Bruce In Philly

Yes, I think the motivations at Porsche to produce a better engine were many. I gambled on the 9A1 given my history. I figured (hoped) that Porsche would have to design a far superior engine or risk damaging the brand. Before I purchased a 2009, I waited to read up on failures first and, given terrible (yes terrible) performance of the M9X platform at its introduction, the 9A1 was showing itself far superior. I even drove my mom's old Camry for about 8 months until I felt comfortable making the move back to Porsche. I know this is not science and forums can be... well... not always reliable, but from participating on Porsche forums since 2000, a reader can get a good "feel" for reliability and there is no doubt at all, the 9A1 had a stellar introduction compared to the introduction of the M9X platform.

One of the clinchers for me was that video Porsche released of the 9A1 under development showing off its oiling system on a simulated Nurburgring run. This was not about its oiling system so I presumed. To me, this was a clear message to the market that this engine was thoroughly tested prior to release. Who was complaining about the oiling system that warrented Porsche releasing this film? There were many things to complain about that lead to failures and maintenance issues such as the water pump. Naw, this was about preparing the market for a new engine platform.

I also made an assumption: Porsche was (and still is) under big competition in the horse power wars, and any weakness in a design will only get worse as you increase stresses on the design. I know, I have no idea what I am talking about, but this was an assumption I made when I chose to get back into the brand.

So far, I am over the moon about my 9A1. Better than I hoped for. Porsche not only addressed the known weaknesses, but seemed to strengthen almost everything about this engine, whether in the core, or stuff bolted on to it.

A provocative comment from my scarred, pedestrian perspective: When I see scope pictures of .1 engines where someone wants to know how good/bad the pics are, and there are "scuff" lines... sorry folks, I gag at this. I have seen opened engines from '60s GM blocks and Ferrari blocks with my own eyes... shiny and smooth. I don't get it. Scuffs... well not for me. Again, I am really skeptical of that platform. I would change my opinion on scuffs, if someone can show me a clutch of 9A1 bores where scuffs are common across blocks and years.

Peace
Bruce in Philly (now Atlanta)

PV997

Certainly weight savings played a role but I don't think that was the main reason. I suspect Porsche marketing thought the buying public wasn't savvy enough to understand the difference between the IMS itself and the IMS bearing. They knew the acronym IMS had a huge stink associated with it and just decided to get rid of the whole thing. That way they didn't have to explain the the uniformed why it was no longer a problem as the whole thing was gone.

Fahrer

My understanding is that an IMS has been used because cam chains were not strong enough to drive four camshafts. I believe I had read that Porsche felt they were able to acquire stronger chains which enabled them to eliminate the IMS. Whether these newer chains are that much stronger/durable will be something everyone will eventually learn.

Floyd540

Good beer hall speculation. If you engage the "way back machine" to the early nineties (last century) Porsche was going through one of its feast or famine economic cycles and at this point they were broke. We all know the story about the fact that the Boxster saved the day for Porsche. Being broke doesn't mean you cannot design great stuff but having a capital/ tooling budget of insufficient size and no time means painful compromises has to be done. If you look at and study the stories of the designers for those cars and the 993 and 996, you will recall that they all discussed the lack of tooling money to carry out the full wishes for their designs. This carried through to the chassis and the new and necessary water cooled engine. Die cast cylinder head tooling is horrendously expensive and if you have to tool up two of them, a right and a left, you are out of luck on having the money or the time to tool up. these were rush projects to save the sinking ship (economically). Using a symmetrical sand cast cylinder head that could be used for both the left and right side was chosen for cost and time reasons. With this, common cylinder head ,the IMS was required to make this work. The fact that it was at the end of the engine with no native oil supply made a bad idea worse. Machining the common casting made the left and right versions of the heads ( easy and cost effective). Also the "not true dry sump " oiling system was based on cost and time, not engineering. Open deck design and crankshaft hardening thickness was also cost driven. Many other parts were designed with the same doctrine that this engine is going into a new street driven vehicle and is not to be considered our "top" sports car. Think 914 for us olde guys. Also remember that in theory the famed "Mezger " engine did not meet its design goals of delivering 160 HP and being capable of future expansion up to possibly 200 HP. It just happened to prove out being way overdesigned.
Porsche did what they could with the financial constraints at the time. Mistakes were made. Brand new designs always have issues. Everybody remember the chain tensioner problems we all had on our early air cooled 911's? 100% failure , no admittance from the manufactured that there was a problem.

sandwedge

I've thought about this too. Just how much power can they squeeze out of the old flat 6 design without going overboard, jeopardizing reliability of the whole package? As already mentioned, the 997.2, the 991 and 992 seem highly reliable despite increased HP with each new introduction but there has to be a limit I would think requiring a whole new engine design if chasing more HP. I suppose they could go from 3.8 to 4.0 which is already done by independent shops but could they do it in mass production scale to the same standards as the independents who do these mods one car at a time and seem to do it with amazing reputation for quality of work and reliability?

Referring to my post above, the non IMS cars have been on the road for 13 years now and I've read of very few engine failures compared to the IMS versions. As I've said before, what we read on this forum represents a very small amount of 997 owners so I doubt that it's a good representation of the 997 engine reliability as a whole. Might be a clue though. Trying to find it but can't. There was a great story of how Porsche, scarred by a bad reputation and a class action IMS law suit "over designed" the engines starting with the non IMS DFI engine. They wanted their reputation back and spared little to accomplish it.

silver_tt

Sign of the times: logged in to Bloomberg terminal this morning and there's an article, "Barrage of Air emissions Rules to Bring Challenges for Industry". Goes on to discuss how the Biden administration is pursuing an aggressive air-emissions agenda. The section on "Transport, Soot" goes on to say that a panel of independent science advisors to the EPA released formal recommendations last month urging the agency to tighten particulate matter (PM) levels under National Ambient Air Quality Standards (NAAQS). I think the USA is going to be not far behind Europe and, just for example, you will see gasoline particulate filters on the cars here soon very likely like already exists in Europe.

Bushbaby

Hi Jake - really interesting comment on 997.1. Would you mind elaborating, please? Thanks so much!