981 S Engine Failure at 43k miles
#16
Former Vendor
Mike,
You have quite a few options.. One of them takes a lot longer, costs a lot more, but pays dividends of value. Its the only choice that’s handcrafted, and has the factory cylinder issues addressed.
Hppy to help you in any way that we can...
I hope that your chat with Mr. Raby was informative :-)
Flat 6 Innovations 4.0 built from a 3.4 foundation
4.2 liters of fury.. The factory never caught us....
You have quite a few options.. One of them takes a lot longer, costs a lot more, but pays dividends of value. Its the only choice that’s handcrafted, and has the factory cylinder issues addressed.
Hppy to help you in any way that we can...
I hope that your chat with Mr. Raby was informative :-)
Flat 6 Innovations 4.0 built from a 3.4 foundation
4.2 liters of fury.. The factory never caught us....
#17
Well, I'll be the first to admit, I'm new here and no expert on these cars. However, I've owned many high performance cars and old enough to have heard about Jake Raby's reputation and his exemplary work with VW aircooled technologies and modern Porsche engines. I've been to car shows and his name comes up as one of the experts in the motor research, engineering, and design. My gut feeling you're not going to get any goodwill out of Porsche with a warranty that expired a year ago. And, why would you want to repeat history with another failure prone motor? I wouldn't. Years ago, I owned a Mazda that was known to break timing belts which would lead to catastrophic engine failure. I replaced it with a proven, more durable part. Mazda was just going to put same failure prone belt in the motor. I could give you lots of examples when I went the cheaper route and regretted it down the road. Hope you get the car repaired correctly and back on the road.
#18
Three Wheelin'
I know there's tons of variables when things go wrong but I can't help but draw a correlation to the use of the Cobb and to a lesser degree the headers. That was actually the first thing I looked for in reading your first post. Also I think that would be one of the first things PCNA would ask/look for in considering any sort of goodwill... and also the fact that you seem to have done most of the modification work yourself. My guess based on past experience is that it would be unlikely to be covered even if it was under warranty due to the modification. I would be curious if Porsche generally looks more favorably on things like that; I can tell you firsthand that Subaru and BMW most certainly do not. It usually starts at the dealer denying warranty, and then escalates to the manufacturer, and they generally tend to favor the dealer. If there's any sort of modification whatsoever (particularly regarding changing the factory tuning parameters) it's almost a certain denial. I'd expect similar from Porsche, but would be helpful to know for my own edification.
I know you don't blame Cobb but as someone who may consider one down the line, it would be helpful to know if it in any way factored into the engine failure.
I also realize the philosophy of "gotta pay to play", and really hope you find a way to deal with this that doesn't introduce significant personal hardship. There's also the reality that some of the most interesting cars are born from catastrophes like this, and seeing some of the posts above talking about interesting engine swaps or rebuilds is exciting... but seeing those dollar amounts- this is a scenario I would definitely hope to avoid.
I know you don't blame Cobb but as someone who may consider one down the line, it would be helpful to know if it in any way factored into the engine failure.
I also realize the philosophy of "gotta pay to play", and really hope you find a way to deal with this that doesn't introduce significant personal hardship. There's also the reality that some of the most interesting cars are born from catastrophes like this, and seeing some of the posts above talking about interesting engine swaps or rebuilds is exciting... but seeing those dollar amounts- this is a scenario I would definitely hope to avoid.
#19
Rennlist Member
I'd be curious to know what happened here. I wonder if the failed coils, which resulted in unburned fuel being sprayed down that cylinder for at least some period, contributed. 4 coils failing in 10k is a ton, even for a tracked car. It's speculation to think Cobb, Fabspeed, or anyone else had anything to do with this at this point. One could equally speculate that the oil change and plug change that occurred 1k miles before the incident contributed (not saying they did, at all, but that the close coincidental timing still exists).
#21
Three Wheelin'
I'd ask for references for where you've seen someone actually do this- but no, I really, really don't care. If these cars would benefit from a v8, Porsche would have built them with one.
