50 captured repliesDiscussion pagination complete · Source accounts, not a confirmed diagnosis
THIS DISCUSSION / SOURCE-DERIVED OVERVIEW
Discussion summary
YOUR RESEARCHCylinder Scope 2004 C2
Leading reported evidence
Run diagnostics according
Performed · outcome unconfirmed
No successful repair reported for this finding.
0
Reported fixes
0
Unsuccessful attempts
1
Discussions
Read evidence and context
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Discussions that performed work without a confirmed outcome
1
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0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed · Original poster
I ran diagnostics according to LN's recommendations with my Durametric (Minus the oil analysis and barometer since I was replacing the AOS anyway).
Leading evidence: 'Run diagnostics according' (no explicit attributable resolution; this is a reported action or suggestion). Across 1 matching discussions, the most frequently mentioned possible cause is 'wear metals started' (1 discussions; 0 report identifying it and 1 suggest it). The most frequently discussed action is 'Replace /serviced' (1 discussions). For that action, 0 discussions report a resolution and 0 report an unsuccessful attempt. No action has an explicit, attributable resolution report under the current rules. These are forum reports and suggestions, not a confirmed diagnosis.
Source reports, not a diagnosis or a success probability. Counts refer to discussions and can overlap.
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Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Performed · outcome unconfirmed
This is the same oil I used back on 9/22/17 sample.
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Discussions that performed work without a confirmed outcome
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Performed · outcome unconfirmed
But I still don�t worry about it, because there are options that range from cheap (roll the dice on a band-aide used engine), or spend $$$$ on a real nice rebuild.
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Discussions that performed work without a confirmed outcome
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
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Explicit resolution reports before identified causes, performed actions and suggestions. Within each level, matching component labels precede direct query mentions and inherited thread context; successful versus unsuccessful discussion counts, owner confirmations and independent discussion support determine order. This is not a probability of success.
Discussions that suspect a cause
1
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Suspected cause
In your scenario likely the wear metals started to drop because as the one cylinder started to wear, the contaminants were drained in the oil, and since damage was done, the wear debris that was identified was reduced.
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Suggestion
The fuel has been laced with all sorts of other additives that change it as well, and we have seen the changes first hand on the dyno with BSFC values, power output, and efficiency.
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Suggestion · Original poster
As I was changing plugs, now that the engine is out, I scoped the cylinders with the goal of documenting that everything was ok at the time of doing all of this work.
These are separate views of the same evidence. Frequency alone does not establish a fix, and these counts must not be added together.
wear metals started
No successful repair reported for this finding.
0
Identified cause
1
Suspected cause
0
Reported fixes
Read evidence and context
Discussions that suspect a cause
1
0 original-poster resolution reports. Counts can overlap; they are not unique people or a success rate.
0 discussions have direct query context; 0 report a fix in that context. Other evidence may inherit the discussion’s subject.
Suspected cause
In your scenario likely the wear metals started to drop because as the one cylinder started to wear, the contaminants were drained in the oil, and since damage was done, the wear debris that was identified was reduced.
Counts describe captured discussions, not unique people or a diagnosis. Author identities are not reliably stored. Exact duplicate evidence is counted once across matching discussions; one discussion counts at most once per action/state. Multiple repairs reported together remain a combination. Suggestions and failed attempts do not establish a fix. Matches cover whole discussions and can include related faults, model variants and incomplete threads.
50 eligible posts · 0 unverified posts · 1 discussions match the subject in their title or opening post.
Rennlist: 1 discussions
0 evidence records excluded for query context · 0 excluded by outcome qualification · 0 adjusted by outcome qualification.
0 acknowledgements have no verified action link; they do not establish a repair result.
