Difference between revisions of "GM Iron Duke engine"

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{{Infobox Automobile engine
{{Infobox Automobile engine
| image = [[Image:Detroitdiesel62.JPG|250px|Detroit 6.2L Diesel]]
| image         =  
| name = Detroit Diesel/General Motors V8 Diesel
| name         = Iron Duke
| aka =
| aka           =
| manufacturer = [[Detroit Diesel]], [[AM General]]
| manufacturer = [[Pontiac]]
| type = V-8
| type         =[[Straight-4]]
| production = 1982-1993 and 1992-current
| bore         =4 in (101.6 mm)
| predecessor = [[Oldsmobile V8 engine#LF9_Diesel|LF9]] 5.7 liter diesel
| stroke       =3 in (76.2 mm)
| successor = [[Duramax V8 engine]]
| displacement =151 cu in (2.5 L)
| bore = 6.2L-3.98in, 6.5L-4.06in
| length       =
| stroke = 6.2L-3.80in, 6.5L-3.82in
| diameter     =
| displacement = 6.2L/379cid and 6.5L/395cid
| width         =
| length =
| height       =
| diameter =
| weight       =
| width =
| block         =[[Iron]]
| height =
| head         =[[Iron]]
| weight =
| valvetrain   =
| block = Iron
| supercharger  =
| head = Iron
| turbocharger =
| valvetrain = 16 OHV
| fuelsystem   =
| turbocharger = Borg-Warner GM-X series, also available naturally aspirated
| fueltype     =
| fuelsystem = 1993 And older-Mechanical rotary pump.  1994 And newer-Electronic rotary pump
| oilsystem     =
| fueltype = Diesel
| coolingsystem =[[Watercooled]]
| oilsystem =
| power         =85 hp (63 kW)
| coolingsystem =
| specpower     =0.56 hp/cu in (25.2 kW/L)
| power =
| torque       =123 ft·lbf (167 N·m)
| specpower =
| compression   =
| torque =
| fuelcon       =
| compression = 21.5:1, Marine 18:1
| specfuelcon   =
| fuelcon =
| oilcon       =
| specfuelcon =
| power/weight  =
| oilcon =
}}
}}


[[General Motors Corporation|General Motors]] introduced a line of [[Diesel]] [[V8]] engines for their [[Chevrolet C/K|C/K pickup trucks]] in 1982. This engine family, designed by GM division [[Detroit Diesel]], was produced by GM through 2000, when it was replaced by the new [[GM Duramax engine|Duramax]] line. AM General's subsidiary General Engine Products (GEP) still produces a military variant of this engine for the [[HMMWV]].<ref name=autogenerated1>[http://www.amgeneral.com/vehicles_gep_productinfo.php AM General :: General Engine Products :: Product Information<!-- Bot generated title -->]</ref>
The '''Iron Duke''' (also called the '''2500''', '''151''', '''Pontiac 2.5''', '''Cross Flow''', and '''Tech IV''', though the decal on the air filter assemblies actually reads "4 Tech") was a 2.5&nbsp;L (151&nbsp;[[Cubic inch|cu&nbsp;in]]) [[Straight-4|I4]] [[piston engine]]. All Iron Dukes were built by [[Pontiac]] beginning in 1977 and ending in 1993.  


The General Motors light-truck 6.2 and 6.5&nbsp;L Diesel engines were optional in all 1982 through 2000 [[Chevrolet C/K|Chevrolet and GMC C/K series]] [[pickup truck]]s, [[Chevrolet Suburban|Suburbans]], [[Chevrolet Blazer|Blazer]]/[[GMC Jimmy|Jimmy]], [[Chevrolet Tahoe|Tahoe]]/[[GMC Yukon|Yukon]], [[van]]s, [[motor home]]s, and the [[AM General]] [[HMMWV]]. The ready availability and low cost of these engines has made them popular for conversion projects and kit vehicles. These engines are often a popular choice for conversion in [[Land Rover]]s, [[Toyota Land Cruiser|Land Cruisers]], and similar vehicles.
This 151 was also used by [[American Motors]] (AMC) starting in 1980, as the base engine option in the RWD [[AMC Spirit|Spirit]] and [[AMC Concord|Concord]], and continuing in both cars through 1982. The AWD (4x4) [[AMC Eagle|Eagle]] carried the 151 as standard equipment for 1981, and carried it midway through the 1983 model year. It was also available (as the ''Hurricane'') in economy model [[Jeep CJ]]s. AMC replaced the Iron Duke 2.5L I4 with a [[AMC Straight-4 engine|150cid Inline-4]] of their own, derived from their evergreen sixes.


