cylinder scoring - can it be solved with a block heater?

As titled.... just wondering if anyone is doing this... as I researched that most engine failed in scoring is due to cold weather cold starts.... would a block heater help to prevent this? thinking if i can warm up the block before i start the car, it shouldn't have the issue, right??

I would think anything that gets the engine and/or fluids closer to operating temp would be better for a cold start.

Cold starts are certainly a common correlation, but it's not 100% and there doesn't seem to be consensus about a specific temperature where the risk goes up significantly. That said, I can't see that it would hurt though, just don't know how much it will help (mainly depends on how warm it keeps the block/oil).

IMO and really just IMO These cars run really rich when starting to (learned on here) heat up the cats. Combine really rich starts with not bringing the engine up to temp as in short drives will lead to carbon junk building up in the chamber. Enough of that junk builds up and you're going to start seeing either detotnation due to that junk heating up and igniting the mixture to then that junk getting loose and scratching things up. In order to score, you need to have something like that to scratch, or else it's mostly smooth on smooth. Another theory would be, along those lines, that when cold fast acceleration would go above and beyond what the oil can handle, and now you have piston on cylinder, which could lead to friction and eventual scoring. Or a combo of the above. IMO, and again IMO, these engines need to be warmed up a little before taking off as per "keeping it under 3k" until the heat builds up, or else you run the risk of the oil breaking down, and these engines need to be driven up to temp often enough to keep junk from building up. It would help cold starting though... So in a round about way, yes, the block heater would help, but you really need to warm them up and drive them. Again IMO and I could very well be wrong, but I'm able to sleep at night.

Loose carbon build up will not scratch the bores. They are too soft for this. An oil sump heater pad would be ideal for this. Someone needs to make an adapter plate that goes into the webbing of the sump pan and create a flat surface on the other side to allow the heater pad to properly bond (glued) to it. I had this on my old TDI and (the oil pan was smooth so it was bonded directly to it) and it warmed up the oil enough that the engine easily started even in -32C. After a couple hours of plugging it in, the oil pan next to the heating pad was too warm to touch it for more than a couple of seconds.

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Thanks! I stand corrected.

If your really worried, use climate control, block heater, and automatic accusump accumulator to pressure up before start and circulate after shutdown. Prelube is great from what I hear.

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Lot of owners cold start the engine in their cars with no problems. And bore scoring is as common as dirt in the UK it seems and it doesn't get real cold there. My point is I'm not sure a block heater would help all that much. There are different kinds of heaters. The heater pad style -- my own terminology -- just applies heat to a local area of the sump. The oil is warm while the amount of warmth the rest of engine has is anyone's guess. A car inside an unheated garage is going to be one thing while one parked outside is going to be something else. Then if the car is driven someplace where the heater can't be plugged in there's that too. Even in the midwest winter my Boxster would get darn cold, near ambient, just being parked out side at the office for 8+ hours. Another style is one in which the coolant is heated and circulated by a pump. The benefit of this style is the engine gets heat to all regions that the coolant gets to but of course the oil in the sump may not be as warm as it would be with the heating pad heater attached to the oil sump plate. In both cases, the problem is still one of possibly inadequate lubrication at cold start. Inadequate possibly due to the oil being cold or just past its change by date given the climatic conditions, vehicle usage. I'm thinking contaminated oil of course. Some bore scoring arises at least in a few cases from the wrong oil being used for the ambient temperature. For temps -25C (-17F IIRC) and lower Porsche states to use 0w-40. I'd be inclined to use 0w-40 starting around 0F. No science to offer just a feeling. Another contributor to this bore scoring could be the driver failing to adhere to the keep RPMs under 4K until warmed up guideline. Now in defense of the driver in some cases it is hard to next to impossible to know when the engine is warmed up, I mean fully warmed up. It is one thing to have the coolant temperature gage needle on the "180" hash mark. It is another thing for the coolant to be at that temperature or above it and for the considerable volume of oil to be up to that tempeature as well. Recently I have been driving a new Cayenne Diesel. This has among other things a digital coolant temp display and a digital oil temp display. Coolant temp gets to 200F PDQ even though of course I'm taking it easy. And we are not talking about north of the arctic circle temperatures but maybe 28F is as cold as it has been where I live during my time with this Cayenne. But the oil temperature takes many more miles of driving before it is up to 200F. Roughly coolant temp reaches 200F in just a mile or two down the highway while 200F oil temperature takes another 10+ miles of driving. My point is if someone without the benefit of an oil temperature gage/display relied solely upon the coolant tempeature gage/display and pushed the engine RPMs up over 4K he could do so with the oil at least still rather cold. And it can be worse. Oil doesn't flow heat very well. I have watched the oil in the hydraulic oil tank of large (very large) machine tools and the oil return line puts warmed up oil in the tank and the pump of course pulls oil out of the tank. I can see the oil as it is being pulled in by the pump form a small depression at the pump intake and the warmer oil from the return line flow across the colder oil and downhill and right back to the pump pick up. But if the operator say does something to increase the oil requirement outlying oil, still very cold oil, then gets ingested by the pump. The same or nearly the same can happen with these engines. Just a portion of the oil is being circulated through the engine and then the driver "steps on the gas" and of course the oil budget goes way up and the outlying colder oil then gets pulled into the pump. Now the engine has "cold" oil being routed through its oil passages and this cold oil may not flow as well at higher RPMs. Bore scoring could be the result. I am not arguing against a block heater. Enough car makers offer this option for cold climate usage. If I lived where it was colder I might have one but my problem is what to do about the car once it is away from its garage and the block heater? So any solution that uses a block heater still has to rely upon good engine oil hygiene -- the right viscosity grade for the temperatures encountered and oil that is not past its change by date or mileage - and a driver sympathetic to the plight of the engine given the cold temperature and one who is religious in his allowing the engine plenty of time to get warm. And in the winter it may never get real warm. I recall when I was back in the mid-west in Dec. 2014 and temps were in the single digits and even though I was careful with my Turbo -- which had 5w-50 oil in the engine -- to drive it gently until the coolant temp gage needle had been on the "180" hash mark for a while and the hot idle oil pressure was where it usually was when the engine was when driven in warmer weather I still avoided high RPMs. I don't think I took engine RPMs much over 4K the whole time I was back there. This was my concession to a large (and expensive!) engine with a lot of coolant and oil volume being used in extremely cold weather.

