Bore Scoring

When did all this "Bore Scoring" start? Is it just a Porsche problem....I had never heard of this a few years ago... Did this just start with the introduction of the water cooled engines?

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There are many reasons for it. It�s all explains in the Flat6Innovations bore scoring series on YouTube. Do a search it�ll come up...

Subscribe to Jakes Rennvision video series on YouTube an get all the info one could ask for.

And it�s not just a Porsche thing. Someone here experienced the same with a Hyundai their daughter owned. I�m sure there are other marques plagued with it as well.

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that was me, it's funny when I see Hyundai elantras go by I listen to them and many of them have the ticking noise.

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Seems like I've read from Jake that he states that the bore scoring problem is the #1 and oldest mode of failure. It's just now that our cars have hit the 20 year mark that more are showing their asses. As others have said, check out "Rennvision" on YouTube and search for bore scoring. Jake spells it out better than anyone. This problem no only affects the M96, but M97 and 9A1 cars too. Yep, that means even the 991 with Alusil can suffer from bore scoring.

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That's in large part due to the aftermarket vendors recently learning they can make big money by hyping this "problem" a la the IM$ business model.

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Nobody "hyped" me...This is a problem that can be diagnosed. I've never heard of anyone saying let's rebuild your engine to "prevent" scoring from occurring. Maybe I'm listening to different people.

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Billy, Your listening, lot better than most do like finding fault in how its diagnosis or symptoms are presented. Sorry to read this earlier, but good to hear that your going to address it properly. I don't think anyone "hyped" you into this problem, but with Jake's help you were able to diagnose it properly. whether you used his shop or not is to me irrelevant. though I do think he is a honest and trust worthy vendor.. Mke

^^^Thanks Mike. I guess it upsets me when somebody "insinuates" scoring is not a problem just a sales technique and if it does occur it's still not a problem. Scoring is a problem in any engine when/if it occurs. My previous profession was a manager with a major railroad supervising the maintenance/repair/overhaul of diesel locomotives. I cannot tell you how many power assemblies we changed due to scoring. If it was all just "hype" we could have saved millions in material/labor/downtime. It is NOT hype! I've seen what scored liners can do to large engines in my work career as well as smaller engines in my racing endeavors. I wouldn't want that to happen to any car I own. I know there are people who have run scored liner engines for long periods of time by just adding oil. To me that's rolling the dice and creating more internal damage. If that is what they want it is their car/pocket book. To each their own and more power to them if it works out. End of Rant

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Who exactly are you referring to when you say aftermarket vendors that "hype" the problem? Millennium Technologies? LN Engineering? Hartech? Flat 6 Innovations? Which one are you referring to?

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Exactly! Well said. I guess if we start talking about head cracks and intermix, it's all fair game to troll Len Hoffman and make him out as an opportunist? He doesn't even fool with forums and I'm sure someone would accuse him of over-hyping the problem.

Just seems "new" to me... Every engine/transmission has it's problems.... The first I remember was back in the 70's with the BMW 2800 engines, Bavaria/3.0's)..they had an overheating problem (solved by having a larger/ more core radiator made) , and a cam problem on one of the cylinders.... Next I remember the early 911's had to have Hydraulic oil lines for the lifters added and a "pop off valve"for backfires As far as transmissions go...THEY seem to be much improved and "bulletproof" Now its IMS and Bore Scoring...whats next?

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That's it, just bury your head in the sand and pretend it's not making that "lifter noise"... Oh did I roll my eyes yet?

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The sky is not falling. These are great cars. Yes, they have their problems, but if you use good situation awareness and sound preventive measures, you'll get years of reliable use. I don't have time to get wrapped up in forum/vendor drama, but still wise enough to listen to trustworthy sources of information. After much research, I recognized that the plain bearing IMS design of the Mezger engine was superior to the sealed ball bearing that Porsche used in the M96/M97 engines. Therefore, I didn't mess around and had it changed out with the IMS Solution along with the RMS and AOS. I plan to do the same about the other known wear parts that could lead to serious engine problems.

