page_title: Quad 4 engine
section_title: LD9
hierarchical_section_title: Quad 4 engine / LD9
caption_attribution_description: English: The engine of a 1997 Pontiac Sunfire
context_page_description: The engine family known as the Quad 4s was debuted to the public in the spring of 1987. The Quad 4 is a 2,260.5 cc DOHC inline four-cylinder produced by General Motors' Oldsmobile division. The Quad 4 name is derived from the engine's four-valve, four-cylinder layout. The engine was a modern design for its time, using a cast-iron block and an aluminum head. Even though belts were more popular for this purpose on OHC engines at the time, chains were used to time the camshafts to the crankshaft. The water pump is also driven by the timing chain. The Quad 4 was the first wholly domestic regular production DOHC four-cylinder engine designed and built by GM; the only prior DOHC four-cylinder engine offered by GM was the Cosworth Vega, which featured a DOHC head designed by Cosworth in England.
  First released to the public as a regular production option for the 1988 Oldsmobile Cutlass Calais and Pontiac Grand Am, the engine's availability expanded to Buick in late 1988 and Chevrolet in 1990, after which it became a mainstay in GM's lineup until its cancellation after the 2002 model year.
context_section_description: The LD9 Twin Cam was a 2.4 L (146 cu in) Quad 4 variant with balance shafts, and a redesigned cylinder head which debuted in 1996. In the mid-nineties, these engines, like their earlier 2.3L counterparts, were known for timing chain failures, as well as water pump failures, in which the water pumps were often difficult and costly to access and replace. They also had very small oil passages, making for less than adequate lubrication, and costly engine repairs if not maintained properly. Bore was decreased from 92 to 90 mm (3.62 to 3.54 in) and stroke increased from 85 to 94 mm (3.35 to 3.70 in) for better torque. Power came in at 150 bhp (112 kW). This engine received a minor update halfway through the 1999 model year that eliminated the exhaust gas recirculation, increased the compression ratio from 9.5:1 to 9.7:1, and switched from low impedance fuel injectors to high impedance. For increased reliability this engine also saw other minor updates in the 2000s towards the end of its use in General Motors vehicles. In 2001, changes included a smaller knock sensor, flat-top pistons instead of dished, new oiling passages, newer stronger timing chain, a newer-designed water pump, a redesigned starter motor and a higher capacity catalytic converter. An improved belt tensioner was introduced in 2002.
caption: A 2.4 L (2,392.3 cc) Twin Cam in 1997 Pontiac Sunfire
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