The IMS Solution and IMS Retrofit: An Exhaustive Overview

      This post is presented by The Knowledge Gruppe.

      Porsche sports cars have become incredibly collectible, with the market showing no signs of slowing down. However, amidst the excitement for Porsche models, the 996 and 986 still stand out as some of the most affordable options for entering the realm of Porsche ownership. There are various factors contributing to this, from aesthetics to public perception, but the most significant and persistent stigma attached to these M96-engined vehicles has plagued them since their inception more than 25 years ago.

      The primary issue at hand is the feared intermediate-shaft bearing failure, commonly known as “IMS failure” or simply “IMS.” The notorious tendency of the M96—and later the M97—engine to fail catastrophically without warning has severely impacted the valuation, respect, and accessibility of the 996 and 986 models. Many will argue that a dramatic demise of every M96/M97 is not a matter of chance but rather an inevitability.

      Conversely, a lot of enthusiasts assert that the M96/M97’s fundamental flaw has been “fixed” in the nearly 20 years since the final 996 rolled off the production line, claiming that their cherished 2003 Boxster is equipped with the “IMS fix” and can endure another 100,000 rigorous miles with just basic oil changes.

      This scenario highlights the collision of two significant streams of misinformation and misconceptions generating a considerable amount of confusion. Is it definitive that every stock M96 will inevitably devolve into a heap of scrap metal? Absolutely not. Is there a genuinely worry-free solution to the problem? Yes—under certain conditions.

      Let’s delve into the issue.

      Porsche

      What’s the Problem?

      Travel back to 1997, the year the very first Porsche Boxsters were introduced to dealership showrooms, marking Porsche's initial attempt to incorporate water-cooling into their signature flat-six engine. Commonly known as the “M96,” this water-cooled six-cylinder engine powered Boxsters, Caymans, and 911s, with minor updates leading to the M97 model used through the 2008 production year.

      With a few notable exceptions—which we will address shortly—the M96 was a fresh design, largely dissimilar to earlier air-cooled Porsche engines. However, it did maintain a connection to the brand’s history with an intermediate shaft that indirectly drove the camshafts from the crankshaft, a mechanism traceable back to Porsches from the mid-1950s. Initially, this design featured a conventional journal-type oil-fed plain bearing that supported the intermediate shaft, offering steady, reliable performance throughout the engine's lifespan.

      A critical turning point came when the M96 deviated from this tried-and-true setup and adopted a sealed ball-bearing, possibly due to cost or manufacturing convenience. The trouble initiated with the grease seal, which wasn't designed to withstand high oil temperatures, causing it to harden and become brittle. Eventually, the seal fails, permitting oil to leak in and wash out the grease, minimizing lubrication available to the bearing. Consequently, the IMS tube, essentially a hollow pipe, fills with dirty oil as the engine shuts down since it remains fully submerged in engine oil.

      Once the grease is depleted, the compromised seal hampers the flow of fresh oil, allowing the bearing to operate solely in contaminated oil, especially exacerbated by lengthy oil change intervals. This situation leads to accelerated wear and potential catastrophic failure, which can send metallic debris throughout the engine. If the car continues to operate even briefly after this point, a genuine IMS failure compromises camshaft timing, resulting in damage to pistons, cylinders, cylinder heads, and the valve train—ultimately causing compression loss and harming any component lubricated by the engine oil.

      The effects can vary; sometimes, all failures occur, while in other cases, it might be just one. What remains certain is that a complete engine rebuild is necessitated.

      The IMS Solution and IMS Retrofit

      As many owners of the 996/997/986/987 are aware, the masterminds behind the IMS Solution and IMS Retrofit kit are Charles Navarro from Chicago's LN Engineering and Jake Raby from Flat 6 Innovations in Georgia. They have created the original components and resources necessary to mitigate this problematic Achilles’ heel, either temporarily or permanently.

      Today, if you opt for LN's well-established kits, the concern over M96/M97 IMS bearing issues is more of a manageable inconvenience than a grave flaw—many engines that have undergone these improvements boast trouble-free miles.

      Initially, only Porsche service centers comprehended the gravity of the problem, although the specific nature of the issue remained somewhat opaque. Owners of new cars that experienced IMS failures simply knew their engines were unusable and that their warranties would cover repairs at Porsche's expense. One dealer noted they could be installing between 20 and 30 engines each month at the peak, with new crate engines available at a mere $5,000 from the factory at core exchange. If an engine