Has your 996 or 997 engine had a major rebuild?

Has your 996 or 997 engine had a major rebuild?

Poll: Has your 996 or 997 engine had a major rebuild?

Total Members Polled: 867

No: 488
Yes because of the IMS: 65
Yes because of scored bores: 91
Haven't bought one because of known faults: 183
Yes because of D Chunk failure: 9
Re-built prior to purchase, not sure why?: 44
Author
Discussion

LordHaveMurci

12,034 posts

168 months

Tuesday 17th May 2016
quotequote all
fastgerman said:
996 C2 seems like great value for money now but doing a search is quite confusing for making it a reliable daily.

From some google led confusion:

- 3.4 is more reliable if you change the IMS bearing to a ceramic one? This is what RPM Technic offer and have a good reputation. The US law suit ended up with an LE engineering bearing, which is different?

- 3.6 has more chance of bore scoring but IMS is already upgraded?

Whats the thoughts now :-)

Use - 10k miles a year including stop start traffic and some b road fun instead of using VW Golf's all the time.

Thanks
Hartech who seem to be the top of the heap where M96/M97 engines are concerned recommend leaving the original alone or if it needs replacing, replace with a large OEM but remove the seal to allow clean, cool oil in to lubricate the bearing.

Think is the option I'll take if/when I have to face it on my 3.4

fastgerman

1,911 posts

194 months

Tuesday 17th May 2016
quotequote all
Thanks Guys

So a 3.4 is best for daily reliable use on a 996 and if stock, can somebody list out the must have mods for engine reliability?

Cheers :-)

ps it is interesting how quickly opinions change on these cars in terms of preventative work/upgrades

hartech

1,929 posts

216 months

Wednesday 18th May 2016
quotequote all
On the subject of changing opinions and advice - "Opinions" have not always changed from everyone.

It is 13 or more years since we started publishing advice about our expectations of the most likely failure areas, the technical reasons behind them and reliable solutions in which time we have always made it clear that we think they are great cars and that these failures while rare are still at a higher rate than most would expect from the marque.

To start with when we advised that the IMS bearing was basically too small and that obscuring the bearing from a fresh oil supply was not as beneficial as removing the seal - we were criticised.

Since then that has become accepted and many alternative solutions have been manufactured and put on the market - many of which we have had to replace since (although usually after a reasonable mileage) - so we have not changed our advice in that period and the market has gradually come to accept it.

We also explained back then why the cylinders were too weak and will all go oval in time and eventually crack (which also came true) and that bore scoring would become prevalent but not stop the cars from running until long after it started (which has also become the norm).

When specialists and owners tried to save a few pounds by using cheaper replacement cylinder materials we advised that many of these may fail due to the basic unsuitability of some of the methodology to the type of cylinder block construction in this engine and since have had to replace many of those as well.

Our confidence in our engineering opinions resulted in us backing them with considerable investment in research, products, machinery and staffing that have now enabled us to provide an excellent top level service to those small numbers that require rebuilds.

No one likes a clever Ba****d but many have benefitted from us being on the ball back then and our advice has not changed since. What has happened is that many others have entered the growing market trying to grab a part of it for themselves (which is normal and perfectly acceptable) who either misunderstand the importance of some engineering solutions (and weaknesses of others) or blatantly slant their advice to benefit their own businesses (again all perfectly normal and to be expected).

Competition is always good overall but in this specialist and highly technical area it is wise to weigh up the reasons for some suppliers being far more reliable than others and consider the huge numbers of successful rebuilds and the excellent reputation that some provide rather than be talked into alternatives by those entering the market later, with less numbers to back up their provisions and usually less technically qualified staff to design and develop their own products who are simply trying to get your business with inferior overall provisions.

Our advice has always been consistent and reliable even though it is often "not what owners want to hear" when it is bad news or they feel let down anyway by their own car's failure we have been proven to be as good a source of information as you will find anywhere else, not pushy nor abrupt and backing up our advice with good solid professional information from what has become accepted as the leading M96/7 engine rebuilders.

By all means take alternative advice from different sources and compare things but you would be well advised to include us in that as we are always happy to explain and advise but accept after that - that we are in a free market and customers are free to choose whoever they prefer to fix their problems - we just know that if they choose us they will get a first class rebuild and if they do not - they might regret it!

Much information is available from our web site www.hartech.org and our rather old and lengthy buyers guide information is due to be improved soon with a more reader friendly version.

Baz


griffter

3,981 posts

254 months

Wednesday 18th May 2016
quotequote all
anonymous said:
[redacted]
On this thread:

http://www.911uk.com/viewtopic.php?t=108257&po...

There are suggestions that the dual row bearing is/was less reliable than a small single row. The thread is very long and I haven't got all the way through it!

fastgerman

1,911 posts

194 months

Wednesday 18th May 2016
quotequote all
Thanks Cmoose

Baz - you clearly have a lot of knowledge on this topic, so please can you give me your advice on the following (it may be the same as Cmoose):

1) which 996 would you recommend for 10k miles per year commuting including stop start traffic - 3.4 or 3.6 (both with no issues on purchase and similar condition with around 60k miles on the clock)

2) what modifications (if any) would you make to the car chosen for best reliability?

