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What REALLY breaks your IMS & contributes to bearing str

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So once again....which oil should we be using!???? (gen1 carrera s)
 
Gibbo205 said:
GT4 said:
bazhart said:
GT4 - I am really sorry to have taken this on because you usually are so helpful and provide interesting answers usually quire rightly. I don't like arguing with those I respect on here but on this occasion - something is all wrong - and I cannot understand why - you are too clever to be pushing out this sort of stuff and I DON'T BELIEVE THAT YOU THINK IT IS RIGHT EITHER.

Please explain that IF the bearing is not up to the job - why then can we fit a new bearings of the same specification, not re-fit a seal, fit a stronger spindle (just because the old one is so weak in design it is a disgrace breaking all the notch rules for metal fatigue failure taught at colleges and universities Worldwide) and find that ever since they have all performed perfectly - hundreds of them? despite the fact that we are fitting them to older engines with worn parts in some areas (where customers do not want or cannot afford to replace all of them) and they still work just fine. If it is all to do with oil, toraional stress, revs, owners etc - how come just removing the seal fixes it?

Remember the other end just runs as a plain shaft running in an aluminium hole. I agree it only has one chain that end (not two) but that never gives any problems and being the other end of the same shaft has all the same torsional loadings as its opposite end.

I think your logic is misplaced on this and our experiences prove ours works and works better than the original design - for basically just replacing the same bearing without a seal. We even replaced the double row bearing with the single row one fitted to later cars (which is actually slightly stronger due to deeper tracks) together with a spacing kit and they are all OK too.

The proof of a solution is in the experience of it working or not - it works when the seal is removed - it doesn't if it stays in place.

My comment was sarcastic - sorry - but in the light of all the pading - I thought it a little obvious to state that it is better to have oil in the engine than not. I am sure that even those that run around with low oil know that and they didn't let their oil run low because they think it is OK - they just don't think or couldn't care less. For me it was stating the very obvious - somethingwe could all do and fill pages of answers - to no ones benefit.

Thin oil when hot also sqeezes out of all the tensioners and tappetts quicker (under the load from engaged tappetts and chain tension) than thicker oil - so when you switch off - loses more oil and pressure and on start up renders the car with more work to do to fill and support the loads. Tickover loads are negligible and by the time most people are motoring their cavities are full anyway and the car is running on full pressure.

Where did you get these explanations from - are they your own assessment or are you reading it from something someone else wrote on the subject?

Furthermore - If thin oil is so good why do all racing engines run thicker oil?

Even furthermore - if piston clearances new are OK for thin oil - after say 40K when they have increased by about 0.1mm - by what logic can the same oil be the best?

Usually - it is a difficult situation to criticise Porsche when their reputation was so good. Even when they made other errors that tuners fix - the general public are often sceptical about the solutions that small businesses provide (even though they are usually right). But in the case of these engines - with known problems with IMS bearings, "D" chunk failures, scored bores and pistons etc by what standards or logic can a conslusion be reached that they are always right when small businesses with comparatively limited resources can quickly see the p roblem and provide a solution that is proven to work and solve the problem and on that basis - from which stand point can anyone argue they are wrong and Porsche was right and if so why should any other of their publicity about oil grades and IMS failure causes be given any credence?

Did you also read my recent point reproducing all the benefits claimed by Porsche for their closed deck Mk2 997 engine design and my comment as to why - in that case - if it is so good - was it not fitted to the earlier models manufactured for 13 years when we managed to do so to the very first engine we saw - having imediately identified the problem.

If we can see a problem that they did not and fix it - why - when it comes to the IMS bearing - all of a sudden are Porsche right about it all and not us - especially when ours works and theirs often didn't?

You don't need to waste time replying on this - you got it wrong mate - you cannot win your argument - and the best thing to do is let it drop and pick up on something else where your input is usually so valuable.

One failure against so many good and valuable postings is not something to worry about.


Baz

I think I covered the fact my post does not vouch for the bearing quality or not, but only the affect of oil viscosity on the system the bearing is in.

Yes, my nan could do with a new heart valve, but instead of the cost and risk associated with a cure, she just doesn't run up and down stairs.

All owners who have an M99/97 engine have the IMS risk, my advice is just to help preserve it before is needs open Hart surgery.


But your advice is going against what others have said.

The advice to preserve the IMS is to use 5W-40 instead of 0W-40 and perform more frequent oil changes.

Your saying its better to use 0W-40, wheras Hartech, LN Engineering amongst others say 5W-40 is better.

So the question is who is right?

You do realise an oil such as 5W-40 has more wear prevention than say a 0W-40 oil yes?

As its the bearing in the IMS which is the issue, its all about preventing the wear of that bearing, which a 5W-40 does better than a 0W-40, yet your suggesting otherwise.

