my 996 engine blew up.

my 996 engine blew up.

Author
Discussion

andymin

197 posts

211 months

Tuesday 19th January 2010
quotequote all
http://x17online.com/celebrities/mark_wahlberg/mar...

how black is that oil!

Edited by andymin on Tuesday 19th January 16:50

GT Glee

705 posts

174 months

Tuesday 19th January 2010
quotequote all
evswift said:
The Porsche 911 was my dream car. A couple of years ago I bought a 2000 model Porsche 996 with 70,000Kms on the clock and full service history from Porsche. I had it 3 months and the engine stopped. I took it in and they said that the conrod had gone through the block! - The engine was destroyed! - I called around to get a 2nd hand motor and it seems that these 3.4 engines are a disaster! Porsche wouldnt do anything about it and I am shocked that I paid so much for a "reputable" brand and it blew up!

I sold it on Ebay broken. I lost $22,000 on it. I will NEVER buy a Porsche again because their after sales was shocking. They know that there was a problem but would not help me. If you have a 996 sell it quickly or it could blow up at any time. I had no oil leaks, not a drop! FULL service history every 10,000kms (6,000 miles) and it still died! Now I can afford a new 997, but I wont be buying one because I cant trust Porsche as a company. The R8 looks nice..... hmmm....
Strange how this is your first PH post as a new member TODAY. How come you've never shared a positive story about your 'dream car'??

Regarding your particular issue, I've not heard of rods letting go (Type 2's????). The much documented issues relate to cylinder or intermediate shaft bearing failure, on around 5% of the normally aspirated engines produced.



Edited by GT Glee on Tuesday 19th January 17:48

supersport

4,032 posts

226 months

Tuesday 19th January 2010
quotequote all
GT Glee said:
evswift said:
The Porsche 911 was my dream car. A couple of years ago I bought a 2000 model Porsche 996 with 70,000Kms on the clock and full service history from Porsche. I had it 3 months and the engine stopped. I took it in and they said that the conrod had gone through the block! - The engine was destroyed! - I called around to get a 2nd hand motor and it seems that these 3.4 engines are a disaster! Porsche wouldnt do anything about it and I am shocked that I paid so much for a "reputable" brand and it blew up!

I sold it on Ebay broken. I lost $22,000 on it. I will NEVER buy a Porsche again because their after sales was shocking. They know that there was a problem but would not help me. If you have a 996 sell it quickly or it could blow up at any time. I had no oil leaks, not a drop! FULL service history every 10,000kms (6,000 miles) and it still died! Now I can afford a new 997, but I wont be buying one because I cant trust Porsche as a company. The R8 looks nice..... hmmm....
Strange how this is your first PH post as a new member TODAY. How come you've never shared a positive story about your 'dream car'??

Regarding your particular issue, I've not heard of rods letting go (Type 2's????). The much documented issues relate to cylinder or intermediate shaft bearing failure, on around 5% of the normally aspirated engines produced.



Edited by GT Glee on Tuesday 19th January 17:48
This story sounds identical to another chap that was on here a couple of years ago even down to being his dream car. I thought he had been driving it around even though it had behaving badly and in the end it exploded.

JT944

283 posts

221 months

Tuesday 19th January 2010
quotequote all
so what baz is saying is if you have a 996 with 50.000 miles on it pull out the engine and fit some new shells and seals as part of a big service and you will save mony in the long run

kVA

2,460 posts

204 months

Tuesday 19th January 2010
quotequote all
supersport said:
Regarding your particular issue, I've not heard of rods letting go (Type 2's????). The much documented issues relate to cylinder or intermediate shaft bearing failure, on around 5% of the normally aspirated engines produced.
+1

Broken con rod has no relation to any of the much exaggerated IMS / cylinder wall issues and as for Porsche not helping - are you surprised after 10 years!!! Can you name any car manufacturer that will give you a 10 year guarantee?

Jeez!

GT Glee

705 posts

174 months

Wednesday 20th January 2010
quotequote all
"If you have a 996 sell it quickly or it could blow up at any time" blabla

Time to bring out the..

