C.B.B.C.- Cayman big bang club. - Page 3 - Boxster/Cayman - PistonHeads UK

It's a good question. My dealer says they've never had to dismantle a 3.4 litre engine.

Ozzie Osmond said: It's a good question. My dealer says they've never had to dismantle a 3.4 litre engine. They probably just replace it with a new engine!

Does this assume it is only the 3.4 Engine?.How many 2.7s have Hartech or OPC.s revived?.

Thankyou--Long may that Continue ----

AFAIK D hunk was only early 2.5 Boxsters, the M96/97 engine suffers other issues such as IMS, Bore Scoring & Oval bores. A more minor issue is RMS leaks.

Ouch, news to me I wasn't aware later cars did it

So sorry to see the photo------------What mileage?.

In the short term it is cheaper to manufacture a casting with the top of the cylinder just a round circle compared to a closed deck design - as this prevents the need for hardened sand cores to be placed in the mould and enables higher pressure castings to be used which usually result in more accuracy, better material consistency and lower production costs. However it leaves the cylinder free to flex under the pressure from the piston pushing on one side of the cylinder bore to drive the car along and like a baked bean tin - if you squeeze it in one direction - it goes oval. It does this every time a power stroke is applied - so perhaps on average 1500 times/minute of normal driving. The manufacturers know flexing occurs and to prevent this resulting in chatter at the cylinder head gasket often relive the gasket design to allow it to flex yet stay located to the mating faces (as in this case). The problem is made worse if the cylinder thickness is too thin as this directly reduces the strength of the cylinder tube and increases the amount of flexing until metal fatigue results in a crack. The original 944 and 968 version of an open deck cylinder had much thicker wall thickness cylinder tubes and a stronger material - and lasted OK (except in extreme turbo applications). These are made of less strong (but easier to machine) alloy with a weaker central core material and to prevent this "D" chunking they needed to be thicker, stronger or fitted with a top security ring. The larger the piston (and the faster the car is driven) the greater the forces and the sooner they fail - so it is hardly ever seen in anything under 3 litre, rarely (or only on very high mileage examples) in a 3.2, but increasingly evident in a 3.4, 3.6 or 3.8 versions. When we repair a "D" chunk by fitting a new alloy cylinder we also convert the new cylinder to a closed deck design so it cannot distort oval again and therefore will not crack again. At the same time we offer customers two further improvements to the remaining cylinders. The first is to re-round the otherwise permanently oval cylinders (now with too much piston clearance) and fit an auxiliary security restraining ring to convert them to a closed deck design as well and the second is to replace all cylinders with new alloy cylinders. In the past few years there has been several alternatives offering steel (or iron) liners - with or without Nikasil coatings that is minimally cheaper than our alloy Nikasil liners. Almost every week we hear from yet another specialist who has tried this and found that they failed - with too much oil consumption or liner slip. The difference in piston expansion rates and piston clearances needed to allow the right clearances from driving such a car at 30mph and 170 mph are beyond the ability of these different materials with widely different expansion rates to cope. If the cold and slow driving clearances were right for good oil consumption they would be too tight when the engine was flat out and similarly if they were right when it was flat out they would be too large to resist high oil consumption at low speeds. This is why manufacturers of high performance sports cars with large pistons exclusively try different types of all Alloy engines and cylinders - and have done for many years. If the cylinder bore diameter is smaller, steel/iron liners can be made to work as the relative expansion in total is reduced and if they are cast in (as many are) this prevents the slip caused by differential expansion). We know how to (and therefore could) fit similar liners so they didn't slip but know that it is not the right long term solution and resisted offering it as an alternative - despite initially losing some business as a result of other offering it. Since then our decision has been totally vindicated and while our liners continue to prove a complete solution, more and more specialists are coming back to us, having had their fingers burned trying to save a very small amount for a solution that has been discredited for this type of engine for several decades - meanwhile our pile of replaced steel liners (originally fitted elsewhere) continues to increase (as witnessed by 2 different Porsche Club visiting members in the last few months). In the last week we have heard again from a respected specialist who for some reason decided to try this steel/iron solution and has already rebuilt the engine twice and still without it working properly. It is no surprise that the more powerful (and regarded as almost bullet proof) GT and Turbo versions of the same models also fit alloy Nikasil closed deck cylinders of very similar design to ours and that these prove extremely reliable. It would have cost very little during manufacture to fit restraining rings to every engine and this in itself would have prevented early "D" chunking. Unfortunately several years of production of a wide range of versions - are of this design and - will gradually have increasingly oval cylinders, increasing piston clearances and probably "D" chunk one day although the pressure from the piston (losely related to the amount of throttle opening and aggressive driving) also increases the ovality rate and those driving more carefully may well get high mileages out of the cars without cracks - but then - why did they buy such a fast car if they didn't intend to use the performance - you might ask? The first time we saw inside one of these engines (over a decade ago) we predicted cylinder ovality and "D" chunking would result so researched and designed a solution that would eradicate that possibility - so it is surprising that the small extra cost of fitting restraining rings was not adopted during manufacture as in the long run it would have improved the reputation of the manufacturer and saved in warranty replacement costs. Meanwhile we are often accused of scare mongering about the long term expectations and similarly to be unnecessarily running down the steel/iron solution - often with the argument that some F1 engines use steel liners. This simply is an uneducated conclusion not realising that it is easy to build an engine with the right clearances for either modest power or continuous flat out performance but that the problem for road cars with relatively large piston diameters - is finding a solution that works perfectly for both thermal extremes. The Gen 2 engines have reverted to a closed deck cylinder design and so should prevent this type of failure although there are already some signs that other cost saving measures will emerge with a few failures for other reasons. Regardless of all this - the vast majority of owners actually never use even a fraction of the available performance (or only rarely) and as a result they still get acceptable mileages out of the cars without failures and so this is still a relatively rare problem affecting relatively few examples - so there is no need to panic over the weaknesses these engines incorporate (especially for those intending to use the car's full performance potential). Meanwhile they are fantastic cars to own and drive and there are several different types of cover you can obtain to remove or minimise the repair costs if the worst happens. Furthermore the oldest examples are reaching an age (and lower cost) when it is not unreasonable to consider a preventative rebuild that incorporates various improvements for longevity. Baz

