The Mopar 2.2 and 2.5 Liter Engine - Carb and TBI
The 2.2 is one of the most reliable four-cylinder engines ever made, and in all its forms, from under 84 hp to 224 hp, was a long-lasting sturdy piece of equipment (though some years and models required an occasional head gasket). [2.2 liter engine specifications]
The 2.2/2.5 liter engines were originated by engineering genius Willem L. Weertman. He was Managing Engineer of engine design from 1955-62, Assistant Chief Engineer of Engine Design and Development from 1962-76, and Chief Engineer of Engine Engineering from 1976-87. He had a large role in just about everything from the small-block V8s to the 426 Hemi, including the slant six. Another major influence on the design was engineer Pete Hagenbuch, who headed Chrysler's engine performance group and, later, its emissions group.
The 2.2 was fitted with a carburetor in its earlier years; that gave way to turbochargers with multiple-port fuel injection, or a single throttle-body injector. The most common was the single throttle-body injector, or TBI. The reason both for keeping carburetors as long as they did (and for keeping them on the Omni and Horizon for longer than on other models) and for using single-point injectors was cost; carburetors reportedly cost half as much as the single injectors, and of course four injectors cost far more than one. The downside was lower gas mileage, lower power, and a less competitive vehicle.
The multiple-port fuel injection engines (using four separate injectors rather than just one, firing into the intake ports rather than the throttle body so fuel would stay atomized and time delays would be minimized) did not spray fuel into all cylinders at once, but alternated the injectors to avoid wasting fuel. This allowed the turbocars to avoid the aspirator or air pump.
2.2 and 2.5 turbo information has been moved to a separate page; click here to visit.
General information
The 2.2 was introduced in 1981 as an all-new design, the first metric Chrysler engine. It was originally built at the Trenton Engine plant, which made the slant six and 440 RB. Though the two have some basic similarities, Pete Hagenbuch, who worked on both engines, wrote that "As far as I know there was absolutely no commonality between the 170/225 engines and the 2.2/2.5." The design philosophy may have held commonality, but not the actual design. See our interview with engine designer Pete Hagenbuch , which covers the 2.2 and other topics.
There are several different 2.2 blocks. They feature siamesed cylinder bores (no cooling in between), a short crankcase skirt, and partial open deck; it was designed to be machined by milling to achieve lighter weight, but uses a cast iron (rather than aluminum) block because aluminum technology at the time was not what it is now. The oil pump is mounted internally. High performance versions, such as the Shelby engines, have modifications such as .8 mm milled off the top of the deck surface. Even on the 225 horsepower 2.2 Turbo III version, the engines had a timing belt. One of the engineers explained: "I always hated belts, but the weight penalty for chains was as big a factor as cost." Oil sealing was also a factor. 2.2 liter engines are all noninterference designs, so they generally are not damaged when the timing belt breaks.
The early 1981-83 blocks weigh about 87 lb; the turbo block weighs about 90 lb. A special racing block (96 lb) was designed for IMSA racing, before the turbo block was available and before a Champion RS series rule change made the 2.2 noncompetitive.
Pistons are aluminum with steel struts, and rings are iron. Different years and engines (e.g. turbo I, turbo II) used different pistons. Mopar Performance sold a heavy duty oil pump for most of the 2.2's life, which can be handy in high performance situations.
The 2.2 liter engine was originally to be 2.0 liters, but the K-cars needed some extra power, so the engine was enlarged during the development. Priority was given to moving exhaust heat to the floor of the intake manifold, underneath the carburetor, to warm it up more quickly and get better cold responsiveness; the carburetor was moved as far back as possible to make it safer during a front-end impact, and also to make assembly similar to the 1.7 liter Volkswagen engines already used in the Omni and Horizon. This move made the spark plugs and oil filter easier to change. The distributor, belt adjustment, and power steering pump were also easy to access (reference for this paragraph: Chrysler Engines, 1922-1998.)
Carbureted models used a staged two-barrel carburetor, a Holley Weber design. Feedback units were used on domestic (American) cars, usually a model 6520 carb. Some Canadian and Mexican cars used a Holley Model 5220, staged nonfeedback dual venturi carburetor.
The 2.2 engine was brought out in 1981, and used an electronic feedback carburetor (except on turbocharged models); Chrysler phased in single-point, throttle-body fuel injection starting in 1985 (Laser, Lancer, LeBaron and LeBaron GTS, and Caravelle), with every car except Omni/Horizon and Turismo/Charger using fuel injection in 1986, and the final conversion, of the L bodies, in 1988. The electronic fuel control system on carbureted engines measured engine speed and load, starting condition, coolant temperature, throttle (open or closed), ambient air temperature, and output from the oxygen sensor to control ignition timing and adjust the air-fuel mixture at the carburetor. Engines with the 2.2 cut fuel during deceleration for better gas mileage, using a solenoid-controlled valve that opened during deceleration to allow more air into the idle system; it was also used to prevent “dieseling.”
Carburetors had one major advantage over fuel injectors: they cost far less, despite their growing complexity. They could not provide the emissions control of fuel injectors, though — even when just one fuel injector was used. Unfortunately, Chrysler was spending as little as it could on emissions controls; had the company used multiple point fuel injection from the start, its powerplants would have had more power, better gas mileage, lower emissions, and better responsiveness and idle quality, attracting more praise and more buyers. As it was, later TBI models were frequently dismissed by auto journalists as relics, despite their attractive pricing and, often, their advantages over Japanese and other domestic models.
