JM993

Thanks Jake and Tony. It's fantastic to have both of you contributing to this thread. For me as a potential purchaser, it probably makes sense to wait and see how the M97 makes out from a reliability standpoint. If the IMS bearing proves problematic in the M97 engine, it seems there is no fix w/o a teardown - not good. On the other hand, maybe the new IMS bearing works and some of the other issues (intermix, rods, chain tensioner ramps etc) have been fixed.

Cheers,
Joe

simsgw

Actually, sarcasm was the politest mode I could manage for this... thread. We come here for mutual entertainment, so it is best that I not post to it anymore since I can't be civil.

ADias

I'm pleased to see that that the OP agrees after all that the 9A1 engine may have potential when he writes "I have more trust in the new MA101 and MA102 engines at this point."

Thanks to Jake Raby for confirming my early post when he says "The M97 is simply a glorified M96, it is NOT an entirely redesigned engine as many believe." And noting further that "with the M97 the IMS bearing is NOT possible to replace with the engine assembled as the larger OD of the /97 bearing is larger than the ID of the case bore."

I think this settles the discussion.

ClaylG

Joe, many Porsche owners go from owning a 993 to a 997 and vise versa. Is that your plan too and if so, why the switch? I'm considering both (to replace my 3.2 '87) and was curious as to your experience in this matter.

TCallas

I have no reservations in stating that the MA101-102 engines “have more potential”. Better manufacturing processes, mechanical design and less reciprocating mass not to mention a redesigned lurbcation system all equate to a better engine. I didn't think that I needed to go into why the DFI system is superior and how much I like it, that goes unspoken. I just have substantial concerns over excessive carbon build up on the intake valves in relation to these early DFI engines. ADias, I am curious, where is the 9A1 term utilized? We have the repair information and I have yet to locate this classification.

JM993

Don't want to derail this thread, but the short answer is that this will not be a switch - I'm keeping my 993 (hopefully) forever. The 997 and 993 are both great, but different. Feel free to PM me if you'd like to discuss further.

Cheers,
Joe

ADias

PM sent.

rmccarthy1234

Great thread guys. I wish we had threads like this on the cayenne forum. Anyways...I have a 09 Carrera S with PDK and other than the pdf software upgrade I had to have done when I first purchased it, this car has been awesome. Its light years more refined, faster and more responsive than the 2000 996 that I had. Everytime I drive it, I get a smile ear to ear on what this baby can do. Glad I purchased this over the 08 997.

BMiller33

I have no ties to LN Engineering but I found this link to be quite useful in understanding the IMS issues and potential fixes/upgrades.

http://www.lnengineering.com/ims.html

Alstoy

It would appear that there are potential issues with all Porsche engines. Yet, there are more old Porsches still on the road than any other mfg. Wonder how Porsche stands up to other cars, as far a durability, etc?

simsgw

Well, I'm a first time Porsche owner, but I am a design engineer, and it's been those same forty years and then some. I agree completely with F4 plt. Well, almost. I've seen no evidence the DFI engines use more oil than earlier generations. We've had ours for thirteen months and ten thousand miles now and it hasn't used a pint of oil yet. I love the engine and the design.

After hearing people almost come to blows over the arcane question of which operating system to use on a computer, I suppose it shouldn't surprise me to hear such hostility toward the new engine. It should not, but it always does. Here we have mechanics railing at a doctorate engineer over a question of whether at some time in the future a particular engine design choice will turn out to be a problem. Give me a break.

I always respect the opinion of people who work on a device, even if it was one I designed myself. Whether it's a satellite or a piece of software or a rolltop desk I built in the garage. There always is some gap between design intent and the practical reality in the field. Sometimes bigger than others. But we're not talking about practical experience here. Not with Porsches. We're talking about predicting the future of a design and these predictions sound... well, let's say premature. And without foundation in current field experience.

It is true that some cars with direct fuel injection have had problems. But in the first place, the problems aren't anything that would worry me even if I expected them to come with the Porsche design as well. More important, the flow geometry inside the cylinder head of a modern engine is ill-suited to the casual grinding and polishing we used to do when I was a car-loving kid. You cannot eyeball the head design of a modern high performance engine and say "Oh wow. That's going to be a problem." These engines are not so blunt and straightforward as those lovely old engines were and you cannot predict from a simple title "direct fuel injection" that one engine design is going to suffer the same problems as another on which marketing has bestowed that title.

We've been using direct injection in various engines for a long time now. The subtle details of a particular design mean a lot more than the general category description. Until we start seeing problems that say otherwise, I think it is smart to assume that Porsche engineers knew about the Audi problems and took them into account.

And all that notwithstanding, let's get back to reality if we can. Does anyone really suppose that those of us who can afford a dot two are seriously worried about the hypothetical need to spend a couple of thousand cleaning the intake valves at fifty or eighty thousand miles? Geez.

If you can afford one, buy it, drive it, and enjoy it.

Gary

simsgw

I've seen this discussion before, and I agree that 9A1 is not the designation in the support documentation. Nevertheless, it is the term that has been widely used since the early press reports back in... I'm not sure, 2007 or so, about the then-new DFI engine. I've seen it a lot more than the MA numbers.

Very likely it is derived from the project designation during the design phase. It isn't at all unusual to have our working titles changed into one name for the marketing people and another one for the maintenance documents. In any case, it is quite clear we're talking about the same engine, so it's pointless to worry about it.

Gary

flavorflavorflav

guys, I appreciate all the wisdom.

I have purchased a 05 997 with an m97 motor --car build date 2/05--from my research, it was built 600 engines BEFORE the beefier ims upgrade may have gone into effect.

Going to take it in for a ppi tomorrow.

I got a good deal and love the car.

But I have the ability to return the car by Thursday and get my money back--on general principles I could, and just wait for another deal, and get an 06 or 07. For that matter, could also plunk down some more money to just be safe (997.2?)

I just want to be able to sleep at night and won't be for the next couple nights until I figure out what I should do.

Thanks in advance for any advise. It's do or die decision time for me!

Sharkys

Do you worry about dieing from:

Self-intentional harm?
Cancer?
Falling down?
Motor Vehicle?

If not, then you shouldn't worry about an IMS failure. Vegas wasn't built on winners. Seriously, if you can't sleep at night, then upgrade to a 997.2.

alexb76

The OP knows what he's talking about, no BS, and very accurate information as to differences in the engines, M97 superiority over M96, and 9A1 better overall design with caveat being the long-term impact of carbon build-up.

Anyone trying to discredit the OP, is just trying to further their own agenda, saying I KNOW BEST, *my engine* is best, Porsche cannot do any wrong with new designs, etc... M97 has been VERY SOLID, basically all the IMS BS worries are completely taken care of, all you need is frequent oil change, use of better oil than CRAP 0W40, and proper maintenance. As I stated in another thread, the head Porsche mechanic who is flown everywhere for 997 engine rebuilds told me personally, that he is NOT aware of any M97 engine IMS failure in all of Canada... so ADias, you are totally wrong saying the IMS issues are the same between M96 and M97, that's definitely not the case.