Thanks

hartech

1,929 posts

216 months

Friday 20th May 2016
quotequote all
Another explanation could be that they failed earlier and most were replaced under warranty - because we now know that if they survive the initial running in period (where the double row bearing generated a larger proportion of minute metallic particles), after the seal wears a little - despite the remaining lip only creating a very small gap - enough splash oil can get in for them then to last a long time. Indeed this fact that has emerged with the fullness of time supports our pint made long before anyone else - that there is sufficient splash oil to lubricate the bearing and that the best thing is to remove the outer seal. Perhaps enough did that to then create a less unreliable set of statistics?

We started repairing the double row bearing engines quite a lot early on (all out of manufacturers warranty then) and then they all dried up - either already replaced or survived long enough to escape the critical mileage pattern.

There were certainly plenty failing just out of warranty a decade or so ago - so I guess a lot of owners paid for new engines after being out of warranty and so may be it would not be in a manufacturers interests - if that bearing was say equally unreliable - to admit it later - if they had already suffered the financial consequences on a different version?

Baz.


Sine Metu

302 posts

125 months

Saturday 21st May 2016
quotequote all
griffter said:
anonymous said:
[redacted]
On this thread:

http://www.911uk.com/viewtopic.php?t=108257&po...

There are suggestions that the dual row bearing is/was less reliable than a small single row. The thread is very long and I haven't got all the way through it!
I've been through that thread. The overwhelming consensus (and it is a dedicated 911 site) as far as I can determine (bearing in mind there are some long and tricky posts to unravel) is the following:

It is actually the 3.4 dual row IMS that presents the rarest of all issues for M96's today, whatever happened in the past. The cumulative experience is that the earlier the engine the more reliable it is now, today. In general. Whether thats because a lot were fixed or their IMS seal has worn away by now allowing good lubrication is not clear, but whatever imperial evidence that does exist, it always points to the early 3.4 as being the MOST reliable in terms of IMSB. This is supported by the US claim and user experience. More and more of the specialists seem to be acknowledging this as fact.

After that it gets a little more vague. Later changes came about. A new single row bearing arrived that seems less than reliable and affects later 3.4's I think but mainly 3.6's. (C4S's for example). Why Porsche made that change has never been explained. Then a third evolution occurred that was an even larger single row bearing that seems to be pretty reliable. In essence they went from good bearing to somewhat dodgy bearing to very good bearing, So the biggest issue is really that first wave of 3.6's. Apparently their oil cooling cylinder head ports were not big enough either. By the time we get to 997's it's really bore scoring that becomes the primary issue. Bore scoring doesn't really seem to be much of an issue with 996's.

The third conclusion i can gather is that aftermarket 'snakeoil salesman' preventative stuff is just opportunistic companies cashing in. So your L&N ceramic bearings, direct oil feeds (to something already bathed in oil) and all that guff is nonsense.

And the fourth conclusion is that most of these cars are heading for 100k, are brilliant engine generally and probably getting to the point where they justify a full engine overhaul anyway - so factor that into purchase price as the cars merit it. And with modern hindsight, a refreshed engine is better than new. So talk of getting a Hartech or similar rebuild is akin to going to the gym midlife and sorting yourself out, not an indictment of the original engine. For a car of such performance, it's a reasonable thing to consider. There are numerous things that can go wrong with any engine so why not invest in this most precious of components? Buy a 996 3.4 and your more than likely absolutely fine for another 80K miles. Be a bit more proactive with 3.6's in terms of checking the bearing but should be fine. 997.1's, definitely get a bore score check up. 997.2's are sorted and Porsche back on track. Or alternatively, just go for the engine overhaul and still have an amazing classic everyday legend of a drivers supercar for almost peanuts. But the 'humble' 3.4 is becoming a bit of a later life swan, terrific power per litre and real world reliability and more proven every day as the cars continue to age and put on more miles reliably.. The naysayers were basically wrong.

Final conclusion, ignore most of what you read in magazines. They're just articles pulled together by journeymen writers, semi-bloggers with no engineering knowledge, generally possessed of a certain prejudice and working for media companies reliant of advertising revenue from the self same snake oll salesmen and are consequently never factually based.

SO if I was buying a 996 this is what I would do. Whether it's a 3.4 o4 3.6, it doesn't matter. I'd try to get a really clean well loved example for about 15K (so about 80-100K) and spend about 5K on the engine. If your lucky, you'll find private sellers or the odd dealer offloading a car as low as 10-12K. One way or another, 20K should get you, between the donor car and after sales refurbishment a cracking, ultra reliable mega performing purists analogue dream drive. And a car that will do it every day. And one that should hold it's value. So ultimately for free. They'e no brainers really now that there are some great experienced specialists around that can really throw the TLC on them that they deserve.



Edited by Sine Metu on Saturday 21st May 01:23

EGTE

996 posts

181 months

Saturday 21st May 2016
quotequote all
Fantastic post.

LordHaveMurci

12,034 posts

168 months

Saturday 21st May 2016
quotequote all
EGTE said:
Fantastic post.
£5k on an engine rebuild?

