
l have yet to release any info about reducing the risk of bore scoring. Ultimately l believe its either going to happen to an engine, or it isn’t.
While there’s always things that can be done to treat symptoms, or what we may believe will be/ can be as symptom, the things would arguably be effective.
While we can make a lot of calls based on our experience, we can’t correct what people have been taught concerning oil service intervals, and oils. The “annual” oil service for these engines definitely plays into these problems. Modern fuels and their additives also play into starting the downhill spiral. At the end of the day only so much cvan be done to an engine that is already in service, and has been for years with a certain regimen.
Maybe l’ll try to put together 5 points that may help avoid this, and do a video on it.
All of these engines and cars have the chance for a problem occurring. Its mechanical, afterall. It starts to die the day that it’s built.
My focus is, and always will be developing components, procedures, and lubricants for my engines. This way we are hitting a big reset button, building the engine by hand, controlling variables, and starting it’s new life on an application specific oil.
Outside of my F250 the newest car l own is my 1995, 993. The mid 90s was the last time that engineers were in charge at most companies, after that the accountants took over, along with the lowest bidder for components, and just in time manufacturing. None of which were favorable from my perspective.
Started on a 4.4 today.. :-)
I have to say, it's a bit frustrating that you believe it's more or less a coin flip; whether the failure mode occurs or not. Which would lead me to believe that it is in fact a Porsche issue and not a "care" issue, would you agree?
So for now, I'll move to the DT40 oils, spin on filter, and a "slow" driving warm up: til the oil temp reaches 200*. And then whatever else you find important....
Still love the car. Still love your work, and hope to one day, have a phone call with you to build an engine.
Last question, sorry, but do y'all do any open house events or anything at the shop to where I could drive in and chat with y'all and see where this stuff happens?
I have to say, it's a bit frustrating that you believe it's more or less a coin flip; whether the failure mode occurs or not. Which would lead me to believe that it is in fact a Porsche issue and not a "care" issue, would you agree?
So for now, I'll move to the DT40 oils, spin on filter, and a "slow" driving warm up: til the oil temp reaches 200*. And then whatever else you find important....
Still love the car. Still love your work, and hope to one day, have a phone call with you to build an engine.
Last question, sorry, but do y'all do any open house events or anything at the shop to where I could drive in and chat with y'all and see where this stuff happens?
Cw
These DI issues are not specific to Porsche. Many manufacturers are going through the same things, and did at the same times. They are all learning, and guess who their guinea pigs are? The aftermarket figured these issues out before the manufacturers did (again!) because we work to solve problems in a different manner.
While l’d like to say that there’s a secret sauce oil that you can pour in as liquid gold to solve these issues, that’s not realistic. There’s so many things that play into bore scoring that we simply do not know exactly how to cure it at this time. The LSPI is an easier challenge, and we can only hope that the better boundary layer protection that is offered by the oil helps with resisting bore scoring.
We don’t host an open house, though the past 2 years the 914 Okteenerfest stopped by and we had a lunch for the group. We tend to carry out our operations at the main facility behind steel gates in a compound that is akin to a Vietnam era forward operating base. One reason we are good at what we do, is because we have total focus. We don’t have to deal with a flow of traffic in and out of the facility, walk in customers, and etc. All of those things get in the way of getting the job done in many cases.
l do offer hands- on technical training classes at my training facility, which is 2 hours south of the “compound”. Maybe you can sign up for one of those someday :-)
These DI issues are not specific to Porsche. Many manufacturers are going through the same things, and did at the same times. They are all learning, and guess who their guinea pigs are? The aftermarket figured these issues out before the manufacturers did (again!) because we work to solve problems in a different manner.
While l’d like to say that there’s a secret sauce oil that you can pour in as liquid gold to solve these issues, that’s not realistic. There’s so many things that play into bore scoring that we simply do not know exactly how to cure it at this time. The LSPI is an easier challenge, and we can only hope that the better boundary layer protection that is offered by the oil helps with resisting bore scoring.