hartech said: The Gen 2 engines have reverted to a closed deck cylinder design and so should prevent this type of failure although there are already some signs that other cost saving measures will emerge with a few failures for other reasons..... Baz Interesting, care to expand?

A quick question, Baz. When replacing pistons and liners in the 3.4, can you incorporate an increase to cubic capacity option such as the 3.7 litre one that Autofarm offer.

ilduce said: tr7v8 said: AFAIK D hunk was only early 2.5 Boxsters, the M96/97 engine suffers other issues such as IMS, Bore Scoring & Oval bores. A more minor issue is RMS leaks. YKL. Here is my 2007 Cayman 3.4 with a D-chunk. Is that a dfi engine?

They weren't selling them in 2007, unless that's a DeLorean...

Of course, it would help immensely if I read things properly before replying...

A very useful reply Baz

As always Baz very informative. It gawls me that for the sake of what a few hundred pounds, Porsche could have built closed deck engines and aleviated these problems. That said and I mean it in a good way. Their F up has allowed you to build and establish a very good business. So out of something bad, something good has come.

Zyp said: Is that a dfi engine? No, the DFI is a closed deck design.

If you summarise all that detail what is it that causes the problem to emerge, Regular high rpm? Regular high torque? Using too much power from a cold engine" Slow engine warm-up? rpm too low with a cold engine? Too much gentle driving?

graemel said: As always Baz very informative. It gawls me that for the sake of what a few hundred pounds, Porsche could have built closed deck engines and aleviated these problems. That said and I mean it in a good way. Their F up has allowed you to build and establish a very good business. So out of something bad, something good has come. Yes, would be nice to see the discussions and internal engineering white papers before the design was signed off.

