The AMC V8 may refer to either of two distinct OHV V8 engine designs developed and manufactured by American Motors Corporation (AMC) starting in 1956. These engines were used in cars and trucks by AMC, Kaiser, and International Harvester, as well as in marine and stationary applications. From 1956 through 1987, the automaker equipped its vehicles exclusively with AMC-designed V8 engines.
The first generation was produced from 1956 through 1967. A Bendix Electrojector version was to be the first commercial electronic fuel-injected (EFI) production engine for the 1957 model year.
The second generation was introduced in 1966 and became available in several displacements over the years, as well as in high-performance and racing versions.
In 1987, Chrysler Corporation acquired AMC and continued manufacturing the AMC "tall-deck" version until 1991 for use in the Jeep Grand Wagoneer SUV.
American Motors Corporation Gen 1 (1956–1967)
American Motors' president, George W. Mason, had negotiated a verbal agreement with Packard that the two companies would supply parts for each other when practical. The arrangement was a prelude to a possible merger of the two companies at a later date, but the corporate consolidation did not materialize. With the industry-wide acceptance of V8 engine designs after World War II, AMC purchased Packard V8s in 1954 for the 1955 Nash Ambassador and Hudson Hornet.
These Packard V8s were supplied to AMC with extra-thick head gaskets to reduce power output and were mated only to Packard "Ultramatic" automatic transmissions. In addition to the verbal agreement, Packard sent AMC some parts bids, which were rejected as too expensive. After Mason's sudden death in October 1954, George W. Romney, AMC's new CEO, decided against further relationships with Packard. Reportedly, Romney gave orders to design an in-house V8 engine as quickly as possible.
Design work on AMC's first V8 engine began in 1954, yielding versions produced in three displacements for AMC automobiles: in 1956-1961, in 1963-1966, and from 1956 until 1966. This engine series is often called the "Rambler V8". The 327 versions of the Rambler and the Chevrolet V8, which was introduced later, share the same bore, stroke, and displacements; they are unrelated.
A 1956 SAE article entitled "The New American Motors V8" describes the results of development efforts and problems of constructing an engine that is economical, low in weight, durable, and flexible. The entire program was under the direction of Meade F. Moore, Vice-President of Automotive Research and Engineering, and through his efforts, the project was carried on cooperatively by our Kenosha and Detroit Engineering Departments. Obviously, such a division of both design and development required the utmost in teamwork by F.F. Kishline, Chief Engineer, and his assistants, E.L. Monson and J.S. Voigt in Kenosha, and by R.H. Isbrandt, Chief Design Engineer, and W.S. Berry, Chief Mechanical Engineer, in Detroit."
The engineering team was able to get the clean sheet V8 into production in less than 18 months, due in part to being able to apply the research and development efforts done by Kaiser-Frazer for engines that never reached production. One of AMC's engineers, David Potter, had worked on developing V8 engines for Kaiser-Frazer.
American Motors' first V8 engine debuted with in 1956, with a version in 1957. The larger displacement engine included a pioneering electronic fuel-injected (EFI) system sourced from Bendix, the "Electrojector" version in 1957.
All first generation engines share common external dimensions, lightweight - about - forged crankshaft and rods, as well as most other parts. The stroke for all Gen-1 V8s is . Engine displacement was a factor of the bore: the has a bore, , and the a bore. A number indicating the bore size is cast on the top of the engine block's flywheel housing immediately behind the right bank cylinder head.
The block features a deep skirt where the casting extends below the crankshaft centerline, forming a very rigid crankcase gallery. The oil system feeds a central gallery to the cam and crankshaft first, from front to rear, and then divides at the front to feed the two lifter galleries from front to rear. From the rear of the two lifter galleries, oil is then supplied up to the two rocker arm shafts which serve as galleries to lubricate the valvetrain. The fore-and-aft direction changes are designed to eliminate stagnant oil areas that tend to form sludge deposits.
250
American Motors' first in-house V8 engine, the was used in AMC automobiles from 1956 through 1961. It is a modern OHV/pushrod engine design and debuted in the Nash Ambassador and Hudson Hornet "Specials" of 1956. These cars had the top-of-the-line model trim, but were built on the shorter wheelbase (Statesman and Wasp) models (hence the name "Special"). The 250 uses solid lifters and came in two- and four-barrel carburetor varieties. However, all the Nash/Hudson "Specials" featured a four-barrel carburetor.
The 250 V8 was optional in the 1957 Rambler. All 1958 through 1960 V8 Ramblers were called "Rebels" and designated as a different series. The Rambler V8 and the 1958 through 1960 Rebel line are not the same as the 1957 Rambler Rebel, a limited edition muscle car featuring a high-performance engine. In 1961, the Rambler Six was renamed the "Rambler Classic" to avoid model confusion in the Rambler line-up. A V8 engine then became an option on the Classic rather than being a separate model
287
The 250 engine was discontinued in 1961. A V8 engine was not offered on Rambler models, except for the 327, which was available only on the top-of-the-line Ambassador series.
Dealers complained about the lack of V8 engine, so the V8 was introduced in mid-model year 1963 as an option for the "mid-size" Rambler. Like the 327, it uses hydraulic valve lifters. Only two-barrel versions were produced, there were no four-barrel options from the factory for the 287 because this was the positioned as the economy V8. The 287 engine was produced through the 1966 model year.