Bund

2,623 posts

220 months

Wednesday 20th January 2010
quotequote all


"whos looking at you kid"

Edited by Bund on Wednesday 20th January 11:52

GT Glee

705 posts

174 months

Wednesday 20th January 2010
quotequote all


"Damn those humans in their expensive sports cars. Wait til we trolls take power.. then we'll show them grrrrrrrrrr".

hartech

1,929 posts

216 months

Wednesday 20th January 2010
quotequote all
I found it very interesting - reading back through this posting (mostly relating to replies over three years ago) and I am pleased to find all of our predictions holding up and indeed we have now not only been using the dedicated 996/Boxster engine building room (mentioned then as a future intention), but have just finished a second larger one to house the increased number of engines we are rebuilding (now more than one/week) and recruited and trained more staff and invested in more equipment (including our own in house cylinder block machining centre with diamond tooling), diamond faced hones etc, etc. In fact we are now expanding our engine rebuilding range to include replacement liners for 944’s and 968’s including the potential to increase bores on a 944 turbo to 104mm to make a 3 litre version. Also relevant to those postings are that we are also testing our own 996/Boxster crankshaft repair system with wider shells, to solve the increasing incidence of crankshaft failure – often resulting in a broken rod (but so far always caused initially by a bearing failure) and will eventually provide oversized pistons to increase rebuild options as cars drift towards becoming future classics.

Having so much more experience of so many engine rebuilds now – I can perhaps offer a more balanced view of things.
The original Porsche engines were designed decades ago and manufactured with a huge safety factor enabling much more than standard power to be put through the basic engines with complete impunity. For example our own 3 litre 944 turbo handles twice the standard torque through the original transmission with no problems and many other 911 variants used “standard” parts in turbo versions and could still be tuned up even more to deliver more power safely. However this also means that were originally made with larger, heavier and stronger internals and better cooling and lubrication systems than the standard engines really needed, and by manufacturing methods that were outdated and expensive – contributing to Porsche’s severe financial problems in the early ‘90’s.

With modern pressures on manufacturing costs, mpg, performance and emissions (requiring internals as light as possible) I would argue that Porsche had no alternative but to lighten internals to satisfy only the demands of each particular engine and follow more modern manufacturing methods – making engines designed just for the purpose intended and not with so much in reserve that they could double up as something much more powerful (hence those versions now having different designs, internals and costing much more). If they had not done this most current owners would not have been able to afford their Porsche Boxsters and std 996’s which would have become a Ferrari type supercar just for the very rich.
For the vast majority of owners they achieved that balance perfectly but whereas the pre ‘96 engines went through years of gradual development as they also increased outputs – each refining a good basic design and making it better and better – inevitably some minor mistakes were made with these new engines resulting in a small number of serious failures and probably in the future a slightly earlier need to recondition engines at lower mileages than before. What surprises me however is the difficulty they apparently had doing anything about it when the weak spots seemed easy to identify and simple to fix.

The Lokasil cast in liners are brilliant for lubrication, low wear and production costs and simply needed stronger thicker supports or retrofitted support rings to solve their creep to ovality and cracking. The IMS bearing simply needed the seal removed and a stronger spindle. The cylinder head needed some internal section thicknesses increasing or webbing to strengthen the area that fatigue cracks (mainly for those engines driven hard too soon while not fully warmed up). The RMS needed fitting to an extended crank carrier rather than the cases (so it was in line and shrouded from the increased oil delivery in the area). The oil separator needed a longer lasting better quality diaphragm. The crankcase joint sealant material should have been changed to avoid overspill blocking oilways.

All this could have been achieved without major re-tooling or costs and I suppose it was internal politics or lack of experienced problem solvers that resulted in it taking 15 years to do something about it (it certainly was not lack of financial resources that delayed solutions).

The fact that oversized pistons and undersized shells and cranks that can be re-ground are not available also suggests a change in general policy that engines should be replaceable not re-buildable and is never the less in line with most modern engine manufacturers influenced by the increase in labour costs in the West and our increasing ability to afford the latest and most fashionable things and discard perfectly good products that we simply don’t want to be seen to own anymore. So Porsche should not be too concerned about what owners who can afford a 10 or 15 year old Porsche need in this era but should concentrate on what they want to buy new next year and the year after (which they seem to be doing very well indeed).

For those disappointed with a slight reduction in the expected longevity and reliability of these models – the spirit of free enterprise will always come to the rescue as people see an opportunity to provide services or products to solve their problems – as we have – with our low cost Maintenance Plan and a range of engine rebuild options that are reasonably priced and solve the technical weaknesses they may have experienced – as anyone on our scheme should have nothing to worry about and if they keep their car long enough - will eventually benefit from a very inexpensive engine rebuild, when something goes wrong – while those not on the scheme can still get out of trouble in most cases, by paying far less than the cost of a new engine, similar to the cost of a used engine and similar to the cost of rebuilding the top end of an older 911 or a 944 engine rebuild – with many options and alternatives made available depending on their long term plans for the car.

