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YOUR RESEARCHBore scoring survey
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Check on this years ago it was like $35
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Yes the Etching Paste can be had when I checked on this years ago it was like $35 for a tube and the Diamond Hones were several hundred bucks, and I think a lot of shops are now using very similar Diamond hones ...
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I've etched/cleaned nik'd cylinders many times with muriatic acid on a sponge pad(very carefully).
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There was a couple of years i was too busy professionally and personally so I didn"t track the car and only changed the oil in the spring and early winter.
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Yes the Etching Paste can be had when I checked on this years ago it was like $35 for a tube and the Diamond Hones were several hundred bucks, and I think a lot of shops are now using very similar Diamond hones ...
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Suggestion
, show the technology's potential with impressive Abbott Firestone curve results and a clean bill of health from the test engine, indicating that Sumebore could offer a robust solution for combating the known issue of bore scoring in these engines, according to a recent YouTube update from early 2022.
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Suggestion
5k mile oil changes with cheap oil that doesnt lubricate properly, which is loaded with fuel and water from old fuel injectors, and never getting the oil hot enough to burn it off, sure doesnt help prevent the issue.
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Suggestion
Got a question for Charles, that same engine you have a picture of, how many miles do you think that engine would last using the recommended oil and driving it correctly with temperature warmups would that engine last before you think it would have to be removed and overhauled.
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Suspected cause
The OOR/Taper is due to the Ovaling and not really that hard to correct...You could just use an "internal jack-screw" to jack it back round and place an aluminum support ring around the top to hold it true...
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This should be a interesting survey. I had my car scoped at part of PPI in 2018 at 70K km. Now have 80K km. I was fine at 70K, I have no plans in checking as until it becomes symptomatic, I try not to worry about it. I have done all the usual stuff to prevent it. I hope it doesn't happen but not much can be done to avoid it IMHO beside letting it warm up, quality oil with often oil changes. And I pray. Honestly, I love my car but bore scoring is by biggest worry and it does somewhat take away from the ownership experience.
Borescoped mine in November 2018 and found no evidence of borescoring.
Ran DT40 and followed Jake’s advice for keeping borescoring at bay.
When my engine was torn down in October 2022 for the elective FSI 4.0 build, found that my piston coating was worn away on some pistons.
So I had the beginnings of borescoring, but my bores looked fine.
According to Jake, he finds that most if not all have started.
Since borescoring is mostly on Bank 2 and especially on cylinder #6, I have to believe that heat and friction are the main cause....
I would think that a thicker oil than a 40 weight with Moly and/or Ceratech and /or Nano Copper particles will cure it on the ones most susceptible like those with FerroPrint piston coatings..
Mine was discovered during the IMS Solution qualifying stage. Decided to have FSI Stage 1 rebuild to take care of all known issues with the M96 and very happy that I did.
I�m definitely in the don�t know don�t wanna know club. I have no symptoms as of yet. No oil consumption, no smoke on start. Runs strong. I avoid winter time driving for what it�s worth. Religious about annual or bi annual oil changes. I have a youthful engine by miles ( under 40k) but the age it�s getting up there. I don�t wanna spoil a good thing.
at this point an engine rebuild is cheaper than buying a new car. So gonna roll the dice til it seems like it�s reasonable to look and then act accordingly.
figure the 996 is such a stout understood car at this point. cheaper than the ridiculous priced 992 and it�s fun as hell. At 20 plus years old. There�s nothing not known about em.
party on! And here�s to keeping your bumper on for servicing and oil changes in your driveway if you choose to.
@TexSquirrel
was your Ferroprint coating "flaking off" or was it "worn-away" ?
Flaking-off would be from Adhesion failure of the coating to Piston skirt ..
Where Worn-away would be from high Friction and/or lack of Lubrication of the piston skirt
So, in 20000 miles went from no bore scoring to bore scoring.
This substantiates many comments I have read around it is
Not if my car has bore scoring but when will it get bore scoring.
Of course this is just a sample of 1 but still important information.
I have an '03 with less than 50,000 miles (78000 km). Every time I start it up, I listen for the dreaded rhythmic bang. Was clean at 70000 km when bore scoped in 2018.
worn away
I don�t believe there was any evidence in the cylinders, but there would have been eventually.
Using Jake�s recommendations for keeping borescoring at bay seemed to be helping, but I believe eventually it would have progressed.
I only mentioned it because I thought my car was in better condition.
Pre-COVID I was putting 12k miles on my car per year.
At that rate I bet I�d start experiencing borescoring soon.
Now I work from home and retirement is getting nearer.
I put less than half that many miles on my car now.