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I've addressed items that cause light going off and other preventive maintenance items. I plan on addressing AOS/Coolant tank as soon as possible. that is one of my last 2 items that leave me in doubt from taking a cross country trip or at least a day away from home base. Do I lay awake at night, no, only .when I driving it for a few hours. I have less than 40k miles and now worry about things getting brittle and breaking/leaking. I still get immense driving satisfaction out of the car.

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An interesting, and maybe unique perspective. Porsche admitted to the high rate of IM$ bearing failures in court, and they offered remediation(too little too late, but...). If it was an aftermarket vendor business model, why does Porsche not get on the ball and offer a competitive market product a la the LN Solution? Seems if LN is making money on it, a product with the imprimatur of 'Porsche' would have done quite well. As for bore scoring, is it some kind of warped marketing tool that Porsche built into the engines? Are there aftermarket vendors out there pouring sand into the crankcases? Are they selling some voodoo additive that scores the cyl bores? Is it a legitimate failure mode that Porsche, and all the aftermarket vendors should just ignore? "That ticking, slapping, clanking noise is normal for the M96 based engine. It lets you know it's a real PORSCHE!" ??

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This made me laugh. So the only way for something to be considered an "issue" is only when EVERYONE knows about it? :confused Just to mention a few.....broken rod bolts, timing chains breaking, scavenge pumps seizing, cylinder heads cracking, cylinder walls cracking/"chunking"/wearing unevenly, oiling issues. Well, on the bright side, it's rare for the head gaskets to fail. lol

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Whatever someone can come up with I guess... I've asked both techs I use (both experienced, both love to charge me for things I need, so if there were money to be made on these items/issues, I'm sure they would wholeheartedly recommend them and take my money) about these things and both come back with negative responses about 'needing' these things. Same goes for every other 996 owner I've met in person. My 03 C4S has just under 91k miles on it, and I was terrified from buying a 996 years ago because of things like this I read on forums like this and others, and it's not exactly 'honest' how some go about it, especially since if a 'fix' is needed, it can be done relatively cheaply. And then for some, like my high-mileage car, the odds of these failures happening decreases over time according to both my techs, and other pubs/mags I read who do this stuff for a living, so I just go by that. I've had nearly 13k worry-free miles at this point, and plan to have many more to come. I've had WAY more issues (engine and other) from newer and 'more reliable' cars than my 911 so YMMV it seems. Is RMS still a thing? He seems to be the odd man out with IMS still front and center and bore scoring being a new draft pick.

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Since the first design of the first reciprocating Otto cycle engine. Been fighting it ever since. Water cooling is not relevant to bore scoring, but the tightness of the piston/cyl and the design of the engine are more likely. So, in a kind of hard to define way, one could say yes, the water cooled engine has more propensity for bore scoring. But - before the nattering nabobs get all panty wadded, there are a billion other parameters that have an affect. Rod length to stroke is a major factor, short skirt piston is another. Piston pin geometry, ring location, valve/port location(flame propagation), spark plug location, and on, and on, and on...

Every engine has components that are most likely to fail first. In some engines, it's variable valve timing hardware, in others it's valve guides, in the M96 and M97, it's the IMS bearing and bore scoring. Mechanical things fail eventually. Remember that these normally aspirated engines are designed for almost 100 hp/liter.

Anyone know what kind of cylinder liners get installed after a problem like this? I have come across some called Ductile Iron Cylinder Liners

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If I'm not mistaken, the LN "nickies" rebuilding program bores out the old damaged lokasil/alusil cylinders and replaces them with billet aluminum nikasil plated cylinders with the build quality of the turbo and GT models. Iron liners??? This was just addressed on the 997 forum by Baz from Hartech. Basically, iron sleeves in an aluminum block = bad bad! You should have seen some of the pictures they posted when the iron reacts with the other metals.