Just park your car in your living room....assuming your heater and/or fireplace is on...

Heat tape?

200 watt shop light.

Hot oil or cold oil, I thought that synthetic oil was supposed to remedy viscosity change with temperature? I don't understand how heating synthetic oil would help lubricate a cold engine.

The cold is just one of the variables that play into this. Actual running clearances vary from engine to engine, and the quality of the localism cylinders, and the protective piston skirt coating does, too. The adhesion of this coating to the pistons is a key player in the cylinder failure, as it often occurs first, before the cylinder fails. No single thing is going to help this scenario. I have tested a block heater kit that we made up, but no one would buy it, and on top of that, when you truly understand the dynamics behind this failure, you realize that engines that are going to die from this are already injured as we talk about this as they have already had the perfect storm set up, and it just has to play out. This is a failure where luck is the major variable. The biggest mistake people make is firing the car up in winter and allowing it to warm the cabin before they get in, or allowing too much engine warm up time at idle. This keeps the cold start, and just started enrichment higher and for a longer amount of time. All the while the injectors are dumping excess fuel to help light the catalytic converters off, with help of secondary air injection. This fuel is pure solvent, washing down the oil thats the lifeblood of the cylinders and pistons. Load= Heat. Get in, strap in, fire up and drive away lightly and the engine will not see nearly as much over- enrichment.

Whilst on the topic, what does the secondary air pump actually do? I know it's to reduce emissions. We don't have them here in Australia.

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Great info! I have no experience with it (in other words, my opinion means nothing), but it seems logical that pressurized prelube would help more than a block heater.

I don't think it would help much on cylinder scoring if the damage is done but it would sure make life easier on the crank and rod bearings, valve-train, etc.

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No amount of pressurized oil will help if the clearance between the piston and the cylinder is not sufficient due to cold temperatures. A bock/oil pan heater will help to increase these clearances so any amount of heat is better than none, if clearance is the problem. It's basically a big bad drier (air pump) that pumps air into the exhaust manifolds when the engine is cold to help get the catalytics working sooner.

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When I'm starting a car in very cold temps (freezing or below) I let it idle for a few seconds (10 seconds or so) and then drive gently off. I also keep the heater OFF. I know that sounds crazy to some people but you want the engine to get to temp as quickly as possible and driving away with the heater off helps to do it. I read that years ago in a book about making your car far outlive the average vehicle. I realize a lot of people will not get into a car unless it's warm and toasty on a cold morning but that's how I've been driving my (water cooled) cars for years.

The heater core draws heat from the coolant; the thermostat doesn't allow circulation of coolant until the engine is hot. I'm curious (genuinely, not being argumentative at all) how not running the heat makes the engine warm up faster. I'd think that the air-cooled cars would benefit more from keeping the heater off than the water-cooled models...

Idea being the cold air being blown across the heater core reduces the coolant temperature, causing it to take longer for the coolant temperature to rise and the thermostat to open. Thermostat (as I understand it) prevents flow to the radiators, but the coolant is still circulating through the block as the water pump is still turning. Aircooled cars rely on exhaust heat to generate cabin heat, so no difference there.

That's why my suggestion to use all three. Climate control, block heater, and pre-lube. The only problem I can see is this would not help if the climate control/block heater options are not available every place you park the car long enough for it to get down to cold ambient temperatures. I would imagine it would not be an option at every place one travels during the winter months in cold climates. Hence, the best practice is to stick with climate control storage until warmer outside temps are back.

