AMC V-8s

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(a few tidbits to fill in missing information, deleted double information and innappropriate reference to Chevrolet small block V8 'Vortec' heads)
(Overview)
 
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[[File:Amc v8.jpg|right|420px]]
 
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The AMC V8 has a [http://www.crankshaftcoalition.com/wiki/Talk:AMC_V-8s storied] history. Read about the pros and cons of both AMC V8 engines. This article will touch on the highlights.  
 
The AMC V8 has a [http://www.crankshaftcoalition.com/wiki/Talk:AMC_V-8s storied] history. Read about the pros and cons of both AMC V8 engines. This article will touch on the highlights.  
  
{{Note1}} Portions of the following text came from [http://www.wps.com/AMC/Rambler-327/The%20New%20American%20Motors%20V-8%20Engine%20%28SAE%20Paper%20details%29.htm The New American Motors V-8 Engine] by John F. Adamson, Carl E. Burke and David B. Potter of the American Motors Corp. This paper was first presented at the SAE National Passenger-Car, Body and Materials Meeting, Detroit, Michigan, March 7, 1956.  
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Portions of the following text came from [http://www.wps.com/AMC/Rambler-327/The%20New%20American%20Motors%20V-8%20Engine%20%28SAE%20Paper%20details%29.htm The New American Motors V-8 Engine] by John F. Adamson, Carl E. Burke and David B. Potter of the American Motors Corp. This paper was first presented at the SAE National Passenger-Car, Body and Materials Meeting, Detroit, Michigan, March 7, 1956.
  
 
==In the beginning==
 
==In the beginning==
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Wherefore it may be said that not only was the Rambler V8 'state-of-the-art', AMC set a new standard of excellence for the US industry.
 
Wherefore it may be said that not only was the Rambler V8 'state-of-the-art', AMC set a new standard of excellence for the US industry.
  
==Engine design==
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==Engine design (Gen-1 AMC V-8, also called Nash V-8 and Rambler V-8)==
The Rambler V8 design features a visually identical 'Hudson X' crankcase gallery, having the main bearing webbing form an 'X' around the main bearings transferring load from the the crankshaft into the block with extreme stiffness and minimized vibration for maximum durability. The Rambler V8 shaft mounted rocker arm assemblies are visually identical to the the former Nash inline six cylinder engines. The engine features an excellent oil system, which is perhaps the best oil system of any US V8 ever made and serves as a model of oil system design theory for it's attributes.
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American Motor's first '56-'67 Rambler V8 design features a tall 9.98" deck height with an obvious 'Hudson X' styled crankcase gallery. Having the main bearing webs form an 'X' around the main bearings transfers load from the the crankshaft into the block with extreme stiffness and minimized vibration for maximum durability. Only the 4bbl 327 CID versions feature 'solid mains'. All other versions feature 'windowed' main webs for weight reduction. The Rambler V8s feature shaft mounted rocker arm assemblies which are visually identical to the the former Nash inline six cylinder engines. The engine features an excellent oil system, which is perhaps the best oil system of any US V8 ever made and serves as a model of oil system design theory for all it's attributes.  
  
 
There were three sizes of AMC Gen-1 V-8s:
 
There were three sizes of AMC Gen-1 V-8s:
 
*1956-'61 250
 
*1956-'61 250
*1957-'66 327
 
 
*1963-'66 287
 
*1963-'66 287
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*1957-'67 327
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(the 327, named 'Vigilante V8' was used one more year in Jeep Corporation Wagoneer and Gladiator vehicles)
  
All having the same internally balanced forged steel crankshaft leveraging a 3.25" stroke with 6.375" forged steel connecting rods to the 'divorced skirt' . The 1963-up AMC (non-Kaiser Jeep corp.) versions all came equipped with  revised/improved high-flow exhaust manifolds, though AMC did not change their advertised rating of 4bbl 327 from it's former rating of 270hp. From the factory, the main difference were in the bore diameter; The 250 used a 3.50" bore, the 287 a 3.75" bore and the 327 a 4.00" bore. There were three different block castings. It is rumored that early 287 blocks can be bored out to 4.00", but the best advice is to have the block sonic checked '''''before''''' boring. All three of these will easily take an 0.125" over bore, but beyond that is pushing the limit. 327 Rambler V8 engines have been successfully bored and stroked to 418 cid, with no known durability issues. 
 