From a specialists perspective, one thing that I think Barry at Hartech will agree with, which may not be clear from forum posts and could potentially cause people to avoid a Boxster, Cayman, 996, 997 or even a 991, is that these failures are much less common than internet posts might suggest. D-Chunk, Oval-Bores, RMS leaks, IMS Failure etc all have happened, and when they do happen, they happen in exactly the same way, but other than that, these engines do not seem to suffer things which usual engines might suffer, such as engine wear... I have customers with 300,000 miles on an original engine without issue.. But I have also seen the occasional poor bugger suffer any of the above common failures, and when they happen, it sometimes happens to the most pampered cars. As an example of how rare these things are.. Every day we see several Boxster, Cayman, 996, 997 and the odd 991.. Thats a lot of example cars. If the failure is an IMS Bearing failure, RMS, chain, oil scavenge pump, cam followers, head gasket, etc.. We deal with it in house.. Anything to do with the Block, such as D-Chunk or oval bore, we post the engine to Hartech and are completely transparent about that, but only charge what Hartech would charge direct.. Which, in itself, is an indication of how rare these problems are.. If we had more than one car a year suffering D-Chunk or oval bores, we would deal with them in house.. But what Hartech offer is a centralised expert service on reclaiming the crankcases after failure and making them better than new... But it really is that rare. We have seen only a very few cars d-chunk.. from memory a 2.5 Boxster in 2002, a 3.4 996 in 2004, another 3.4 996 in 2007 and that is it. Of IMS bearing failures, I think we have seen one 3.4 996 in 2007, but have seen roughly 3 to 5 IMS Bearing failures per year on 3.6 996 models per year, but no 997's, 987-Boxsters or Caymans. Bore ovality, or as it prefer to call it drooping bores, I have seen maybe one a year, and it is always a 997 or 987 based engine. Maybe it is early days. It really is the minority.. With the 996 and 986 Boxster, it is well worth having your IMS bearing updated at the same time as a clutch, just as insurance.. If you have a coolant change, waterpump, expansion tank etc.. Get the cooler thermostat at the same time.. And although I have not seen any direct evidence of a link between oil system issues (everything from cam followers through to more serious ones) I do think that the even the 996 and Boxster service schedule on oil changes (such as the Porsche dealer low mileage service!) are not frequent enough, let alone the 997, 987 Boxster and Cayman 2 yearly idea.. My reasons for not thinking this is good enough, goes beyond just how bad the oil is after two years, but also covers how many expensive faults could be nipped in the bud as inexpensive repairs with more frequent inspections. But.. the reason for this post is to say that what Barry has said is 100% on the ball, but it really is not as frequent to suffer terminal engine damage as some may believe, a lot of owners have bailed out of Porsche ownership fearing the engines are hand grenades waiting to explode, but in reality, I think they are no less reliable than any other engine.. I am sure some specialists of other Marques will agree that every engine by every manufacturer has a way they can terminally fail and when they do, they fail in a similar way on that model. BMW's had an issue of bore issues.. My friends and I have had BMW's of that engine type without any of us suffering that issue back in the day.. all in all.. the internet is a wonderful thing, but I think in reality, if as many engines failed D-chunk as the internet would have people believe, with the volume of M96 engines out there, every specialist would have one of each engine variation on the shelf and ready to go.. Hell, if I knew I would need one of each type on just a yearly basis, I would keep them in stock. So, if you have one of these engined cars, stop worrying.. If you have suffered failure then I really do feel for you, you have been really unlucky, but the good news is that it should never happen again... I have not known of a Hartech engine re-failing, and I have not heard of a factory replacement engine failing (although more likely than a Hartech one).. Back in the day, the 3.4 996 and 2.5 Boxster were known as "ones to avoid" as at one point between 2002 and 2008 they seemed to be the ones that had issues.. But, now they seem to be the most reliable ones.. Which makes me think, some engines leave the factory destined to have a life of under 60,000 miles... Once they got past that point, they seem to live a long life, as do those that have failure and have a Hartech or Factory replacement engine. Anyway, just my opinion.. I personally have 3 Porsche with watercooled flat sixes, and other than changing the IMS Bearing for an updated one whenever the opportunity crops up, changing the thermostat for a cooler one, I don't expect any of them to suffer a failure... I think they are more likely to get t-boned by someone than they are to suffer engine failure with the right maintenance. In the words of Hitchhikers guide to the galaxy "Don't Panic!"

