Another GT3 RS Engine Failure
09-13-2018, 08:43 AM
#33
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$10K for the repair. Seems like an equitable opening offer by the dealership. Offer them $5K and see what they say. Cut your losses, pay, and move on. Who gets to keep the core? That has value $$$ too.
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ubtrippin (09-23-2019)
09-13-2018, 09:04 AM
#35
09-13-2018, 11:17 AM
#36
Rennlist Member
Hi all,
My friend was driving his car the other day, had the warning to add oil, and then safe mode activated. Took the car to the dealer and it turns out misfire in cylinder 4. fast forward a few weeks and the results came out as a head failure.
Now here is the dilemma, the car was painted the first week the car was received to match the owners colour preference so Porsche dealer has refused to cover it under warranty. We are trying to prove that this is a known defect and that is common in all GT3 RS'. My question is how many 991.1 GT3 RS have had engines or heads changed? Is there a documented number?
My friend was driving his car the other day, had the warning to add oil, and then safe mode activated. Took the car to the dealer and it turns out misfire in cylinder 4. fast forward a few weeks and the results came out as a head failure.
Now here is the dilemma, the car was painted the first week the car was received to match the owners colour preference so Porsche dealer has refused to cover it under warranty. We are trying to prove that this is a known defect and that is common in all GT3 RS'. My question is how many 991.1 GT3 RS have had engines or heads changed? Is there a documented number?
09-13-2018, 11:19 AM
#37
Just curious why you titled this thread "Another GT3RS engine failure"? It seems as though there has not been a big issue with the RS models or do you have more detailed information on the subject? I hit on the thread immediately expecting to see horror stories on multiple cars.
09-13-2018, 11:25 AM
#38
Burning Brakes
Different country and not even disclosed
What country? Country determines fuels available, and fuel quality as well. Porsches are not sold in certain countries because there is not even gasoline minimum requirements.
What fuel? Try running on 83 octane leaded fuel on a hot day at a track, damage guaranteed
Was a coil damaged and kept running the car hard on 5 cylinders? Coils fail on excessive heat.
DME report?
So far, my service rep has not seen the first 991.1 GT3 RS engine failure, but quite a few of 991.1 GT3 failures (still a small number compared to the total production numbers).
What country? Country determines fuels available, and fuel quality as well. Porsches are not sold in certain countries because there is not even gasoline minimum requirements.
What fuel? Try running on 83 octane leaded fuel on a hot day at a track, damage guaranteed
Was a coil damaged and kept running the car hard on 5 cylinders? Coils fail on excessive heat.
DME report?
So far, my service rep has not seen the first 991.1 GT3 RS engine failure, but quite a few of 991.1 GT3 failures (still a small number compared to the total production numbers).
09-13-2018, 12:48 PM
#39
Rennlist Member
With that said, the 4.0 has the exact same hydraulic lifter design as it's 3.8 brethren, albeit, it has lower engine speed and most likely does not have the metallurgical inclusions that were found in many 3.8 liter motors, hence no widespread failures.
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mattw1093 (05-05-2022)
09-13-2018, 12:49 PM
#40
Seems sketch. Never heard of any RS engine failures.
09-13-2018, 12:52 PM
#41
Rennlist Member
There have been several documented 991.1 RS engine failures, but I am not aware of any engine failures specific to the primary failure mechanism in GT3 motors, which is the metallurgical inclusions of the finger-followers.
https://f10.m5post.com/forums/showthread.php?t=1166090
https://f10.m5post.com/forums/showthread.php?t=1166090
09-13-2018, 01:03 PM
#42
Three Wheelin'
The primary failure mechanism with respect to the 3.8 liter GT3 motor was metallurgical inclusions on the finger followers of the valve-train. This caused premature and sometimes catastrophic wear on the camshaft lobes, thus inducing failure. The camshaft wear was further exacerbated by the higher engine speed of the 3.8 liter engine 9000 RPM vs. 8600 in the 4.0/RS. The second iteration of the G series 3.8 liter engine has allegedly resolved the "metallurgical inclusion" issue, and no known G6/second iteration G series motor has exhibited this specific failure mechanism AFAIK.