==6.2L==
The Iron Duke is often confused with Chevrolet's [[Chevrolet Straight-6 engine|Stovebolt]]-derived ''[[Chevrolet Straight-6 engine#153|153]]'' from the 1960s [[Chevrolet Nova|Chevy II]], but the engines are entirely different - the Iron Duke's intake manifold is on the passenger side, as opposed to the driver side.
The original 6.2&nbsp;L (379 ci.) Diesel V8 was introduced in 1982 in the [[Chevrolet C/K|Chevrolet/GMC C/K trucks]]. It was produced through 1993. The 6.2L diesel hit the market as a high-MPG alternative to the V8 gas engine lineup, even while achieving better mileage than the 4.3L gasoline V-6 of the 80s, at a time when power-on-tap wasn't necessarily needed and the market were more focused on the MPG it could achieve.


===Applications===
Applications:
* 1982–1993 [[Chevrolet C/K|Chevrolet/GMC C/K]]
* 1977 [[Pontiac Astre]]
* [[Hummer H1]]
* 1977-1980 [[Pontiac Sunbird]]
* GM version of the [[CUCV]]
* 1984-1988 [[Pontiac Fiero]]
* 1982-1985 [[Pontiac Firebird]]
* 1982-1985 [[Chevrolet Camaro]]
* 1985-1990 [[Chevrolet Astro]]
* 1985-1990 [[GMC Safari]]
* [[Chevrolet Citation]]
* [[Chevrolet Celebrity]]
* [[Chevrolet S-10]]
* [[Chevrolet S-10 Blazer]]
* [[GMC Sonoma]]
* [[GMC S-15 Jimmy]]
* [[Chevrolet Monza]]
* [[Buick Skylark]]
* [[Buick Skyhawk]]
* [[Buick Century]]
* [[Pontiac 6000]]
* 1985-1991 [[Pontiac Grand Am]]
* [[Oldsmobile Ciera]]
* [[Oldsmobile Omega]]
* [[AMC Concord]]/[[AMC Spirit|Spirit]] (1980-82)
* [[AMC Eagle|Eagle]] (1981-83)
* [[Jeep CJ]] (1980-83)
* [[Grumman LLV]] [[United States Postal Service]] delivery vehicle


===Specifications===
{| cellpadding="2" cellspacing="2" style="margin: 0 0 1em 1em; border:3px solid #87CEEB;"
* Engine Code: LH6 and LL4
!Year
* Displacement: 6.2L / 379 ci.
!hp (kW)
* Bore x Stroke: 3.98 x 3.80 (in.)
!ft·lbf (N·m)
* Block / Head: Cast iron / Cast iron
|-
* Aspiration: Natural
|1978
* Valvetrain: OHV 2-V
|85 (63)
* Compression: 21.5:1
|123 (167)
* Injection: Indirect
|-
* Power / Torque (at start): {{Convert|130|hp|kW|0|abbr=on}} @ 3,600 rpm / {{Auto ft.lbf|240|0}} @ 2,000 rpm
|1979
* Horsepower / Torque (at final): {{Convert|143|hp|kW|0|abbr=on}} @ 3,600 rpm / {{Auto ft.lbf|257|0}} @ 2,000 rpm
|90 (67)
* Max RPMs: 3,600
|128 (173)
|-
|1980
|86 (64)
|128 (173)
|}


==6.5L==
==LS6==
The 6.5&nbsp;L (395 ci.) version was introduced in 1992 to replace the 6.2. Most 6.5s are equipped with a turbo. This engine was never meant to be a power and torque competitor with Ford/International and Dodge/Cummins, but rather a simply designed workhorse engine that made credible power and achieved then-decent fuel economy. The [[GM Duramax engine|Duramax 6600]] replaced the 6.5 in light trucks beginning in 2000, but the 6.5 (6500 Optimizer) is still produced by [[AM General]] for the [[HMMWV]].
The '''LS6''' was a 151&nbsp;cu&nbsp;in (2.5&nbsp;L) [[Straight-4|I4]] engine produced from 1978 to 1979.