Also I did not suggest using different oils during Summer/Winter here in the UK, our climate is not cold enough to warrant using such thin oils and I am fully aware oil is not like a switch as such why in the UK as our winters are rather mild and our summers just warm the same oil all year round is fine. But in more extreme climates they either run a thinner oil or change to a thinner oil for winter.

I think I answered that the first time you asked, two or three posts up the page :?

And the answers still stand.

A thicker oil will stop wear, a thicker oil will require more force and power to move around and be slower to move around.

You pays your money and takes your choice.

I choose to protect my IMS at start up and take care not to wear it out by not loading the engine before it fully lubricates, actuates and reaches operating temp (where "Xw" has no bearing anyway).

I don't think I made any statements about the frequency of oil changes.

I did however make the point you MUST keep it topped up (to some extent irrespective of grade).

The whole point was the optimum way to run the hydraulic systems: that
requires a lot of oil (ie brimmed) and requires oil as quick as possible.
 
:tea: :grey:

Apart from careful warming up from cold, regular oil changes(every 5/6k) the thermostat upgrade, regular rad cleaning(+ coolant flush every 20k) and using good quality oil to prevent IMS failure, it's a bit of a lottery which car gets this issue.

btw £166m up for grabs in the lottery. Win that and you won't give a damm about IMS failures :lol:
 
GT4 I have been asked if it is better for a M96 or M97 engines (that's the standard 986,996,987.1 and 997.1 blocks) to run high viscosity oils, like 10w40.

BAZ My answer is YES

10w40, you're kidding, right?

GT4 The reason is the favourite bête noir of the water-cooled flat sixes - the IMS (intermediate shaft).

BAZ Air cooled flat sixes have one and it has proven perfectly OK – the only difference is that in those it is not a ball bearing on the shaft shrouded from an oil supply but a shell bearing (like big ends and main bearings – force fed oil.

Almost all cars have an "IMS" (or layshaft). The engines on a 993 and 996 are so similar, you're kidding right?

GT4 Low oil levels and low oil pressure (at idle when the engine is hot) can result in some or all systems inside the engine being starved of oil.
BAZ Really – come on GT4 is there anyone out there that thinks it is better to run with low oil and low oil pressure?

Apparently this was a joke :dont know:

GT4 Lack of oil to these systems (which control the valves etc) will at best cause increased component wear and reduced operating life, at worth their destruction and ensuing catastrophic engine failure.
BAZ Does anyone need this explaining and what has it to do with the IMS bearing failures?

Not sure if this is meant as a joke too, but how many people owning a 9X6, 9X7 know how the hydraulic tappets, Variocam and VariocamPlus work and what they depend on for their efficacy and longevity?

GT4 It is the oil pump at the end of the IMS that puts the biggest rotational stress on the IMS. However, ironically, it is the oil pump that actuates the Variocam system that needs to be supplied with equal, stable and sufficient oil and oil pressures to prevent IMS imbalances (lateral stress) and bearing stresses!

BAZ Not had a problem though with the pump or shaft.

:frustrated: I must be speaking Mongolian. I never said there was a problem with the shaft or pump, just that they are what the shaft drives or what the shaft works against. Additionally, as stated, if the pump fails to feed the oil actuated chain tensioners controlling the cams, then laterall stress may occur across the IMS and/or the timing is (by definition) disrupted.

GT4 Ignore all the numerous IMS and IMS bearing and IMS seal modifications that Porsche made over the years (three just during the 996's lifetime, two more in the 997's lifetime, not including its final removal).

GT4 None of these fixed the problem: they were attempting to cure for IMS stresses, not a prevention of them.

BAZ All the above relates to the IMS (or intermediate shaft). While much of it is reasonably accurate it is irrelevant because this is not what fails – it is the bearing that fails – and the reasons for that failure have nothing whatever to do with the shaft (otherwise how come all the ones we modify have never had a subsequent failure?).

Hmm, I wonder what might be over stressing the (admittedly under engineered) bearings :?:
I know, I'll write it all down and post it on the forum.
Just because you can produce an engineering cure, does not preclude trying to implement some prevention


BAZ Remember we are not really interested in the IMS failure – only why the bearing fails.