With that said, the 4.0 has the exact same hydraulic lifter design as it's 3.8 brethren, albeit, it has lower engine speed and most likely does not have the metallurgical inclusions that were found in many 3.8 liter motors, hence no widespread failures.
With that said, the 4.0 has the exact same hydraulic lifter design as it's 3.8 brethren, albeit, it has lower engine speed and most likely does not have the metallurgical inclusions that were found in many 3.8 liter motors, hence no widespread failures.
The GT3RS benefited from those changes and there has been some statement that the springs in the 991.1 GT3RS valve train are lower pressure as well.
991.1 GT3RS motors have been very reliable and at least a few owners are watching oil analysis looking for an indication these motors may eventually have a similar failure mode at higher operational hours.
Ryan
09-13-2018, 01:07 PM
#43
Rennlist Member
This is not a technically accurate description of the 991.1 cam follower / cam failure mode. The issue was not inclusions or imperfection at the interface between the follower and the cam. The root cause of the issue was a combination of consistent oil film and finger to cam lobe pressure. The Diamond Like Coating (DLC) that was added increased the surface hardness at the interface. There was also reprogramming that adjusted the oil pressure at mid RPM.
The GT3RS benefited from those changes and there has been some statement that the springs in the 991.1 GT3RS valve train are lower pressure as well.
991.1 GT3RS motors have been very reliable and at least a few owners are watching oil analysis looking for an indication these motors may eventually have a similar failure mode at higher operational hours.
Ryan
09-13-2018, 01:12 PM
#44
Rennlist Member
This is not a technically accurate description of the 991.1 cam follower / cam failure mode. The issue was not inclusions or imperfection at the interface between the follower and the cam. The root cause of the issue was a combination of consistent oil film and finger to cam lobe pressure. The Diamond Like Coating (DLC) that was added increased the surface hardness at the interface. There was also reprogramming that adjusted the oil pressure at mid RPM.
The GT3RS benefited from those changes and there has been some statement that the springs in the 991.1 GT3RS valve train are lower pressure as well.
991.1 GT3RS motors have been very reliable and at least a few owners are watching oil analysis looking for an indication these motors may eventually have a similar failure mode at higher operational hours.
Ryan
Dr. Walliser ran this presentation. He explained the cause of the finger follower wear issue, and the steps Porsche has taken to resolve it. Without getting into a great amount of detail, which we are unqualified to do, the issue is caused by a metallurgy defect (inclusion) close to the surface of the finger follower. Most finger followers do not have these inclusions, or they are not close enough to the surface to cause increased finger follower wear. This explains why the vast majority of 991.1 GT3's do not, and most likely will never experience this problem."
09-13-2018, 01:24 PM
#45
Three Wheelin'
"Porsche's Second Presentation: Understanding The Issue
Dr. Walliser ran this presentation. He explained the cause of the finger follower wear issue, and the steps Porsche has taken to resolve it. Without getting into a great amount of detail, which we are unqualified to do, the issue is caused by a metallurgy defect (inclusion) close to the surface of the finger follower. Most finger followers do not have these inclusions, or they are not close enough to the surface to cause increased finger follower wear. This explains why the vast majority of 991.1 GT3's do not, and most likely will never experience this problem."
Dr. Walliser ran this presentation. He explained the cause of the finger follower wear issue, and the steps Porsche has taken to resolve it. Without getting into a great amount of detail, which we are unqualified to do, the issue is caused by a metallurgy defect (inclusion) close to the surface of the finger follower. Most finger followers do not have these inclusions, or they are not close enough to the surface to cause increased finger follower wear. This explains why the vast majority of 991.1 GT3's do not, and most likely will never experience this problem."
There are also some other presentations that show DLC cams with the DLC coating abraided from the surface and embedded in the adjacent bearing journals.
There was also a presentation by one of the 918 flying doctors during which he described the construction of the 991.2 4.0 valve train. He focused almost entirely on the amount of pressure between the cam and follower as the impetus to move to the solid lifter.
While the material consistency of the cam followers may have contributed to discovery of the issue, I would consider it a contributing cause but not the root cause.
Ryan