And yes.. Porsche should have made them closed deck.. But their focus seems to be on making cars last the warranty these days, and sometimes they fail at even that.. Back in the past they made cars where they had the attitude of "Sod the extra £XXX we will make it last".. But that era had them frequently on the edge of bankruptcy.. But also where do they draw the line.. My dads old Rolls Royce is built to be bullet proof.. But it weighed 3 tons.. Maybe Porsche should make better wishbones, engines, exhaust clamps, coil packs, PCM screens, expansion tanks, key heads... the list is endless of things which eventually fail on a Porsche.. But making them all last and be as good as they can be, is not compatible with being a sports car, as like the rolls royce, the car would weigh a lot more... I think Porsche do a pretty good job of making a car down to a price which as a rule can last forever and give performance.. The only place I think they really fall down, is not in design, but in customer service when something goes wrong within the warranty or when just out of warranty.. I think that has given them a bad name more than the actual failures themselves.

Very good to hear Jon! As you say, back in 03-04 the worst we had to worry about was the RMS where people made a huge fuss of an oil leak. Later problems as discussed here are much larger. Going back some, my 2.7RS lunched one side when the timing chain let go. Upgraded to oil fed tensioners, then the crankshaft broke as the oil cooling was insufficient, both on track though. It was all a learning exercise, but expensive. None of my four water-cooled P cars have had any mechanical problems. Nic

You seem to have had 2 comprehensive replies to consider saying almost the same things and we both mention how relatively rare the occurrence of failures is. I agree it is a shame that a small number of weaknesses have blighted what would otherwise have been a brilliant all round car in every respect. However the stress creep that results in "D" chunking - while affected by material quality and consitencey (and therefore varying between cylinders) and influenced by how the car is driven (to some extent) never the less is taking place all the time on all the engines and although some last longer than others - it will eventually cause problems. It is a greater shame that the change of piston coating in the early 2000's added yet another potential failure of scored bores which often occurs before the cylinders have gone oval enough to crack. Fortunately our replacement cylinders solve both problems in one go. Although the closed deck design of the Gen 2 engines should prevent "D" chunking - we are still a little worried that the new piston coating will not last as long as the original coatings did used previously with this type of Alusil cylinder. I agree numbers are still very small but I don't know how they compare to other similar engines and repairs are very expensive. It seems to me that this problem it typical of anything in life that is a rare occurrence but very expensive to fix where the traditional solution is to share the potential cost by the majority of users (like car or house fire insurance) and as such options are presently available (and as the typical cost of these cars lowers and the "average" buyer probably has less resources to cover the cost of a repair) that investigating and taking up one of the better options might very well be the best way to deal with the problem and in my view explaining all this empowers those involved to do something to protect their interests - where they may otherwise be in blissful ignorance and be severely caught out. We have been able to provide an excellent solution at a very reasonable cost because very early on we identified these weaknesses and believed it would result in a lot of potential business and decided to invest a huge amount in research, testing, machinery, training and organisation - which has paid off. We continue to test and research new solutions and to minimise a few other weaknesses and if numbers increase (as we suspect they will) will carry on with that philosophy so high quality reliable repairs are possible and affordable. As mentioned above - we supply in various levels and stages to all the very best independent specialists - doing all we can to help those in difficulty find a reliable solution wherever and however their rebuild is to be tackled. When you handle hundreds of rebuilds each year and have the facilities in house to carry out all the machining and manufacturing you also find lots of other small issues you can improve during the rebuild which those handling a handfull each year would not be aware of - and in this case numbers do improve the outcome for all involved. We also continue to race the models involved to assess lifespans and various ideas by putting them to the ultimate stress and strain levels (even though in doing so we may shoot ourselves in the foot in public by testing something to see how long it may last - so far (fingers crossed) without too many problems). This starts all over again at Brands Hatch next Saturday in which the engines we are racing with still have many original features or parts that were replaced three seasons ago - being assessed for longevity. Those unable to attend will be able to pick up on the races some days later on Motors TV and I hope by mentioning our previous 100% engine reliability record - it will not prove to be a boast I regret while continuing this testing. There is little anyone can do to avoid problems with ovality and scoring. Changing oil more frequently and fitting a LTT will help prolong life as will not driving at full throttle to soon from cold or after a brief driving pause - but if you want to use the full potential frequently - and can afford it - a pre-emptive rebuild with all 6 cylinders replaced - may prove to be the best answer. Baz