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What Quadcammer said. When you turn your heat on you're opening up the valves that circulate a (now) larger volume of water through the system - taking longer for it to all warm up. On a cold morning in my daily (BMW 325i), I can drive off and leave the heater off, or, turn it on and watch how fast the water temp (idiot gauge) reaches its normal range. With the heater off the needle gets there quicker. I can also drive off with the heater off , watch the temp needle rise, then turn on the heat and watch the temp needle pause or even start to reverse direction momentarily and then start to rise again. Not sure if a 996 temp gauge would behave the same way. Starting up and letting the car idle for five minutes with the heater on really takes a while for the engine to warm up. Like Jake says - that's the worst for numerous reasons. Now, if I lived in Wisconsin, parked outside in winter, I might have the heat on but still drive off without a long warm-up. As a side note, my 325i has 200,000 miles on it and uses about 10 ounces or so of oil between 6500 mile changes (if there is any relevance there...).

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Thanks for the great input Jake. How much engine warm up time is too much? I typically start my car and wait till the high speed idle drops down (maybe a minute or two...I store in winter months, so don't deal with extreme cold). Is this too long?

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Well, BEST practice would be to move to a place where "winter" requires quotes because it's otherwise indistinguishable from the other seasons...

Can someone who believes cold temps/starts contribute to this please define what these cold temps are? Also, please provide some empirical data to back up the theory. Cheers

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I see most of the cars come from the midwest US, and all across Canada. We don't really see the issues from south of Tennessee/ Arkansas, unless a hard winter was experienced, like we've had the past two years. During those two years I had failures from as far south as Alabama and northern Texas. We'd never had that before. The Canadian C4 cars are the worst with the failures. Why? Because they are effective in snow. Monday someone called and I answered the phone. He says "I am in Toronto, and I have a 2005 C4 997" I stopped him right there and said "...and your engine started making a ticking sound, that sounded like a lifter, and you were told that it was. It got a little louder, then the engine started to consume more oil than normal.... then it started to throw misfire codes, and now one of the tailpipes is darker than the other, and the ticking noise is even louder than ever". The phone went silent. I had to ask if he was still there. He then said "How in the world did you explain my issue to me verbatim, has my son already called you this morning?". My reply was "Sir, I hear this every week, sometimes 2-3 times per week, if I couldn't take the words out of your mouth, you'd never believe that I actually know what your issues are from over 1,000 miles away." The exact temperature this becomes an issue is not known, and won't be, because of the variables that I mentioned earlier, which effect the dynamics of the failure and makes each a case by case basis. Sure, I could lie to you, and say that one issue is the root of all this evil, but thats not how I am wired. That said, winter blend fuels, especially in the mid- west are another contributing factor, and one reason why I see more vehicles from there, than we do from the NE, when there are more of these vehicles in the NE. As far as sharing empirical data, well, I won't do that. Why? Because its just an argument point here online, and on top of that, the data costs money to collect, and I'm not running a charitable organization here. Development is what I do, its my business, and business is good. You can learn all you need to know with an M96 block & piston, a freezer, a bore gauge, and a micrometer. You just have to understand what the engine, and those data points are telling you.

Interesting, Curious because we have 3 motors right now with scored cylinders. Spent most of their lives in the western/southwest states, so when I hear cold weather being the issue it begs the question... Not sure if you will be here anytime soon providing a WorldPac course (I didn't see any listed this year), but I will enroll and we can discuss our findings. But, I will shoot you an email offline or give you a ring and we can share our thoughts. Cheers

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Oh brother, there is so much BS in your posts regarding this issue(not to mention the other B.S. you continually post) that I don't even know where to start. However, there is one thing I do know and that is you get to retain the doom and gloom/fear monger King award. Yes, not even the troll KK can take this honor from you, IMHO, as he does not earn money from posting his nonsensical scare tactics -- but you do.

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Do a carfax on those vehicles and see where they have been earlier in their lives. When I get a phone call from Florida with this set of symptoms, the vehicle typically has spent a lot of time in a colder climate, and traveled south with it's migratory owner, or its prior owner. That said, the things I mentioned earlier that go along with this failure, as contributing factors can add up to the problem as well, without the cold factor. What proves that is how many scored cylinders occur in the UK (tons) where the winters are very mild compared to here in the USA. These failures also occur with Cayenne engines, and the symptoms, as well as the worn components look almost exactly the same. This is odd, because the cayenne blocks are alusil, not lokasil, like the M96/M97. The cold weather operation factor is just a catalyst for this failure. It is not THE root issue, but it forces the root issue to create symptoms faster. BTW- Tony Callas and I quit instructing classes for Worldpac early last year. We now instruct for www.theknowledgegruppe.com in cooperation with SSF Auto Parts, and have online, and hands- on classes listed for 2016 on the site now. Dream Carerra, How many M96 engines have you disassembled with scored cylinders? How many M96 components have you developed? Where's your data?

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How about with your detailed information about how anything Jake has said is "BS"? How about your resume to show how you have enough experience and knowledge to be considered an authority on the subject? You sir are the one being a troll and detriment to the thread/forum by posting such useless commentary in an attempt to derail the thread.