Also... the manuals in these cars are apparently about maxed out as far as torque is concerned. Porsche themselves had to cut back on the torque (by a whopping 9 lb-ft) of the manual of the 718 because they said the transmission was the bottleneck.
A C7 vette has like 180% of the torque of a 718 GTS.
#22
Former Vendor
The 9a1 platform has proven to be a much better engine than the predecessor. That said, we have had a steady stream of the internal work coming through our doors since we completed the first engine back in 2010. Over the past 18 months we have seen a big increase in the demand for the 9a1. Today it makes up abput 1/2 of our workload, rather than the 10-20% that it used to. Part of this is due to some cars seeing high mileage and simply suffering from normal wear. Another portion of from those seeking more power from a 4.0, or a 4.2, etc.
We’ve only found a handful of failure modes for this engine platform, but we seem to see the same ones over and over, with the same circumstances. The factory played things smarter with these engines, and warranty/ goodwill compared to the predecessor. We’ve also only shared one of the modes of failure that we’ve seen, which is a completely different scenario than we did with the predecessor. More of these engines have come to us with cylinder failures than any other mode of failure. Actually, the failure of the cylinder is typically collateral damage, but is seldom identified as such.
These are very good engines, failure with them seems to be the exception, and not the rule at the current point of time in service. By this point with the M96 we’d already noted 20 different modes of failure, so this engine is much, much better in many ways. We do learn new things every day, and as we see more and more of these engines with their guts exposed we will continue to add to the knowledge base.
I think with this one, the original poster just had a stroke of bad luck. Luck plays a key role.
We’ve only found a handful of failure modes for this engine platform, but we seem to see the same ones over and over, with the same circumstances. The factory played things smarter with these engines, and warranty/ goodwill compared to the predecessor. We’ve also only shared one of the modes of failure that we’ve seen, which is a completely different scenario than we did with the predecessor. More of these engines have come to us with cylinder failures than any other mode of failure. Actually, the failure of the cylinder is typically collateral damage, but is seldom identified as such.
These are very good engines, failure with them seems to be the exception, and not the rule at the current point of time in service. By this point with the M96 we’d already noted 20 different modes of failure, so this engine is much, much better in many ways. We do learn new things every day, and as we see more and more of these engines with their guts exposed we will continue to add to the knowledge base.
I think with this one, the original poster just had a stroke of bad luck. Luck plays a key role.
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Deepbluejh (05-08-2021)
#23
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EDIT: nevermind, I was typing this when you were typing your previous post.
If this happened to my car, I'd be going aftermarket for a solution, like one of the beautiful engines from Flat 6. If Porsche would repair under warranty, I think I would go that route just to save the $$.
Regarding possible cause here, as others have referenced, cylinder scoring can be as simple as a leaking fuel injector, one that never really shuts off flow.
Cobb tunes (and others) are used on engines that are raced and/or driven on street for thousands of miles with no issues. And a tune would affect all cylinders, not just one.
#24
Former Vendor
@okie981
Absolutely, fuel is an evil, evil thing when it comes to these issues. We are seeing all generations of engines suffer from fuel related internal damage, and it is getting worse. Bad injectors with poor spray patterns, injectors that leak down when the engine is shutdown (and hot) are a huge issue. We’ve known that this was a driving force behind M96/97 cylinder scoring for years. We’ve caught engines in the process of failure, swapped injectors, and avoided complete engine loss.
We’ve taken more than a few of these engines apart and found broken top piston rings, which always seems to go hand in hand with bore scoring, as the ring causes the damage.
This one had 4,400 miles, and a broken top ring. Never tracked, never even had the factory oil changed, and wasn’t tuned.
#25
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@okie981
Absolutely, fuel is an evil, evil thing when it comes to these issues. We are seeing all generations of engines suffer from fuel related internal damage, and it is getting worse. Bad injectors with poor spray patterns, injectors that leak down when the engine is shutdown (and hot) are a huge issue. We’ve known that this was a driving force behind M96/97 cylinder scoring for years. We’ve caught engines in the process of failure, swapped injectors, and avoided complete engine loss.