If I still had the old cylinders borescoring would take longer to advance.
But now I have Nickies so I no longer even think about borescoring.
Unfortunately, I don't drive my car very often. Traffic where I live is just brutal. Makes LA traffic look like fun. Takes all the fun out of driving. Used to take it to work. Rarely bother now. Would like to use to go to cottage on weekends - dog doesn't fit in back seat. He was in there once - his front legs were by the gear shift! I too am nearing retirement and one of the aspects I'm looking forward to is using the car much more.
I�m somewhere between �don�t have it� and �don�t wanna know�.
I scoped the bank 2 cylinders from the spark plug hole and couldn�t find a trace of bore scoring in my 3.4L. I didn�t scope bank 1, and if I were to do so, I�d also go through the spark plug holes.
But I acknowledge that this method won�t reveal the full extent of bore scoring, so maybe I do have some and just don�t know. I remember seeing some flakes of Ferroprint material in my oil filter back when I was running 5W-40, though�
I will submit a vote once I scope the remaining cylinders.
Of the 10 that "have it " I wonder how many are 3.4 engines ?
For sure the "Official Word from Porsche" was that the FerroPrint piston coating started in 2002 with the 3.6 engines ...but rumor has it that "some" late 2001 3.4 engines had the FerroPrint also instead of the " Iron Plated FerroStan " ...
Bore score and seven years ago, bought my c4s running strong and haven�t had an issue yet. Runs strong. Still on the original AOS, had the ims rms and clutch done by owner before me. Clean start up Doesn�t burn oil and has survived 2 track days without a hitch. Do all the maintenance every year. It�s by far the most solid car I own with how it feels when I drive it, and it�s 20 years old. The 991 and 992 gen cars I just don�t think are gonna last 20 years
If you followed all the right advice what do you think created the bore scoring? Are you in a cold weather climate? How often did you change your oil? Any other factors you think might be the guilty ones?
I don't have any evidence of bore scoring as of yet in my 3.6. Just had it scoped a little over 2 years ago to check, as well as i test the oil a couple of times a year and have seen no evidence.
But yet, I live in the Chicago area with plenty of cold weather, drive the car around town and have tracked it well over 100 times over the last 23 years.
The only thing I can point too that has probably kept my bores in good shape is that I have had over 100 oil changes on average every 700 miles since 2002. Probably helped that I ran very good oil for the last 17 of the 23 years, replacing Mobil 1 with Millers Nano, and now running DI50. So the oil had the right ingredients and never had a chance to loose its lubrication qualities because it was always fresh.
The other three things i can point to that may or may not have helped are a byproduct if taking my car to the track.
1. I have run a 2qt deep sump with the Motorsports AOS and then the UAOS Track since the beginning of time, which means I always had plenty of high quality oil.
2. I proactively kept my coils, plugs, maf, injectors amd oxy sensors relatively fresh, so my AFR was always solid and my engine was responsive on the track.
3. I never shied away from using the rev range once the engine was properly warmed up on the street or track. But I always kept the revs low until it was good and hot.
What will probably get my engine is cylinder ovaling or a bearing someday. Doubt it will be the IMSB because i run the LN Retro and refresh it, nor will it be hydrolock from AOS failure since I run the UAOS track, nor a cracked head from the water pump since i keep it fresh.
But it will be something because every engine known to man will eventually need to be rebuilt. Just the way of physics. Especially one that is over 20 years old.
In the mean time, i continue to have a blast with my 996.
I always put fresh oil in the engine after wintet, before I track it, and always before it sits for a few cold months in the winter. When I start it in the cold months, I make sure I drive it for a good hour or two to get it good and hot to burn off any fuel/moisture in the oil.
All this comes out to under 700 miles on average. There was a couple of years i was too busy professionally and personally so I didn"t track the car and only changed the oil in the spring and early winter. Probably ended up being 1000 mile change intervals at that time.
Yes it does. Or it would be just 2x a year. I am now only doing 2-4 track days a year to keep up my driving skills and enjoy the car on the track. As a result, that's an additional 2-4 oil changes on top of 2x a year. While all of those oil changes may get expensive, especially with Millers Nano or DI50, it seems to have worked well for the bores.
I posted these pictures before.
'99 3.4L, ~130k miles, lived it's entire life in SoCal with regular maintenance.
Cylinder #6
Cylinder #5
Cylinder #4 (I think)
UOA doesn't show any wear metals to be concerned about.
Pretty minor compared to what else I've seen, but I'm not an expert. I switched to Driven DT40, and am just enjoying it. It it needs a rebuild in another 50k miles (~10 years) then so be it. What non-Mezger 996 won't have a rebuilt engine at that point?