Generation: 20261026T222516Z · outcome-qualification-6. Deterministic extraction; no AI model inference. How we use sources
For those familiar with signs of bore scoring, from videos I have seen of bore scoring, I'm mostly concerned with cylinders 2 and 5 on the attached videos. I was still getting used to how to move around the scope for cylinder 1 and 2 so you would have to bear with the moments in the video that aren't useful. For Cylinder 2, if you move to about the 3 minute mark it has the best video. I have the engine out of the car at this point planning to do clutch, rms, ims retro, aos, etc�
Cylinders 2 and 5 seem to have some scoring but maybe earlier stage? You can also see a little moisture on one spot on Cylinder 2. I would appreciate input from someone with experience with this.
Thanks
Those videos don't appear to play as I had to convert them from MP4 to MOV and the free converter I used is putting a watermark on it that I guess you can only play the video with their player. I'm going to have to find some other way to share the videos
Here are a series of photo's of the area of cylinder 2 that showed some discoloration on the cylinder wall. I looked at my photo's and video of 5 again and I'm convinced I was seeing shadows. In any case this area of Cylinder 2 shows the only signs I see in all the cylinders. I can't really make out any scoring in the video or photo but it is discolored in streaks in this one section
I don�t know if that�s scoring or just normal wear but what are all the bits of debris on the pistons? Are those just anti seize granules that fell in after removing the plugs?
Stage 3 scoring on one, and looks like stage 4 scoring on the other the best I can tell. I'd expect this one is making a lifter ticking sound, and has started eating some oil by this point?
You have longitudinal scoring over at least 2/3 of the piston travel, it appears.
If you pull the sump plate, and sneak in to the bottom of the bores (#5 is really tough to do) you'll probably see more scoring. The issues start at BDC and the piston covers the area up, which fools a lot of people.
Like I always say, if you are going to have a failure, this is the best one to have.. Little to no collateral damage to the components that wouldn't be getting thrown away, no matter what. I am doing several videos for the Rennvision channel this week on bore scoring. We sold 4 engines last week (unheard of in January!) and of those 4, 3 of them had scored bores. Bore scoring is leading to more engines coming our way than all the other failures combined. I plan to do several videos about diagnosis, and actually performing this bore scope analysis with a cheap smart phone bore scope that anyone can buy, and use.
I did release one page on the
www.flat6innovations.com
site a few weeks ago that has helped a lot of people understand this mode of failure.
http://flat6innovations.com/cylinder-bore-scoring/
Interestingly enough, that little puddle that you see... Guess what that is? When you figure it out you are close to understanding the most misunderstood contributing factor to this affliction...
Two questions then Jake:
1. If there is no collateral damage "no matter what", at what point does an engine with bore scoring NEED to be rebuilt?
2. When do I KNOW my injectors need to be replaced/serviced?
I watch my fuel trim numbers and put seafoam through my tank every month, but the loss of perceived power I am getting by running 91 octane no-ethanol gas is not being offset by the sense of self righteousness I am experiencing knowing I am protecting my bores.
Without looking at the Flat6 site, I am going to guess gasoline that has been "washing" oil from the cylinder. Probably due to injectors spraying too much fuel (running rich).
Fuel trim won�t show injectors that leak down when an engine is hot. There�s no data that can be collected via OBDII that will.
It takes old fashioned, hands dirty diagnosis and a human brain to do this.
As far as the collateral damage not effecting �rebuild� from collateral damage... Well, that�s ONLY for our program where the original cylinders are removed with a huge CNC milling machine. The parent material above the cooling jacket is removed entirely, so the more that�s worn away, the less has to be machines. With my program all the things that see collateral damage from this mode of failure are thrown away, no matter if they are good, or bad. Again... These parts are thrown away even if they are in �perfect condition� at the time of disassembly. Why? We know they won�t last as long as the rest of the components that we are replacing, so reusing them is a compromise to save a few dolllars. You won�t find that here, anything that we have identified as a weakness in the platform at the time we complete an engine is replaced, and our base pricing for this includes 100% of these items in 100% of the cases.
Now, to someone who just replaces whats worn, and thats it (pretty much everyone else) the engine wold see extensive collateral damage if it suffered a cylinder scoring event, and resultant failure.