There are several GM 6.5 liter diesel engine production options.  The Turbocharged L56, (VIN "S") was used in all 1/2 ton (1500) and light duty 3/4 ton (2500) trucks. Heavy duty 3/4 ton and 1 ton trucks used the Turbocharged L65 (VIN "F") engine.  The L56 is emissions controlled with [[EGR]] and catalytic converters.  The L65 engine has no EGR, and has no [[catalytic converter]].  There is a soot trap on L65 engines that is often mistaken for a catalytic converter. The L49 (VIN "P") and L57 are both normally aspirated engines. L57 is listed as HO or Heavy Duty.  Additional [[Regular_Production_Option|RPO codes]] are LQM (175HP) and LQN (190HP).
==LS8==
The '''LS8''' was a 151&nbsp;cu&nbsp;in (2.5&nbsp;L) [[Straight-4|I4]] engine produced for 1979.


Changes were made by GM to the 6.5 in their light trucks for emissions or reliability improvement.<br />
==LX6==
The '92 and '93 model years used a 6.5 specific Stanadyne DB-2 mechanical injection pump.  GM replaced the DB-2 with the electronic throttle DS-4 in '94+ vehicles.  <br />
The '''LX6''' was a 151&nbsp;cu&nbsp;in (2.5&nbsp;L) [[Straight-4|I4]] engine produced from 1977 to 1978.
In mid 1996 GM implemented a redesigned engine cooling system incorporating twin non bypass-blocking thermostats and a 130GPM water pump.  This improved the flow through the block by @70-75% and flow to the radiator 7%.


===Applications===
==LX8==
* 1994 - 1999 Chevy 2-door Tahoe / GMC Yukon
The '''LX8''' was a 151&nbsp;cu&nbsp;in (2.5&nbsp;L) [[Straight-4|I4]] engine produced from 1979 to 1980.
* 1992 - 1999 [[Chevrolet Suburban]] / GMC Suburban
* 1992 - 1999 Chevrolet and GMC C/K
* 2000 Chevrolet and GMC C/K 2500 & 3500
* 2001 Chevrolet and GMC C/K 3500
* ????-Present [[AM General]] [[HMMWV]]


===Specifications===
==Crossflow==
* Engine RPO Codes: L49, L56, L57, L65, LQM, and LQN.
Cross-flow cylinder heads were added in mid-1979, leading people to refer to this version as the '''crossflow'''. Output stood at 90&nbsp;hp (67&nbsp;kW).
* Displacement: 6.5L / 395 ci.
* Bore x Stroke: 4.06 x 3.82 (in.)
* Block / Head: Cast iron / Cast iron
* Aspiration: Turbocharged (Borg-Warner GM-X series)  Also available naturally aspirated.
* Valvetrain: OHV 2-V
* Compression: GM Early 21.3:1, GM Late 20.3:1, AMG/GEP Marine 18:1
* Injection: Indirect
* Power / Torque (lowest): {{Convert|180|hp|kW|0|abbr=on}} @ 3,400 rpm / {{Auto ft.lbf|360|0}} @ 1,700 rpm
* Power / Torque (highest): {{Convert|215|hp|kW|0|abbr=on}} @ 3,200 rpm / {{Auto ft.lbf|440|0}} @ 1,800 rpm
* Max RPMs: 3,400


==Common Problems==
==Tech IV==
{{Infobox Automobile engine
| image = [[Image:2.5l tech 4 engine.jpg|250px]]
| name          = Tech 4
| aka          = Iron Duke
| manufacturer  = [[General Motors|GM]]
| type          =[[Straight-4]]
}}
 
[[Image:GM Engine Tech4.png]]
 
Iron Dukes were fitted with [[fuel injection]] (TBI, via a single injector in the throttle body) in 1982. This version was christened the '''Tech IV''', though ''[[Car and Driver]]'' later ridiculed it as the ''low''-Tech IV. Power output remained at 90&nbsp;hp (67&nbsp;kW).
 
This was replaced by a swirl-port head with 9.0:1 (instead of 8.2:1) compression ratio in 1984 for a 2&nbsp;hp (1.5&nbsp;kW) gain. Other additions for 1985 included roller lifters, improved bearings, and a new crankshaft.


Main bearing web cracks in both 6.2 and 6.5 engines.  Reportedly fixed with a combination of improved higher nickel cast iron alloy and lower block re-design including but not limited to a main bearing girdle.  These features are in the new for 2007 AM General GEP P400 6500 Optimizer 250-300hp enhanced 6.5 diesel presently being sold to the US Government for the 6 ton armored HMMWV.<ref name=autogenerated1 /> 
A more-modern serpentine belt and crank-triggered ignition was added in 1987, increasing horsepower to 98. The engine was updated one final time one year later with [[balance shaft]]s, new pistons, rods, crankshaft, and an in-pan oiling system. This 1988 Tech IV produced 110&nbsp;hp (73&nbsp;kW).