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Typical response from you...Where is my data??? Where is your data??? There have been almost 200,000 M96 engined cars built by Porsche, many of which have lived and been extensively used in frigid climates with no ill effects. Seriously, if what you profess is true then we would be seeing mass scoring issues with this engine and that is simply not the case. Post your "freezer" data here. Certainly there are others on here with the same parts that can confirm or deny your figures...after all this isn't rocket science, even though in your own mind you think you are some mechanical genius. Such a huge number of these cars are regularly driven in freezing temps that if temp was the sole reason for scoring then there would be an overwhelming number of cars exhibiting scoring. Simple common sense proves you are full of BS...would you really have us believe the top German auto manufacturer built an auto, their flagship model no less, that could not be used in cold weather conditions.

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You haven't answered my questions, sir. Further, you have not read/ comprehended my posts in this thread, and others on this topic. Cold is the catalyst, as I have stated over and over. The other contributing factors can combine to create the failure without cold operation being in the picture, if given enough time to play out. Cold operation helps to complete the perfect storm earlier. That's all, and that's why I posted that a block heater won't help. At the end of the day the biggest factors are cylinder wear surface quality, and the running clearances between the cylinder, and piston.

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Where are you getting this data? Hartech? The same Hartech that basically said IM$B failure is an overblown myth...the same overblown myth that you used to build your biz?

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And he is not going to nor read/comprehend what you have written (e.g. you clearly stated that you believe cold is a contributing factor an not the source of the problem). Please turn a new leaf this year and just ignore trolls like this

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...and you haven't answered mine. I am not attempting to sell anything here. I don't need to supply confirming data...you on the other hand do if you want to receive credibility.

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Nope, from our UK customers, and those who inquire with us from the UK and we enter into the failure logs here. You still have not answered my questions, sir. I have answered yours.

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HAHA, I am a longtime 996 owner/user just like you. I am in no way a troll. Contributing factor? JR clearly stated that the "freezer" data would prove his point. This to me sounds like a statement of fact and not a "contributing factor." Well then, let's see the freezer data.

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You answered my question? You provided your proving "freezer" data?

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You entered UK "inquiries" into your failure log? Sounds quite scientific. Interesting...

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lol, receive credibility? From everything I've seen, he has a lot more credibility than Porsche does when it comes to these motors. As gruff as he can sometimes be, he seems to be the go-to person for m96 motors. And you...are not. You're some guy who owns the car (hello vested interest) that seems to think every problem these cars have is "fear mongering" because you personally haven't experienced it. Yeah, porsche built a lot of these cars, and not all of them, or even the majority of them have issues. That doesn't mean that the problems presented by Jake are non existent. YOU, sir, are the one who has no credibility, no experience, no knowledge, and no basis to call BS on anyone, much less Jake.

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You are being the definition of a troll in this thread. Reading != Comprehending obviously. Cold is a contributing factor. Cold makes metal contract. Cold makes oil flow less efficiently. Those things make the other issues (tolerances, material issues, etc..) that Jake has described more apparent. Cold doesn't create the issue, but it certainly helps it.

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You are still an idiot I see who continues to suffer from keyboard tourettes syndrome. As I said to you before, if I need fashion advice I'll send you a PM...

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The troll in this thread is the resident fear mongering vendor who pulls this "freezing" line every winter to scare the crap out of the owners on this site during the winter months. Let me guess, I'll bet JR's engines don't suffer from scoring. BTW, still waiting for JRs data that proves his cold weather connection...

The freezer data only illustrates the behavior of the components during thermal changes, and in a different environment than most things would be precisely measured. Then grab the piston and hold it in your hands for just 60 seconds and re- measure it. compare what happens before and after with the piston sizing and that gives an indication of how fast the piston responds to combustion chamber temps that elevate and soak into the Pistons on the very first power stroke of the engine. This is just a simple way that anyone with a few tools can do. When I did this in a Cayenne engine class, every jaw in the room dropped.

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Thanks for the info, Jake. Ignore the trolls. So, do UK cars/owners do a lot more idling and pre-driving-warm ups than US owners? Even worse fuel quality??

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The fuel is another factor that's very suspect. I say this because here in the states these issues just showed up all of a sudden with M96/97 and Cayenne engines as well as AMG engines, which we have developed as well. Just like the IMSB failure, cylinder failure has no single root cause, it's the recipe of contributions made from the other variables that lead to it.

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Well which is it -- the freezer data will tell you "all you need to know" or that it "only illustrates the behavior...blah,blah,blah" ? Basically, you will post anything here because 1.) you know it will be eaten up by the mindless posters here without question(i.e. they never hold you to posting concrete data), and 2.) anything that bashes the M96 will be a benefit to your biz.

The truth is a bitter pill to swallow for some. Certainly there are thousands of 996/997s out there that are unaffected. There also happens to be thousands of 996/997s that are second or third cars and are tucked away in the garage for the winter, only to come out on sunny days. And the UK and Southwest cars that are driven year around but are still plagued. As has been stated, it sounds like a combination of factors that come into play that may or may not affect one's car. I can't imagine Jake trying to drum up business - that's silly. The guy sounds overworked and in need of a vacation. If I had a year long back log for engine rebuilds I'd disappear from the forums - he doesn't need to be here for his business . That is clearly evident. But I think the majority of forum members appreciate his insight. I'd like to purchase a 997 someday and find his posts invaluable . Thanks for your posts, Jake!

