to combine cam-phasing variable valve timing with dual-profile variable valve lift in the American market. The table below lists the specifications of the two camshaft profiles. Toyota commissioned Yamaha to design the 2ZZ-GE, based on Toyota's ZZ block, for high-RPM operation and producing a power peak near the top of the RPM range. The high-output cam profile is not activated until approximately 6,200 rpm, (lift set-points are between 6,000–6,700 rpm depending on the vehicle) and will not engage until the engine has reached at least . The Toyota PCM electronically limits RPM to about 8,200 RPM via fuel and/or spark cut. The "lift" engagement and the engine redline vary by application. Lotus 2ZZ-GEs are rev limited to 8,500 RPM, for example, whereas Celicas were rev limited to 7,900 to 8,200 RPM in North America, depending on the model year. The first Japanese versions were rev limited to 8,600 rpm with a peak of . Consequently, it is impossible to "over-rev" the engine with the throttle alone; a downshift from a higher gear must be involved. A typical "over-rev" can damage the oil pump, commonly disintegrating the lobe ring, resulting in damage similar to the picture at right. The oil pump is the Achilles heel of the 2ZZ, though incidents are rare and usually occur due to fault of the driver. Even the briefest period of oil starvation is usually fatal to this engine design. For the first few years of production, the engines were notorious for failing "lift bolts". This did not damage the engine, but would hamper performance as the high output cam profile was unable to properly engage. Toyota fixed the problem in late 2002 with a redesigned bolt that was installed on later engines. Earlier engines with the problematic bolts can be fixed via a Toyota-issued TSB simply requiring the new bolt to be installed in place of the old one. The 2004 and newer Matrix and Corolla XRS models were equipped with smog pumps and have an extra hole above each exhaust port in the engine head and manifold where air is injected to achieve complete fuel burning before the exhaust stream reaches the catalyst. All 2ZZ-GE heads from 03/03 onwards carry this modification even if the vehicle does not have the air injection system. The high-pressure die-cast aluminum alloy engine block of the 2ZZ-GE featured Metal Matrix Composite (MMC) reinforced cylinder walls. MMC is a