bazhart

Feedback requested from Gen 2 997 owners or specialists with experience of Gen 2 engine problems.

We have been involved one way or the other with information about a bore scoring problem with a very few Gen 2 3.8 engines.

To see if we needed to do anything about it we have bought a car, a good engine, spare crankcases and now have our first car with the problem to repair - all measured and checked over to assess the issue.

What makes it difficult to be sure of the results is the small numbers - yet we hear of a few engines being replaced (rather like the early stages of Gen 1 problems) so we think it is worth our while to see if we need to provide an alternative solution.

The Gen 1 was relatively easy to analyse - numbers were wuite high and made it easy to be sure and predict that weaker thin cylinder material with larger forces on it was leading to cracking, changes to piston coatings being less resistant to wear and an IMS bearing system that was often inadequate.

The Gen 2 is far better made - should be almost bullet proof - a brilliant engine - yet we have identified one technical area of concern.

Generally (not Porsche specific) problems that relate in some way to the number of complete thermal cycles the engine goes through (probably regardless of mileage) are impossible for manufacturers to reproduce since it require a full heat to fully cold cycle to be reproduced "x"K number of times with a lot of sample vehicles - so if and when it occurs - it is often too late to alter the production or find an alternative solution from them.

It would help me enormously - if anyone who has had any experience of a failure World-Wide - would kindly send me the following information.

(1) Where did the piston score (one thrust side or both sides and in the centre of the piston thrust face or on either side of it?).

(2) What age was the car?

(3) What mileage did it occur at?

(4) Which bank did it occur on?

(5) Or which cylinder failed?

(6) What capacity was it?

This request is absolutely not scare mongering nor seeking business - because we are providing a solution in any case and making a small number of parts for stock. We are also working at full capacity anyway and numbers of M96/7 Gen 1 engines are not diminishing.

I expect the numbers to be so small it is not something for existing owners to be overly concerned about. However as we are going to provide a solution anyway - this request is mainly to help confirm if our understanding fits all examples and at what age or mileages it is likely to occur.

Thanks in advance to anyone that can help,

Replies can be sent direct to baz@hartech.org

Baz

jhbrennan

M97 or 9A1? I'm not sure what Gen 2 means in your question. Gen 2 of the 997 had the 9A1 I believe.

mcfisticuffs

9A1. 997.2. DFI. 2009+

Gen 1 = 997.1. M97. Basically a 996 with a face-lift.

bazhart

Yes 9A1 thanks,

Baz

snake eyes

I think you will VERY few failures..

Porsche completely over engineered the 9A1 and I'm fine with that
Variations of the 9A1 now power everything from the 2017 911 RSR - 911 GT3 RS etc etc
https://www.youtube.com/watch?v=fv53RbvgfGc
just look how brutally they tested it - official video of development

cool flash

In the beginning of your post you mention gen 2 3.8 liter engine. Are you only interested in data for that engine or 3.6 liter engine as well?

I am happy to hear that you are investigating the DFI engines.

Regards,

CF

Quadcammer

some regular reports of bore scoring from the raby camp I believe.

That development video is very overhyped

myw

it does happen, but not often, which is probably why i can recall the examples at the top of my head from scouring the forums

gopirates dfi 3.6 - https://rennlist.com/forums/997-foru...l#post13837017

car25 - 991 dfi - https://rennlist.com/forums/991/9528...d-at-idle.html

not mumbles's car, but he had a friend with a low mile gts 2012 (dfi 3.8) that had his engine replaced due to scoring of sorts (can't recall exactly what)https://rennlist.com/forums/991/9660...l#post13805523

hope this helps.

Flat6 Innovations

My count is at 4 dozen since 2010.

This engine will school you! It schooled us for the first 4 years, but since then we've had 100% success. Our first developmental car was brand new in 2010 and came apart with 11 miles on the odometer. Yes 11 miles.

bazhart

Many thanks for the responses so far guys.

The brutal testing mentioned would not have any influence on the cause that we have identified - which is a time based thermal heating and cooling cycle issue and its consequences. So far discussions with others and measuring different engines has revealed the same trend in all of them and the older they are and the higher the mileage the closer they get to initiate scoring. Assuming age has some correlation to warm up to full temperature and cold again and that mileage has some relationship to amount of use (and hence heat cycles) so far on the small number we have been involved with a fairly reliable and predictable graphical trend towards the problem is being revealed.

However although I am quite confident in the conclusion despite the small numbers - the more data I can collect the better those conclusions will be.

Jake - if I understand your post correctly you have been involved in many more bore scoring failures already. If so and if you stripped the engines and didn't just exchange to replace them - I would appreciate some feedback from you.