I wasn't, I was interested in what stresses are put on the IMS (and its bearings), not the bearing themselves. That's why I haven't discussed them, or the multitude of other parts (good or bad) in a 996

BAZ There are a few reasons for the failures.
BAZ The bearing starts out filled with grease and sealed to prevent oil getting in. The bearings are an interference fit and some are so tight that they run initially very hot (because the grease is trapped and has higher viscosity) and grinds off a lot of small 'running in"particles and while the heat melts the grease (which exits the bearing) that remaining grease and small metal particles turns into a mixture like grinding paste and wears out the internals.
BAZ The pressure on the outer cage from the bearing being too tight can metal fatigue the cage which splits.
BAZ The wear and heat wear through the ball cage which splits in two halves allowing the balls to crowd together. When they do this the mating faces of the balls run against each other in opposite directions (vreating more wear and heat) while the centre of the shaft runs slightly off to one side. The heat generated is much higher than normal. Eventually the hard surface of the bearing is compromised and results in complete failure.
If a bearing started out loose enough to avoid this problem - the heat generated is less and the loss of grease slower and by the time the grease is running out the seal has worn enough to allow a small amount of oil to penetrate into the bearing to lubricate it (and there is oil being sprayed at high velocity by 2 chains right next to that bearing housing (like a chain running @ 40mph in an oil bath) and the pressure from the splash of that oil will get inside the bearing once the seal has worn a bit. Hence usually if the bearing lasts for say 60K – it may go on for the same amount of time again.
BAZ In view of my explanation – the following padding seems just a lot of hot air about nothing very much at all.

Glad you rolled out yet another speech on bearings again, when I have made no comment on bearings per se.

This time I get to say irrelevant, as that was NOT what the OP asked me about in his PM ref: 0w40 or 10w40.

If you have something to add in the respect of oil grades, I would be grateful.



GT4 Manufacturing fractures to bearing/bearing cage or shaft - this is "discovered" quite quickly during the engines life and is almost instant in its failure mode. Usually only affects one batch of bearings or shafts. IMS failures have spanned a DECADE. This is not likely to represent a common cause over time. Under German and US laws Porsche would have to document the issue to the relevant TuV/DoT regulators. No such documents have been filed.

BAZ How come then that we can re-use the same shaft with modified bearing parts with complete success once we remove the silly seal that causes most of the problems?.

Erm, this list of three "possibilities" were meant as a process of elimination. If you re-read that first paragraph, it is written to conclude NO batch manufacturing fractures to bearing/bearing cage or shaft have been proved. ie you actually agree with the conclusion?

GT4 2) Out of balance shaft due to manufacturing or build alignment - this would cause the bearings to rapidly wear, wear unevenly and eventually collapse. However, the noise created by an out of balance IMS would be unmistakably evident on start up. The engine would run badly as the valve timing would-be out and would trigger the DME to illuminate the CEL (engine warning) to full emergency FLASH mode (warning of impending disaster). This would allow an observant driver enough time to turn off the engine before it explodes. Again, if this were to occur, once the engine had been returned to Porsche and investigated, under German and US laws Porsche would have to document the issue to the relevant TuV/DoT regulators. No such documents have been filed.

BAZ An out of balance shaft would not put any valve timing out (only a complete beraring failure does this once it has failed) – nothing would be triggered - just load the bearing a little more radially than a well balanced one.

Again, this "possibility" is put forward in the process of elimination and is then eliminated on our way to a definitive cause of IMS failure (or at least the most common or probable). So again you actually agree with the conclusion?

GT4 3) Lack of engine oil to hydraulic systems - this is caused by both true low oil, the wrong oil and instantaneous low oil (starvation) during start-up, high hydraulic use and high-G cornering etc. This is the most likely cause of the intermediate bearing collapse. This is NOT to be confused with the oil (grease) in or not in the IMS ball-races, this is the hydraulic and general oil system the IMS pumps and uses to balance itself (or at least without, becomes imbalanced).

BAZ This has nothing to do with it in a standard grease filled bearing with the seal still in place since replenished oil is not what it is using for lubrication.

Yes – low or no oil will not help any lubricated system to survive but this is just a smoke screen.

Never said it did have any affect on the supposed SEALED (or at least the bizarrely intentionally sealed at inception ball-races). This is all about how one grade of oil or another may affect instantaneous stresses on the IMS.

I know the old adage that everything to a man with a hammer looks like a nail, but really, not every question has the answer "defective bearing".


GT4 (3) has no other cause other than the owner or driver's use or abuse.

BAZ There is no use or abuse I can think of that will have any influence on the IMS bearing unless it is to drive with low or no oil so the other parts of the engine suffer and add load and heat to the IMS bearing that way.

OK, so it's the bearing again. I can't argue with that as A) that wasn't the point of my post, B) I am getting tired of all this bearing stuff.

Use and abuse can, oddly, affect ALL the cars systems


GT4 Porsche partially recognised this oil significance and bumped up the 996 crankcase capacity by another 6% (0.5 litres) in MY1999 and also modified the bearing housing (this is in addition to the three 996 direct IMS mods).

BAZ None of which achieved anything because they all retain the seal.