Crank failures.  Related to age failures of the harmonic balancer, the vibration damped accessory drive pulley, or the dual mass flywheel.
The Tech IV uses the same bellhousing pattern as the 2.8&nbsp;L ''[[GM 60-Degree V6 engine|60-Degree]]'' V6.  


The PMD (Pump Mounted Driver) thermal failures.  The PMD is screwed to the DS-4 injection pump on the 1994-2001 GM 6.5 diesel utilizing fuel flow to dissipate heatThe injection pump is mounted in the intake valley (a high heat area). The PMD contains two power transistors that should be cooled by proper contact with the injection pump body.  If the pump is not precisely machined to make complete contact with the transistors via the silicone thermal gasket and paste, the PMD is improperly installed without the gasket or paste, the PMD is installed off center with the pump body, or corrosion develops on the mounting surface the PMD will overheatSeveral companies manufacture an extension harness and heat-sink kitsThese allow an owner or their mechanic to relocate the PMD away from the injection pump to a lower heat environment and/or a place that can get more air flow.
Over the years, the Tech IV engine has proved to be a reliable, if noisy, workhorse for owners--when not pushed to its limitsAll 1978-1990 Iron Duke L-4's are outfitted with a micarta camshaft gear that meshes directly with a steel gear on the crankshaft (no timing chain)1991-92 VIN R and U engines received a timing chainThe timing gear has a tendency to crumble a tooth anytime after 80,000 miles .    The cam gear simply shears a tooth at startup and the engine won't start. When the cam gear loses a tooth, the camshaft AND distributor stop rotating during engine cranking.


== References ==
Replacing the gear requires heating the new gear in hot oil and quickly installing it for a press fit on the cam stub 
<references/>
 
A few Tech IV owners experience minor driveability issues with the engine.  There are several cheap/easy repairs that the shadetree mechanic can perform to keep this engine running at its best.
 
Inspection (and replacement, if necessary) of the MAP sensor, and its accompanying vacuum hose, is often a solution to many driveability problems.  This sensor largely controls the engine's driveability.  Stuck EGR valves are also very common on the Tech IV.  When replacing the EGR, a mechanic should only use a new, Delphi-sourced or AC Delco part, as aftermarket EGR valves have diaphram springs that are too weak for this engine.  This causes hesitation, sag, stumbling, and sometimes, hard starting.  Oxygen sensors should also be replaced every {{convert|30000|mi|km}} on this engine.
 
Applications:
* 1985-1993 [[Chevrolet S-10]]/[[GMC S-15]] Sonoma
* 1985-1994 [[Chevrolet Astro]]
* 1990-1992 [[Chevrolet Lumina]]
* 1984-1988 [[Pontiac Fiero]]
* 1982-1985 [[Chevrolet Citation]] II
* 1982-1984 [[Pontiac Phoenix]], [[Oldsmobile Omega]]
* 1982-1991 [[Pontiac 6000]], [[Chevrolet Celebrity]], [[Oldsmobile Cutlass Ciera]], [[Buick Century]]
* 1985-1991 [[Pontiac Grand Am]], [[Oldsmobile Cutlass Calais]], [[Buick Somerset]], [[Buick Skylark]]
* 1982-1986 [[Pontiac Firebird]] and [[Chevrolet Camaro]]
 
==Racing versions==
Though not a production engine, the '''Super Duty 4'''[http://en.wikipedia.org/wiki/Pontiac_V8_engine#SD4] racing engine was notable and widely publicized at the time. It was the basis for [[NASCAR]]'s Touring Car series.
 
[[Cosworth]] also produced a [[multi-valve|16-valve]] head ([[Cosworth]] Project DBA, 1987) for the Iron Duke.


==See also==
==See also==
* [[List of GM engines]]
* [[GM H platform]]
* [[GM Duramax engine]]
* [[GM engines]]
 
== External links ==
* [http://www.jeeptech.com/engine/gm151.html Jeep 151 information]
 
* [http://en.wikipedia.org/wiki/Chevrolet_Opala Chevrolet Opala information]


[[Category:GM engines|Detroit Diesel]]
[[Category:GM engines|Iron Duke]]
[[Category:Marine engine manufacturers]]

Latest revision as of 15:27, 3 February 2009

Iron Duke
ManufacturerPontiac
TypeStraight-4
Bore4 in (101.6 mm)
Stroke3 in (76.2 mm)
Displacement151 cu in (2.5 L)
Block alloyIron
Head alloyIron
Cooling systemWatercooled
Power output85 hp (63 kW)
Specific power0.56 hp/cu in (25.2 kW/L)
Torque output123 ft·lbf (167 N·m)

The Iron Duke (also called the 2500, 151, Pontiac 2.5, Cross Flow, and Tech IV, though the decal on the air filter assemblies actually reads "4 Tech") was a 2.5 L (151 cu in) I4 piston engine. All Iron Dukes were built by Pontiac beginning in 1977 and ending in 1993.