What a slam to the membership of this forum. In my last class almost 1/2 the enthusiasts in attendance came from this forum. They were some of the brightest, and intense attendees I have ever experienced in a class. That really means something when you factor in that we've had over 1450 people attend classes since 2007. These people were not "mindless", in fact they outperformed most technicians that attend these classes! Its easy to sit here and say that I am posting for business purposes, but I'm a 996 owner too ()got another one last month), and my wife still holds 4 standing Land Speed Records in a 996. I have personally owned and registered more than twenty 996s over the years. Its plain to see that you don't like me, and I am okay with that. I learned a long time ago, that if you aren't pissing people off in today's world, that you really aren't getting anywhere. Its all Unicorns and Rainbows, isn't it? When I take a vacation, I want to be back at the shop; because this isn't "work" and it never has been.. Well, at least till keyboard warriors make it "work" here on the forums. I am able to do what I do, because I love it. So what if I was here for business? You don't see me making ad posts like other vendors, even though I could, given my monetary support for Rennlist. We don't have to advertise, because the work finds us. This mostly comes from shops that refer work to us that they know is either over their head, or they don't want to attempt. These shops find out about us through classes, or through their parts wholesalers, all of which deal with us and carry the parts that we develop. Very, very, very few are people from these forums, so thats why I don't make those ad posts, because they proved to do us no good. Our purchaser is seldom a forum member, because many people here are DIY. We offer nothing for DIY, and don't sell parts- just engines. There's always "that 10%". The people who have to constantly stir up drama on the forums. Funny thing is, they always tend to do it only during business hours, probably while they are being paid to do something else. Its a good thing that they don't have me for a boss :-)

[QUOTE=DreamCarrera;12905712]The troll in this thread is the resident fear mongering vendor who pulls this "freezing" line every winter to scare the crap out of the owners on this site during the winter months. Let me guess, I'll bet JR's engines don't suffer from scoring. BTW, still waiting for JRs data that proves his cold weather connection...[/QUOT I do not see any comments here as fear mongering as know one has suggested proactively replacing the cylinders as a fix. The fact is that some engines will score the cylinders and cold weather climates are a contributing factor. In my previous life as a line mechanic with ford we replaced dozens of Taurus motors for this exact same problem. Unlike Porsche, Ford gave us detailed information on what was causing the issue, excessive expansion of the # 3 and 6 piston skirt due to the rate of expansion of the block in that area. The fix was a redesigned piston with revised skirt webbing. This problem only effected cars operated in cold climates. And no, the cylinders being used by Flat 6 will not have this problem. If you actually compare the stock liners to the replacements it is obvious.

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Outstanding! I can see the Little Jake Raby kids on the playground with the school bully: School Bully : " Well, my mom is prettier than your mom !" Little Jake Raby : " Well my mom still holds 4 land speed records in a Porsche !" [Little Raby drops microphone on ground, and walks away] [fade to black]

Perfect example! That happened with the early SHO engines, for sure. I studied those failures and learned that the "cam" of the skirt (the point where the skirt is at it's largest diameter) was an alteration that the factory endeavor used to solve the issue. This is something that I also alter during reconstruction, moving the "cam" up the skirt a bit makes a huge difference in skirt wear. I have a daughter, she is 4... She'll be in a Jr. Dragster as soon as they'll let her :-) Mom is a great influence on her love with cars. Her favorite toy when she was 2 years old was an IMS Solution prototype.

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You may not make any/much money money from the DIY crowd, but I think the majority of us would agree that you offer a considerable amount of details and information that makes the DIY life easier.

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What "details and info"...I never see JR post any real details, its always conjecture and fear mongering. I'm still waiting for JR to post the details that he has that are relevant to this topic.

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Still no data? I'll stop now because I can see that you are on the verge of a whining and crying fit where you'll feel compelled to post a "should I stay or should I go now thread." I'll get back to work now and stop wasting my boss's/company's money...

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As a father to two daughters, and an employer to many females in my company, I love it when women break stereotypes. I'm all about girl-power.

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Outstanding.

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As I am familiar with the problems on the SHO motors, This problem was present on the plain vanilla 3.0 Vulcan motors. We were replacing 3-4 engines per week at our Dealership. Getting back to the M96, especially the 3.4's with their weak design its surprising that the failer rate is so low. The dimensions of the cylinders and pistons have got to be a moving target.