  
All 250 models use solid lifters, the 287/327s are hydraulic. These engines were also used by Grey Marine for boats in the late '50s and early to mid '60s. All the marine engines used solid lifters regardless of size.
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All these feature the same 3.25" stroke forged steel crankshaft and 6.375" forged steel connecting rods and were internally balanced from the factory. The 1963-up AMC (non-Kaiser Jeep corp.) versions all came equipped with  revised/improved high-flow exhaust manifolds, although AMC did not change their advertised rating of 4bbl 327 from it's former rating of 270hp. The three CID versions were made by increasing bore diameter; The 250 made with a 3.50" bore, the 287 with 3.75" bore and the 327 a 4.00" bore. All three CID variations can be confidently bored 0.125" oversize since the stock factory cylinder walls are approximately .25" thick. Rambler V8 327 engines have been successfully bored and stroked to 418, and another to 443 CID, with no known durability issues.
  
The AMC Rambler V8 has only recently been labeled 'Gen 1' by newer AMC enthusiasts. This labeling was first used by AMC writer Frank Swygert (aka editor/forum member 'farna') in an effort to place the engine where it technically "should" be. Technically the labeling is correct; this is the first generation of AMC V-8s, AMC having been formed in May of 1954 and V-8 engine development starting in 1955. The 1966-'69 second generation models and 1970-'91 third generation models are very similar, but having a different block and head casting led to the labeling of Gen-2 and Gen-3. "Series" could have been used instead of "Generation", but "Generation" (shortened to "Gen") seemed to be the most correct description. Previously the first generation AMC V-8 had been (and still is) referred to as either the "Nash V-8" or "Rambler V-8". It was used in both Nash and Rambler branded, as well as AMC branded cars ("Rambler" was dropped from the 1965 Marlin and 1966 Ambassador, those being branded as AMC models). Technically it was built by the American Motors Corporation, not Nash or Rambler.
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All 250 engines were made having solid lifters and adjustable rocker arms. All 287 and most 327 versions came with self adjusting hydraulic lifters. These engines were also used by Grey Marine for boats in the late '50s through the mid '60s. All the marine engines used solid lifters regardless of size. The easily removed 'two wingnut' style valve covers imply original solid lifter design.
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AM's first V8 was called 'Rambler V8' in all the old automotive literature. The alpha-numeric 'Gen-1,2,3' names were never used in any American Motors publication.  
  
 
'Gen-1', 'Gen-2', etc. labeling ideas were first used by Chevrolet small block V-8 enthusiasts to distinguish the differences among that group of very similar engines. This has apparently led many to believe the terms were "borrowed" from the GM engine family or that a GM enthusiast created the labels. There was a small effort to distinguish between GM and AMC labels: GM models are typically labeled with all capitals (GEN-1, GEN-2, etc., sometimes with no dash), whereas Frank used a single capital (Gen-1, and always a dash). The label was used because it is technically correct and fits. GM's labeling wasn't even considered until others pointed out the similarities, and made the assumption that the labeling was "borrowed".
 
'Gen-1', 'Gen-2', etc. labeling ideas were first used by Chevrolet small block V-8 enthusiasts to distinguish the differences among that group of very similar engines. This has apparently led many to believe the terms were "borrowed" from the GM engine family or that a GM enthusiast created the labels. There was a small effort to distinguish between GM and AMC labels: GM models are typically labeled with all capitals (GEN-1, GEN-2, etc., sometimes with no dash), whereas Frank used a single capital (Gen-1, and always a dash). The label was used because it is technically correct and fits. GM's labeling wasn't even considered until others pointed out the similarities, and made the assumption that the labeling was "borrowed".
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| bgcolor="#ffffff"| ||1958-'66||align = "center" |2V||250 @ 4900||align = "center" |340 @ 2600
 
| bgcolor="#ffffff"| ||1958-'66||align = "center" |2V||250 @ 4900||align = "center" |340 @ 2600
 