Hmm, Porsche add oil capacity to increase consistency of supply to hydraulic ancilleries and some how that has what to do with an unrelated seal?

GT4 So, the oil should always be filled to the brim (so to speak), we know that (and can handily check from the driver's seat without even pulling the dipstick, you have no excuse!).

BAZ I cannot argue with that.

Thank **** for that!

GT4 But what oil? Well Porsche is pretty specific and unequivocal about this: 0w40.
Yes, it is thin and, yes, that means it can leak (especially with an old or ill fitting RMS), but to not bother getting to the cause and rectifying seals and gaskets or simply tightening block bolts etc by bodging with a thicker (non-leaky) oil is inexcusable. The "0w" in that code means it is exceptional thin when cold.

BAZ But this is only because if it was thicker when the engine was newer it would be more difficult to get into the seal and lubricate the bearing – which of course simply removing the seal does very nicely.

Oh FFS, who brings a bearing to a hydraulic ancillery fight?
Look, Porsche never intended oil of ANY grade to enter your damned bearing as they conciously SEALED it! (and no, I don't want a discussion about how they shouldn't we all know that, and after-market is by definition in hind-sight. But is ISN'T anything to do with oil grade used


GT4 This is when the engine is at most stress, the pump is at most stress, the engine is unlubricated, all those hydraulic systems (tappets, Variocam, VariocamPlus etc) are all unpressurised and ineffective.

BAZ The engine is at most stress at peak revs and full throttle – in this condition the oil delivery is at the maximum oil pressure the oil pressure relief valve allows and all systems are receiving the maximum oil delivery in volume and pressure possible.

Outside of simple heat stresses or friction wear, which obviously occur most at high engine speeds, peak oil pressure is most defininitely an indicator of high stress loads. Guess what, you get 5 bar plus at start-up. All this post was about was using thicker or thinner oil ("Xw") at start-up (not operating temp, as "Xw" has no bearing :doh: then). Did you just say "all systems are receiving the maximum oil delivery in volume and pressure possible", so you want the pump to pump oil to where it is needed as quickly as possible, and you ant the pressure transmitted without viscosity losses :?:

If only there were a fast moving, low-viscosity loss oil for use at start-up?


GT4 So help it out: the "0w" (low viscosity oil) will operate all its hydraulic systems as quickly as possible and get around the engine quicker and hence reduce your start-up wear.

BAZ But as clearances increase (this is what wear is) a thinner oil is less effective and seeps out of the gaps left when the car is parked up resulting in less oil on start up (which is when most wear takes place).

Yep, this advice is for un-shagged engines. This is for when they are young, before they develop IMS failure. If the engine has survived long enough to round out, then it has probably gone past the point where the IMS failure we all dread can happen. At that statge everything is just fair wear and tear.

Every post I have every made before has advocated 0w40 as long as the engine is young and tight enough eg:

http://www.911uk.com/viewtopic.php?t=64051
http://www.911uk.com/viewtopic.php?t=60002
http://www.911uk.com/viewtopic.php?t=46081
etc etc


GT4 Most importantly, when it comes to the IMS, the super thin "0w" will be less stress on the pump at the end of the shaft and will balance the Variocam tensioners across the IMS quicker, and hence reduce IMS bearing stress.

BAZ Only when new but once the tensioner seals wear and shafts wear they leak quite a lot and this reduces the pressure on the tensioners – so a thicker oil actually leaks less and preserves pressures better. The main stress to the bearing is the result of the cams having large bumps (or lobes) on them and clattering into tappets, valves and springs 12 times every 2 * revs creating tension changes in the chains and hydraulic tensioners and transmitting this down to the sprocket which is therefore subjected to continuous acceleration and deceleration and therefore torque.

Exactly! Thicker oil is used to hide losses or leaks, not for the benefit of the systems it is supposed to run. 10w40 is for mechanics who can't be bothered to change a seal, gasket, tighten up bolts or simply swap out the old for new.

GT4 Because of all this, DON'T rag it cold either, or even "warm", wait until it is good and hot (at operating temp and oil pressure <2 bar at idle), then the oil is even thinner. That oil pressure gauge is saying how much stress the pump and IMS are under. Try to minimise it.
The IMS is under greater stress if the delivered oil pressure is higher at higher revs -

BAZ but all the other parts are more likely to wear if the running oil pressure is below maximum (which it is at low revs) – it is not the shaft we are worried about – but the bearing which is not pressure fed anyway.

So ignoring the bearing (yet again), are you saying Porsche designed an oil pump that can't pump enough?

Oil is incompressible, it doesn't matter how thick or thin it is, it WILL transfer ALL the pressure everywhere almost instantaneously - that is the point of ALL hydraulic systems, be they the brakes on your car or the rams on a JCB. If, however, if it is thick, it will present FLOW problems.

