991.1 Finger follower progress
05-23-2018, 03:21 PM
#31
What sort of performance are you expecting with the "upgraded" engine (HP and TQ estimates)? Is the upgraded engine synonymous with the 4.5L or is the 4.5L another option? PAG warranty aside, there is probably a market for folks interested in a stronger engine in the 991.1 (to rival the 4.0L in the .2). Now combined with Dundon's already proven race/sports headers, that could be a wicked track car with the good looks as well.
05-23-2018, 03:29 PM
#32
Race Director
It's important to remember F=MA. The 4.0 in the RS has lower redline (8600), and optimized DLC coating and oiling etc. Mitigation vs. resolution. The FF forces experienced are nearly exponential wrt RPM, that extra 400 RPM in the 3.8 is not linear. This topic has been somewhat beat to death, but again, look at any NA high revving motor (Superbikes excellent example with 14-15k RPM limits) they all utilize solid lifter designs due to the intrinsic inertial drag of hydraulic lifters and forces involved. Ducati dominated in the 70's with desmodromic valve trains, because they reduced inertial drag by ditching valve springs and extracting extra RPM and HP. Notice how the 991.2 RS has a 9k RPM limit....because the FF forces are significantly less now with solid lifters.
Porsche did what they could to optimize and mitigate the FF wear within the boundaries of financial limits, but it's still far from a robust design. It pains me because I was dead set on 991 GT3, but even with the 10 yr warranty I'm staying away and holding out for 991.2.
Porsche did what they could to optimize and mitigate the FF wear within the boundaries of financial limits, but it's still far from a robust design. It pains me because I was dead set on 991 GT3, but even with the 10 yr warranty I'm staying away and holding out for 991.2.
05-23-2018, 03:40 PM
#33
Rennlist Member
Everybody gets to make up their own mind and vote with their wallet. Again, Porsche showed with test data that the .1 issue is fixed, and the wear problem is not an issue. Other than that the engines are solid, and PAG put their money where they mouth is to the tune of 10 year/120k miles. Good enough for me!
05-23-2018, 04:03 PM
#34
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Excuse me but i didn't understand. You say here that Engine G also fails...
so when you say:
What do you mean?
Because in my opinion it's not fixed... It seems the only solution is to put a 991.2 engine. It's possible to replace the 991.1 engine with a 991.2?
Thanks
Best Regards
Everybody gets to make up their own mind and vote with their wallet. Again, Porsche showed with test data that the .1 issue is fixed, and the wear problem is not an issue. Other than that the engines are solid, and PAG put their money where they mouth is to the tune of 10 year/120k miles. Good enough for me!
Because in my opinion it's not fixed... It seems the only solution is to put a 991.2 engine. It's possible to replace the 991.1 engine with a 991.2?
Thanks
Best Regards
05-23-2018, 04:13 PM
#35
Rennlist Member
Excuse me but i didn't understand. You say here that Engine G also fails...
so when you say:
What do you mean?
Because in my opinion it's not fixed... It seems the only solution is to put a 991.2 engine. It's possible to replace the 991.1 engine with a 991.2?
Thanks
Best Regards
so when you say:
What do you mean?
Because in my opinion it's not fixed... It seems the only solution is to put a 991.2 engine. It's possible to replace the 991.1 engine with a 991.2?
Thanks
Best Regards
05-23-2018, 04:37 PM
#36
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There have been reports here of G engines needing replacement. There are also 991.1 RS engines (4.0's) that have failed. This FF issue is a wear problem induced by excessive load/force. Porsche improved oiling and added DLC coating to mitigate the wear. But the forces at play are still the same. They only enhanced/reduced the friction variable in the equation, not the load. Time will tell the magnitude of the issue.
05-23-2018, 05:29 PM
#37
Race Director
Hey guys really don't want to continue to beat a dead horse on this. Figure out what makes sense to you. It is just a car. But I have not heard of any .1 RS's experiencing this issue. The problem was fixed in the .1 GT3, so if you have a bunch of miles on yours and don't experience this problem, then you didn't win the lottery. And if you do experience it, the new engine solves the problem. Congrats. I am jealous. Regarding solid vs hydraulic lifters, it isn't like Porsche hasn't used hydraulic lifters in the past, including 2001+ cup engines, 997 GT3's, GT3 RS', etc. They have been around forever, and this finger follower problem was due to...the finger followers and not the existence of hydraulic lifters in the engine. The fact that PAG went to solids is more about them trying to get the most power and least valve train weight out of the engine. Which is great, but it does not somehow make the 991.1 engine with hydraulic lifters a problem.