|}
 
|}
'''<nowiki>*</nowiki>'''Bendix Electrojector. AMC decided it wasn't reliable enough at the last minute and pulled it as an available option. Sources vary on the number built, only two can be verified; they showed up at Daytona Speed week in February 1957 where manufacturers were showcasing their new products. An Electrojector-equipped 1957 Rebel was the second fastest car in Daytona from 0-60 mph. At 7.2 seconds, it was beaten only by a Rochester fuel injection-equipped Corvette that clocked a 7.0 second 0-60 time. It easily outpaced larger Hemi powered #354 and 392 cid# cars, but it must be pointed out that those engines were also in larger, heavier cars #a 1957 Rambler Rebel weighed around 3400 pounds, a Chrysler 300C weighed 5000 pounds#.
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'''<nowiki>*</nowiki>'''Bendix Electrojector. AMC decided it wasn't reliable enough at the last minute and pulled it as an available option. Sources vary on the number built, only two can be verified; they showed up at Daytona Speed week in February 1957 where manufacturers were showcasing their new products. An Electrojector-equipped 1957 Rebel was the second fastest car in Daytona from 0-60 mph. At 7.2 seconds, it was beaten only by a Rochester fuel injection-equipped Corvette that clocked a 7.0 second 0-60 time. It easily outpaced larger Hemi powered 354 and 392 cid cars, but it must be pointed out that those engines were also in larger, heavier cars. A 1957 Rambler Rebel weighed around 3400 pounds, a Chrysler 300C weighed 5000 pounds.
  
 
==Performance upgrades==
 
==Performance upgrades==
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The first AMC V8 engine became widely known as 'Rambler V8', and was also labeled by AMC as 'Ambassador V8' (327cid) in those models. The second all new design AMC V8 debuted in 1966 with 290 cid, then a 343 cid version in 1967 and a 390 cid version in 1968. AMC raised the deck height of their second V8 engine design in 1970, stroking the 290 to 304 cid, the 343 to 360 cid and made a new connecting rod for the 390 version. Along with the raised deck, AMC increased the head bolt size to 1/2" from 7/16" and redesigned the rectangular exhaust ports to have a raised port floor with an enlargement of the outlet beside the port floor underneath one of the exhaust flange bolts (called the 'dog leg' exhaust port to differentiate it from the rectangular port heads). The second design V8 engine has good interchangeability due to sharing the same basic architecture. The first AMC V8 engine also has near total interchangeability between the 250, 287 and 327 cid versions; only the pistons do not because cid differences were made with bore size change only.
 
The first AMC V8 engine became widely known as 'Rambler V8', and was also labeled by AMC as 'Ambassador V8' (327cid) in those models. The second all new design AMC V8 debuted in 1966 with 290 cid, then a 343 cid version in 1967 and a 390 cid version in 1968. AMC raised the deck height of their second V8 engine design in 1970, stroking the 290 to 304 cid, the 343 to 360 cid and made a new connecting rod for the 390 version. Along with the raised deck, AMC increased the head bolt size to 1/2" from 7/16" and redesigned the rectangular exhaust ports to have a raised port floor with an enlargement of the outlet beside the port floor underneath one of the exhaust flange bolts (called the 'dog leg' exhaust port to differentiate it from the rectangular port heads). The second design V8 engine has good interchangeability due to sharing the same basic architecture. The first AMC V8 engine also has near total interchangeability between the 250, 287 and 327 cid versions; only the pistons do not because cid differences were made with bore size change only.
  
At first glance, the Rambler V8 (also renamed 'Gen 1') looks much like the Studebaker V8; they both have similar sized rounded top large valve covers attached to the block with two large wing-nuts, a rear mounted distributor, a dual plane free standing intake manifold, a tin valley cover and a front-of-block 'free standing' water outlet manifold having the thermostat and outlet for the upper radiator hose going to the radiator. The Rambler V8 looks physically big primarily because of the large valve covers, and that the exhaust ports continue out to the edge of the block before they terminate to the exhaust manifolds. (Pontiac V8 and Ford 'FE' V8 exhaust ports have a similar design).
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At first glance, the Gen-1 V8 (also called 'Rambler' or 'Nash' V-8) looks much like the Studebaker V8; they both have similar sized rounded top large valve covers attached to the block with two large wing-nuts, a rear mounted distributor, a dual plane free standing intake manifold, a tin valley cover and a front-of-block 'free standing' water outlet manifold having the thermostat and outlet for the upper radiator hose going to the radiator. The Rambler V8 looks physically big primarily because of the large valve covers, and that the exhaust ports continue out to the edge of the block before they terminate to the exhaust manifolds. (Pontiac V8 and Ford 'FE' V8 exhaust ports have a similar design).
  