^^^ That 2004 3.6 looks terrible at 60K miles...
^^^ that 1999 3.4. at 130k looks pretty good with not much wear
Old School Iron engines at 90-100K would have a ridge at the top of the cylinders so bad you have to use "ridge-reamer" to cut the ridge down before you could even get the pistons out due to the rings catching on the ridge...
They would be "smooth looking " but worn to hell out all but the last .375" at the top where the rings never touched...
3.6 engine here. 66k miles on the odo but unknown mileage on the engine because it was swapped in by a previous owner with no documentation available. This photo from my PPI was described as 'very light' scoring and was the worst of 4 cylinders that showed any signs of scoring.
Agree that 3.6 looks terrible. Kind of looks like what Charles explained/showed as the silicone impregnated lokasil layer coming apart and silicone migrating out of the structure. Believe thats what the little divots/dimples are..? Defective block structure.
I still have my old ridge reamer. Haven't used it in decades.
Used it all the time on rebuilds. Many times on old bone yard v8's I use to recondition. Did all of them,from 289's to 454, Hemi's, big blocks, wedges, small blocks you name it, I've built it if it was a older v8.
I've found that after cutting off the ridge and disassembling the engine, hot tanking the block, then measuring everything, most with a ridge big enough to catch your finger nail still were in spec, or maybe slightly over size but still mostly straight, not out of round alot or tapered a lot.
Most of the ones that didn't get bore jobs, had under .002" out of round/taper, many with way over 100,000 miles. Making sure the reciprocating parts were all in great renewed shape and balanced, made for a solid lower end. A quick hone job with my Sunnen hone put in a nice new cross hatch and slightly straightened things out for the new pistons and a loose high reving high hp build. The 426 was my favorite, with a set of forged hi comp pistons, built loose as a goose those engines just lasted and rev'd right out and lasted with tons of abuse. the music those engines made was intoxicating....
Thats my biggest biatch with the
m96 1 time use block, not rebuildable
in any normal sense of the word, especially considering.m96 were an expensive car. To me its unacceptable to need too replace total engine, or have to re-engineer the engine block at great cost to the owner...
jmho
The M96 is not rebuildable with the Old School Methods due to being Aluminum/Silicone bores, but according to Kolbenschmit ( who does them) they can be refurbished using new methods/tooling...
The OOR/Taper is due to the Ovaling and not really that hard to correct...You could just use an "internal jack-screw" to jack it back round and place an aluminum support ring around the top to hold it true...
So, what is this new Kolbenschmit method/fix, and is it available in the USA, where & how much to have it done...?
Remember reading something about Hartech stopping using that upper cylinder ring some years ago because it wasn't a permanent fix...? And they went with a nik'd alum sleeve, similar fix as LN nickies.
Yes less than 5 years ago Hartech was reconditioning the aluminum/silicone bores using the Kolbenschmit procedure ( they invented the Lokasil/Alusil)..and doing 1 or 2 cylinders or all 6 ...I thought the "re-rounding" and support ring was the best idea that Hartech had came up with at the time...
Hartech has gone the way of "re-sleeving" with Wet Aluminum/Nikasil Sleeves similar to what LN has been using forever..
Re-Conditioning the Lokasail takes special diamond hones, and a "paste" to etch the aluminum/silicone bore...as per the Kolbenschmit Handbook on Re-Conditioning Aluminum Engines ...
The Issue Hartech had was with the piston coatings...They tried several piston skirt coatings and none would hold up like the original Iron Plating ( FerroStan ) that is no longer availible......
Since Nikasil is still available and is known to be compatable with aluminum/silicone I see no reason why the piston skirts can't be plated with Nikasil and ran with the re-conditioned Lokasil bores....
Seems it would be a cost effective way to re-construct the M96 for a Robust and Frugal overhaul....although I think the procedure would get poo-pooed on by many who were not well versed in this type re-conditioning..
I recently purchased a 996 with 65k miles. As part of a pre purchase inspection I had the shop drop the oil pan and scope the bores. All was clean in the pan and the bores were in great shape. Car is a FL and CA history vehicle and I have read that bore scoring is more prevalent in cars from cooler climes when they have been started and immediately left to idle to �warm up� which is a no no on any vehicle and doubly so on a specialist car like a Porsche .
Interesting option.
Who would do this type of locasil cyl reconditioning here in the USA, or anywhere for that matter..? Wonder its cost..?
"Re-Conditioning the Lokasail takes special diamond hones, and a "paste" to etch the aluminum/silicone bore..."