05-23-2018, 05:49 PM
#38
Rennlist Member
Hey guys really don't want to continue to beat a dead horse on this. Figure out what makes sense to you. It is just a car. But I have not heard of any .1 RS's experiencing this issue. The problem was fixed in the .1 GT3, so if you have a bunch of miles on yours and don't experience this problem, then you didn't win the lottery. And if you do experience it, the new engine solves the problem. Congrats. I am jealous. Regarding solid vs hydraulic lifters, it isn't like Porsche hasn't used hydraulic lifters in the past, including 2001+ cup engines, 997 GT3's, GT3 RS', etc. They have been around forever, and this finger follower problem was due to...the finger followers and not the existence of hydraulic lifters in the engine. The fact that PAG went to solids is more about them trying to get the most power and least valve train weight out of the engine. Which is great, but it does not somehow make the 991.1 engine with hydraulic lifters a problem.
So, for official clarification. PAG says excessive FF wear was due to metallurgical inclusions in the FF's which subsequently exacerbated FF and camshaft lobe wear to the point of failure. The initial G engines (G0-G1) DO NOT include the revised metallurgical refinements to the FF's, but the G6 series motors do? And as of now, no G6 series engine have had known and or recorded FF related failure requiring a new engine to the best of our knowledge?
P.S. hydraulic lifters used in the past were not rotating at 9k RPM engine speeds (apples and oranges). They will exacerbate wear due to inertial drag. Had the lifters been solid, high probability this would of never been an issue to begin with. With that said, I honestly hope Porsche is telling the truth, however, my gut says this is "can kicking" and "saving face" with really good band-aids. If no G6 FF failures surface over the next 5-7 years, I will humbly eat my words
05-23-2018, 06:35 PM
#39
Correct me if I'm wrong here?
Who was at the meeting with PAG? Any engine engineers that could understand anything Porsche said? Or were there just owners that wanted to hear what they wanted to hear? From what I have been told and shown, the problem with the 991 valve train is so simple even a non engineer could figure it out. I think you were shown and told only what they wanted you to see and know.
Just an observation. Some really smart and experienced engine engineers have looked at this and differ from what Porsche are saying.
I think they realized they screwed up and figured the less costly "fix" is to play the numbers and give warranty's and challenge every failure whenever they can. To change the new engine to solids does help with performance I'm told, but it has everything to do with "fixing" the problem.
The only thing Porsche "fixed" was to get out of a potential class action law suit. Just what the parent company did not need.
If the culture is to lie and cheat, why would you think they will tell you the truth about the finger problem?
Who was at the meeting with PAG? Any engine engineers that could understand anything Porsche said? Or were there just owners that wanted to hear what they wanted to hear? From what I have been told and shown, the problem with the 991 valve train is so simple even a non engineer could figure it out. I think you were shown and told only what they wanted you to see and know.
Just an observation. Some really smart and experienced engine engineers have looked at this and differ from what Porsche are saying.
I think they realized they screwed up and figured the less costly "fix" is to play the numbers and give warranty's and challenge every failure whenever they can. To change the new engine to solids does help with performance I'm told, but it has everything to do with "fixing" the problem.
The only thing Porsche "fixed" was to get out of a potential class action law suit. Just what the parent company did not need.
If the culture is to lie and cheat, why would you think they will tell you the truth about the finger problem?
05-23-2018, 07:00 PM
#40
Race Director
Rob, first off, thank you for all the information and COG contribution. It is greatly appreciated.
So, for official clarification. PAG says excessive FF wear was due to metallurgical inclusions in the FF's which subsequently exacerbated FF and camshaft lobe wear to the point of failure. The initial G engines (G0-G1) DO NOT include the revised metallurgical refinements to the FF's, but the G6 series motors do? And as of now, no G6 series engine have had known and or recorded FF related failure requiring a new engine to the best of our knowledge?
P.S. hydraulic lifters used in the past were not rotating at 9k RPM engine speeds (apples and oranges). They will exacerbate wear due to inertial drag. Had the lifters been solid, high probability this would of never been an issue to begin with. With that said, I honestly hope Porsche is telling the truth, however, my gut says this is "can kicking" and "saving face" with really good band-aids. If no G6 FF failures surface over the next 5-7 years, I will humbly eat my words
So, for official clarification. PAG says excessive FF wear was due to metallurgical inclusions in the FF's which subsequently exacerbated FF and camshaft lobe wear to the point of failure. The initial G engines (G0-G1) DO NOT include the revised metallurgical refinements to the FF's, but the G6 series motors do? And as of now, no G6 series engine have had known and or recorded FF related failure requiring a new engine to the best of our knowledge?
P.S. hydraulic lifters used in the past were not rotating at 9k RPM engine speeds (apples and oranges). They will exacerbate wear due to inertial drag. Had the lifters been solid, high probability this would of never been an issue to begin with. With that said, I honestly hope Porsche is telling the truth, however, my gut says this is "can kicking" and "saving face" with really good band-aids. If no G6 FF failures surface over the next 5-7 years, I will humbly eat my words
PAG said that the FF wear was due to metallurgical inclusions. They were able to reproduce the issue on the bench with revised test protocols. They changed the spec on the FF (as I remember), and retested it on the bench again. In the previous tests the FF's were showing significant wear, but the new FF's on the same tests, with much more hours on them, looked brand new. So...problem solved. We asked if this was isolated to the E and F engines and were told that even G engines could have this problem (GT3 only, not RS).