Again, this is all a smoke screen (as you might put it), as 99% of the time 0w40 = 5w40 = 10w40 = Xw40 as it will be at operating temp. For the first few minutes in every drive I want my oil where it is supposed to be as quickly as possible, everything else is irrelevant.


GT4 In the words of Swiss Tony:
"Driving a Porsche is like making love to a beautiful woman - make sure she's hot and wet before the rough stuff" (or something like that)

BAZ I cannot argue with that but intend to test out the theory - again!.

:floor:

GT4 Here is the IMS and the oil pump, and the Variocam tensioners and the VariocamPlus cam control and the valves etc etc:

BAZ IN CONCLUSION I think I could have probably written GT4's report if I was instructed to write an article to deflect attention from the true situation, weave a lot of true but completely irrelevant points into it (to gain the nod of readers as they plod through it) and generally try and make it seem that it was just one of those things. I reads like an employee asked to write a whitewash story full of basically true but practically irrelevant points that provide a smoke screen to the real cause of the problem – the idiotic decision (IMHO) to fit a seal to shroud the bearing from a cool and refreshed oil supply (which the actual bearing manufacture also commented in the same light to me). It was brilliantly executed too – FULL OF TECHNICAL ISSUES THAT ARE ALMOST RIGHT OR RIGHT BUT HAVE NOTHING TO DO WITH THE PROBLEM OR THE SOLUTION, but I find it hard to believe that GT4 has not read my reports before (detailing all the above) and I suspect that he already knows that after fitting the same basic bearing to shafts that are not too tight on the interference fit, with a stronger spindle – but no seal – there has never been any problem whatsoever – and this in itself is the ultimate proof that the only problem is with that silly seal and the consequences. Even without a seal - when the car is left standing the groove in the bearing is vertical so retains oil in the bottom so there is always oil there on start up.

Sorry to disagree GT4 – I simply could not allow such a lot of misleading stuff be recorded as the oracle on the subject without putting in my point of view (surely you already knew I would).

We all have an opinion – many differ – mine is from the point of view of a qualified design engineer and engine designer of previous merit and performance that has found a simple explanation and solution that has works 100 % and is currently responsible for the rebuilding of one engine/day and therefore not only probably sees more failures than anyone else Worldwide – but also provides the most satisfactory proof that his diagnosis and solution is right.

Baz

OK, so thanks for ending on a, guess what, a bearing note, but I again ask what this has to do with:

I have been asked if it is better for a M96 or M97 engines (that's the standard 986,996,987.1 and 997.1 blocks) to run high viscosity oils, like 10w40.
 
Baz Hartech vs gt4 for the world heavyweight unification title.

I watched the haye klistcho fight on the weekend but this 911uk title bout between the forum big boys is both more interesting and more actionpacked!

For what it's worth I'm with gt4 on this one, thinner oil is better for cold engine start ups plus Porsche have it as their recommended oil - now Porsche know best surely ;)
 
In fairness, I find it hard to argue logically with a design engineer who thinks water turns to air when it boils :? :

hartech said:
JM1962 said:
Baz
Not wishing to be picky, but when the coolant boils it forms steam bubbles not air bubbles.
Thanks for that JM1962 I suppose it is only fair for you to point out that my description was not 100% accurate although I don't think it adds anything to understanding the events or causes I was describing.

In my defence - unfortunately if I explained all the engine problems on here in the correct technical way without any background or analogies that enabled less well qualified people to follow the salient points - fewer people would benefit (and to be fair I have not noticed any other contributor covering anything like the technical issues I try to convey to the public to empower them to understand them if they need to or help them make informed choices to protect their interests). I try to find a balance between simplifying things and being correct so the majority benefit from being able to understand the issue - but this is always dangerous - as your posting demonstrates.

For your benefit (if I remember my schooling of 40 years ago correctly)
Coolant behaves like water and as such has different states from frozen to gas and in the middle steam. There are two types of steam - vapour and superheated steam (which is a gas).

Vapour is difficult to explain because it has lower density than liquid and hence increased volume. The problem is that increased volume of coolant (as steam bubbles) pushes coolant out of the expansion cap - so next time after it cools there is less coolant left inside and it doesn't neccessarily reach the same running pressure hence can boil/release steam bubbles/air bubbles whatever at a lower temperature than before and decrease the cooling potential at the source - the cylinder wall.

Fourty years ago we did not study atomic science much or molecular thoeory - but nowadays it is built into the education system from a very early age - a much better way of dealing with such issues.