Baz

GT Glee

705 posts

174 months

Wednesday 20th January 2010
quotequote all
When looking for my 996 Carrera, I came across a 130k mile '98MY 3.4. Original engine, absolutely sod all wrong with it. Yet, on the other hand you hear about engines dropping out with less than 20k miles on the oddometer. This to me suggests either manufacturing/process or conditions of use as opposed to fundamental design. Very confusing headache

hartech

1,929 posts

216 months

Wednesday 20th January 2010
quotequote all
It is confusing and that is a very sensible conclusion and exactly what we thought at the outset - but it didn't explain all the results.

Modern production and inspection methods greatly reduce manufacturing costs but while the vast majority of production is every bit as good as those made the old ways, unfortunately there is often a small percentage that results in failures. This creates a manufacturing option to make a product the old way that is say 99.9% perfect, but costs more to produce (increasing final sales prices and reducing sales volumes and profitability) or make it the new way that is say 99% perfect - costs much less, allows a competitive sales price (increasing volumes) and still makes more profit – the only downside being that extra 0.9% failure rate (nine times as much as the original method produced).

If the additional profit generated using this philosophy is more than 1 % (and it is usually much more than that) then it can be more profitable to repair or replace the failures FOC than revert to old fashioned methods. Furthermore if your competitors (or even just one competitor) uses the more modern methods and offers his product at a more competitive price – they sell more – your volumes reduce and with it your profitability plunges – so there is little option unless you want to be a very low volume high price product provider.

In the case of engines - if you make an engine far stronger and better than it actually needs to be to fulfil its primary function, with well proven technology - then although it will be expensive - it should be very reliable - because if it is never stressed anywhere near its design, lubricating or cooling limits - then despite slight differences between the quality of the parts making up each car - they will still almost never fail.

However if you make something operating much closer to all its various design limits, then it's performance should actually be better (as a lot of bits will be lighter) - but - even with the same quality or degree of tolerance/quality variation - there will be some occasions when a slightly inferior component in the mix now causes a failure – because it was closer to its limits anyway. That same variation may not have resulted in a failure if it had occured in an older design of engine because even with the slight reduction in fit, quality etc it is so far inside its designed limit that it still works perfectly OK.

So I think that a mixture of a few design failings, a general reduction in design safety factors combined with modern production methods - makes up the full explanation.

Items like bore ovality and cylinder head design needed a design change and so all could eventually fail - the time scale simply being different in different cars - some probably never actually cracking before the car is put to rest. The Lokasil was actually a clever idea that had the potential to make a brilliant bore surface but the problem of creep in metal matrix composites is very new technology and not fully understood – needing more time to gather information. However the relatively small extra cost of a new core pattern producing a thicker cylinder wall or the fitting of restraining rings could have completely eliminated the possibility.

Items like crankshaft bearing failure, is more because the reduction in case hardness depth, slightly inferior shells, lighter less strong con rods with a different manufacturing method (cracked joints), narrower shells (reducing load tolerance) and also that in some cases of the overspill from crankcase sealant finally breaking away from the joint and blocking either the oil pick up intake or an oil delivery hole.

Items like the IMS bearing relate both to design and tolerances because without the seal they would all be better lubricated and enable wear particles to escape while minute differences in the manufacturing sizes/tolerances will result in some being fitted tighter than others and more prone to the closeness of that design to the failure point – some failing while others manage to get through the initial running in period and then last (as the lower quantity of particles has managed to escape and the seal has worn allowing more oil to pass through).

Most manufacturers now find it more profitable to use modern production methods and tolerances that result in most products being perfect but a slightly higher incidence of failure than before – the difference here being the manufacturers attitude towards responsibility and contribution to costs (as I am pretty sure that if Porsche had decided to cover the costs of these typical failures or make reasonable contributions towards them – they would still have made the biggest profit ever).

Baz

GT Glee

705 posts

174 months

Wednesday 20th January 2010
quotequote all
Thanks for the comprehensive reply, Baz. I can see your point and would like to add..

One of the original design goals was to reduce weight 'thanks' to ever increasing safety standards tending to increasingly bloat modern vehicles. Given this objective I can imagine a fit-for-purpose engineering mentality, since any excess would be deemed dead weight. But as you point out, engineering tolerances become more finite and thus a higher component failure (or potential failure) rate could creep in, or evidently has crept in. We are also looking at a % failure rate of a higher volume, since IRO 160,000 996 models (of all types) were manufactured. The 997 of course inherited the M96/01> series engine and therefore the story doesn't necessarily end with the 996.

There was a 3-fold+ ramping up of manufacturing volume for the 1999 model year due to Porsche preparing for sales in the US. The increased work load feasibly having an impact on the proportion of failures.