I realise you regard us as competitors - I am perfectly OK with that - but for our part we regard the market as large enough and continually growing in overall numbers - that for the few specialists like us we think co-operation of some sort between otherwise competitors can actually help us in our quest to try and justify the investment to try and find solutions for problems from a comparatively small business resource.

We are already in progress with our solution - so nothing you can add is going to influence our product or its availability - its just trying to be sure of the trend which knowing the answers to my questions will assist with.

However I understand if you decline - no problem!

Cool Flash - I am also very interested in 3.6 experiences. So far I have only heard about 3.8's scoring bores but I have bought a 3.6 which will be stripped soon to see how generic that model is compared to a 3.8. My guess is that it will either never be a problem or may take longer to be one (for similar reasons that the larger the capacity of the otherwise generic versions of the M96/7 engines fail much earlier than their otherwise almost identical smaller capacity family) - but at the moment that is just guesswork.

Thanks again everyone,


Baz (technical Director - Hartech Automotive UK)

Flat6 Innovations

Baz,
Find my replies below in your own text.

We've seen this trait as well, but really own in the 3.8 engines. The others also score bores, but they will often do it at lower mileage points, and with a different portion of the bore being scored.

Yes, as always, but in the end the variables that are imposed by fuel differences, behavior of drivers just after start up, engine oil selection, and servicing, and etc will make all the differences. These are the variables that developers hate, but must be considered.

Ok, under no circumstance will I just "replace" an engine in a Porsche. Thats not what we do. As developers of processes, and components, as well as builders of engines its our job to be first on scene, figure the issue out, and create our own version of the engine. I have only installed one "engine replacement" from Porsche in my life, and that was because a factory engine had failed, and the customer received a replacement from a dealer at low cost. That wasn't a DFI engine, but rather an M97. Anyone can swap out an engine, and thats just plain boring to me.

The first DFI/ 9a1 engine that I tore into was in 2010. It was done electively to Cayman X, the test vehicle for LN Engineering. Within 3 months we already had developed my 4.2L engine that made 360 RWHP on the first try. Till the block cracked! Over a period of two years we worked to further develop the platform, and during this time I continued to work with engines that had some form of cylinder problem, or one of the other modes of failure. The first year over 120K was spent to develop the engine as a joint effort between LN and my company. The next year that figure was still over 100K, and over and over again we fought with deviations in the blocks, as Porsche was ever- changing them in so many ways. This engine schooled our asses, one test engine required 12 tries to get right, another took 4, and another was scrapped altogether since the block had so much core shift that we plunged deep into a water jacket while boring. The biggest rule with these monolithic alusil blocks is DO NOT WELD ON THEM! Pre- heating, post- cooling, or any other procedures won't help you. Been there, done that.

To date the majority of what I've done with these engines has been related to making them big. Bigger than anyone else, and the factory still hasn't gone where I did almost 8 years ago. To date I've developed the following components and tools for these engines:
-Direct Nikisil plating of blocks
-Sleeved cylinders in bore sizes up to 105mm
-Motorsports grade timing chains with master links (to address stretched/ broken timing chains)
-Billet chromoly PWM oil pump drive sprockets (to address elliptical OE sprockets that kill oil pumps, and simplex oil pump drive chains)
-Simplex oil pump drive chains with master links
-Billet chromoly connecting rods
-Billet crankshafts with strokes to 86mm
-Under and oversized rod and main bearings
-Manganese bronze valve guides
-Hi performance valve spring/ retainer packages
-DFI specific piston profiles with hard anodized top rings, altered offsets (to run quieter) and altered crowns to promote stratified charge
-Total Seal ring packs, specifically configured for DFI cylinder pressures
-DFI specific engine oils (with Driven Racing Oil)
-Intake and exhaust port profiles, and studies to try and understand why in the world they configured things the way they did.
-Tools for adapting my Faultless wrist pin and clip installation tool to the 9a1 engine
-Tools for the finite adjustment of the DFI oil pump drive index (from the factory no tool exists)
-Tools for installing valve springs, and keepers (just wait till you tear into a cylinder head the first time)
-Tools for altering camshaft timing, and assembling the engine with factory timing as well.
-Billet 2 quart deep oil sump
-Dry sump conversion kit, makes any 9a1 engine into a dry sump, similar to the GT3

This isn't all, but its what I want to share.

There's more when it comes to ancillaries, too. The guys at LN and BILT Racing have been campaigning these engines in Cayman race cars for the last 4 years. We've seen a lot of oddities come from on- track failures, and developed fixes for those as they occur. The biggest of these has been the failure of the oil pump drive sprocket on two occasions, which was a real eye- opening experience. I knew from day one that we'd see failures with this component.

I regard every soul in this business as a competitor. I love to fight, and I love to go there, and do that before the other guy. Thats my nature. Thats the ONLY thing that drives me, and is the only reason why I do this work, as I have much more profitable businesses under my umbrella. This is why I pulled apart a 9a1 engine with 11 miles on it, without having any special tools, or even a workshop manual.