 
==Identifying size==
 
==Identifying size==
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==Transmissions==  
 
==Transmissions==  
 
===Automatic transmissions===
 
===Automatic transmissions===
AMC used GM hydramatic transmissions in 1957 switching in the '58 model year to a Borg-Warner automatic transmission behind their Gen-1 engine. Only manual transmissions were used in the 1956 Specials. AMC called the GM automatic "Flashaway" and the Borg-Warner transmission "Flash-O-Matic". It's a three speed cast iron case Borg-Warner Model 8 with a vacuum modulator valve. The column shift quadrant will read P-R-N-2-D-1-L. The 1 and 2 are small.  
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AMC used GM hydramatic transmissions in 1957 switching in the '58 model year to "Flash-O-Matic" units manufactured primarily by Warner Gear Division of Borg Warner. Only manual transmissions were used in the 1956 Specials. AMC called the GM automatic "Flashaway" and the Borg-Warner transmission "Flash-O-Matic". It's a three speed cast iron case Borg-Warner Model 8 with a vacuum modulator valve. The column shift quadrant will read P-R-N-2-D-1-L. The 1 and 2 are small.  
  
 
A dash mounted push-button shifter mechanism was used in the Rambler 6 and Ambassador from 1958-'62. The American models used a column shifter. The push-buttons were marked N-R-D2-D1-L, with a Park lever under the dash. P-R-N are self explanatory. In D2 the transmission will act like a two speed. It starts in second gear and shifts to third, downshifts only to second. This was mainly used for slippery conditions such as driving in snow or ice. Using second gear prevented excessive wheel spin. Many people think they have a two speed transmission because this is the third forward position on the transmission. Slip it down to D1, however, and you'll find the missing gear! In D1 the trans shifts from first through third and back down. L (low) is first gear only, no up shifts. The trans can safely be shifted into Low at any speed. As a safety feature the trans will not shift down until it has reached a safe speed to do so. If in third it will got to second, then down to first once a safe speed is reached. It will not shift back up until shifted into D1 or D2. To manually shift through the gears start in L, shift up to D1 then as soon as the trans shifts, go back to L. It won't downshift if accelerating. When ready for third gear go back to D1.  
 
A dash mounted push-button shifter mechanism was used in the Rambler 6 and Ambassador from 1958-'62. The American models used a column shifter. The push-buttons were marked N-R-D2-D1-L, with a Park lever under the dash. P-R-N are self explanatory. In D2 the transmission will act like a two speed. It starts in second gear and shifts to third, downshifts only to second. This was mainly used for slippery conditions such as driving in snow or ice. Using second gear prevented excessive wheel spin. Many people think they have a two speed transmission because this is the third forward position on the transmission. Slip it down to D1, however, and you'll find the missing gear! In D1 the trans shifts from first through third and back down. L (low) is first gear only, no up shifts. The trans can safely be shifted into Low at any speed. As a safety feature the trans will not shift down until it has reached a safe speed to do so. If in third it will got to second, then down to first once a safe speed is reached. It will not shift back up until shifted into D1 or D2. To manually shift through the gears start in L, shift up to D1 then as soon as the trans shifts, go back to L. It won't downshift if accelerating. When ready for third gear go back to D1.  
  
1965-'66 models used a throttle valve cable instead of a vacuum modulator to control internal pressure. This is the M-10, internally similar to the M-8 except for the TV cable and valve body. The cable '''must''' be connected for the transmission to work correctly! Otherwise it will burn up like a cable equipped GM TH700R4 or a Chrysler transmission without the "kick-down" linkage connected. An electric solenoid inside the valve body controls kick-down (passing gear). A switch on the throttle linkage (usually on the engine) is activated at wide open throttle to force a downshift for passing, etc. It will not kick down over a certain speed, usually in the 60-70 mph range.  
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1965-'66 models used a throttle valve cable instead of a vacuum modulator to control internal pressure. This is the M-10, internally similar to the M-8 except for the TV cable and valve body. The cable '''must''' be connected for the transmission to work correctly! Otherwise it will burn up like a cable equipped GM TH700R4 or a Chrysler transmission without the "kick-down" linkage connected. On the '67-'71 "Shift Command" versions, an electric solenoid inside the valve body controls kick-down (passing gear). A switch on the throttle linkage (usually on the engine) is activated at wide open throttle to force a downshift for passing, etc. It will not kick down over a certain speed, usually in the 60-70 mph range.  
 