We don’t host an open house, though the past 2 years the 914 Okteenerfest stopped by and we had a lunch for the group. We tend to carry out our operations at the main facility behind steel gates in a compound that is akin to a Vietnam era forward operating base. One reason we are good at what we do, is because we have total focus. We don’t have to deal with a flow of traffic in and out of the facility, walk in customers, and etc. All of those things get in the way of getting the job done in many cases.
l do offer hands- on technical training classes at my training facility, which is 2 hours south of the “compound”. Maybe you can sign up for one of those someday :-)
l have yet to release any info about reducing the risk of bore scoring. Ultimately l believe its either going to happen to an engine, or it isn’t.
While there’s always things that can be done to treat symptoms, or what we may believe will be/ can be as symptom, the things would arguably be effective.
While we can make a lot of calls based on our experience, we can’t correct what people have been taught concerning oil service intervals, and oils. The “annual” oil service for these engines definitely plays into these problems. Modern fuels and their additives also play into starting the downhill spiral. At the end of the day only so much cvan be done to an engine that is already in service, and has been for years with a certain regimen.
Would it be way off base to say there are basically 2 modes of failure? 1 being maintenance failure and the 2nd being mechanical failure. By that I mean failures occur due to poor/improper preventative maintenance and/or operation. Unless you're the original owner how can we possibly know if the car was ever taken to redline 30 seconds after startup in -10 degree weather? A DME report won't show us if the owner tossed his keys to his 18 yr old kid who put 87 octane in it and flogged it around a Walmart parking lot. Having receipts for oil changes is great, but no way to know if it was driven with a couple quarts short for 3 months before the change etc etc.
And mechanical failure being the result of quality control from the OE supplier or the Porsche factory itself. For example, a cylinder being manufactured slightly out of round, one connecting rod weighted just a little off from the other 5, centerline of the IMS bore not quite bang on dead center with the crank. You get the drift. There will always be manufacturing errors. No amount of DT40 will ever fix those.
So we have 2 options. 1st is buy the car new, maintain it correctly and hope it wasn't a "Friday" build. Or 2: buy a used car, get a PPI, do the proper maintenance and drive it like you stole it & enjoy your purchase. At that point, if it's gonna blow, it's gonna blow. Nothing you can do. So why stress over it. If it's the forever car, build up a rainy day fund and if/when it goes bang, call FSI.
While l’d like to say that there’s a secret sauce oil that you can pour in as liquid gold to solve these issues, that’s not realistic. There’s so many things that play into bore scoring that we simply do not know exactly how to cure it at this time. The LSPI is an easier challenge, and we can only hope that the better boundary layer protection that is offered by the oil helps with resisting bore scoring.
Fantastic report and comments including the video. Short and sweet question since there's been a lot of oil talk in this thread: I'm due for an oil change. Unless I tell my dealer otherwise they will refill with Mobil 1. If my car was your car (2011 997 GTS), what oil would you put in the car after the old Mobil 1 was drained?
I have not had time to look at Rennlist for a while but was interested when I came across this topic and your Great Video Jake - well done indeed.
I also concur with your sentiments about posting opinions when the public always think they know better - it takes for ever to defend ones opinion from those that frankly often know very little at all.
Since our communications many months ago, we are still flat out remanufacturing the M96/7 engines but as you know we have repaired a few 9A1 engines in the UK (not as many as you though).
Not wishing to contradict anything you or anyone else has posted and for what it is worth we have found a few failure modes - mainly bore scoring - which we reported on many months ago.
What we have found so far is that while many have perfectly round and parallel bores the ones with bore scoring showed signs of age related stress relieving distortion that concentrated from the middle to low down the cylinders and that we think was primarily caused by the thick main bearing part of the crankcase casting pulling the bores out of round adjacent to the edges of the solid main bearing area (as your own video appears to show too).
Although it is difficult to measure scored bores (due to damage), we also found that all the engines with scored bores showed some minor distortion on the adjacent cylinder of the same bank - but not the furthest one away at the opposite end. All but one of the scored cylinders were always at one end as well.
You will already know but for the interest of those that don't, age related stress relieving is historically an issue with castings for over 200 years and takes place very slowly and is influenced by the cooling rate of the original casting and how much temperature stress relieving is carried out on the casting before machining and any that might be carried out during the machining process.
I doubt very much that the manufacturing process at Porsche includes a mid machining stress relieving (if any at all at the point of casting) and it is clear from the engines we have repaired that have failed for other reasons (and not bore scoring) that they all had perfectly round and parallel bores - so there is clearly the majority perfectly OK but a small number that are not.