That said, its not just alcohol (ethanol) in the fuel that has caused the injector issues. These cars are OLD! The fuel has been laced with all sorts of other additives that change it as well, and we have seen the changes first hand on the dyno with BSFC values, power output, and efficiency. Aircooled engines with carburetors now want jetting thats 15% greater than it used to be for the same engine just a few years ago.
We can even tell a difference in how the fuel smells in the dyno cell, and now it gives us all a headache in 15 minutes in the text cell, no matter what kind of ventilation we employ. 10 years ago we could work in the cell and control room all day long and never experience this.
No, buying �ethanol free� doesn�t help. From what we�ve seen developing engines, and even fuel stabilizing additives (Driven Injector Defender, Carb Defender, and Storage Defender) it doesn�t really matter what fuel is chosen, it al sucks. For my personal cars l am now buying drums of the VP Vintage Unleaded, as l got so sick of all my carbureted cars needing the fuel systems redone every year. No matter what else l put into it, l still had issues.
I have never had to add oil between oil changes and have not noticed a ticking/lifter sound that is prominent. I have often thought I heard a faint ticking sound but at times but never consistently and never long enough that I could trace it so I chalked it up to 996 paranoia.
The engine is on a lift table now and I don't currently have a stand to hold it so coming in from the sump isn't practical right now. Nor does it matter I guess because it won't reverse the diagnosis in any way. And here I thought I was just doing documentation to show a good condition when doing the ims replacement!
Looking forward to the knowledge gruppe class Thursday. Good timingi in an ironic way. The question I will have which maybe we can discuss Thursday night, I wasn't budgeting for an engine rebuild (probably no one ever does) this year. What is the risk to doing the other repairs, fixing/replacing the injectors and re-installing the engine to plan for rebuild next year? I usually put about 5K miles annually but its been quite a bit less lately as my motorcycle has taken priority on any kind of decent weather day.
Think of how many people are walking around with cancer and we don�t even know it. We are all dying, but when...
The good news is that you have more info now, because ignorance doesn�t change reality.
My 996 makes some pretty nasty noises upon cold start, with about 61,000 miles. So my engine might be even worse than yours. But I still don�t worry about it, because there are options that range from cheap (roll the dice on a band-aide used engine), or spend $$$$ on a real nice rebuild. Either way, it�s happening one way or another, sooner or later.
Someone needs to make an electric conversion kit for these cars..
Asking this question is a lot like asking the Dr. how long you�ll live.. You can start eating right, and reducing stress, but if you do that too late, well the results will not be the same as if you�d been doing that years prior.
This engine is the same way. It is injured, and it is failing. You may slow the progression of the cylinder scoring down some, and it may last a while. Certainly doing these things won�t hurt anything, and how much they help you�ll determine later.
That said, the new engine that you�ll build will need injectors anyway, so you�ll already have them. I am happy to help you nurse this along a bit, and when it starts to consume oil, l have a liquid �silver bullet� for you.
See ya Thursday :-)
Looked familiar. This is from my engine at 98k miles (and that included a LOT of hard track miles over the years). The valve seat broke apart and you can see that had the chipping at the piston.
The car went on to 170k miles and continued track usage over the years until the engine blew up (wrist pin backed out apparently) and now sits in my garage waiting for a complete engine that I'll be sourcing soon. Just haven't had the funds to dump so much money into this project. It's sad really.
She was sure fun though the 13 years it lived.
Man, I don't know, if it was me I don't think I would rip into that motor. Sure you can see some marks but you have no idea how deep that scoring is. It doesn't use any oil, it doesn't make any noises, it isn't down on power, you don't have material in the oil, so basically it runs great. While I am new to these flat sixes, I have rebuilt a lot of motors - it is one of the things I enjoy more than anything. I have pulled plenty of motors apart that have marks in the cylinders like that and they run great and have for a long time. How long has that scoring been there? It could have been there for years. Is it possible that scoring could have been done from running the engine hard in cold weather before properly warming it up? Maybe I am missing something and will freely admit there are much smarter people than I in here, but I would at need at least some symptom that the motor is wounded before I spent the money rebuilding it.