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These are reasonably heavy duty transmissions. They are equivalent to a Ford-O-Matic or FMX three speed, which were used behind their 352 and 390 cid engines. In fact, they are nearly identical. Borg-Warner, Studebaker, and Ford formed a development team for an auto trans in the early 1950s and introduced one around 1953-'54. Ford contracted to buy 50% of their automatic transmission from Borg-Warner through 1958, and built a factory to build the other 50% on their own. That's why the same trans kit will work with Borg-Warner and several Ford auto transmissions; BUT it '''is not''' a Ford transmission! The Ford transmissions '''should''' bolt to the AMC bellhousing, no one I know has tried since the older Ford transmissions and parts availability is about the same as the Borg-Warner units.
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The only "problem" with these transmissions is finding someone familiar with rebuilding them, and that there are no performance parts. Most good performance torque converter shops can rebuild the stock converter, and should be able to change the stall speed. Some are busy enough with more familiar/popular transmissions that they don't work on odd-balls like this any more. The only other performance mod is to change the line and/or converter pressure valve springs. There are no springs made specifically for this purpose, but some have either stretched or shimmed the stock springs or replaced them with other springs they have found, but this takes some searching and experimenting, so be careful!
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Parts are available from several old auto trans sources. [www.nwtparts.com Northwest Transmission], Fatsco (www.fatsco.com), and Dave Edwards (www.autotran.us) are good sources.  
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These are reasonably heavy duty transmissions. They are equivalent to a Ford-O-Matic or FMX three speed, which were used behind their 352 and 390 cid engines, moreover in smaller V8 Ford 150 thru 1979. Borg-Warner's website history page states they made Ford-O-Matic in 1950. Ford contracted to buy 50% of their automatic transmissions from Borg-Warner through 1958, and built a factory to build the other 50% on their own. That's why the same trans kit will work with Borg-Warner and several Ford auto transmissions; BUT it '''is not''' a Ford transmission! The Ford transmissions '''should''' bolt to the AMC bellhousing, no one I know has tried since the older Ford transmissions and parts availability is about the same as the Borg-Warner units.  
  
 
Kaiser Jeeps used a TH400 in the Wagoneer and pickup from 1963-'67. It's the "universal" TH400, which was the Buick Nailhead model. Buick Nailhead engines have a deep flange on the back of the block covering the flexplate/flywheel which require a shallower bellhousing than other GM engines. That shallow bellhousing left room to make an adapter without adding length to the engine/trans, so GM sold it as a "universal" model and continued production a few years after the Nailhead was discontinued. If you get one, make sure you get the 1-1/2" to 2" thick cast iron adapter as well as the flexplate and spacer. The crank will need a pilot bushing to match the flexplate. As stated, a Nailhead TH400 will work if you get just the adapter. Rolls-Royce and Jaguar used the universal TH400, among other smaller makers who didn't need enough units to warrant casting a new case. If using another AMC sourced transmission behind a former Jeep 327 with auto, make sure the thin pilot bushing is removed first. When Kaiser-Jeep became part of American Motors in 1970 (AMC/Jeep) the TH400 bellhousing was switched over to the AMC V8 and 72-06 inline six pattern. AMC phased in the use of the Chrysler Torqueflite for the 1972 model year (both AMC and Jeep vehicles used the Torqueflite with the exception of the Jeep Wagoneer which continued the use of the GM-sourced THM400 until 1979 when it was replaced by the Torqueflite 727 (later the 36RH).
 
Kaiser Jeeps used a TH400 in the Wagoneer and pickup from 1963-'67. It's the "universal" TH400, which was the Buick Nailhead model. Buick Nailhead engines have a deep flange on the back of the block covering the flexplate/flywheel which require a shallower bellhousing than other GM engines. That shallow bellhousing left room to make an adapter without adding length to the engine/trans, so GM sold it as a "universal" model and continued production a few years after the Nailhead was discontinued. If you get one, make sure you get the 1-1/2" to 2" thick cast iron adapter as well as the flexplate and spacer. The crank will need a pilot bushing to match the flexplate. As stated, a Nailhead TH400 will work if you get just the adapter. Rolls-Royce and Jaguar used the universal TH400, among other smaller makers who didn't need enough units to warrant casting a new case. If using another AMC sourced transmission behind a former Jeep 327 with auto, make sure the thin pilot bushing is removed first. When Kaiser-Jeep became part of American Motors in 1970 (AMC/Jeep) the TH400 bellhousing was switched over to the AMC V8 and 72-06 inline six pattern. AMC phased in the use of the Chrysler Torqueflite for the 1972 model year (both AMC and Jeep vehicles used the Torqueflite with the exception of the Jeep Wagoneer which continued the use of the GM-sourced THM400 until 1979 when it was replaced by the Torqueflite 727 (later the 36RH).

Latest revision as of 21:32, 22 November 2023

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