LaurasOtherHalf said: hartech said: The Gen 2 engines have reverted to a closed deck cylinder design and so should prevent this type of failure although there are already some signs that other cost saving measures will emerge with a few failures for other reasons..... Baz Interesting, care to expand? +1 please could you expand Baz

Ozzie Osmond said: If you summarise all that detail what is it that causes the problem to emerge, Regular high rpm? Regular high torque? Using too much power from a cold engine" Slow engine warm-up? rpm too low with a cold engine? Too much gentle driving? Its a combination of the open deck design and thin/weak cylinder walls. I am not sure that driving style makes much difference. In theory, they will all D chunk eventually.

Bumble SV said: LaurasOtherHalf said: hartech said: The Gen 2 engines have reverted to a closed deck cylinder design and so should prevent this type of failure although there are already some signs that other cost saving measures will emerge with a few failures for other reasons..... Baz Interesting, care to expand? +1 please could you expand Baz I think he might referring to the piston coating!this has been mentioned before and failures may not occur until higher mile ages but is yet to be proven!

I have written so much on this subject on other Internet forums that when the same questions, objections and criticisms arise here it becomes too big a task to answer every question on here all over again - sorry. I will look back and see if I can find some previous answers that cover the questions as they emerge. However if this topic here follows previous typical content - you will find a lot of people arguing (for reasons best known to themselves) about things they know relatively little about - often completely wrong about many issues. We do not need to prove anything and frankly it is impossible to prove anything at all because it would take research facilities and costs that even Porsche could not afford - the best you can do is to consider why people have the opinions they do and basically who to believe. At Hartech we have three graduate engineers, one of whom previously designed engines and gearboxes that obtained podium positions in Grand Prix's, one of whom built one of the fastest 1/4 mile production cars in his class and a lot of other engineers in various disciplines. Our staff between them have solved technical problems for many of the World's leading automotive manufacturers in Europe and Japan - so in terms of experience - we know our stuff. One engineer several decades ago was probably the first to manufacture alloy racing cylinders using chrome, steel and Nikasil bore coatings in the UK - so just by coincidence happened to have more experience of this subject than you are likely to come across elsewhere. The number of alloy Nikasil liners we fit each year is approaching 4 figures and so - by comparison with any other source - we not only have the experience and analytical capability to work out what is going wrong but also strip, inspect and analyse far more engines of all types than any other Porsche specialists by a massive factor - and this means that we see more problems, see which repeat themselves, can work out what the failure limits are, can consider if there are common factors etc, etc. All this adds up to our opinion on any issues relating to these problems - likely to be at a more reliable level than you are likely to find anywhere else. We have explained a lot of these problems in our buyers guide (sections 4 and 5) available on the Internet in www.hartech.org but although all the content is right and correct - it is now several years out of date - with much more that we could add if we had time - as a result of being more busy than we expected repairing engines and unable to find the time to update the latest information. I suggest anyone really interested reads it all first before asking further questions. The main problems relate to cylinder walls being too thin is that composite liners suffer from "creep" resulting in permanent distortion in the direction of repeated stress and heat resulting in ovality. We measure every engine and can confirm that once a cylinder has reached 0.25mm oval it will soon crack. When one of the six cylinders is at 0.25mm there are usually 5 others distorted between 0.15 and 0.25mm - but all different (due to manufacturing differences). The main problem with bore scoring comes from the combined issue of the silicon particles entrapped in the Lokasil matrix becoming dislodged and the oil film between the cylinder wall and the piston being unable to provide a thick enough oil film to allow the minute particles to escape whereupon they impinge on the piston coating and with the later plastic coating gradually wear them