Well, the diamond hone is now common in most cylinder plating shops and even many engine rebuilding shops. So thats not a problem. But...
The "paste" to
etch
the aluminum/silicone bore" seems like it wouldn't be unreasonable to procure, if its available. Sounds like its an acidic type etching paste.
Not sure how any amount of etching would fix a badly bore scored locasil cylinder as etching only removes material. And a bad bore score needs more material added...? And iirr locasil cylinders can not be diamond honed to size even if materiel was somehow added, something to do with the impregnated silicon particles suspended in the aluminum cylinders iirr.
I've etched/cleaned nik'd cylinders many times with muriatic acid on a sponge pad(very carefully). It eats off the aluminum debris left from the pistons on the nik'd cylinders cross hatch. After this is done correctly original cross hatch looks like new many times. This allows one to install new pistons rings in a glazed cylinder thats not worn/damaged without diamond honing the cylinder....
I'm assuming, could be wrong, correct me please,,, the Kolbenschmit procedure does similar to etching with an acid on a nik'd non damaged cylinder to de glaze remove debris, and enable a new piston/ring set to be installed... Maybe not a fix for bore score or badly out of round cylinders..?
jmho
Yes the Etching Paste can be had when I checked on this years ago it was like $35 for a tube and the Diamond Hones were several hundred bucks, and I think a lot of shops are now using very similar Diamond hones ...
Most of the Bore-Scoring I have seen looks like it would only take few thousands to clean it up, and the Diamond Hone could do that without boring...
I would think 90% M96 engines could be Re-Conditioned using this procedure.... 1 .. use a jack-screw to re-round the cylinders, then 2 .install the top support ring to keep them round and add strength...3 Hone the Cylinders using the Diamond Hones to clean up the cylinders . 4 Use the Paste to Etch the cylinders to the correct finish ....4 Plate the Piston Skirts with Nikasil to the desired thickness to match the bore size...5 file the ring end gaps to specs...
I think the key is using Nikasil Plating on the Piston Skirt... This is something I think No ONE has thought of......No other "coating" seems to hold up against Lokasil ( except the NLA FerroStan )...but Nikasil has already been proven to work very well against Aluminum/Silicone...
1999 C2 purchased about 1 month ago with 96K miles. Purchased from my uncle and he had the car scoped prior to me taking delivery...no signs of scoring.
Original owner (my uncle was the 2nd owner) was a Service Manager at a Porsche dealer in Socal...so the car got a lot of attention.
To me, with stats of 67% NO bore-scoring and 33% YES bore-scoring is good news given the M9X engine has been around for over 25 years. Quite frankly, I would have expected closer to 50% given the age of these engines. Seems we have alot of owners that ignored Porsche long frequency oil change recommendations. Hope more owners take the poll.
IS that on the upper/thrust side of #6 Cylinder??
To me it looks like chunks of Carbon stuck between the Piston and Cylinder wall leaving those black streaks...
If it were mine I would do a Blow-By test, then use some Driven Fuel system cleaner in the tank....Then have another look-see in 3k miles...
Pics from the Camera of Cylinder 6. There does appear to be Carbon deposits in here. The black streaks on the cylinder walls are on the lower cylinder.
I put in Driven Injector cleaner about 150 miles ago.
Thoughts??
Our 2000 C2 project car had spun rod bearings and 4 cylinders showed boring scoring. We needed a new crank and bank 1 head as it was cracked. Our nickies rebuild is almost ready to so back in the car.
Anyone know what's going on with SUMEbore coating? That was supposed to be the next thing after Nickies. Before JR left the forum, he was researching it and said he initially had good results if I'm remembering correctly. That was a few years ago.
I had wondered also, this is what AI says, so nothing newer than 2022 to report.
Sumebore is doing well, demonstrating promising results in Porsche 996/Boxster engine development through a dedicated project, though the technology is still in its developmental stages and not yet widely available for consumer application. Initial tests, including a
3-year, 15,000-mile field test
, show the technology's potential with impressive Abbott Firestone curve results and a clean bill of health from the test engine, indicating that Sumebore could offer a robust solution for combating the known issue of bore scoring in these engines, according to a recent YouTube update from early 2022.
Sumebore's Progress:
Positive Performance Data:
Tests on the Sumebore cylinders show exceptional Abbott Firestone curves, which indicate improved surface finishes and functionality compared to other methods, according to this YouTube update from March 2022.
Since Oerlikon closed the SUMEbore line in the US, blocks have to go to Switzerland to be coated. It adds cubic dollars and time. Currently it's a process only available on R-Series engines from Jake.
I sold my Boxster that had one of the SUMEbore test engines to Lake Speed Jr. He's still happily driving that car all over the place.