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This is why all the manufacturers in the 90s that went to an "open deck" cylinder design, have now closed the deck back up again. This includes Subaru, that fought horrendous cylinder head gasket issues due to this with their EJ25 engines. Porsche went to a closed deck with the 9a1, and all Cayenne engines are closed deck. The design of the Mezger GT3 and TT engines is also one of a closed deck design, with their water jacket characteristics. My largest bore engines (102.7mm) have also gone to a proprietary closed deck arrangement, as my development proved that at such a large bore size the cylinders weren't staying as straight I'd like. Doing this opened the doors for even more enhancements, that I am still learning about. The resource materials I have published with the Knowledge Gruppe, and my assembly guide for the M96 will continue to help with this. I have been contacted to develop a new DIY specific program for another company. This will be what looks like a one stop shop for all things associated with M96/ M97 engines, right down to hardware kits, and internal engine components that are designed to enable the DIY'r. I have not decided whether I want to have any association with it, yet, though. The last thing I need is someone buying a hardware kit, and blaming me when one bolt isn't the right length. I've been through that in the aircooled days, and I basically gave my parts business to LN so I didn't have to field those, or even deal with it. I do believe that the 996 is the DIY dream right now, and it will remain that way. There is a real need for true step by step guides, compatible parts lists/ parts, and even tools for these engines. We know exactly what people need, and I am sure thats why I am the guy who got the phone call to develop it all... I have a little too much to do with the GT4 engine development, and waiting on the first new turbo 4 cylinder to arrive, so I can get started on it!

I agree, there is nothing mystical about assembling the engine. But the DIY'r has to realize that the cylinders and pistons cannot be reused, and sleaving with Iron is not an option. Once the weak parts are replaced I kind of like the design. Off topic, have you found any way to fit a twin scavenge pump on the drivers side of a 996.

I think that those who attended my enthusiast Rebuild School last month wouldn't agree with that statement after seeing how many things we showed them, that generally didn't come naturally to the engine assembly. No, room doesn't exist there for them, unless the suspension upright is chopped on. They are totally, and completely un- necessary, anyway.

Nothing is mystical after you learned the tricks I'm very tempted to try the piston and block in the freezer test but I don't have a freezer in my garage. I'm a "trust but verify' kind of guy. I bought a roller and disassembled the engine and measured a few things just to satisfy my own curiosity https://rennlist.com/forums/996-foru...l#post12583536 Found exactly what Jake has been saying all along. You don't really need to build 100's of engines to understand it. One disassmbly and study of the internal structure, oil paths, coolant path are good enough. That's before I attended Jake's engine rebuild class. Once you've seen (and measured) the internals and attended Jake's class, you will tend to agree with Jake and will see his posts differently.

So, after all of that, let's get back to the original question. Understanding that there are multiple factors causing this issue, is it reasonable to say that eliminating one of them, by using a block heater, may help?

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It could, IF you could warm enough of the block uniformly. The best block heater would run an electric pump to transfer the coolant through all of the coolant passages evenly, warming the entire engine. The issue with that, is as the coolant passes through the radiators, you then cool the temperatures down significantly just from heat exchange with the environment. I guess an electric blanket could be employed over them, though!

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Jake, do you have any thoughts on additives that might help with the contribution winter blend fuels add to this issue? It occurred to me that those in the mid-west might like to know this. I would be surprised if the fuels we get here in the SE are much different in winter, but I could be wrong!

1. Exactly. Jakes advice here is free. Enjoy it or discard it, your choice. 2. He is a site SPONSOR and is certainly allowed to advertise his services anytime he wants. 3. These harsh disrespectful comments are strange even coming from DC. What the hell happened to him in the new year?

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I have no idea about an additive that could balance this. Between all my experience with oils, and fuels, the only time to use an additive, is never... Its possible for an additive to imbalance what it is being added to, based upon the composition of the product. This mode of failure is the one where luck is either on your side, or it isn't.

WOW! Not sure what just happened there! Jake: Thanks for your info shared freely and congrats on maintaining proper behavior. Not sure I would have! My guess is some just want to stir the pot or need "proof" to accept anything. "Trolls", I guess or perhaps just sadly misguided/damaged.

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Its ok, its always this way here. Its kind of a game for me to guess which of the members will take issue with what I say, what they will say, and who is going to call me a fear monger first.

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Every now and then some really useful data might pop up but you have to know what you are reading to pick this up. Majority of the info is " partial information" that's enough to gain interest in the average reader to act as an advertisement for Jake. Vast majority of Jake's post has some burried advertisement in it. This is not what the gearhead/DIY community is all about but then again we are not here to make money either so the agenda is different. How when he is accused of not sharing info, fairly shortly after this, all of a sudden some useful stuff will surface from him but this is a rare occurrence. I fully understand why his data is proprietary but constantly reminding those that ask about it is BS. If you bring up or join into a topic that you have some real data and then saying "sorry it's proprietary" is a really low move. It's nothing more than advertisement. Over time DIYers that work on these engines will share data and slowly vital data and info will become available to everyone but for that, the 996 owner demographics need to change. And it will, it already started a few years ago. In the next 5, most owners will be like those on the 928 or the 944 forum where you can find information on how to fix ANYTHING on those cars and people that are genuinely willing to help you with no hidden agendas. Couple others and myself are the few that are willing to share our experiences during our engine projects. In time there will be more like us.

I don't really have much useful to contribute. But I'll post a few pictures... I drive my 996 year round. While it parks in a garage at home, it's out in the elements at the train station when I'm at work. I had a ticking sound, coming from the top of the engine - like a lifter...

