The Quad 4 (called Twin Cam after 1995) was a DOHC straight-4 automobile engine produced by General Motors' Oldsmobile division in the 1990s. It was a modern engine for the time, but was criticized for roughness, and balance shafts were added in 1995, but the 1996 2.4 was the real upgrade to the engine. The name refers to the engine's four valve per cylinder design and its four cylinders, but some variants with a single overhead camshaft were produced. The Quad 4 used an iron block and aluminum heads.

The Quad 4 debuted in 1987 and was replaced after 2001. Quad 4 engined were produced at Oldsmobile's Delta Township, Michigan plant.

Applications:

• 1995 Pontiac Sunfire, 150 hp (112 kW)

Quad OHC

A SOHC variant of the Quad 4 was intended to replace the Tech IV. Debuting in 1992, this Quad OHC was an 8-valve engine and produced 120 hp, 40 hp less than a Quad 4 from the same era. Although power and economy were much better than the pushrod Tech IV, the Quad OHC was retired after 1994.

LG0

The High-Output 2.3 L LG0 version produced 180 hp (134 kW). It used a new intake and hotter camshaft.

Applications:

• 1990-1991 Oldsmobile 442
• 1990-1993 Chevrolet Beretta GTZ, 180 hp (134 kW)
• 1994 Chevrolet Beretta Z26, 170 hp (127 kW)
• Pontiac Grand Am
• Oldsmobile Cutlass Calais and Supreme
• Oldsmobile Achieva SCX

1995

For 1995, a balance shaft-equipped version of the 2.3 L version was produced. A clever arrangement ensured a constant load on the shafts: The crank drove one shaft, which drives the second, which drives the oil pump. However, the shafts spun at twice the engine rpm, forcing the red line to be reduced from 7000 to 6500 rpm. Output was down to 150 hp (112 kW) and 145 ft.lbf (197 Nm). This was the only Quad 4 family engine produced in 1995.

W41

The W41 version was the highest-output Quad 4 at 190 hp (142 kW).

Applications:

• 1991 Oldsmobile 442
• 1992-1993 Oldsmobile Achieva SCX

LD9

The LD9 Twin Cam was a 2.4 L Quad 4 variant with balance shafts, debuting in 1996. Bore was decreased from 92 mm to 90 mm and stroke increased from 85 mm to 90 mm for better torque, and power remained the same at 150 hp (112 kW).

Applications:

• 1996 Chevrolet Cavalier Z24
• 1996 Pontiac Sunfire GT
• 1996 - 2004 Pontiac Grand Am SE

See also

• List of GM engines