The American Motors straight-6 and straight-4 engine family was used by a number of AMC and Jeep vehicles from 1964 through the present. All are OHV pushrod engines with a cast iron block.
195.6
AMC's first straight-6 was the 195.6 in³ (3.2 L). It was produced from 1958 through 1965 in both OHV and "flathead" side-valve versions.
AMC introduced an aluminum version of the pushrod 195.6 in³ (3.2 L) engine in 1961. It was produced through 1964.
Generation 2
The company reengineered the engine for 1964, and this version was produced through 1987.
First produced in 1964 (for the 1965 model year), the 199 in³ (3.3 L) and 232 in³ (3.8 L) inline-6s were AMC's first modern 6-cylinder engines. They replaced the Nash 196 in³ (3.2 L) OHV and L-head engines. They featured a 3.75 in (95 mm) bore, and either a 3.0 in (76.2 mm) or 3.5 in (88.9 mm) stroke. The 199 was discontinued in 1970; the 232 was offered alongside the 258 during the 1970s, but was unpopular and was discontinued in 1978.
199
The 199 in³ (3.3 L) 199 was produced from 1964 through 1970.
Applications:
232
The 232 in³ (3.8 L) 232 was produced from 1965 through 1978.
Applications:
258
The 258 in³ (4.2 L) inline-6 was produced from 1970 until 1989. It featured an undersquare 3.75 in (95 mm) bore and 3.90 in (99 mm) stroke; it was otherwise identical to the 199 and 232. Later 258 models (starting with the 1980 model year for California AMCs, 1981 for California Jeeps and 1982 for all other applications) are equipped with AMC's CEC system.
Applications:
2.5
The 2.5 liter inline-4 was a version of the 258 bored to 3.88 in (99 mm) and de-stroked to 3.19 in (81 mm). It appeared in 1985 and was produced through 2002 for the Jeep Wrangler. Output that final year was 120 hp (89 kW) at 5400 RPM and 145 ft.lbf (197 Nm) at 3250 RPM.
This engine was used in the following vehicles:
4.0
The 4.0 L (3956 cc) EPH straight-6 was an evolution of the 258 and 2.5 and appeared in 1987. It had the same 3.88 (98.4 mm) bore as the 2.5 with a longer 3.41 in (86.7 mm) stroke. Although it was called the Power Tech Six in 1996, that name is more connected with the replacement for this engine, the 3.7 L PowerTech V6.
Output in 2004 is 190 hp (142 kW) at 4600 RPM with 230 ft.lbf (312 Nm) of torque at 3000 RPM. It has an cast iron engine block and cast iron OHV cylinder heads. It uses SFI fuel injection, has roller rockers, and features cast iron connecting rods, a one-piece cast camshaft, and a cast aluminum intake manifold.
This engine was used in the following vehicles:
See also