Follow up after 500 mile of Techron to clean up the carbon. It did a decent job of cleaning the carbon but that is the only good news.
Cleaner cylinder walls in #6 now reveals scoring more so than the dark possibly carbon lines before. The scoring is on the top of the engine. 180 degrees above the oil that is pooling in the bottom of the cylinder. NOT IMPRESSED!!
I guess I don't need to pull the motor to do the cam shaft guides as that is a fart in a hurricane at this point. A few pics for reference below....this is a 99 3.4L C4 Cab
Now to figure out what to do. WIll reach out to LandN, Hartech and a local shop. I don't see this being resolved for under $22-25k which is what I paid for the damn thing but she's a keeper so I'll have to make a choice. I think I'll drive and monitor for the winter. I need to keep an eye on cam deviations though...not sure how long I can really let that go. No CEL but bank 1 is at 7.8. Again....2 thumbs down not impressed.
Cylinder and piston is cleaner after 2 tanks of techron and an italian tune up
I'm guessing the oil is getting in now that the bore is scored and there's a gap??
2 thumbs down
I had a car scoped today that I'm considering purchasing that has a 3.6x51 engine with ~35k miles. There is some light scoring on 1,2,3, and 5 from what I can see. The worst looks like cylinder 2. With cylinders 3 and 4, I'm not sure if that's light scoring or normal wear and streaks.
The filter and sump looked alright, nothing too large in there. The oil was too fresh for an analysis so I held off on that.
What are your thoughts on how these look?
I haven't scoped my own car yet which is a 2002 c2 with 68k miles. Oil analysis so far is good, but I'm looking to scope it soon.
A lot of photos, but TIA.
TLDR: Yes, I have Bore Scoring! There! I said it!
Got my 2004 cabriolet in November 2024 and PPI showed mild bore scoring on cylinder 6at 77k miles. Generally no smoke on start-up, and no oil burning between oil changes (2500 miles). I tracked the car right after I bought it, and it performed admirably. Since then no track days, I'm assuming that if i drive responsibly (DI40 or DI50 oil, frequent changes, no high revving until oil gets warm, etc.) I can drive until it starts to burn oil. I just added Tribotex at last oil change ( 82000 miles) and hoping that gives me a few more smoke free miles before rebuilding rears its ugly head.
I'd like to know if anyone has developed a spreadsheet of the cost associated with the various rebuild options. Everything sounds expensive, but it would be nice to have rough (perhaps very rough) ideas of what the options are. I had a C5 Corvette prior to my 996, and the dearth of threads on the Corvette forums relevant to SEDS (Sudden Engine Destruction Syndrome) makes me long for the sound of an LS engine behind the seats.
(couldn't find the apostasy emoji)
2002 C4S with 130K km; from my service last December:
BORE SCOPED ALL 6 CYLINDERS AND THEY ALL LOOK VERY GOOD!
Car has had the IMS solution for a few years now too; so I'm pretty relaxed about it.
spark plug holes; which i realize is less "100% conclusive". I was getting a little bit of misfiring due to the plugs and ignition coils aging out which is why they were in there. Even so I was happy that it was "good news".
Actually, spark plug hole bore scoping is 100% accurate contrary to some opinions. Hartech/Slacker, probably the biggest m96 builder conglomerate on the planet, agree and recommend spark plug hole scoping.
For those that disagree please show pics of m96 cylinders that only have bore score below BDC. Asked for these pics before and no one seems to have any.... Thats got to tell you something. Pics have been posted on this forum showing how spark plug hole scoping shows up all bore score engines.
But by all means don't believe and get under your sump, get oil dripped in your eyes and camera while trying to thread a scope thru convoluted wrist pin holes while turning the crank to get the perfect piston height to allow the scope to thread thu.... good luck with that.... many a scope has been pinched/crushed doing this unneeded procedure....
If no bore score seen from spark plug holes, you have none, you're good to go for sure...
We just had someone who is looking at buying a used 2002 Porsche 996 just emailed us with this. The seller had these photos from a PPI done by a "specialty Porsche shop". The PPI stated “small stuff, nothing too scary” - but that's not true. I will say good on them that they scoped it through the sump, but this is very early bore scoring and something that you won't see from the spark plug side. At this point, it's going to fail from bore scoring - it's not a matter of if, but when.
The whole point of scoping through the sump is make sure that it hasn't started at all yet. Through the spark plug won't tell you that.
This^^^^.
Don't know why Hartech thinks all borescoring can be seen from the sparkplug holes, when it starts at the bottom of the cylinder walls. Doesn't matter, I'll stick with recommendations from Charles.