This 151 was also used by American Motors (AMC) starting in 1980, as the base engine option in the RWD Spirit and Concord, and continuing in both cars through 1982. The AWD (4x4) Eagle carried the 151 as standard equipment for 1981, and carried it midway through the 1983 model year. It was also available (as the Hurricane) in economy model Jeep CJs. AMC replaced the Iron Duke 2.5L I4 with a 150cid Inline-4 of their own, derived from their evergreen sixes.

The Iron Duke is often confused with Chevrolet's Stovebolt-derived 153 from the 1960s Chevy II, but the engines are entirely different - the Iron Duke's intake manifold is on the passenger side, as opposed to the driver side.

Applications:

Year hp (kW) ft·lbf (N·m)
1978 85 (63) 123 (167)
1979 90 (67) 128 (173)
1980 86 (64) 128 (173)

LS6

The LS6 was a 151 cu in (2.5 L) I4 engine produced from 1978 to 1979.

LS8

The LS8 was a 151 cu in (2.5 L) I4 engine produced for 1979.

LX6

The LX6 was a 151 cu in (2.5 L) I4 engine produced from 1977 to 1978.

LX8

The LX8 was a 151 cu in (2.5 L) I4 engine produced from 1979 to 1980.

Crossflow

Cross-flow cylinder heads were added in mid-1979, leading people to refer to this version as the crossflow. Output stood at 90 hp (67 kW).

Tech IV

Tech 4
2.5l tech 4 engine.jpg
ManufacturerGM
Also calledIron Duke
TypeStraight-4

GM Engine Tech4.png

Iron Dukes were fitted with fuel injection (TBI, via a single injector in the throttle body) in 1982. This version was christened the Tech IV, though Car and Driver later ridiculed it as the low-Tech IV. Power output remained at 90 hp (67 kW).

This was replaced by a swirl-port head with 9.0:1 (instead of 8.2:1) compression ratio in 1984 for a 2 hp (1.5 kW) gain. Other additions for 1985 included roller lifters, improved bearings, and a new crankshaft.

A more-modern serpentine belt and crank-triggered ignition was added in 1987, increasing horsepower to 98. The engine was updated one final time one year later with balance shafts, new pistons, rods, crankshaft, and an in-pan oiling system. This 1988 Tech IV produced 110 hp (73 kW).

The Tech IV uses the same bellhousing pattern as the 2.8 L 60-Degree V6.

Over the years, the Tech IV engine has proved to be a reliable, if noisy, workhorse for owners--when not pushed to its limits. All 1978-1990 Iron Duke L-4's are outfitted with a micarta camshaft gear that meshes directly with a steel gear on the crankshaft (no timing chain). 1991-92 VIN R and U engines received a timing chain. The timing gear has a tendency to crumble a tooth anytime after 80,000 miles . The cam gear simply shears a tooth at startup and the engine won't start. When the cam gear loses a tooth, the camshaft AND distributor stop rotating during engine cranking.

Replacing the gear requires heating the new gear in hot oil and quickly installing it for a press fit on the cam stub

A few Tech IV owners experience minor driveability issues with the engine. There are several cheap/easy repairs that the shadetree mechanic can perform to keep this engine running at its best.

Inspection (and replacement, if necessary) of the MAP sensor, and its accompanying vacuum hose, is often a solution to many driveability problems. This sensor largely controls the engine's driveability. Stuck EGR valves are also very common on the Tech IV. When replacing the EGR, a mechanic should only use a new, Delphi-sourced or AC Delco part, as aftermarket EGR valves have diaphram springs that are too weak for this engine. This causes hesitation, sag, stumbling, and sometimes, hard starting. Oxygen sensors should also be replaced every 30,000 miles (48,000 km) on this engine.

Applications:

Racing versions

Though not a production engine, the Super Duty 4[1] racing engine was notable and widely publicized at the time. It was the basis for NASCAR's Touring Car series.

Cosworth also produced a 16-valve head (Cosworth Project DBA, 1987) for the Iron Duke.

See also

  • GM H platform
  • GM engines

External links