That said, you must not check your PMs here, as I have sent you a message over a month ago telling you that we needed to collaborate on M96 work at that time. To date you are the ONLY competitor that has;t stolen something from us, or had to be put on notice for Patent infringement. You have been fair to work with, and we share the same tenacity, and work ethic. It makes sense to team up and make for a stronger force against the evil out there. Check your PMs.

You need to know what I have already learned. Trust me. The challenges you will face with this one are broad, and just assembling the first engine I can save you 10 hours of wasted effort with one sentence of advice.The assembly order of this engine is crucial, but you won't figure that out until you've done it.

Yes, we MUST work together.

Like I said, check your PMs.

I have seen it occur in all the engines. The 3.6 with it's longer (longest stroke of all) does play into this scenario, and lots can be a learned from that alone.

This engine is finally gaining ground with independent shops. It has taken 4 years of effort to fill my online 9a1 engine classes. I just had one of the last night, and had 15 very enthusiastic techs attend. We now have enough interest to offer a hands- on engine rebuild school in January of 2018. People are too slow to learn, and that bites them in the *** hard. When Porsche releases a new engine, buy one ASAP and LEARN! That said, I'll tear into my first 718 engine in about 2 weeks from now, as its time to move on.

Here's some photos to check out.
-Cayman R teardown from 2 years ago:

A 3.4 to 4.2 build from 6 years ago:

3.4 to 4.2 Cayman R build from last year:

Another 4.2L build from 6 years ago:

The third time around with Cayman X:

DC911S

Pics are not showing.......

bazhart

Great reply Jake - most informative thanks - and yes we will enjoy co-operating.

One of the reasons we have been so slow in getting into stripping one is simply being flat out continually improving our flow production system to handle the increases in demand and expanding the facilities and workforce. The methods needed are not unique and our guys managed it very well thanks (after making some special tools).

I am sorry if I missed your PM. If it was sent to our usual E-mail address I don't get to see it unless it gets forwarded to me. Now well past retirement age I am not always at work and deal mainly with technical matters these days, training, and helping steer our brilliant younger team in the right direction (hopefully).

When I was younger I used to design motorcycle racing engines and make them (achieving wins in the Isle of Man TT, European Internationals and at GP level (and the Silver Dream Racer in the David Essex Film - before your time?) - but I moved on from there to end up running aerospace company's for plc's - not a happy experience.

Like you - starting Hartech was to pursue a lifelong love of Porsche engineering as a first priority (1st a 356C when I was 22) and I didn't want the stress of expanding too much or too quickly - just loved being involved in the engineering.

I never expected so many basic issues to appear in post M96/7 production - nor that the very same technical issues I solved 40-50 years ago would afflict them - nor that I would end up in small scale manufacturing again - but I absolutely love it.

I expect you get the same sort of criticism we do for daring to mention any shortcomings in the recent engine ranges - little do most know that I could be far more direct and restrain my comments enormously - just concentrating on how to make the engines serve their purpose as I expected them to do when I decided to make this my last venture.

I am a bit of an "anorak" with data and data crunching - finding it makes the causes easy to establish and then that in turn makes the solutions often obvious.

Different engineers will often find different solutions to the same problem that both work just as well and in our opinion it is not worth the time wasted on it to try and discredit competitors - but - like you - we are proud of what we achieve and promote it whenever we feel it will be productive.

Yes we are all competitive - but that can often turn counterproductive and with the size of the tasks we face and the limited information available I will be happy to join with you on technology exchange discussions where it will help the marque and our owners.

Thanks again for the reply - more power to your elbow.

Baz

Flat6 Innovations

Sorry about the pics... I linked them to our facebook photos page.

Baz,
I am with you on things being hard. It was very tough to break away from the M96/97 at a point when it was booming for us (and still is). I am fortunate, because other than building unique things for therapy, I am the developer here. My team was doing the M96/ M97 and aircooled work while I was able to blow time and money on the 9a1.

We learn that we HAVE to make time. We HAVE to be ahead of the other guy. Why? Because he will wait as long as he can to get started, and then he's well- behind.

I tend to not take the road, but leave a trail behind me. Email me
jake@jakeraby.com

German888

Would love to hear both Baz and Jake's answer to the following question:

How does the M96 / M97 engine (fully rebuilt from either builder with all the upgrades) compare to the 9A1 in stock form as well as a comparably rebuilt 9A1 engine in terms of reliability, performance and any other factor you care to elaborate on?

I think it's an important question since anyone facing the decision will be weighing the idea of how good will the M/96 97 platform ever be when compared to the significantly different 9A1 engine.

Would the owner be better off spending the money on the new .2 car as apposed to the rebuild of an inferior engine that might never be on par...