The Lancia Flat-4 engine is an aluminum, pushrod, and later overhead camshaft, flat-four (boxer) engine made by Lancia, initially for the Flavia, from 1960 through 1984. Though it was designed as a pushrod engine, it was advanced for the time. The pushrod version of the Lancia boxer was only ever used in the Flavia, and its derivatives including the Lancia 2000. In 1976, a new overhead cam engine based on a similar layout was designed and brought into production in 2 and 2.5-litre displacements for the Gamma.

Pushrod

1500

The original version was the 1500 cc introduced in 1960; it used an 82x71 mm bore and stroke. It was revised on 1963 with a smaller 80 mm bore and a longer 74 mm stroke, thus displacing 1488 cc. A final version was introduced in 1967 with an even longer 80 mm stroke coupled with a 77 mm bore, giving a displacement of 1490 cc. Production ceased in 1970.

1800

The first 1800 was a 1727 cc introduced in 1962. It used an 88x71 mm bore and stroke. One year later it was replaced by a true 1800 cc engine thanks to a longer 74 mm stroke. In 1967 appeared the 1816 cc version using an 85x80 mm bore and stroke.

2000

The 1991 cc 2000 version was the ultimate Flavia engine. Bore and stroke was 89x80 mm for a good oversquare ratio. In 1971, the 2.0 L produced 115 bhp, and in the HF Coupé in 1972 it produced 125 bhp. This engine was produced from 1968 through 1974.

OHC

Lancia developed the large light-alloy overhead camshaft 2.0-litre and 2.5-litre flat-4 engines specifically for the Lancia Gamma, rather than using Fiat derived engines as used in the Beta and Montecarlo and were in production between 1976 and 1984.

2000

Replacing the 2.0 L pushrod engine used in the Flavia, the new 1999 cc OHC engine produced 120 bhp at 5500 rpm and 172 Nm of torque at 3500 rpm.

2500

The 2484 cc engine was initially available with twin-choke Weber carburetors, but in the last few years of production it was equipped with fuel injection. In both forms, it produced 140 bhp at 5400 rpm and 208 Nm torque at 3000 rpm.