Lee Jenkins (left) and Brandon Clark (right) after completing Slakker's first Hartech engine rebuild (center).
Slakker and Hartech
When Brandon founded Slakker Racing Development, he sought out the help of Hartech Automotive. Since their founding in 1984, Hartech has developed a reputation as the world's premier engine rebuilder in the early water-cooled Porsche communities. They are best known for their solutions to the primary failures of the M9X engine -- rod bearing failure, IMS bearing failure, and cylinder ovality and scoring -- and their technical reports -- exhaustive write-ups on their development findings -- that they openly share with the community for free. Hartech has shared their wealth of engineering and process knowledge with us so we can offer Hartech engine rebuilds to the US market.
Rebuilt to Last
Over two decades of M96/M96 engine innovation, Hartech's focus has been on building the most reliable, cost-effective engine that can be possibly built. This is why Hartech engines run for 150-200k miles before engine basic engine wear items need to be replaced. This focus on reliability has also lended to success in the endurance racing world, the ultimate test of an engine's longevity. In 2022, Hartech engines were proven the ultimate in performance and reliability by bringing home year end championships in both WRL (2 - 8 hour races per weekend) and the British Endurance Championships (2 - 3 hour races per weekend). These were both on capacity increased engines utilizing stock heads and valve train.
Our internal R&D is geared toward building higher-powered engines, but the reliability that's at the heart of our rebuilds is the reason we can do so. We push the M9X engine platform forward, but we do so by standing on the shoulders of giants. Here is the engineering that sets Hartech/Slakker apart:
Hartech Engine Improvements
Cylinders
At the heart of the Hartech engine design is their closed deck replacement cylinders. The stock cylinders are open deck, meaning the cylinders are only supported at the bottom of the cylinder wall. The rest of the cylinder is surrounded by coolant passages, leaving it unsupported. As the cylinder is repeatedly heated when the car is driven and cooled when the car sits overnight, it have no supports to hold it in its original shape, and it becomes misshapen over time. This is known as cylinder ovality. Hartech replacement cylinders are closed deck, meaning the cylinder walls extend out to the sides of the case so the cylinder is fully supported. This is similar to how Porsche solved this issue as well in 2009 with the MA1 engine, which is also a closed deck design.
Hartech's cylinders are also Nikasil-plated, which prevents the development of bore scoring. The M96 engine was designed during a time of financial difficulty for Porsche, so they saved production costs by using Lokasil, a cheap-but-weak material, to coat their cylinders. Porsche tried to address this by switching to Alusil, a cheaper Nikasil alternative, for the MA1 engine, but Alusil still lacks the durability to withstand years of spirited driving. Nikasil plating is the "gold standard" of cylinder linings for aluminum engine blocks. It holds up exceptionally well to time and intense driving in both street and motorsport settings. Nikasil is used today primarily in engines for Formula One, ChampCar, and other racing applications.
In addition, Hartech also increased the external surface area of the cylinders and opened up the coolant channels in order to provide the cooling required for endurance racing both their standard and increased displacement engines. For capacity upgrade engines, Hartech also manufactures a lower support ring that is installed to support the bottom of the cylinders for a truly hardened engine that's rebuilt to last.
Hartech Racing Sumps
Oil starvation is the most common cause of failure on M96/M97 engines that we see. Slakker and Hartech have done extensive research into this issue and have found that it is 100% preventable. By using a high quality 60W oil at the max fill level with a Hartech Racing Sump, we have proven through extensive data logging and testing that the extreme pressure drops indicative of the oil pump sucking air can be eliminated. Hartech racing sumps are required for dedicated track engines and recommended for any engines that will be aggressively driven.
IMS
The non-serviceable larger bearing M97 Intermediate Shaft (IMS) was Porsche's solution to what was essentially their biggest black in history. Like Porsche, we recommend upgrading all '99-08 M9X IMS's to the larger bearing and in addition, we remove the seals to nearly double their rotational rating using splash fed oil. This is a permanent solution.
Rod Bearings
The M96/M97 OEM rod bearings, when combined with inadequate oil pressure, are the major weakness of these engines from the factory and account for over 50% of the engine failures that we see. To help overcome this issue, Hartech Developed a tri-metal Motorsports Rod Bearing that is stronger and also increases the bearing surface area by 12%. This bearing is now used in all of our engines, giving motorsports-grade protection to both street and track customers.
Main Bearings
Porsche increased the size of the main bearings for the 996.2 and 9x7.1, overcoming some of it's limitations. However, in order to withstand the rigors of endurance racing, Hartech developed a Motorsports Main Bearing as well that is a tri-metal race grade bearing. This bearing is a recommended upgrade for track engines.
Pistons
Hartech cylinders and pistons are custom manufactured to their specifications by Capricorn, one of the leading providers of cylinders and pistons for Formula 1. After the Nikasil plating process, each cylinder is precisely honed to the exact specification for its matching piston and they are provided to us as a numbered set.