If you understand this better than me I would be interested to learn exactly what steam vapour consists of. You are right it is not "air" bubbles because steam as a vapour is tiny droplets of water (or coolant) which I think must then be mixed in with with a gas (since the density reduces). But the gas will not be air because it has been formed from H2O - so is I suppose some form of a mixture of Oxygen and Hydrogen (whereas air is mainly Nitrogen - 78%).

It would be interesting to have this clarified but - in terms of helping readers understand the issues so they can decide for themseves what to do in the future to protect their interests or what questions to ask of their chosen repairer before commiting a rebuild or investigation somewhere that has limited options - I don't think whatever this gas is - makes any practical difference.

Read the rest here, it actually gets worse:

http://www.pistonheads.com/gassing/topic.asp?h=0&t=400915&r=16679193&hm=191711&mid=191711#16679193
 
:evil:

Bullet-proof residuals, bullet-proof engine reliability, bullet-quick performance and now cheap servicing.

Where do you GT1-block boys get off from rubbing it in :sad:
 
This is a good debate,some very knowledgable individuals posting information of interest to us all,pls dont turn it into a ***** fight,there is nothing of benefit in that for those of us who are recent owners
 
Yes it is getting out of hand and I also must apologise for mistakenly posting a response on the wrong web site (in my defence just rushing to answer things while very very busy all the time at work - think I did that at home after work - my mistake - sorry.

What worries me is that most of the readers really don't know enough about engineering to judge who is right and who is wrong and the arguments we put forward are often over their heads. I worry about this – not over the 'who is right or wrong" (personally I couldn't care less about what others think of me) but because it is them that may have to make a value judgement one day and not know whom to believe when there seem to be two opposing views of the same issue – and they could get it all wrong.

I don't have time to respond in detail any more - sorry - I wish I could - but the problem is - even if I dissected each and every statement and put the right answer to it – recent history suggests that GT4 would just cloud his response with a lot of other irrelevant facts (in themselves probably reasonably accurate) but in no way proving his answers are right (except by reference to some technical point - not practical results) and the readers won't know what to make of it.

In Politics the best politicians always answer difficult questions by relating a lot of academic facts that the public would agree with (but actually don't answer the question) and then if you are lucky) throw in a brief response half answering the question they were put and carry on with irrelevant issues - luring the public into finding they agree with almost everything they said - although they never actually answered the question with a bit of metal. GT4 - go into politics - you would be brilliant.

I am not good at politics and technically you could break down this problem into tribology, manufacturing, materials specification, dynamics of machines, stresses and strains, metal fatigue etc etc and fill a book with lots of specialists answers on the whole subject - without anyone actually putting their finger on the simple and salient issues.

So I am going to withdraw from future responses on this one as I don't think we are helping anyone to be better informed any more.

I must just make the following points.

You say you protect your IMS bearing by waiting for it to fully lubricate yet also state that Porsche never intended it to be oil lubricated - bit of a nonsense logic there for anyone to read.

You also suggest my posting is just to sell our IMS kit - but we don't retail it - we just fit it as an option to engines we rebuild - with no failures. you still have not answered the simple "real issue" that removing the seal from the same parts you criticise at length renders the system acceptably reliable - how is that possible if all the other problems you state are contributory factors still exist?.

For those confused about all the technical posting content - let me just say that the bearing manufacturer recommended no seal and we think it is the cause of the problem and that removing it has proven us right. There are paragraphs of postings from GT4 about all sorts of other technical problems with the IMS system (but not mentioning the seal) while we find simply removing it totally solves the problem. Readers should ask - what then is relevant to the issue?

Finally - there are some people able to regurgitate a lot of technical stuff without having ever designed or made anything successful (which is hundreds of times more difficult) and they tend to give themselves away by regurgitating the same stuff while never actually finding the simple answer or proving it - all just theoretical answers.

There are others who have a long record of successfully actually designing real and tangible things and proving they work and also re-designing problems in other engines and proving they could find the problem and fix it. Sometimes it is difficult to explain where such people get their inspirations from - but they if they are good at it they usually have a long history of similar success.

I hope I am too modest to use this to reveal my full history - but - in the context of this particular argument - can I just cover a very small part of it - as follows. Designed the production machinery that revolutionised the manufacture of the Trent titanium fan blades for Rolls Royce. Designed several complete engines (including transmissions, manufactured them and won numerous races with them against full blown largely Japanese multinationals manufacturers (best result of which 3rd in the French GP), numerous International and National class race wins and British Championships. Solving technical problems for Ducati, Suzuki, and Norton. Re-designing racing parts later adopted by main stream engine manufacturers. Designing and building the prototype of Barry Sheen's 650cc square four racer. Writing a technical manual on designing with composites for "metal engineers" and I could go on and on.

