991.1 Bore Scoring
#166
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A general statement repeated verbatim from what we were told.
I see the blend material for F2071 is oxide ceramics. What if you use no blend material and use an oxide ceramic for the matrix material (F6418)? Looks like friction reduction and wear resistance are off the charts using that coating.
Maybe the most exciting thing is that the cost has apparently come down ~50% in the last 5 years. Given the direction of ICE, definitely seems like this is the way of the future. That is an impressive list of engines.
#167
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I understand; you've already been more than gracious with what you provided. I know you have been working on this a while because it's mentioned it in your white paper on bore scoring.
#168
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We do recondition the blocks and have for many years, however we do not rebuild 9A1 and later engines. Here's a summary of our program:
https://lnengineering.com/products/w...ayman-911.html
https://lnengineering.com/products/w...ayman-911.html
I have a 2016 2.7L Cayman, never had any oil consumption issues... although it does drop a bar by the time I'm closer to an oil change. I guess I should start putting in a bottle of the injector defender every 6mo or so, since it's always on top tier gas. Good insurance policy for ~$11. Great thread, thanks.
#169
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Bore-stroke ratio certainly plays a factor but I don't believe it's as much as a problem on the 9A1 engine as it was on the M96 engines when they increased the stroke to 82mm from the 78mm. The increase in stroke resulted in the piston coming out of the bore 7mm at BDC (versus 2mm on the shorter stroke engines).
#170
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various cheeses (06-29-2021)
#171
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There is another component to scoring on 9A1 engines as the piston to cylinder clearance in these engines is very, very tight (.0007" total clearance new) and the bores can move at BDC and close that clearance up to a point that the piston starts to seize.
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IXLR8 (06-29-2021)
#172
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With Oerlikon's SUMEbore, there are several types of coating. The one we have the most experience with is their F2071 which is designed for corrosive fuels and environments and actually has ceramic in it. It took some time to figure out the right rings to run and now we're playing with different lubricants. I can tell you it doesn't like Mobil 1 0w40...
#174
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As Porsche did not use the F2071 coating, I can't say one way or not whether the info we've learned during our testing would be directly applicable to Porsche engines with SUMEbore coated bores. We are in the process of evaluating two more different coating used by VWAG (and Porsche) to see how they compare to the coating we have already used in both aircooled and watercooled Porsche engines.
#175
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Right now we are evaluating different oils. We were running a conventional test oil and had no oil consumption whatsoever. When we switched with M1, the engine started to consume oil but it seems to have stabilized at about 1/2 a quart in 3,000 miles. I'm pretty happy with that. I'll add back when we were working with Driven to develop DT40, we learned that different brands of fuels and also winter blends would affect oil consumption. Likewise, some oils seem to be better about oil consumption than others, as does what cylinder material (or coating) the engine uses.
As Porsche did not use the F2071 coating, I can't say one way or not whether the info we've learned during our testing would be directly applicable to Porsche engines with SUMEbore coated bores. We are in the process of evaluating two more different coating used by VWAG (and Porsche) to see how they compare to the coating we have already used in both aircooled and watercooled Porsche engines.
As Porsche did not use the F2071 coating, I can't say one way or not whether the info we've learned during our testing would be directly applicable to Porsche engines with SUMEbore coated bores. We are in the process of evaluating two more different coating used by VWAG (and Porsche) to see how they compare to the coating we have already used in both aircooled and watercooled Porsche engines.
Consider the following which is my experience with DI40. At 75k miles my cast iron 2.0T burned basically no oil running VW 502.00 5w-30 but I discovered the timing chain to be severely worn so I could fix things before it completely destroyed the head. In fact using oil consumption alone as a proxy for engine health can be a red herring.
When I switched to DI40, a 0w-40, I noticed increased oil consumption especially right after the switch. It has since stabilized and I now burn about 1/2 - 3/4 quart per 5,000 miles. But the UOA looks solid. I suspect with the thinner 0w-40 oil a little more is making it past the rings. But make no mistake, my engine is extremely healthy. I also noticed I burn a little more during city driving which I think makes sense as the car is idling more and not under load. When I took a 1,000 mile road trip to Chicago a few weeks ago it burned nothing.
In my view a relatively small amount of oil consumption is a small price to pay for running a higher quality oil with all the benefits that come along with it.
#176
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Thank you for the information, I appreciate it. I agree with everything you are saying 110% and you are offering the community good information. Goes without saying but you cannot judge an oil by consumption…..even as a proxy.
Consider the following which is my experience with DI40. At 75k miles my cast iron 2.0T burned basically no oil running VW 502.00 5w-30 but I discovered the timing chain to be severely worn so I could fix things before it completely destroyed the head. In fact using oil consumption alone as a proxy for engine health can be a red herring.
When I switched to DI40, a 0w-40, I noticed increased oil consumption especially right after the switch. It has since stabilized and I now burn about 1/2 - 3/4 quart per 5,000 miles. But the UOA looks solid. I suspect with the thinner 0w-40 oil a little more is making it past the rings. But make no mistake, my engine is extremely healthy. I also noticed I burn a little more during city driving which I think makes sense as the car is idling more and not under load. When I took a 1,000 mile road trip to Chicago a few weeks ago it burned nothing.