When it comes down to it, it's your car/potential car, and your money. Do what you're comfortable with. I'm on the search from my next 996 and when I find a car I like I'll pay to have the sump dropped and the cylinder bores scoped from the bottom. up so I have peace of mind.
As for no one sending Allcool pics of borescoring below BDC, Charles just did. The vast majority of 996 owners are not on this site, and those that are may not be paying attention to his post so no reply's doesn't mean it never happens.
.
Bore scoring starts at the bottom and works its way up and so naturally it makes sense to scope from the sump. Slakker has limited experience having only been on the scene a few years now (since circa 2022 or 2023 if I recall).. and many of the things they have stated clearly illustrate that.
Got a question for Charles, that same engine you have a picture of, how many miles do you think that engine would last using the recommended oil and driving it correctly with temperature warmups would that engine last before you think it would have to be removed and overhauled.
I would choose to use both methods. Use the spark plug hole as a preliminary screen to determine whether it�s worth investing the time and materials cost to investigate through the sump.
Time and materials to get in through the sump is essentially nothing. Very small cost for sealant when you put it back on? Maybe some time to let the oil drain but you can go do something else while you wait or just let it sit overnight so why is that an issue? Even aside from bore inspections, when buying a car looking at the sump is good practice. You could find metal, plastic bits from guides or other clues that you would want to know about before paying for a car. I have seen all sorts of things in the sump. I never understood what the aversion to accessing the sump or why such a big deal is made of it. It's directly accessible, just some bolts and it comes right off. It's one of the easiest things to do on this car... why try to take shortcuts especially on something that could have such a large consequence? I don't get it.
It makes a difference when the indies charge a $500 difference between the two methods, especially to find out that it had major scoring after going through the sump. I�m not saying to reject the sump method, but rather to use it later. If you have five different cars that you�re interested in, the cost of PPIs would quickly become overwhelming.
I'd imagine probably quite a few thousand miles if you address any lingering issues that are contributing to the scoring.
Used oil analysis at every oil change will monitor the progression of the bore scoring.
Credit to you sir. May I ask but what is the current mileage on your engine?
There�s no disputing that bore scoring typically starts at the bottom of the cylinders. However I think the reason that Hartech/Slakker advocate to scope from the spark plug holes is because it isn�t usually a potential problem until visible from the top.
In other words, if there is some mild scoring at the bottom of the cylinder, which isn�t visible from the spark plug holes - it could take thousands of miles/years before it becomes a problem.
There�s also the argument that scoping from the spark plug holes is less labour intensive. It is therefore more cost friendly for those checking - which are usually a prospective buyer as part of a PPI or an avid owner as part of a Major Service (which involves replacing the spark plugs).
68.5k miles. 2002-2005 it was a daily driver year round in Chicago with alot of track days in 04-05. Then it was a second car with alot of track driving and some local tooling around for a very long time. More recently its been 4 track days a year, local tooling around and a couple of long distance road trips.
Someday bore scoring will appear. Its inevitable in just about all German cars with aluminum of that era due to environmental mandates. But we can all prolong the life of our bores by just running high quality oil and change it often.
In this pic that was posted above, at least half of the scoring (or more accurately bore scuffing you couldn't even catch a finger nail on) would be seen from spark plug hole @ BDC.
These are pics by a well respected engine builder.
Pics show the BDC line of the ring pack. With piston @ BDC one can easily see the complete cylinder 1/2" above this line. Easily can see where the scoring is all from the spark plug hole. What more does one need..?
And yes, removing the sump is a great idea in a PPI. Doing a scope from the sump, imho not needed to ever put yourself thru this convoluted exercise when a easy spark plug scope along with a compression test will give your ppi much more useful info...
JFYI, A 996 sump will drip for more than a month. Using a full walk under lift might be ok easier to avoid camera lens/your eye/face splattered with oil drips. Try it you'll see what I mean. Doing a sump scope on jack stands on your back, its nothing like the video with a empty block on a nice work bench standing next to it. I've done a sump scope, never again..
The great thing about the M96 in a 996 is you can piggyback service items to save money.
If you are going to replace the spark plugs and ignition coils, you might as well scope the bores from the top.
If you plan on dropping the sump to see whats in it, then you might as well scope the bores from the bottom.
But by all means, test your oil with every oil change. You will learn alot about whats going on in your engine with the trends after a few tests.
One sample doesn't tell you anything, and as was said above, you really should do it with every oil change. Not only will you be able to monitor wear levels, but you can also look at how the anti-wear additives are being used up and if you have a fuel dilution problem that needs to be corrected.