What this means is that - when there is a conflict of explanations or solutions - there are some people who can prove they have and can come up with the right answers again and again and others who can just hide behind technical jargon and cloud the issues - but who have never proven that their understanding of things works because they have never made anything significant.

Regardless of whom non technical people can believe - some people just have the right answers and some just talk a good talk.

Moving on to these engines and oil etc - the very first time I opened one up (before there was any general history of failures) I made two significant statements to my workforce. I said whoever designed the IMS bearing part should be sacked (and would have been if I had employed him) and that the open deck cylinder design would result in premature ovaility. I predicted that they would be less reliable than previous examples and that we should get in early to finding solutions and setting up to rebuild and repair them because the numbers would increase exponentially - and that was absolutely right and we (and our customers) are benefitting from the outcome.

At that time I didn't yet realise that there were also a few other errors in design (IMHO) like the temperature differential between the cylinders and cylinder head etc (that emerged as problems later) but each time a new problem has occurred - we have quickly (and with comparatively limited resources compared to Porsche) come up with the right answer first time and provided excellent cost effective solutions (later adopted by Porsche in their Gen 2 engines).

Readers are free to decide whose interpretation of the problems of oil and the cause of IMS failures they should listen to - I really don't care as long as both sides of the argument are presented for consideration.

I didn't want to make this a personal thing and regret it has become embittered - sorry everyone - I just cannot ignore it when advice is trotted out by anyone presenting themselves as experts when it is clear to me they are obviously mistaken and the consequence misleads the public who are trying to make sense of the issues.

Sorry GT4 - unlike you - I have given good opinion of most of your previous postings (I believe in credit where it is due) and I realise that by disagreeing with you in public - you are bound to need to defend your reputation by cranking up the same misleading and irrelevant nonsense that I responded to in the first place.

All engines wear and some more quickly than others. When they do clearances increase and thicker oil is better than the original thin oil that may well have been OK when it was new. Manufacturers do not seem to advise owners of this but racing engines where there is more load and temperature (and similarly greater clearances) do not usually run on thin oil despite all the nonsense about shear power losses of thicker oil.

Because I don't think any further postings will help anyone still undecided whom to believe - this is my last on this posting - so any of you are free to regurgitate anything in technical books or manuals or Porsche literature - if you want to - please just add (for the benefit of readers) what, when and where you used that knowledge and ability to actually prove you can be relied upon as a source of engineering excellence and your success rate at solving problems with Porsche engines (so it can be compared with ours).

Baz
 
Hmm so who's advice would I take.

1/ Baz who repairs 911's day in and day out and who has invested vast sums of cash in solving engine problems.

2/ GT4 a keyboard mechanic? IMO.

No contest as far as I can see
 
Rimmer said:
Hmm so who's advice would I take.

1/ Baz who repairs 911's day in and day out and who has invested vast sums of cash in solving engine problems.

2/ GT4 a keyboard mechanic? IMO.

No contest as far as I can see


GT4 also fixes keyboards?


In all fairness from what I've read the issue seems to have been a bit confused. I read GT4s original post as an observation of the effect of oil grade and general car usage rather than a criticism of any particular part of the engine.
 
GT4 - go into politics - you would be brilliant.

Thanks, I'll consider it.

I must just make the following points.

You say you protect your IMS bearing by waiting for it to fully lubricate yet also state that Porsche never intended it to be oil lubricated - bit of a nonsense logic there for anyone to read.

Erm, no, I said I'll wait for the ENGINE to become fully lubricated.

For what i can only hope will be the LAST time, all my posts had no intention of discussing bearings at all. This is all about the effect of low oil or different grades of oil in the main engine (hydraulic systems).

You mentioned politic earlier, Margaret Thatcher was brilliant at making the points she wanted to make, irrespective of the question.

NO ONE ASKED ABOUT BEARINGS!!!

To be fair, I completely agree with your work on bearings, and am fully aware of it, but just as I have not touched on RMS seals, I have not touched on IMS seals or any number of other great after-dinner anecdotes.


You also suggest my posting is just to sell our IMS kit - but we don't retail it - we just fit it as an option to engines we rebuild - with no failures. you still have not answered the simple "real issue" that removing the seal from the same parts you criticise at length renders the system acceptably reliable - how is that possible if all the other problems you state are contributory factors still exist?.

I have not criticised (or even discussed) the blinking bearings, the only person talking balls (in a ball-race) is you.
And obviously you don't sell that service of fitting the option? Interesting


For those confused about all the technical posting content - let me just say that the bearing manufacturer recommended no seal and we think it is the cause of the problem and that removing it has proven us right. There are paragraphs of postings from GT4 about all sorts of other technical problems with the IMS system (but not mentioning the seal) while we find simply removing it totally solves the problem. Readers should ask - what then is relevant to the issue?