Sadly this post makes me cringe. About a month ago I noticed the tick tick sound. I thought, nah, it can’t be. Yesterday I heard the tick tick tick sound and puffs of white smoke out of one of the exhaust.
Now or I am curious about the liquid silver bullet.
Man you make too much sense. It's not the Porsche way, you must exhaust all energy striving for perfection (even though it sometimes isn't practical or ever possible)..
Kudo's to Jake for offering to help the OP nurse it along a bit. I like the approach, similar to the Veterinarian who buys a race horse with a broken leg and nurses it back to 90% of its former glory, instead of just shooting it in the head and starting training another fold to race. Sometimes I enjoy nursing along an injured engine fixing the broken things just to see how long it will go!! lol
We have gotten pretty good at nursing them along till we can work them in the schedule.. Some people use these cars as daily drivers with no other car, so when they have a failure they have to drive the car as long as they can. The bad scenarios are the catastrophic failures where nothing can be nursed and the car is an only vehicle.
We currently have 31 engines on the build board.. 19 of those are there due to bore scoring. Of those 7 are elective builds that haven�t failed yet, and the other 5 are a mix of other failures. Statistics don�t lie.
"so why did you do a scope in first place? Did you suspect something?"
My clutch needed replaced. As preventative maintenance, I decided I would replace IMS, RMS, AOS, spark plugs/coils, coolant reservoir and a few other things. I ran diagnostics according to LN's recommendations with my Durametric (Minus the oil analysis and barometer since I was replacing the AOS anyway). I pulled the engine and transmission just to make it easier to do some of those items. As I was changing plugs, now that the engine is out, I scoped the cylinders with the goal of documenting that everything was ok at the time of doing all of this work. And now I have documented that not everything is ok.
I know no one can give me a guarantee that the engine won't blow up in another 1,000 miles. But we all live life making educated guesses based on probabilities. On one hand, I have the motor out but at the end of the day that's a couple days of my labor I waste if I put it back in, drive it a few thousand miles, and then have to take it back out again to rebuild. What i am more worried about is the probability that stalling for another 5,000 miles could double the cost of the rebuild. No guarantees, I understand, but it sounds like that is not likely. On the other hand, I'm not going to put the motor back in and just try and sell it on to someone who doesn't scope the engine. So it will get rebuilt and I think it sounds like a fun project to do the rebuild. So.. maybe I'll go to what may be the last knowledge gruppe hands on training this year and then I'll just have to decide if I dig out the funds to rebuild now or wait for a year and drive it.
I applaud you for being a stand-up person. The good news is that your level of documentation and thoroughness will command higher prices, accompanied by my opinion that the market will go up for these cars. What you will have in the end is far better than any PPI could deliver.
Question: My 996 knocks on cold start if I let it idle for 3 mins. If I drive off right away, the knock lasts 5 seconds. I think RPM being in the 2,000-3,000 range helps reduce the knock. Is it possible that the knock goes away because the knocking item is getting more splash oil and/or pressure/volume than at idle? Everything I�ve read about bore scoring indicates design flaws related to oil being present during certain situations.
During one of my treatments last summer, my doctor told me about another patient who had ignored all the signs of cancer, but was afraid to go to the doctor because he might hear bad news.
He said we caught my cancer early, but the other patient who could have been easily treated was WAY beyond help.
I'd kinda like that option, but kinda not too.
Even if it were a LOT faster, more reliable and cheaper to run, I would still miss the sound of an internal combustion engine.
My 996 sounds awesome!
No other car have I turned off the radio, and left it off for days, and listened to the engine during my commute to work.
A quiet 996 would be kinda sad!
I may buy a self driving electric car someday when I'm no longer capable of driving my 996.