Our conclusion from this is that a very small number of castings - for some reason or another - incorporate castings stresses that very slowly move the bore shape over many cycles of heating and cooling and pinch in on the already tight original piston clearances and because they distort the roundness of the cylinders it can seize the piston in unexpected places (exactly like in your picture).
I wondered if you had similarly carried out any measurements of the cylinder bores in adjacent cylinders and found anything similar over there?
Incidentally I agree these are super engines and the crankshafts are a great design. Porsche mark the cases and cranks with numbers that relate to 3 different shell size options and their recommendation (as far as we have been advised) is to replace them with the same reference numbers on a rebuild.
However we find that the main bearing journals do wear a little more than the big ends and whereas the 3 shell choices are usually slightly bigger and smaller than the most common choice, it is possible to select a better fit in some cases by changing the original as new specified fit.
The 3 choices of shell sizes do not seem to reflect a wider variance in crankshaft manufacturing tolerances but probably rather reflect the modern methods of measuring such parts to very fine tolerances quickly and cheaply and a further tightening of the more typical tolerance choices of typical older engine production.
I probably won't have time to carry this any further but just wanted to add our experiences to the mix for the benefit of those that value it.
I have not had time to look at Rennlist for a while but was interested when I came across this topic and your Great Video Jake - well done indeed.
I also concur with your sentiments about posting opinions when the public always think they know better - it takes for ever to defend ones opinion from those that frankly often know very little at all.
Since our communications many months ago, we are still flat out remanufacturing the M96/7 engines but as you know we have repaired a few 9A1 engines in the UK (not as many as you though).
Not wishing to contradict anything you or anyone else has posted and for what it is worth we have found a few failure modes - mainly bore scoring - which we reported on many months ago.
What we have found so far is that while many have perfectly round and parallel bores the ones with bore scoring showed signs of age related stress relieving distortion that concentrated from the middle to low down the cylinders and that we think was primarily caused by the thick main bearing part of the crankcase casting pulling the bores out of round adjacent to the edges of the solid main bearing area (as your own video appears to show too).
Although it is difficult to measure scored bores (due to damage), we also found that all the engines with scored bores showed some minor distortion on the adjacent cylinder of the same bank - but not the furthest one away at the opposite end. All but one of the scored cylinders were always at one end as well.
You will already know but for the interest of those that don't, age related stress relieving is historically an issue with castings for over 200 years and takes place very slowly and is influenced by the cooling rate of the original casting and how much temperature stress relieving is carried out on the casting before machining and any that might be carried out during the machining process.
I doubt very much that the manufacturing process at Porsche includes a mid machining stress relieving (if any at all at the point of casting) and it is clear from the engines we have repaired that have failed for other reasons (and not bore scoring) that they all had perfectly round and parallel bores - so there is clearly the majority perfectly OK but a small number that are not.
Our conclusion from this is that a very small number of castings - for some reason or another - incorporate castings stresses that very slowly move the bore shape over many cycles of heating and cooling and pinch in on the already tight original piston clearances and because they distort the roundness of the cylinders it can seize the piston in unexpected places (exactly like in your picture).
I wondered if you had similarly carried out any measurements of the cylinder bores in adjacent cylinders and found anything similar over there?
Incidentally I agree these are super engines and the crankshafts are a great design. Porsche mark the cases and cranks with numbers that relate to 3 different shell size options and their recommendation (as far as we have been advised) is to replace them with the same reference numbers on a rebuild.
However we find that the main bearing journals do wear a little more than the big ends and whereas the 3 shell choices are usually slightly bigger and smaller than the most common choice, it is possible to select a better fit in some cases by changing the original as new specified fit.
The 3 choices of shell sizes do not seem to reflect a wider variance in crankshaft manufacturing tolerances but probably rather reflect the modern methods of measuring such parts to very fine tolerances quickly and cheaply and a further tightening of the more typical tolerance choices of typical older engine production.
I probably won't have time to carry this any further but just wanted to add our experiences to the mix for the benefit of those that value it.
Best regards,
Baz (Hartech)
Wow, very interesting. While appearing to be uncommon do have an idea of the average mileage before failure (bore scoring)? Does the age related stress relieving distortion indicate that some blocks were going to fail regardless of how they were treated by the owner and was decided by the metallurgy the moment they were cast?
02-11-2019, 05:29 PM