Iron liners are cheaper but have inherent problems mating them to an alloy block . A differential in thermal Expansion and contraction rates being primary . Nikasil or similar like used by hartech or l&n is a better option

If memory serves me correctly, I think "bore scoring" started with the original air cooled VW flat four engine. They either went a million miles or scored the cylinder walls until the engine froze.

Back in my sand buggy days, we had the air cooled 1600VW engines, bored and stroked out to 2180 and some were 2276cc. For that application, some modest grinding of the piston skirt was common to avoid contact with the crank weights. We used hyperutectic pistons, and mostly iron cylinders, although a few folks spent for the early Alusil/Nikasil stuff to save a few pounds. The iron liners NEVER scored. The Al based ones usually lasted 20-40 hours before they were thrashed and had to be replaced. Most due to scoring, sometimes to oval or taper issues. That's why one or more vendors have tried the iron inserts in the Al block. Fix one problem, create another. We also had fairly sloppy piston clearances, and fairly sloppy ring clearances compared to modern tight engines, so we'd use some oil and had some blowby, but no one cared, we vented the blowby right out to a filter on a pipe and to the air. Early Lamborghini V12 engine had iron liners in the Al block, but they had a flanged deck at the top, and were crushed by the head gasket into the top lip of the cylinder housing. Worked pretty well, but they did have some leakers. This issue also lead to development of slippery piston coatings. Problem is, the slippery coatings didn't stick well to the piston. Who'd a thunk?

Yeah, I forgot about the head bolts (stretching)I on the (air) 911's generally I don't think it grenaded the engine however... I owned a few 911's in the late 70's and 80's, and the ONLY failure I had was a blown air box, on 4 911's and over 100,000 miles.... This was all way before the Internet and Message boards...

I read these posts with interest, this type of failure is an car owner's worst nightmare, if the engine fails you, either fix it (and you may never recoup that repair bill) or sell it as a roller (and lose a large chunk of the value of the car). In watching an unrelated video the other day, this subject was discussed over another manufacturer using the same bore lining process, this time it manifested as ridges/waves formed on the cylinder walls. The tech mentioned that cars that experience cold starts in areas where the winters are pronounced, and their maintenance schedules, are failure factors. Maybe external engine oil heaters/warmers would be a good idea or climate controlled garages. Certainly not easy for everyone to apply these prevention methods. One would think that Porsche engineers would address this issue and eliminate it, or do they just accept the failure rate and these owners are SOL. As I live in Florida, real cold isn't an issue, but I still cringe when I start my car and wonder why Porsche builds in a high idle rate at the worst possible time for engine wear, it soon settles down to normal, but still. It probably has to do with the emissions control.

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Yea because broken fan resistors help the bores expand when the engine gets hot. Lots of failures in the cylinder by the oil cooler? Wonder why that is? These guys wouldn�t be in business if there wasn�t a problem. Stick your head in the sand like the turbo guys that think if they dont track their car the coolant tubes won�t come unglued!

There's no "hyping" the problem. Stating what's happening with these engines doesn't make the engines fail. In fact, the failures are going to occur whether we take the time to share with you all what happens, how to diagnose a failure, or etc. The phone calls are still going to come in, and the failures are still going to happen. Its quite the contrary. Thousands of dollars have been saved by owners already just due to my part 4 of the bore scoring series where I show the owner how to diagnose their own bore scoring at home with a 40 dollar bore scope. Shops are charging 600-800.00 to do a light bore scope on all 6 cylinders, FYI. The vendor haters never cease to amaze me.

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Don't let it idle until it drops, drive off keeping it under 3K until fully warmed up.

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Now? Dak this has been going on for 18+ years...Where've you been?