FINALLY YOU GET IT - yes I made a post that is NOT about seals or bearings. If only we had established that about four pages ago, then you could just have started you OWN thread about seals and bearings.

And guess what, I would agree will every bit of it, but bearings have no bearing on the points MY thread is about.


Finally - there are some people able to regurgitate a lot of technical stuff without having ever designed or made anything successful (which is hundreds of times more difficult) and they tend to give themselves away by regurgitating the same stuff while never actually finding the simple answer or proving it - all just theoretical answers.

Hmm, the same stuff, you find me ANYWHERE else on the internet the issues raised in my original post about all the hydraulic systems and their effects on IMS stresses and I'll buy a bearing kit from you. Stresses which EXCEED the manufacturing tolerances of the bearings. There I said it twice - BEARINGS!

I was originally discussing cause and effect of OIL and IMS stresses- not bearings, you brought up bearings.


There are others who have a long record of successfully actually designing real and tangible things and proving they work and also re-designing problems in other engines and proving they could find the problem and fix it. Sometimes it is difficult to explain where such people get their inspirations from - but they if they are good at it they usually have a long history of similar success.

Oh yes, I've heard of Baz Hart, he's the one who's big in bearings.

I hope I am too modest to use this to reveal my full history - but - in the context of this particular argument - can I just cover a very small part of it - as follows. Designed the production machinery that revolutionised the manufacture of the Trent titanium fan blades for Rolls Royce. Designed several complete engines (including transmissions, manufactured them and won numerous races with them against full blown largely Japanese multinationals manufacturers (best result of which 3rd in the French GP), numerous International and National class race wins and British Championships. Solving technical problems for Ducati, Suzuki, and Norton. Re-designing racing parts later adopted by main stream engine manufacturers. Designing and building the prototype of Barry Sheen's 650cc square four racer. Writing a technical manual on designing with composites for "metal engineers" and I could go on and on.

What this means is that - when there is a conflict of explanations or solutions - there are some people who can prove they have and can come up with the right answers again and again and others who can just hide behind technical jargon and cloud the issues - but who have never proven that their understanding of things works because they have never made anything significant.

Regardless of whom non technical people can believe - some people just have the right answers and some just talk a good talk.

Moving on to these engines and oil etc - the very first time I opened one up (before there was any general history of failures) I made two significant statements to my workforce. I said whoever designed the IMS bearing part should be sacked (and would have been if I had employed him) and that the open deck cylinder design would result in premature ovaility. I predicted that they would be less reliable than previous examples and that we should get in early to finding solutions and setting up to rebuild and repair them because the numbers would increase exponentially - and that was absolutely right and we (and our customers) are benefitting from the outcome.

At that time I didn't yet realise that there were also a few other errors in design (IMHO) like the temperature differential between the cylinders and cylinder head etc (that emerged as problems later) but each time a new problem has occurred - we have quickly (and with comparatively limited resources compared to Porsche) come up with the right answer first time and provided excellent cost effective solutions (later adopted by Porsche in their Gen 2 engines).


[Cue music to "Our Tune" with Simon Bates]

Readers are free to decide whose interpretation of the problems of oil and the cause of IMS failures they should listen to - I really don't care as long as both sides of the argument are presented for consideration.

There is no argument, you bearings bloody briliant, the point of this thread was to discuss the not so brilliant use of THICK oils.

I didn't want to make this a personal thing and regret it has become embittered - sorry everyone - I just cannot ignore it when advice is trotted out by anyone presenting themselves as experts when it is clear to me they are obviously mistaken and the consequence misleads the public who are trying to make sense of the issues.

Sorry GT4 - unlike you - I have given good opinion of most of your previous postings (I believe in credit where it is due) and I realise that by disagreeing with you in public - you are bound to need to defend your reputation by cranking up the same misleading and irrelevant nonsense that I responded to in the first place.

I stand by all the "nonsense" in my first post, and until you contribute anything useful ref: OIL GRADE vs IMS STRESSES, then you needed come back here.

All engines wear and some more quickly than others. When they do clearances increase and thicker oil is better than the original thin oil that may well have been OK when it was new. Manufacturers do not seem to advise owners of this but racing engines where there is more load and temperature (and similarly greater clearances) do not usually run on thin oil despite all the nonsense about shear power losses of thicker oil.

Because I don't think any further postings will help anyone still undecided whom to believe - this is my last on this posting - so any of you are free to regurgitate anything in technical books or manuals or Porsche literature - if you want to - please just add (for the benefit of readers) what, when and where you used that knowledge and ability to actually prove you can be relied upon as a source of engineering excellence and your success rate at solving problems with Porsche engines (so it can be compared with ours).

Baz

AMEN
 
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