327
The AMC is similar to the 287, but its larger displacement is due to the bore increase to . Unlike the 250, most 327s were produced with hydraulic valve lifters. All Gray Marine 327s came with solid lifters, as did the 1957 Rebel.
The AMC V8 is not related or manufactured by Chevrolet, whose 327 V8 was introduced five years later in 1962.
The AMC 327 engine debuted in a special-edition 1957 Rambler Rebel, of which 1,500 were built. They were an early American muscle car. All Rebels had silver paint with a gold-anodized "spear" on each side. The 327 was not available in any other Rambler models in 1957. The Rebel's engine differs from the 327s installed in the 1957 Nash Ambassador and Hudson Hornet models in that it uses mechanical valve lifters and a higher compression ratio. Since both engines were rated at , the Rebel's was probably underrated.
The Nash Ambassador and Hudson Hornet "Special" models were dropped after 1957, replaced by the 1958 Rambler Rebel with the 250 V8. The Rebel was a V8 version of the Rambler six and included associated upgrades such as stronger front springs and a stronger rear axle. The Rebel model name also differentiated it from the standard six-cylinder Rambler. The big Nash and Hudson cars were also dropped after 1957, replaced by the 1958 "Ambassador by Rambler" — a stretched Rebel with the 327 V8 instead of the 250. The 327 was exclusive to the Ambassador line and could not be ordered in a Rebel (or later Classic) through 1964. For 1965 and 1966, the 287 and 327 were both available in the Classic and Ambassador.
The AMC 327 was sold to Kaiser-Jeep from 1965 until 1967 for use in the Jeep Wagoneer SUV and Gladiator pick-up truck. Jeep named it the "Vigilante" V8. Two-barrel carburation was standard on these Jeep models, but a four-barrel high-compression version was available in the highly optioned Super Wagoneer from 1966 until 1968. Kaiser-Jeep switched to the Buick 350 in 1967 after AMC discontinued the 327. The Buick V8 engine option continued through 1971, after which Jeeps returned to AMC V8 engines, American Motors having purchased Jeep from Kaiser in 1970.
There were low- and high-compression versions of the 327 starting in 1960. Prior to 1960, all 327s were high compression. All low-compression models used a two-barrel carburetor and all high-compression models received a four-barrel carb. The low compression of 8.7:1 and high of 9.7:1 was affected by a difference in pistons.
The AMC 327 was also offered as a marine engine as the "Fireball" by Gray Marine Motor Company.
Electronic fuel injection The AMC 327 was to be the first commercial electronic fuel injected (EFI) "Electrojector" production engine. Press reports about the Bendix-developed system in December 1956 were followed in March 1957 by an AMC price bulletin offering the EFI option on the Rambler Rebel for US$395, but due to supplier difficulties, fuel-injected Rebels were only available after June 15. Teething problems with the Electrojector unit meant that only a few engineering and press cars were built, estimated to be no more than six units. At least two pre-production Rebels with EFI, however, are known to have been built. One was sent to Daytona Beach, Florida for "Speed Week" (the forerunner of today's Daytona 500). It was the second fastest car on the beach, bested only by a 1957 Chevrolet Corvette with mechanical fuel injection, and only by a couple of tenths of a second.
The EFI 327 was rated at and the regular four-barrel carbureted model at . The EFI system in the Rebel was a far more-advanced setup than the mechanical types then appearing on the market and the engines ran fine in warm weather, but suffered hard starting in cooler temperatures. All the EFI cars were reportedly converted to four-barrel carbs before being sold; none are known to have existed outside the engineering department at AMC.
The main problem was that early electronics were not fast enough for "on the fly" engine controls. This setup was utilized by Chrysler for the 1958 model year on its Dodge, Chrysler, Plymouth, and DeSoto carlines. It too failed, having the same problems.
Bendix licensed patents based on their 1950s design (patent dated 1960) to Bosch, who perfected it as the basis for their D-Jetronic, et seq. injections system, first used in 1967.
Marine application The 250 and 327 were also offered as a marine engines marketed as "Fireball" by the Gray Marine Motor Company starting in 1958. Gray started offering the 250 in 1959. The 250 was offered in 135, 160, 170, 175, 178, and 185 horsepower versions. The 327 was made in 188, 215, 220, 225, and 238 horsepower levels. Gray used the 250 through 1966. The 327 was used as a 220 hp model in 1967, the last year an AMC V8 was used.
Gen-2 AMC short-deck V8 (1966–1969)
The new-generation AMC V8 was introduced in 1966. It is referred to as the "Gen-2" AMC V8. American Motors kept the cylinder-bore centers in the new engines to use existing tooling and equipment. However, everything else in the engine was reengineered with only the timing chain and drive sprocket interchanged with the previous design.
The second-generation engine is vastly different from the Gen-1 model. The previously rear of the camshaft mounted distributor and oil pump were moved to the front. The aluminum housing for them also carried the water pump. The size and weight of the entire engine was trimmed by use of thinwall techniques, a reduced deck height, as well as by reengineering the cylinder block and head castings. The Gen-1 engine is physically the size of a big-block Ford or GM engine, and is sometimes called a "big-block". The Gen-2 is closer to the physical size of U.S.-made small-block V8s except for the bore centers, which are the same as some big-block engines.