away or pick pieces out until the piston alloy is in contact with the cylinder wall and scores. The older ferrous coatings had a harder surface finish and resisted the particles cutting into them for much longer. The silicon particles in Alusil are better bonded and resist coming lose for longer. The best analogy I have for this is that if you take a bag of ready mix concrete and just lay the contents out flat and pour water on it - when it has set it is not as strong as if it had been mixed up in a concrete mixer first and the stones are easier to chip out as well. The Lokasil preforms are manufactured by a process that results in a similar scenario - so the later "plastic" pistons coating are likely to last longer in Alusil (Gen 2 in which the silicon and alloy are mixed together while molten) than in Lokasil (Gen 1) which is pre-set). The amount of coolant that passes into the cylinders is much less than the earlier Alusil POrsche engines (nearer 10% than the original 100%) and the thermostat is set at a higher temperature - so the cylinder wall temperature is higher between the piston and the cylinder wall in some circumstances than they were with earlier designs and we think results in the oil film strength and thickness being too thin in some circumstances to allow the particles to escape and instead allow them to rub into the piston coating. Having our own "in house" precision machine shop also helps us to manufacture prototypes, fit temperature sensors all over engines (to analyse and confirm what coolant temperatures are in different areas) and experiment with different solutions. We have also experimented with 7 different types of piston coatings (each fitted to a test engine, run for thousands of miles and striped for inspection) - so our background knowledge of different materials different cylinder coatings, various manufacturing processes etc is second to none. These tests alone cost a six figure sum. So when we come to a conclusion it is as a result of experience, test results, the ability to test and try different things and as a result of seeing far more engines and failures than anyone else - probably Worldwide. Presently we find other specialists who have tried to build a handful of engines assuming they know more about the problems than us, we find many that have never stripped an engine or even looked inside one and with no engineering background commenting as if their opinion is more important than ours and of course several other specialists trying to get in on the act with a solution we already know is not the best. All this does not bother us because we are as busy as we possibly could be and do not need any more business, have no desire to expand our business any more and frankly could not care less about our image in terms of our expertise being questioned. We agree everyone has a right to their opinion and they will inevitably be right about some things and we may not be right about everything - but overall this is a problem not created by us and we are just trying to do our best to help those that suffer from it. We recognised the potential failures years ago and set-up to provide a service to repair the numbers we expected to fail and we took that risk so early we now handle vastly more than anyone else with a superb reliability record and customer satisfaction rating. You guys are welcome to choose who to believe and where to go for repairs - we just feel it is necessary for us to counter the misleading information that often gets posted from those we know (for a variety of reasons) are misleading the readers. We feel we should try and at least present the more reliable side of the argument but this is not regarded by us as a competition for honour - we are just often puzzled why so much misleading comment is made by others who clearly have not had a fraction of the qualifications, experience, facilities or repair numbers to compete. It is the downside if the Internet that while it provides a great forum for information it also provides a shop window for others to try and obtain work and elevate their own self importance as a result of the annonimity it also provides. It can become a dangerous mix and we don't have the time or inclination to cover every other posting we find even when it is clear to us it is misleading. So while this subject may be new to this forum, it is not new to us and we are simply too busy trying to repair engines that have failed to embark on a crusade to correct and answer every question raised - sorry -- we hoe you understand our position. Please read the "old" background information on out Internet site first and then we will try and answer any more questions resulting to the best of our ability and in the interests of accuracy and to avoid misunderstandings. Baz