And unless you have trend data, it's hard to know what's normal for your engine and specific operating conditions. Iron, silicon, and aluminum trending upwards are key indicators of bore scoring.
I think it would be useful to have a UOA survey thread where people share their lab results. That would be actionable data.
Lake mentioned in one of his videos that he�s planning to introduce a database of UOAs that will allow us to make comparisons with others with the same engines. I�m really looking forward to that!
havent been here for a while, but thought id submit my data point.
2002 c2 coupe
purchased 2010, ~27k miles
~5k oil changes with mobil1 0-40
aos and ims changed with clutch ~70k miles
2019, 120k miles, started noticing soot on tail pipes, borescope around this time was inconclusive
switched to millers cfs 5w40, yearly changes (stopped driving so many miles)
now with ~134k miles, conclusive scoring on #4 and #6.
smoke on cold start, and excessive soot on bumper.
sorry, no photos of the scoring.
Interesting survey. Of those who found bore scoring, is driving it to some level of severity typical, or do you think most head straight for a rebuild?
What is the liability of short/medium/longterm operation with ongoing bore scoring? Mostly oil contamination risk for other close clearance parts?
By the time you have symptoms, like a sooty tailpipe, elevated Si, Al, and Fe levels in the oil, and oil consumption starts trending upwards, engines usually only last at most 2-3k miles.
As the bores score further, you get increased combustion byproducts in the oil, such as soot. Soot is abrasive. Soot is also the #1 contributor to chain stretch/wear.
Usually once oil consumption reaches a quart in 2-300 miles, you are seeing misfires and are risking serious damage to the engine and subsystems, like the CATs. I've seen engines have d-chunk failures that get run too long with scoring.
The simplest way to extend the life of an engine with bore scoring is to run DI50 or DT50 and cut the oil change intervals down to 1-2k miles, tops. You'll know when the oil is compromised when consumption starts increasing, as it often will decrease for a while after fresh oil is put into the engine.
Another contributing factor to how long it will last is whether or not you take action to correct any issues contributing to scoring, such as bad injectors or vacuum leaks.
My engine is starting to tick when cold but it doesn't do when it's warm. No smoke or soot, the ignition on oil gauge shows full. I check it every time I refuel as a precaution
I watched a video from flatsixinnovartions.com on bore scoring.
Mine appears started on that journey. I don't have the rebuild scheduled until May the following year.
I'll baby it until then and hopefully slow the bore scoring.
Note to self: Don't buy cars from my brother.
So one of the points I see a lot and typically try to avoid with my car is the cold weather starts/driving.
Of those that have scoring ..
Do you or has a previous owner driven in the colder months?
There is a whole discussion 12 years ago about cold climates. A lot of different opinions.
https://911uk.com/porsche/cylinder-s...ke-raby.65364/
Nice read
I suspect those with our model with low mileage are the top candidates from sludge buildup internally from sitting long periods of time garaged. High mileage cars are a better choice.
Following that are those who started a cold engine and putting their foot into it immediately without properly warm. Warmer area aren't exempt from idiots either. Always warm the engine up until the temperature reaches 180F before playing.
Not changing the oil often enough. The maintenance schedule is 10K. Perhaps this is good to go, but 5K or less is more the norm. Check the dip stick more often. Every fill up or at least once a month.
Then you have some simply without rhyme or reason. I believe these poorly coated pistons from the factory, bearing, or bad crank shaft. But these defects would really only be noticeable if most of a lot had these issues. I've not heard of any though.
Note: This information is built from previous posts, videos on FSI or conjecture from a 60s model backyard mechanic who interned a summer at 16 at a foreign car repair shop. That was 52 years ago, so I maybe simply be talking out my posterior (or French substitute)
5k mile oil changes with cheap oil that doesnt lubricate properly, which is loaded with fuel and water from old fuel injectors, and never getting the oil hot enough to burn it off, sure doesnt help prevent the issue.
Easy to solve for in any cold weather town.
1. Run better oil with high viscosity and high moly content.
2. Change it every 2k miles instead of 5k.
3. Proper warm up procedures and then drive the hell out of the car to get the engine/oil good and hot to burn off the fuel and moisture.
4. Keep your fuel injectors and oxy sensures working fresh and working properly so your not dumping fuel in the cylinders.
I did forget to commit on oil quality. But once the issue appears, you can only try to put bandaids on it to last an additional 5,000 or so miles according to Jake Raby and I just have a moderate ticking with no current oil use at 93,000 or so miles on it. Most likely caused by my brother who had it for 10,000 miles previous to buying it. The last 5 years it was garaged and driven on weekends.