Magic919

14,126 posts

200 months

Saturday 21st May 2016
quotequote all
Maybe he meant fantasist.

EGTE

996 posts

181 months

Saturday 21st May 2016
quotequote all
I meant the bit about them being great engines and not to worry.

Keep the money for the rebuild as/when/if needed and his point still stands; these are great cars at a great price.

Budflicker

3,799 posts

183 months

Saturday 21st May 2016
quotequote all
Totally agree regards the car but a full 6 cylinder Hartech rebuild with all the other important bits done is £8129.00 + vat and not £5k.

But agree that the cars are worth it, if my 996 C4S ever lets go at the engine it will go to Hartech for a full rebuild and live a long life from there, and all for £30k in total including purchase and rebuild, which kind of makes the cost to upgrade to a 997.2 a bit of big spend when I weigh it up.

fastgerman

1,911 posts

194 months

Friday 3rd June 2016
quotequote all
fastgerman said:
Thanks Cmoose

Baz - you clearly have a lot of knowledge on this topic, so please can you give me your advice on the following (it may be the same as Cmoose):

1) which 996 would you recommend for 10k miles per year commuting including stop start traffic - 3.4 or 3.6 (both with no issues on purchase and similar condition with around 60k miles on the clock)

2) what modifications (if any) would you make to the car chosen for best reliability?

Thanks
Hi Baz - please can you let me know on the above? appreciate that either could present a problem, however if they were both in similar condition, which is safest? thanks

LordHaveMurci

12,034 posts

168 months

Friday 3rd June 2016
quotequote all
fastgerman said:
Hi Baz - please can you let me know on the above? appreciate that either could present a problem, however if they were both in similar condition, which is safest? thanks
Not an easy question to answer on here, he'll be derided for whatever he says! General concensus seems to be the earlier 3.4, whether a LTT is worthwhile seems debatable, I've changed mine anyway.

Thinking about IMS options, tempted to leave mine unless it shows signs of wear, believe this is what Hartech suggest anyway?

fastgerman

1,911 posts

194 months

Friday 3rd June 2016
quotequote all
LordHaveMurci said:
fastgerman said:
Hi Baz - please can you let me know on the above? appreciate that either could present a problem, however if they were both in similar condition, which is safest? thanks
Not an easy question to answer on here, he'll be derided for whatever he says! General concensus seems to be the earlier 3.4, whether a LTT is worthwhile seems debatable, I've changed mine anyway.

Thinking about IMS options, tempted to leave mine unless it shows signs of wear, believe this is what Hartech suggest anyway?
Thanks, I'll have a search for a 3.4 :-)

It's funny as if you Google, the links from Evo/Car/911 state a late model (2002+) is a safe bet.

http://www.total911.com/in-praise-of-the-porsche-9...

http://www.carmagazine.co.uk/car-news/motoring-iss...

'What's the best-buy of the Porsche 996 range?

A solid, 2002-on Carrera 2 manual would be our pick, which pushes you into £14k territory if you want non-Starship Enterprise mileage, but those £7k cars are out there: it’ll be an early 3.4 with over 100,000 miles on the clock, but that’s a lot of car for the cash.'

LordHaveMurci

12,034 posts

168 months

Friday 3rd June 2016
quotequote all
fastgerman said:
Thanks, I'll have a search for a 3.4 :-)

It's funny as if you Google, the links from Evo/Car/911 state a late model (2002+) is a safe bet.

http://www.total911.com/in-praise-of-the-porsche-9...

http://www.carmagazine.co.uk/car-news/motoring-iss...

'What's the best-buy of the Porsche 996 range?

A solid, 2002-on Carrera 2 manual would be our pick, which pushes you into £14k territory if you want non-Starship Enterprise mileage, but those £7k cars are out there: it’ll be an early 3.4 with over 100,000 miles on the clock, but that’s a lot of car for the cash.'
Views & opinions seem to have shifted over time, those of us that have taken the plunge just enjoy the cars & hope nothing bad happens!

fastgerman

1,911 posts

194 months

Friday 3rd June 2016
quotequote all
anonymous said:
[redacted]
Fancy posting up 3 x 996's under £15k (coupe and manual) that you think look good?

Wallet is getting itchy ;-)

Portiacraft has a silver, 70k car available - seems a good buy

AngryBaldMan

25 posts

88 months

Monday 28th November 2016
quotequote all
So.....

If I'm getting this right, the IMS bearing "might", fail, but the bore scoring will definitely happen with age?

I was looking at a 996, but even if it's had the IMS bearing work done, it's still going to fail later on if it's gone over 100k milesfrown

monthefish

20,439 posts

230 months

Monday 28th November 2016
quotequote all
AngryBaldMan said:
So.....

If I'm getting this right, the IMS bearing "might", fail, but the bore scoring will definitely happen with age?
Not necessarily, but d-chunking and ovalling of bores might.

Adam B

27,142 posts

253 months

Monday 28th November 2016
quotequote all
fastgerman said:
Fancy posting up 3 x 996's under £15k (coupe and manual) that you think look good?
Do you want him to pay for it too? Come on the hunt is part of the fun smile