Someone mentioned that the GT3 engine should've been in the water-cooled 911, period. While the cost of doing this would be prohibitive, there is argument for a similar architecture but using less exotic materials or finishing processes (such as plasma nitriding). But Porsche would then be looking at a heavyweight engine package which among modern luxuries and safety would take the Carrera beyond its objective remit. The GT3 engine is some 75kg heavier than the M96/01 (plus the additional weight of the corresponding geabox since the bell housing is of the air-cooled generation).

If my 3.4 made 150k miles but then required a full rebuild I would consider this normal, or even good longevity for a compact and lightweight unit producing 300hp.



carrera996

1 posts

158 months

Wednesday 26th January 2011
quotequote all
Hello,

I have a 911/996 2003 carrera and last summer i was running with it out of oil but not so long to damage it too bad.So i tried to rebuild th engine so i have bought all the damaged pieces.The axle,bearings,pomps and everything.Now i put all in order but i hardly try to find someone which know how to set up the distribution because i hared that is an order how to put the crankshafts and the chain.Please someone help me i am in a desperate situation because i have broken one crankshaft already because i didn't put them well in order.

thank you very much.

nutrient

3 posts

167 months

Monday 28th March 2011
quotequote all
So...

Is my new replacement 3.4 996 engine from Porsche any different than the one that "blew up"?

I had IMS bearing failure. I heard the IMS bearing pin on the new engine has a larger diameter.Is this true? Anything else changed or is the engine just the same as the original??

Cannot find the answer in this post or any others. Sorry if Im being dumb...

heebeegeetee

28,506 posts

247 months

Monday 28th March 2011
quotequote all
A question i'd like to ask: My Boxster has done 50k miles. So, would it be worth having the clutch changed, and doesn't the IMS bearing sit right behind the clutch so that could be changed too at the same time, thus alleviating any potential future problems?

blueg33

35,401 posts

223 months

Monday 28th March 2011
quotequote all
heebeegeetee said:
A question i'd like to ask: My Boxster has done 50k miles. So, would it be worth having the clutch changed, and doesn't the IMS bearing sit right behind the clutch so that could be changed too at the same time, thus alleviating any potential future problems?
[troll mode] Oh the irony Heeb - isn't this like reading a TVR thread? tongue out [/troll mode]

Edited by blueg33 on Monday 28th March 12:20

nutrient

3 posts

167 months

Monday 28th March 2011
quotequote all
erm...anyway as I was saying, are "replacement" 996 engines any different to the originals?

airbus330

102 posts

160 months

Monday 28th March 2011
quotequote all
nutrient said:
erm...anyway as I was saying, are "replacement" 996 engines any different to the originals?
I understand from posts on other sites that when Porsche supply a new 997 replacement engine it comes with all the available factory mods and new ancillary items. I would suppose that a new 996 engine would benefit from any modifications that Porsche deem suitable. I would be interested to here if that is NOT the case for the 996, just in case I'm ever caught in the engine rebuild nightmare.

Gary11

4,162 posts

200 months

Wednesday 30th March 2011
quotequote all
daegucb said:
hi and thanks for the replies. sure, one post by me but i just had this problem. no need to find out before this happened but now i am very interested about the porsche engines. i'm trying to learn as much as i can... yes. i am in us. and, the us porsche maintenance is 15k intervals...
i need some advice on rebuild vs. buying a new one!!! which way should i go??? rebuild to 4.0 L with steel lining and performance piston parts etc. vs. a new engine??? the cost i am looking at to do is the same. but, rebuild is still the old engine with old block and sensors but i gain 60 horse power and upgrade in parts and the numbers match etc. new engine may have the same problem in future but all new and much better warranty comes with it... i'd appreciate a constructive and informative advice. thanks.


As already said the engines are weak and cannot reliably handle any more power my advice would be repair it and sell it,if its failed at the mileage you mention with opc servicing why would you want to stress an already weak engine with more power Id cringe every time I opened the throttle?

hartech

1,929 posts

216 months

Wednesday 30th March 2011
quotequote all
There are known weaknesses that afflict a small number of cars but some of these can be eliminated or improved on during a rebuild while others can at least be returned to the original as new condition and therefore have lots of life left in them - overall a rebuilt engine with all the mods etc should be a stronger unit than a new to original spec.

However a few weaknesses still remain that are manageable in a standard out[ut engine but less so if more power is extracted.

There is nothing to stop further modifications from rendering the engine suitable to deliver more power - but the cost would probably outweigh the results that could be obtained cheaper by comparison with a more powerful original design that also has brakes and suspension to suit already.

Baz