He and the previous owner only used Mobil 1. It's got a low moly count and not really suitable for the engine.i immediately switched it to Liqui-Moly with a 300 Mml CERATEC additive. But it's too late to be more than a high quality bandaid since the symptoms were there when I bought it. I mistook the sound for a sticky lifter or valve. 3 months later I stumble on a FSI video detailing the symptoms and misdiagnosis many will take along with the expense of replacing, with oodles of money spent trying every fix before the engine gives up the ghost.
You may have it rebuilt by the local shops. That is no guarantee it it will be a quality rebuild either. You have to seek out and find one where the money is well spent before you use the local shop. Rebuild are no guarantee the problem has gone away. That's a problem.
I bought my 2003 C2 Targa manual six months ago and it has run fantastic in the 3,000 miles I've put on it since. The car has 66,300 miles and has spent the past few years being driven in hot 'n sunny Florida with documented 5W-40 Mobil 1 oil changes every 3,000 miles. Nothing but top tier premium fuel is ever used. New 997 injectors were installed 6,000 miles ago. There is never any smoking on startup or otherwise, the left exhaust tip is free of soot, I average 18.4 mpg thru varied driving, and there's no ticking when cold. There IS, however, oil consumption. I've had to gradually add a quart of oil every 1,100 miles and the oil has a faint burnt smell to it. The oil filter was dissected and no shrapnel was found.
I had the car scoped through the plugs and you can see the results below (ignore the incorrect date stamp); there are lines visible in all six cylinders, a spot of discoloration in one, and what the shop thinks may be possible micro cracks in a couple cylinders. Good times. I'm changing the oil with 0W-50 LiquiMoly tomorrow and I guess I'll be keeping a close eye on even more oil consumption and the classifieds for a replacement bottom end I can have re-sleeved in advance for when the inevitable happens. Ignorance was certainly bliss.
FYI, that LM doesn't have near enough moly in it unless paired with their MoS2 or Ceratec additive, but the increase in viscosity will provide some added benefit for sure.
Usually the marks that some shops mistake for micro cracks are just normal marks in the cylinder castings. Almost all of these engines have them. I am sorry to see that you have scoring though. Best of luck.
[Image-only post; no author-written text. Original image references:]
https://cimg6.ibsrv.net/gimg/rennlist.com-vbulletin/908x644/605625419_1493256252707476_7595128291114876983_n_fd737334e95197014ef89f94ffe0382a3ff4367f.jpg
Yes, this picture is a great illustration of the difference. The squiggly line shown will be present in just about every one of these engines -- but it is benign. I have seen this frequently confused as a crack in the cylinder, which is something to be concerned with.
Thanks for adding your expertise to the discussion, particularly concerning moly additives. I'm loving my 996 cab and it's good to know that the extra expense (minimal) of a moly additive along with high quality oil is beneficial to us M96 owners!
Cheers!
Hi- Hoping to get some advice/ feedback! Purchasing a higher mileage 996mk1 and had the cylinder bores scoped as advised by the world. Based on the video evidence tech has told me that "
Cylinder 1 has a few medium score marks", "Cyl 4 with one faint score" , "Overall, nothing to be concerned about".
Does that advice ring true? Is there and acceptable limit to the amount of bore scoring?
There is no acceptable amount of scoring unless you are buying the car at a discount and appropriately pricing in rebuilding the engine. Once scoring starts it will never reverse or get better. It becomes a question of when, not if, the engine will require a rebuild.
I have an '06 C4 with 141k. I drive all year round in Chicagoland. I follow the recommendation to not exceed 3k rpm until oil temp rises above 150 mark (which conveniently is right as I am entering the expressway). Left exhaust has been sooted up for about 30k now. When I changed plugs at 135k I used a scope from work to look at cylinders 4 and 5 (couldnt get into 6 as I didnt drop mufflers) and there was visible scoring but only light marks, no obvious nikasil loss. The car started loudly ticking last winter ('24) when cold but would go away when warm. Now in the last month or so it ticks all the time. I change oil every 2500 mi with DT40, no other additives. I send oil samples every change to Blackstone and my excess metals are all on the high end of the range, but are holding steady. I have started making appointments with local shops for quotes (my first is Friday at Euroquipe in St Charles). Unless I find a better offer locally I'm leaning towards driving it down to Slakker in OKC and fly back, then when finished fly back to OKC and drive it home (plenty of FF miles so essentially free to fly). If I do I will go with the 4.1 build but with stock internals.
06 C4 does not utilize Nikasil unfortunately... if it did you would not have this problem. LN Engineering is local to you, based just outside of Chicago area.