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Classic symptom and classic mid- bore wear. That's textbook. But, it never happened, cold weather can't hurt the engine, and now you are also a fear monger. Lol! Based on what some of you guys claim about my advertising in posts, I think I may have missed my true calling in life, by not founding a marketing company. Damn, I must be good!

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Thanks!

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I hope it comes to that, and maybe it will, but I think the owner demo for the 996 is a little different than it would be for the old air cooled cars or the 944/928. We're generally more likely to bring it to a shop for work than try to do it ourselves, and the cost of doing it ourselves isn't "cheap" anyway. I think we will start to see more DIY when cylinders and other parts come down in price to where a normal person may want to take a shot at it, or to where spare engine prices go down to where we're not tinkering around with a $10-15k engine.

That day won't come with quality items, that are truly developed, and proven. Each year prices go UP, not down with these engines, as the cost of labor, and the cost of business creep up due to inflation. The ONLY chance that the truly developed offerings have in becoming less costly, is if the volume goes up tremendously, and we can make larger runs of parts, which can be produced cheaper per unit. The cheap, less than proven, half assed engines, and components may drop in price, but that'll only be due to the providers doing everything they can to stay alive. I sat back and watched this exact same thing happen with aircooled engines, and cars. The REAL options have a big price tag, but offer value that the people who want to create some start- up company to compete with can't see, or appreciate. They start slashing prices, then they realize the amount of work that goes into it, then they have to cut quality to make a little more money, but by then they have so many engines that have failed that it takes out their reputation. Its a catch 22 then, because even if they wanted to stand behind the engines, they are so broke that they can't afford to. The most expensive Porsche engine you'll ever own, is the cheapest one that you can buy. No one will appreciate this until they experience it. Lots of people have these days, almost 1/2 of our work today comes from the failed attempts of others, thats way different than it was in the early days, when no one else would dare touch one of these engines. As far as the car getting older, and things becoming cheaper, well, I won't touch an aircooled Porsche flat 6 engine for less than 25K, which is more expensive than my most expensive 4.0L M96/ M97 street engine, making 420HP. Most of the aircooled engines run 30-35K, and these prices have been the same since 1999. Hell, I charge the same to build a 4 cylinder aircooled performance 914 engine as I charge for an M96/ M97, and have a line out the door for them. Here's what I am building today... 4.1L 964 based beast for a Beck 904 GTS __________________

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same thing here. Canadian car that spent most of its life in Toronto. 20150309_223405_zpsu8kyrood.jpg I'm fixing it myself. costs so far are in the 12k CDN range. probably spend another $5k Canadian by the time I am done. this includes the tools, jake's course and book. listen to Jake. he isn't fear mongering anyone, he's speaking the truth

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Wow, almost 170k miles! I think you got your money's worth It's amazing how clean your piston top is. No carbon deposit!

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Even at $15k, I think it's a great value for a 4.0L! Interesting the middle cylinder is not scored or was it scored on the other side hidden from the camera?

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Excess oil consumption can blast the piston top clean.. While we are sharing photos, I had these on my phone and handy enough to post.

just 4 & 6 were scored.

Jake, thanks for the photos and explanation. That's not very intuitive as I would have thought excessive oil is burnt inside the combustion chamber and create more carbon. Good to learn new things. Since the middle cylinder should be the last one to heat up and expand, shouldn't we expect it to score more easily (by the rapid expansion of piston skirt at cold start) than the other two? Yet in AWDGuy's case, the middle cylinder is unharmed. Maybe the tapering/ovaling of the middle cylinder actually helped a bit in this case?

This might be a weird question -- but why do bore scored engines make a noise that sounds like lifter tick?

My understanding is the excessive piston/cylinder wall clearance allows the piston to rock causing the piston top to hit the head. In some cases, you see a shiny spot on the piston top edge where it's hitting the head.

oh yeah....that knocking was loud.

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Because the wear starts at the bottom of the bore, where the piston direction changeover occurs. When the issue starts the excess clearance between the cylinder and piston at BDC creates the tick. The sound has the exact same rythym and volume as a bad lifter. As far as the center cylinder not having the issue, that's just proof that cylinder quality matters, as well as piston skirt coating quality. Lots of these failures start off with failure of the adhesion of the piston skirt wear surface (coating). Normal wear can help avoid this, as one of the biggest issue is having too tight of cylinder clearance for cold weather contractions. The wear can increase it just enough that failure does not happen. I see most cylinder failures at less than 80k miles.

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Yes, I have absolutely gotten my money's worth out of this car. But, now, a replacement engine is probably more than the value of the car... Even thought the top of the piston was clean, there was a lot of carbon on the valves - so much, in fact, that there was hardly any compression in that cylinder. Jake, I'm still running my engine - what do you think the final failure will be? Cracked cylinder wall and coolant/oil mix? Metal in the oil causing a bearing failure?