We’ve taken more than a few of these engines apart and found broken top piston rings, which always seems to go hand in hand with bore scoring, as the ring causes the damage.
This one had 4,400 miles, and a broken top ring. Never tracked, never even had the factory oil changed, and wasn’t tuned.
#26
1) There are parts that have to be exchanged from the 981 engine to a replacement 991 engine (new or used). Particularly the wiring harness and the oil manifold. John @ BGB did this as part of my 3.8L X51 upgrade in 2015.
2) Did the car get driven in cold weather? Many people here will disagree, but low mileage 9A1 engines have been reported by people I trust to score the cylinder walls if the car is driven vigorously (> 4000 RPM) in below freezing weather before normal oil temperature is reached (> 160F). Supposedly the piston to wall clearance is very tight until the engine gets to about 25K miles. After 25K miles, supposedly clearance opens up enough that cold temps don't score the cylinders, although it remains a good practice to let oil warm before going over 4000 RPM regardless of mileage.
3) Another possible cause is that a piston ring land/groove crumbled and scored the cylinder. A video borescope inspection might be able to see this if it was the top ring groove that crumbled. The top groove takes a beating due to DFI and high compression. Aftermarket pistons need the top ring groove (or all of them) hard anodized for life.
4) I assume you have pulled the oil filter and looked for metal particles in the pleats. The question is did other parts get damaged by debris (rod and crank bearings, etc). If there is no damage, there is a chance of a rebuild and getting LN Engineering to re-line the bore or bores.
V6
2) Did the car get driven in cold weather? Many people here will disagree, but low mileage 9A1 engines have been reported by people I trust to score the cylinder walls if the car is driven vigorously (> 4000 RPM) in below freezing weather before normal oil temperature is reached (> 160F). Supposedly the piston to wall clearance is very tight until the engine gets to about 25K miles. After 25K miles, supposedly clearance opens up enough that cold temps don't score the cylinders, although it remains a good practice to let oil warm before going over 4000 RPM regardless of mileage.
3) Another possible cause is that a piston ring land/groove crumbled and scored the cylinder. A video borescope inspection might be able to see this if it was the top ring groove that crumbled. The top groove takes a beating due to DFI and high compression. Aftermarket pistons need the top ring groove (or all of them) hard anodized for life.
4) I assume you have pulled the oil filter and looked for metal particles in the pleats. The question is did other parts get damaged by debris (rod and crank bearings, etc). If there is no damage, there is a chance of a rebuild and getting LN Engineering to re-line the bore or bores.
V6
#28
Addict
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The advice I received from my tech is shorter oil change intervals and you should send a sample out for analysis to determine if you have excessive fuel in the oil.
It would definitely be nice to hear of any other preventative tests/checks an owner could do.
It would definitely be nice to hear of any other preventative tests/checks an owner could do.
#29
Rennlist Member
The advice I received from my tech on this is that you should not do extended oil changes and you should send a sample out for analysis to determine if you have excessive fuel in the oil.
It would definitely be nice to hear of any other preventative tests/checks an owner could do.
It would definitely be nice to hear of any other preventative tests/checks an owner could do.
We do make a 987.2 low temperature thermostat (used to be a Porsche Motorsports only item), but it will throw a pending fault for engine temp, however will not put the car into limp mode.
The 981 can be programmed with a PIWIS for hot climate operation where the electronic thermostat is re-programmed to run in an equivalent mode to having a low temperature thermostat.
#30
1) how's the 3.8 X51 holding up after 3 years?
2) previous owner was in GA, I had the car in Florida, never driven hard cold by me.
3) borescope inspection is what was done to identify the scoring, not sure if the rings have been checked yet but that's what I suspect is the issue.
4) I haven't done this yet, happened Friday :/ I had not heard of LN Engineering yet, thanks!
2) previous owner was in GA, I had the car in Florida, never driven hard cold by me.
3) borescope inspection is what was done to identify the scoring, not sure if the rings have been checked yet but that's what I suspect is the issue.
4) I haven't done this yet, happened Friday :/ I had not heard of LN Engineering yet, thanks!
V6