JMGPorsche said: We have seen only a very few cars d-chunk.. from memory a 2.5 Boxster in 2002, a 3.4 996 in 2004, another 3.4 996 in 2007 and that is it. It really is the minority.. I know of 3 other people in my area with Cayman S's that have gone pop in the last 12 months. Maybe you're not seeing them because of what happens: It stops working, you've never heard of D-Chunk, so you take it to the dealer, he strips it down and tells you it's 7k to repair or 1.5k to put it back together and give it back to you still broken, so you can take it somewhere else, but you aren't sure where else to go. No choice really is it? Finally many thanks to Hartech for the explanation, which I (amazingly) understood!

Is bore scoring a precursor to D-chunking or can they occur independently of each other?

BillTheButcher said: Is bore scoring a precursor to D-chunking or can they occur independently of each other? 2 unrelated issues.

mollytherocker said: 2 unrelated issues.

At the moment it seems that in the 3.6, 3.8 and Cayman S engines - the bore scoring is occuring at lower mileages than "D" chunking - so most engine we repair suffering from bore scoring receive new cylinders or re-rounded and supported cylinders so do not then go on to "D" chunk anyway. These are also the engines that are fitted with the later "plastic" coated pistons that we believe will deteriorate quicker than the original ferrous coated pistons contributing to the early bore scoring failures. The evidence of low mileage "D" chunking is reducing and we think this is probably partly because as the cars age the typical owners probably do not thrash the cars as much as some owners of a newer one and also probably are more interested in looking after them with more mechanical sympathy. It is also a fact that there is some difference in quality of the preform Lokasil liners - how they ended up being entrapped in the block and even the quality of the actual Lokasil and the distribution of the silicon particles within it - meaning in simple terms that the engines that happen to have better all round quality in the cylinder blocks will last longer than those that don't. However they all still have "oval" bores so will eventually "D" chunk - but averages for mileages that it occurs at will take longer to materialise. Inevitably driving these cars without high torque delivery (i.e. modest throttles and higher revs) will make them last longer in both bore scoring and "D" chunking modes and lowering the running temperature and frequently changing oil will also help but unfortunately if your engine happens to have vulnerable original Lokasil cylinder quality or lower end piston coating quality - it will still fail sooner than one with better quality that may be driven harder. Titptronics seem slightly more vulnerable because they normally set off in second and release high torque even if the driver is not trying to go particularly fast in it. However we are still talking about a very small number overall failing anyway and although all this information is right - the vast majority avoid failing - either due to being on the better end of manufacturing quality, maintenance, or driving styles and use - so as valid as this advice is - you are still unlikely to experience a premature failure however you look after or drive your car. That said we do not expect them to survive for as long as say 944, 968 or 993 engines are known to. However many 924, Carrera 3.2, 964 and SC engines also needed either top end or full rebuilds at similar mileages we expect to see the majority of these engines failing at but the difference is possibly that these models could still be driven despite the engine deterioration whereas the M96/M97 engines will probably force the issue by failing. Baz

Baz, mine was dealer rebuilt at 66k (both crankcases, but only one piston as it was the only one that was marked, plus water pump etc etc). Is it inevitable that it'll pop again, but just a case of how many miles?