"wonder why Porsche builds in a high idle rate at the worst possible time for engine wear, it soon settles down to normal, but still. It probably has to do with the emissions control." I does, just as any Bosch Motronic controlled engine. It's the idling time after it settles out that is worse for wear. imo

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Sorry to hear about your engine issues. It's unfortunate when an extremely low probability event happens to you but that does not change the fact that it is an extremely low probability event. There are plenty of ways a business can profit indirectly from an issue. For example, a business could seize on an issue and "hype" (i.e., make the issue seem more common than it really is) the issue in its marketing campaign to garner more attention for the business and its services. It's a bonus when the "hyping" of the issue serves to further disparage a product (in this case an engine) in which you happen to offer a modified improved solution to the product.

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Like I said before we must be listening to different people.

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At the time of this thread, most of our 996 cars are at least 15 years old and pushing 100K miles or more. I feel pretty strongly that if you bore scoped bank#2 on 100 cars from owner's here on Rennlist, you'd find that most have some level of cylinder bore scoring and at least a quarter of those car would have scoring severe enough to warrant intervention. What are my odds? Maybe I should spit in one hand and wish in the other and see which one fills up first?

Maybe the vendor haters that say that we are taking advantage of the scenario should focus on the fact that we have foresight, and forethought to see these issues coming. We invested time, and money to ensure that we would have a proven solution to the problem waiting, for when the issues started to occur. This is exactly what happened. Instead of people hating that we'd created a solution, we used to be laughed at for "wasting our time with those motors". This happened to me for years in the early days, so its quite comical to see where things ended up. I can't tell you how many times I've had people on this forum not believe "the hype" or not like what I say, and give me hell about it, only to turn around and need me to help them. One poster here, Pete Passon (sneaky Pete) fit the bill perfectly. He even came clean with me on the phone when he called after his failure and said "I have to tell you, I am sneaky Pete from Rennlist, I hope after you learn this that you will still work with me". I told him that it was no problem, and things went on to the point where I didn't just build one engine for him, but two engines for him. My videos and info on this topic were primarily done to cut down on the same old messages coming through our system. The same symptoms, the same issues, and etc slow us down. Now, after the video series on bore scoring we don't get those questions.Instead, we end up with "My car had some symptoms of bore scoring, and I found your videos on youtube. You described my symptoms verbatim, and I used your video to bore scope my own engine, and diagnose it at home. Thank you for helping me understand this failure" 99% of those never lead to a sale for us. We build engines for the 1% who love their car enough. The other 99% benefit from the videos, that save them money on misdiagnoses, and spending thousands of dollars replacing AOS units, and chasing down phantom issues for an engine that "runs fine, but just burns oil".

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Adapt and overcome Uh-rah!

[Image-only post; no author-written text. Original image references:] https://rennlist.com/forums/images/smilies/popcorn.gif

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I'm used to this mindset. Same happened here on Rennlist and on Pelican when we started making the IMS Retrofit. Some said we invented the problem. Fast forward several years and the Eisen class action lawsuit proved otherwise. Even Porsche developed their own IMS replacement (which made a brief appearance and then disappeared from their parts system) using a sealed single row ceramic hybrid bearing, like our first IMS kit. Just because we developed the Nickies process for the M96 engine and Jake rebuilds M96 engines doesn't mean that we created the bore scoring issue and our posting about it will make someone's car spontaneously have a problem. We see customers engines often misdiagnosed as needing lifters, which is a costly error. Educating owners on how to detect the issue and equally, identifying action items on how to lessen the chance of such a problem, is part of what we do. Nothing changes the fact that the Lokasil (only used by Porsche) and Alusil, used by many European auto manufacturers, can suffer from scoring, and do. This is true of any hypereutectic block. The UMW regime (ultra-mild wear) of hypereutectic blocks is well documented and scoring occurs once the exposed silicon matrix distribution is such that there isn't the required oil film and silicon particles to support the loads. Bam - scoring. Porsche is now transitioning, at least in the sports cars, to SUMEbore, over Alusil, which is allows for an aluminum block with a thin wear coating applied to the bore about .005" thick using a iron/ceramic composite that has excellent wear and friction characteristics. The 918 was the first Porsche to get it and other manufacturers have been using it for some time, like Nissan with the GTR and Ford has a variant of the process called PTWA, that is equally reliable. These cylinder coatings are the future, but again cost, is the reason we don't see this technology used industry-wide.

