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Designed by Aurelio Lampredi, the Fiat SOHC engine first appeared in the front-wheel drive (FWD) Fiat 128 of 1969. The in-line four-cylinder engine comprised an iron block with an aluminium cylinder-head containing a single over-head camshaft operating directly on both the inlet and exhaust valves in a reverse-flow cylinder-head configuration. The camshaft was driven by a belt rather than chain. The engine remained in production until the mid 1990s and grew in capacity over the years from 1100 cc (in the Fiat 128) to an eventual 1600 cc (in the Fiat Tipo/Tempra). The Fiat 130 2866 cc V6 engine, also appearing in 1969, although having cross flow cylinder-head, is directly related to the 128 SOHC engine, but with a 1.20 upscale in bore and stroke. ==Design and production== The engine was designed as a transverse mounted FWD-only power-plant being the second engine/gearbox combination to exhibit the now standard transverse ''engine-next-to-gearbox'' layout with unequal length driveshafts (the first was the Autobianchi Primula, the Mini had its gearbox in the sump of the engine). The one exception to the engines FWD-only design is its revolutionary use as a mid-engine drive-train in the Fiat X1/9. Unusual for the time was the electrically driven fan, rather than it being powered directly by the engine.〔 The 128 engine has five crankshaft bearings. A prominent feature of the Fiat SOHC engine its massively over-square proportions. This over-square design allows large (within the constrains of a reverse-flow configuration) valve sizes relative to engine capacity. A secondary benefit is the short crank throw reduces the accelerative forces on the con-rod allowing the engine to operate at significantly increased engine-speeds. The original engine's limit was only reached at 8000 rpm.〔 The engine was developed for forced-induction use in the Fiat Uno Turbo. It was then further refined for the Uno Turbo Mark II, and later for the Punto GT. As with its bigger brother the famous Fiat DOHC (aka Fiat/Lancia twincam) engine, the Fiat SOHC engine was shared with the Fiat subsidiary Lancia (appearing in 1,500 cc guise in the Lancia Delta/Prisma of the 1980s) as well as being used in the Fiat 128 derived Yugo. The final incarnation of the 128 SOHC engine was modified to utilise 16 valves and dual cam shafts. The engine (using the designation "Torque") featured the bore-spacing, bore and stroke of the 1580 cc 159/160 series engine with a new 16 valve DOHC cylinder-head. To incorporate the extra oil-return-paths and symmetrical head (as opposed to the asymmetrical SOHC head) the cylinder-block was slightly revised making the DOHC head non-interchangeable with the previous incarnations of the 128 engine. Development of the Torque engine took place in the US rather than Italy, whilst Fiat was in partnership with GM. The "Torque" engine (178.B3 - 182.A4) powered the Brava/Bravo, Marea and Multipla Fiat automobiles as well as the second-generation Lancia Delta (never sold in the UK), finally ending production in 1999. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Fiat 128 SOHC engine」の詳細全文を読む スポンサード リンク
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