In my view a relatively small amount of oil consumption is a small price to pay for running a higher quality oil with all the benefits that come along with it.
Consider the following which is my experience with DI40. At 75k miles my cast iron 2.0T burned basically no oil running VW 502.00 5w-30 but I discovered the timing chain to be severely worn so I could fix things before it completely destroyed the head. In fact using oil consumption alone as a proxy for engine health can be a red herring.
When I switched to DI40, a 0w-40, I noticed increased oil consumption especially right after the switch. It has since stabilized and I now burn about 1/2 - 3/4 quart per 5,000 miles. But the UOA looks solid. I suspect with the thinner 0w-40 oil a little more is making it past the rings. But make no mistake, my engine is extremely healthy. I also noticed I burn a little more during city driving which I think makes sense as the car is idling more and not under load. When I took a 1,000 mile road trip to Chicago a few weeks ago it burned nothing.
In my view a relatively small amount of oil consumption is a small price to pay for running a higher quality oil with all the benefits that come along with it.
Case in point, I have a GTI with the 2.0T with the cast iron block as well that burned a quart every 700 miles and the engine is very healthy with 140,000 miles on it. Doesn't worry me in the slightest.
#177
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I can't believe it but had this happen to an acquaintance of mine too. Car purchased at 25k miles (C2s) but hadn't been driven that much for 2 years. 1 month later, clicking sound = bore scoring in two bores after the engine was disassembled. They didn't replace the injectors the first time around. Same issue, and one of the two previously defective cylinders was obviously scored this time. They replaced the injectors this time and things are good. It seems like service centers aren't replacing the injectors by default on the first engine failure. FWIW his car was not CPO and they still covered it (that would've been a very expensive tale otherwise).
I got recommended to use Techron every few months (or at minimum the tank before each subsequent oil change) to keep the injectors clean. Is that something you guys would recommend? The other big thing I've been recommended is an "Italian tuneup" from time to time. And not idling but driving moderately until the engine is well warmed up (because damage is more likely due to the very small clearances right after a cold start). So far (along with my new engine + injectors) I've been fine. We'll see how well this other guy's new engine holds up.
I got recommended to use Techron every few months (or at minimum the tank before each subsequent oil change) to keep the injectors clean. Is that something you guys would recommend? The other big thing I've been recommended is an "Italian tuneup" from time to time. And not idling but driving moderately until the engine is well warmed up (because damage is more likely due to the very small clearances right after a cold start). So far (along with my new engine + injectors) I've been fine. We'll see how well this other guy's new engine holds up.
#178
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I can't believe it but had this happen to an acquaintance of mine too. Car purchased at 25k miles (C2s) but hadn't been driven that much for 2 years. 1 month later, clicking sound = bore scoring in two bores after the engine was disassembled. They didn't replace the injectors the first time around. Same issue, and one of the two previously defective cylinders was obviously scored this time. They replaced the injectors this time and things are good. It seems like service centers aren't replacing the injectors by default on the first engine failure. FWIW his car was not CPO and they still covered it (that would've been a very expensive tale otherwise).
I got recommended to use Techron every few months (or at minimum the tank before each subsequent oil change) to keep the injectors clean. Is that something you guys would recommend? The other big thing I've been recommended is an "Italian tuneup" from time to time. And not idling but driving moderately until the engine is well warmed up (because damage is more likely due to the very small clearances right after a cold start). So far (along with my new engine + injectors) I've been fine. We'll see how well this other guy's new engine holds up.
I got recommended to use Techron every few months (or at minimum the tank before each subsequent oil change) to keep the injectors clean. Is that something you guys would recommend? The other big thing I've been recommended is an "Italian tuneup" from time to time. And not idling but driving moderately until the engine is well warmed up (because damage is more likely due to the very small clearances right after a cold start). So far (along with my new engine + injectors) I've been fine. We'll see how well this other guy's new engine holds up.
Yes, I run a bottle of Techron just before every oil change. I also use the Driven Injector Defender + Booster, which is just as good. As far as "Italian tuneups", yes, these engines prefer to be run at operating temperature and not idled a lot etc, so getting the car out on the highway or whatever pretty often to run it at full operating temperature for an extended period of time, even if you're not banging on it per se, is good form.
#179
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I don’t quite understand. The engine monitoring systems on our cars are super sophisticated. To the point where I had a check engine light years ago on an old Boxster simply because there was a little bit of water in the gas and one cylinder had a miss for a few hundreds of a second.. detected! These things record time spent over certain RPMs to a single engine rotation - and yet we’re saying that they are unable to detect a bad injector, twice, which leads to toasting an engine? I don’t get this. I’m not denying it happens or that it was the cause - but it doesn’t compute that the computers are missing this … anyone ?
#180
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My guess is the spray pattern is altered somewhat or they become leaky so they're still functional but causing excessive washing of the oil of the cylinders (as has been mentioned on this thread). So it's not like the engine is noticeably misfiring per se (which the computer could easily catch).