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DANG! I was going to blame both you and Jake for scoring my cylinders by just talking about the issue! Now you've gone and ruined my plan...

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So when it is a lifter and not bore scoring, what are the symptoms with the m96? Is the noise similar to the noise you have when a bore is scored? I rarely see this discussed and would like to know.

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That's a great question. I've never seen one in our shop need lifters. A bad lifter would cause a similar sound and be accompanied likely by a misfire, but without the symptoms of a scored bore. Usually inspection of the spark plugs will find a scored bore has a fouled plug and one tail pipe (the one for bank 2) will be sootier than the other. These are classic signs coupled with increased oil consumption. I would rule out the scored bore first before even considering the lifters.

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You just explained my bore scoring experience w/o the suspicion of a lifter as I had been reading here for years. In addition my #6 plug was so fouled it was throwing a 0306 code with the misfire. BTW I just realized I need to be nicer to you as my block is probably sitting in your facility at this time.

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Your block and intermediate shaft are indeed sitting in queue to be machined :-) Doing a custom 103mm for Jake right now and once that one is all machined and ready for plating, we can move onto yours!

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Thank you! Thank you! You are most wonderful! I am not worthy! I am not worthy! Seriously though I appreciate the things you and Jake freely share on these types of forums. It was this type of information that led me to determine what was ailing my car without jumping through the indi "Sounds like a lifter to me" hoop. As the symptoms progressed I knew exactly what was wrong and how to definitively diagnose it. Saved me a lot of time and wasted money.

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You are most welcome. Some days it doesn't feel like I accomplish anything because most of the time I'm tethered to my desk answering emails or on the forums, but my primary job is to help educate the consumer and also the shops we work with. Believe it or not, we still have shops call that have never done an IMS and some that haven't even worked on an M96 engine at all, so it's easy to see how an engine can get misdiagnosed. Doing this work on the front end makes everything easier. It's not in our interest to scare people out of buying or owning these cars. That just hurts resale values and that's no good for anyone. Ultimately the customer has to understand what they want and why they want it (or need it), otherwise they won't be happy with decision.

My 69 911,, had 200+K on the factory 2.0 engine.. It was a T motor so had iron jugs, according to the machinist that honed them for me they were actually Ductile(Nodular) iron. Probably the reason they lasted so long and wore out 2 sets of pistons and 3 sets of rings.. Nobody told me they were hard ot rebuild so I just did it.. Of course that motor was WAY simpler to assemble than a 996.. basically a bug motor on steroids..

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Since when is identifying an issue and developing a product/technique to address/fix it, "hyping" it? I think there's a problem with your logic. The fact that you have a RUF logo in your signature makes it look like maybe you have an axe to grind... I don't believe I've ever read a post by either LNE or FSI where they either stated or implied that they were "mechanical geniuses" - actually it's quite the contrary, as they usually state that they've gained most of their knowledge of these engines through "in the trenches" R&D via both racing and street applications. It seems to me that they've earned their reputation as some of the best M96 engine builders/developers by perseverance and by doing things right - as opposed to offering cheap alternatives (as so many of their "competitors" try to do). There's certainly nothing wrong with questioning a companies products or claims (it's actually a good thing and keeps the con men to a minimum), but to accuse them of "hyping" a problem like bore scoring or the IMS bearing is a bit of a stretch.