Also the issue with high wear on the FF was caused by regular street driving, not high RPM use. Their original tests were testing under heavier load, and did not expose the issue. These engines never had thousands of low RPM street driven miles on them in the past. They were mostly track cars driven hard. So this problem isn't a high RPM issue. Again, the FF's were spec'd poorly but didn't show issues on the test bench because they were stressing them.
There is absolutely nothing wrong with these engines except needing higher spec'd finger followers. My personal opinion is that if they had better oiling on both the intake and exhaust, this would not have come up, but even that can be mitigated with a higher spec. Porsche went to solid lifters for a different reason, which makes sense, but also might have some issues later on. Who knows really? Nobody thought we'd have a finger follower issue at the launch of the .1 either.
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AndrewLakes (01-29-2023)
05-23-2018, 07:12 PM
#41
Race Director
This deal was insanely good. Suck a valve on turn one at Sebring? Piston explodes on the back straight at Road Atlanta? Porsche has a new engine waiting for you, 3 years after the .2 GT3 warranties expire. Ponder that one. Put another way, the .2 has a bit more performance than the .1 GT3, but you are really only going to get a taste of that at the track, where the .1 GT3 gets free engines for the next 6+ years. On the street, both are massively overpowered. Two seconds on it and you are in jail territory.
It's the greatest track car ever. The glass isn't half full. It is overflowing.
05-23-2018, 07:29 PM
#42
Kudos to Dundon, but I wonder why anyone would mod their car with aftermarket solutions when Porsche has extended the warranty to 100K Miles. That goes for all the .1 cars, so when the 100K warranty is up, then I think Dundon would have the fix. No way I would go aftermarket until extended warranty is exhausted .BTW I got rid of my 2015 .1 GT3 at 9K miles just prior to the news of the extended warranty because of the anticipated issues. Would have kept it if the "fix" was in!
05-23-2018, 07:44 PM
#43
Rennlist Member
You are welcome.
PAG said that the FF wear was due to metallurgical inclusions. They were able to reproduce the issue on the bench with revised test protocols. They changed the spec on the FF (as I remember), and retested it on the bench again. In the previous tests the FF's were showing significant wear, but the new FF's on the same tests, with much more hours on them, looked brand new. So...problem solved. We asked if this was isolated to the E and F engines and were told that even G engines could have this problem (GT3 only, not RS).
Also the issue with high wear on the FF was caused by regular street driving, not high RPM use. Their original tests were testing under heavier load, and did not expose the issue. These engines never had thousands of low RPM street driving on them in the past. They were mostly track cars driven hard. So this problem isn't a high RPM issue. Again, the FF's were spec'd poorly but didn't show issues on the test bench because they were stressing them.
There is absolutely nothing wrong with these engines except needing higher spec'd finger followers. My personal opinion is that if they had better oiling on both the intake and exhaust, this would not have come up, but even that can be mitigated with a higher spec. Porsche went to solid lifters for a different reason, which makes sense, but also might have some issues later on. Who knows really? Nobody thought we'd have a finger follower issue at the launch of the .1 either.
PAG said that the FF wear was due to metallurgical inclusions. They were able to reproduce the issue on the bench with revised test protocols. They changed the spec on the FF (as I remember), and retested it on the bench again. In the previous tests the FF's were showing significant wear, but the new FF's on the same tests, with much more hours on them, looked brand new. So...problem solved. We asked if this was isolated to the E and F engines and were told that even G engines could have this problem (GT3 only, not RS).
Also the issue with high wear on the FF was caused by regular street driving, not high RPM use. Their original tests were testing under heavier load, and did not expose the issue. These engines never had thousands of low RPM street driving on them in the past. They were mostly track cars driven hard. So this problem isn't a high RPM issue. Again, the FF's were spec'd poorly but didn't show issues on the test bench because they were stressing them.
There is absolutely nothing wrong with these engines except needing higher spec'd finger followers. My personal opinion is that if they had better oiling on both the intake and exhaust, this would not have come up, but even that can be mitigated with a higher spec. Porsche went to solid lifters for a different reason, which makes sense, but also might have some issues later on. Who knows really? Nobody thought we'd have a finger follower issue at the launch of the .1 either.
05-23-2018, 08:19 PM
#44
Rennlist Member
If $ is no object, the 4.5L/solid lifter upgrade/heads on offer conversion can make sense if fun is the common denominator. It is still a RPITA to have your engine fail, and wait for Porsche to drop in a new one-even if warrantied.
05-23-2018, 10:49 PM
#45
Race Director
Kudos to Dundon, but I wonder why anyone would mod their car with aftermarket solutions when Porsche has extended the warranty to 100K Miles. That goes for all the .1 cars, so when the 100K warranty is up, then I think Dundon would have the fix. No way I would go aftermarket until extended warranty is exhausted .BTW I got rid of my 2015 .1 GT3 at 9K miles just prior to the news of the extended warranty because of the anticipated issues. Would have kept it if the "fix" was in!