My son said something about taking my keys away from me someday when I can no longer safely drive.
I told him he would have to catch me first, and that my 177mph Porsche 996 can outrun his Ford 149mph Mustang all day long!
If someone did, they would forever on my **** list.
Electric cars have no soul and so far have proven they are only viable with massive government subsidies. Yeah, I helped pay for your Leaf tax break...
Yes, I knew the electric comments would draw these responses. And I cannot disagree, I love the sound of the IC engine. But I�d still like to have the option. I mean a P100D is delivering 900+ ft-lbs of torque, which is nothing to sneeze at
Just a thought (and totally OT), can you feed power into the front side of the AWD transmission? I mean, if I took out the front differential, and replaced it with an electric motor, feeding that power into the transmission from the front, what would happen? A 996 hybrid? A broken transmission? Would TechSavvySam hunt me down?
It would totally work ! The G96/31 AWD front drive is directly connected to the output shaft. You would have a 996 hybrid ! Nice thought but those heavy battery's would probably be a turn off? And TechSavvySam would not hunt you down since it would still have soul and not totally electric.
Edit: sorry don't mean to help hijack, just couldn't resist.
My car is making all the noises of a car with scoring. I have the sooty left tail pipe and I burn about a quart of oil every 1300 miles. However, my most recent oil report doesn't really show an engine that is about to give up. I have had a few samples with elevated aluminum so I am sure my problems are real.
What they overlooked was the anti wear package getting killed by something in that last sample.. Why? Because its Blackstone.
Yes, you have a problem, something (wear) has killed the anti- wear package, as it is trying to provide wear protection.
I see a few things trending in this data, even with it being Blackstone..
Take this one seriously, it could possibly be saved at the current stage of failure.
Thanks for the comments. This is the same oil I used back on 9/22/17 sample. For what it is worth, twice now I have low wear metals with Quaker St. For the most part I use Motul 5W40. I should really pick an oil and stick with it. I doubt any of these oils are really hurting or helping much over the other. Currently my car has Motul again. We'll see how it does after another 4-5k miles.
Really interesting appreciation.
Last week, I was talking with a reputated Porsche technician that have been worked for a long time in several dealers in Europe (UK and Spain) and in USA and he told something like in his whole carreer, he can remember around 2-3 engines that he had to rebuild due to IMS failure, been the most rebuilds due to "regular" mechanical failures (in high performance engines) like you are mentioning.
You have a problem that you can�t ignore. Please change the fuel injectors on the bank of the engine thats opposite of the sooty tailpipe to give this engine half a chance at survival. Your scenario is being caught early enough that you CAN do something to try and save it, and you should do that. Just driving it, hoping it will get better won�t happen. These problems will ONLY get WORSE.
Now, that said, all the back and forth with the oil destroys the trend data that you have collected. With every different oil formula comes cross pollination of the base stock, and additive packages between the oils. This throws the data validity out the window. Cross pollination is the biggest challenge that we face when developing engine oils, nothing skews results worse. Some of the oils you have used back to back have seriously conflicting additive packages.
Also, people put way too much stock in the wear metals of a used oil analysis. These are the LAST thing l look at, and the thing that tells me the least about the engine. The other things are where l find clues that there�s an issue.i think wear metals are used because you can look at them and see a problem with little to no experience with a certain engine, or oil. The fact is, they don�t show what you need to see. In your scenario likely the wear metals started to drop because as the one cylinder started to wear, the contaminants were drained in the oil, and since damage was done, the wear debris that was identified was reduced. We see this all the time.
That said, no matter what the UOA results say, you have a ticking sound, and you have a sooty tailpipe, and therefore you have a problem. A stated earlier, that problem will only get worse over time.
When switching oils or after buying a call with unknown oil, I will perform 2 sequential oil changes if the new oil is affordable (such as Mobil 1). I make sure it�s fully up to temp on the first change, drive it spirited fashion, drain and refill.
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