FYI- the last "lifter job" that came into Flat 6, that was really a "lifter job" was in 2009. We've had dozens and dozens of misdiagnosed "lifters" over that period of time. Every now and then we find a lifter issue that's causing a misfire, but these never make noise. That's because the lifter actually seizes in the extended position, and holds the valve open, creating the misfire. This is the opposite phenomenon from that of a "noisy lifter", because excessive lash causes the noise to occur. We do find a lot of cracked intake lifters on the variocam "plus" engines, and sometimes these lifters will fail, but even then, they typically don't make any noise, until one of the pieces they shed gets sucked up by a scavenge pump, which locks it up, and causes collateral damage. That said, at the end of the day it is the goal of a business to capitalize on the issues that are made by the manufacturer. If it wasn't for people like us, having the foresight, and forethought to develop, and prove methods, and components to address the shortcomings, everyone would be stuck paying the factory for another replacement that had the same issues. Maybe then these folks would actually hate the manufacturer, instead of us?

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So is it possible that a collapsed lifter can make a similar noise to bore scoring, without causing a misfire? What type of damage could a non cracked lifter (when valve lash is occurring) eventually do in these engines? Also, is it possible when oil pressure goes up that a collapsed lifter could begin working again?

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You mean, as opposed to the mech geniuses that gave us the faulty IM$ bearing fiasco, and has been basically resolved by LN/Raby? Some engineers make mistakes(this one I believe was borne out of a cost situation), then other engineers come along and fix them. Porsche tried to fix it by increasing the size of the bearing. Didn't help. Critics are usually short on alternatives, specifics, and development. But long on how others aren't doing it right. One of the sad parts of the internet is that it gives platform to everyone without any means/value testing. sigh,,,

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Anything can happen. Lifters making noise is a very rare instance with these engines in reality. Even a cracked lifter won�t make any noise. That said, as soon as someone hears a noise that �sounds like a lifter� they should immediately follow my part 4 video found in the YouTube series �a focus on bore scoring� and properly diagnose the sound. I show you exactly how to do this without question for less than 100 bucks, at home. The first concern should be that be that you do have bore scoring and that the noise is not a lifter. The engine is guilty until proven innocent with a comprehensive, and proper diagnostic session. If the traits of bore scoring are not found with this full process, then, and only then does one assume that they have a �noisy lifter�. In almost every case people do the opposite and waste hundreds or thousands of dollars treating a symptom that was misdiagnosed.

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Thanks Jake. I've watched all of your videos and really appreciate them. There's not much info on when it is a lifter and not bore scoring, so just wanted to get some more details.

Do any of the Flat-4 Subaru engines suffer from bore scoring? Mike

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Don't know about scoring but the kid's WRX ate a rod bearing at less than 20k miles and he never beat it. The sound was clearly a rod knock. It was a tsunami era car which might have created some quality issues as it pretty much messed up supply chains.

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I owned a new '05 WRX STi for a few years. I never heard of bore scoring during my ownership. I drove my STi pretty hard with lots and lots of track miles and never had an issue, not one. I did have a friend with a '02 WRX that had the same issue as your son. Mike

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Interesting thing is they "rebuilt" his engine with a factory short block, all new oil piping, oil cooler, turbo, and anything that saw oil(heads were cleaned and flushed). All under warrantee. When done he asked what his cost would have been if no warrantee. Less than $6k. So there are some ownership advantages for some lesser cars.

^^^^ This is true. Mike

Gentlemen - This is a worthwhile and interesting discussion. Let's not allow such a thread to degenerate into personal attacks. Please keep the conversation civil and respectful.

I've seen the bores give up in STI's used for rally.. Remember the stock STI has a relatively conservative redline, compared to a rally car,, so the 8K+ engine runs could be a factor. Another interesting question though,, AFTER a bore scoring event how many folks send their injectors off for testing? Fueling is the source of bore issues in most other engines I've experienced it in.. Rotax engines are very similar in power band and use to the 996 vintage engines,, and they do stick pistons even in their 4 strokes when run hard,, Aprilia,, Yamaha,, go cart motors all so it..

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Leaky injectors have been identified as a factor in scoring for the 996.

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Yes, fuel enrichment is certainly the leading contributor to these issues.