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Please don't. Please stop driving it to death. Core components are getting so hard to find that their value has tripled in some cases. Continuing to drive it will just make more things fail from collateral damage. The microscopic debris that's suspended in your oil is traveling to every part of the engine and delivering wear with it. It will take out everything that's internally lubed, if it's driven long enough. Engine costing more than the car? That's every Porsche I have ever worked with that was more than 10 years old, until it becomes a classic. This is nothing new with the marque. If you love the car, the value from reconstruction of the engine means you can go for many more years together. 75% of the cars we build engines for "are not worth" as much as the engine costs. That only stops the guy that doesn't love and appreciate the car enough...

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My understanding is the scoring only occurs on the bottom (relational to the position of the motor in the car, not piston movement) side of the cylinder. Is that correct or no?

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zTop and bottom.. Where the piston skirts travel. The skirt is the largest portion of the piston, and has the tightest running clearance. The only time it will score on the sides, is when the piston separates from failure.

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Damn that is gona be nice, I've always wanted to do a Beck 904, with that engine is will be a load of fun but probably a bit overkill for it.

Overkill doesn't exist.

Just going back to the accusump, where would be the best place to attach one to the engine, possibly remove the plug on valve cover to oil gallery on 1-3 and install pipe fitting there so accusump would pressurise from this point, I like the idea of pre pressurising oil system and the oil starvation protection it gives, not sure how much it would help with bore scoring though!

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Jumper, your engine still running?? That's some crazy knocking! https://rennlist.com/forums/996-foru...linders-5.html

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Yes, still does that when cold at low rpm until driven hard then it quiets down. History of it 2008 76k km started ticking and noticed it burning more oil then normal 2010 106k km the tick was louder and burning more oil, used to go through at least 1 liter a track weekend, started blue smoke under cold startup but fine after it's warmed up. 2012 120k km I had it looked at, #4 scored and piston crown touching head, burns lot of oil, did one track weekend after this and was adding oil every 2nd session to top up. That was my last track day with it. 2012 bought a 996 tt for track 2016 Now at 136k km

So, cylinder scoring can produce a ticking sound. That ticking sound would be the piston hitting the head? If not, then what exactly is it again?

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more probable is that is it Piston slap

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I can tell you that the noise happens at 1/2 engine revolution speed (sound wave analysis) - so it might only be happening on the power stroke. That's why it's frequently confused with lifter noise, since the camshaft spins at 1/2 engine speed.

Here are a couple of pics from 2 3.4 cayman motors we have had recently.

Those two are classic failures.. Oddly, we see very few US Caymans with cylinder failures, but tons from Canada.

Yes, 2 engines, same failure. These are cars that spent a lot of their time in the US, both were US cars at delivery. Their time in Canada was in BC where we have a hand full of days at most per year where temps are below freezing. Of course, only the owners know if the cars were stored over winter or driven. Have a 997 S apart I can post photos of too. It also was a US car.... Not sure of the correlation of "winter gas", or if it plays a role, as I am not sure (don't think we do) have a change in formulation here. The vast majority of our fuel is sourced from a refinery in WA state.

Cold weather and high octane helps to keep the bore score problem away. If you look close to the most engines with bore score you will find small signs of detonation marks on the pistons close to the cylinderwall. When you have detonation, small aluminum parts will loosen from the pistons and jump between the cylinderhead and the piston and finaly get traped between the cylinderwall/piston and travel upp and down multiple times and creathe the scores. My guess is dust/filling in one or more injectors. So if one injector flows less than the other injectors the ecu will compensate the lower mixture and open the injectors a longer amount of time. Lets say this is cylinder bank 1. 2 injectors will have more flow and this cylinder will run rich and the cylinder with the bad injector will have much less fuel in to cylinder and bad fuel/air mix and cause detonations. But the common lambda will still reach its target. The knocksensor would handle this, but the engine have to knock before the sensor can notice that it actually is knocking. So when engine see knocking time to time for years, sometime the ecu is not fast enaugh and you will have an fullsice detonation and free aluminum partickles traped and create scores.

Cold weather helps prevent scoring?

I disagree. It’s cold here and the OKC Thunder are finally winning a few games. .

Cold engine means more piston to wall clearance, and more bearing clearance, but also the oil is much thicker to compensate for this. Ones the engine is wormed up and the weather is cold, you will have better cooling to the engine, colder intake air and less detonation in combustion chamber. Just my opinion. Maby im all wrong. My guess is more cars are failing in hotter countries. Summer here in sweden is like winter innother countries. Ive never heard about bore score here in sweden. Hot weather summer time and hard driving, oil gets thinner and engine will more easy detonate than colt weather.

wow....wadda theory

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Ok, were told that scored cylinders happens more in colder climates. I know of quite a few here in cold Ottawa, Ontario with the issue.

ottawa = very hott summers and very colt winters. Maby the wear will appear in hot summer driving, ones the weather gets cold and you have bigger clearance att startup you will hear/notice the actual problem. At this point you have a problem and every cold start will wear the cylinder even more. Just opinions again, Im verry interessted in this problem... but if you guys tell me that the only reason is cold start that wears the bore. I�ll install a block warmer.

i just don't drive mine in the winter. The Subaru is much more fun this season anyways.

I just don't drive mine at all and let it sit in the garage where it will appreciate and become worth $90k+ in about 2 years.

lies.