The Olds Quad 4 was the first production, four-valve, DOHC four cylinder engine built by General Motors. When it was introduced in 1987, it was heralded as a revolutionary new design that was expected to be as historically significant as the original Olds Rocket V8 was in 1949.
The Quad 4 had four valves per cylinder, tuned intake and exhaust manifolds, no distributor, no plug wires, lightweight rods and pistons to reduce shaking forces, and a crank with eight counterweights that was designed to reduce noise, vibration and harshness (NVH) and bearing wear. It didn