Just in case anyone is in any doubt (I tried to be clear) When it comes down to anything to do with the crankcases and bores in these engines Barry (Baz) is the governor as far as I am concerned and I believe 100% his observations on the causes, effects and how to deal with them are spot on. Every specialist I talk has 3 options for customers who suffer bore issues with 9x6 or 9x7 models. New engine from Porsche ££££££££ and possibly the same issues looming in the distant future possibly in someone elses ownership.. but still..) Used engine ££££ Russian roulette as the same issue could be just around the corner Hartech engine. Where in my opinion, and other specialists, the issue isnt going to happen again All my observations are based on my Porsche specialist garage with 4 lifts and a catchment area where 50 of the radius is in the English channel.. Barry's observations are based on dealing with just about every engine, that every specialist sends him, which is a massive percentage of all the engines which suffer a bore issue.. So it is pretty much a no brainer why I consider what he says on this subject (as well as a lot of others where he is the daddy) as gospel. My main worry is that there are people out there thinking any 9x6 or 9x7 is likely to have an engine failure.. Which makes people who own them worry about enjoying them, and people thinking of buying one being put off the idea, which then means the people with one see the values heading down the toilet, which is partly because of people being put off buying them. Barry is right, there are things you can do as owners to reduce the risk of engine failure... Frequent oil changes, cooler thermostats, magnetic drain plugs... which can all be done quite cost effectively at the right kind of times during maintenance, or as a one off at slightly more cost. My old 996 had a row or PC hard drive magnets bonded into it and they were checked on every service.. Pure paranoia, but if the car was a keeper I probably would have considered getting a closed deck engine by Hartech. But the only real sure fire way of knowing for sure would be to buy a car with a Hartech engine, or have your engine converted by Hartech, either direct or via your local specialist. But one thing I do need to make clear, on this subject I posted my post to support Barry's opinion and the product he offers, not to throw buns at it, he is one of the handful of specialists in the UK who I have total respect for. Some other specialists might not be so quick to jump in to confirm Barry's points, often because they are less transparent to their customers about who is rebuilding their engine, we are straight about this and have in the past sent 4 or 5 customers direct to him as complete cars if it was obvious without a stripdown that the car was suffering from a bore issue. Jon

Could someone please tell me if the engines in later 3.4 Caymans have fewer problems than those in earlier models, and if so, from when? I'm thinking of getting one as a weekend/occasional commuting car, but don't want to end up with another moneypit, been there, done that...

RYH64E said: Could someone please tell me if the engines in later 3.4 Caymans have fewer problems than those in earlier models, and if so, from when? I'm thinking of getting one as a weekend/occasional commuting car, but don't want to end up with another moneypit, been there, done that... post 1/2009 gen 2 cars are proving very reliable! all cars pre gen2 are subject to same problems no matter what age

itsybitsy said: RYH64E said: Could someone please tell me if the engines in later 3.4 Caymans have fewer problems than those in earlier models, and if so, from when? I'm thinking of getting one as a weekend/occasional commuting car, but don't want to end up with another moneypit, been there, done that... post 1/2009 gen 2 cars are proving very reliable! all cars pre gen2 are subject to same problems no matter what age That's good news, I was thinking of something no more than 2 or 3 years old.

Isn't a 2009 car a generation 1 facelift ? I thought the generation 2 car was the 2014 model year onwards ?

jfk01 said: Isn't a 2009 car a generation 1 facelift ? I thought the generation 2 car was the 2014 model year onwards ? No, 987.1, 987.2 then 981(.1 if you like)

Lets hope the 981 proves less fragile then. real shame that the first generation is destroying people's faith in the brand ....

You only have to look on the Evora thread at the ignorance of those who choose to not listen, that for the last 5 years the DFi engine is a good one. Porsche will forever be tainted with some bad engines. The good ones get overlooked.

jfk01 said: Lets hope the 981 proves less fragile then. real shame that the first generation is destroying people's faith in the brand .... the 981 is the third generation.the engines we are refering to are in the 987.1.the 981 has the same engine as the 987.2 ie the gen2 engines

itsybitsy said: the 981 is the third generation.the engines we are refering to are in the 987.1.the 981 has the same engine as the 987.2 ie the gen2 engines I assume you mean 991?

mollytherocker said: itsybitsy said: the 981 is the third generation.the engines we are refering to are in the 987.1.the 981 has the same engine as the 987.2 ie the gen2 engines I assume you mean 991? no i am talking caymans

itsybitsy said: no i am talking caymans Mmm. I will have a word with myself.

mollytherocker said: itsybitsy said: no i am talking caymans Mmm. I will have a word with myself. no i think some are confusing the gen 1 and 2 engines with model generations!

The initial message was deleted from this topic on 09 May 2015 at 11:06