The fuel injection systems were controlled by a pair of computers, the Logic Module and Power Module (these would eventually be combined); the logic module controlled ignition timing, the air/fuel ratio, emissions control devices, and idle speed, while the power module translated the logic module's demands for air/fuel ratios and timing into signals sent to the fuel injector (altering the length of its pulse) and the distributor. Input from the knock sensor allowed the computers to retard timing as needed to avoid damage to the engine with (for example) low-octane fuel (on turbocharged engines, engine knocking was dealt with both by reducing boost and by retarding timing for the knocking cylinder — and only that cylinder). The logic module was adaptive — it could compensate for changes in operating conditions, including altitude changes (this had been introduced in 1982).
The system could tolerate up to 10% ethanol. In 1984 it used fuel at 36 psi, passing through a small screen, with a pressure regulator mounted to the throttle body, downstream of the injector; the regulator used a spring-loaded diaphragm to uncover the fuel return port, returning excess fuel to the tank. Multiple-point injection systems used 55 psi in 1984, with injectors pulsed in pairs. The multiple point system included a fuel cutoff when the engine hit 6,650 rpm, which would return fuel at 6,100 rpm. It had a limp mode that limited the engine to 2,000 rpm when the MAP sensor failed completely or the wastegate failed to limit boost.
The system included an air conditioner cutout, so that under heavy acceleration, the air conditioning compressor would be shut off, providing more power for acceleration.
1986 saw a new “fast-burn” cylinder head that helped the air/fuel mixture to swirl from the ports (as illustrated below) for better combustion:
The 2.2 ranged in power over its life. In 1985, the carbureted version was rated at 96 hp (but only 119 lb-ft of torque). The fuel injected version started out at 99 hp / 121 lb-ft, with a high output version (for the 2.2 Charger, etc) at 110 hp and 129 lb-ft of torque. The 2.6 had more torque but comparable horsepower. The 2.5 started out at 100 hp and 136 lb-ft of torque, comparable to the 2.6, and would stay at roughly that power output through its life (except with a turbocharger fitted).
| 1982 2.2 | 1985 2.2 | 1986 2.2 | 1986 2.2 Turbo I | |
|---|---|---|---|---|
| Displacement | 2213 cc | 2213 cc/135 CID | 2213 cc | 2213 cc |
| Compression ratio | 8.5:1 | 9.0: 1 | 9.5:1 | 8.1: 1 |
| Horsepower | 84 hp @4800 | 99 @ 5600 | 97@5200 | 146 @ 5200 |
| Torque (ft/lb) | 111 lb-ft @2,400 | 121 @ 3200 | 122@3200 | 170 @ 3600 |
| Bore/Stroke | 3.44" x 3.62" | |||
| Coolant Capacity | 8.5L (9.0 qts.) | |||
| Fuel Recommended | Regular | Regular | Regular | Premium (91 octane) |
| Fuel delivery | Carb | TBI | TBI | MPI |
| Mileage (Aries stick) | 29/41 | 25/35 | ||
More details on the 2.2 and 2.5 blocks
James Corrigan wrote: The 2.5 has a deeper stroke than the 2.2, the 2.5 has a bigger crankshaft with a bigger throw. Basically this means if regular length 2.2 pistons were used with 2.5 crank, the pistons would pop out the top of the regular 2.2 block. So what Ma Mopar did in '86-88 was to build the tall block, basically a 2.2 block but with a higher deck so the pistons won't pop out the top. The 1989 and newer common block is the most durable, but at naturally aspirated (nonturbo) power levels it won't make much difference.
Chrysler common block
Starting in 1989, all 2.2 and 2.5 liter engines, including the Maserati-built 2.2 used in the Chrysler TC by Maserati and the longitudinal engine in the Dakota, used the same engine block. This saved money and gave base engines a stronger block; so starting in 1989 the engines had stronger main bearing supports and caps, thick cylinder walls, balance shafts (on the 2.5 and late turbo 2.2), and cross drilling between the cylinders. Without a lengthened deck, the 2.5 liter engine maintained its displacement with a shortened piston.
The new block was not as high as the 2.5. Casting details were added to increase rigidity and integrity. An acoustical oil pan was added on all passenger car versions of the 2.2 engine, cutting noise; the 2.2 pan had a deep sump for uninterrupted supplies of oil during rapid cornering, braking, and acceleration (this was originally to be used only on turbo models). Crankshafts for all four cylinder engines were designed to use the old 2.5 engine's front seal and retainer; crankshafts were still cast, except on the forged Turbo II (and, later, Turbo III and IV). All engines also now used the old 2.5's camshaft and accessory shaft drive belt and sprocket system, with rounded teeth; a new water pump was driven from the back of the alternator Poly-V belt, increasing traction.
Along with the common block, the 2.5 liter throttle-body engine gained new, lightweight strutless aluminum pistons in 1989; these allowed for a much lighter counterweight.
An acoustic cylinder head was set up as a running change on throttle body models; turbocharged engines already used an aluminum cylinder head cover with better acoustic quality.
Performance and repairs
Performance tips for 2.2 and 2.5 liter non-turbo, fuel-injected engines.
2.2 and 2.5 liter engine (and associated systems) - common repairs
Mopar Performance used to list a supercharger for the carbureted 2.2 engine (P4349478). Development work was done at the Caroll Shelby Performance center, and it was manufactured by B&M (whose part number was 90601). Dealer cost on this in 1987 was $1400! It made 130hp@5200 rpm with the stock carburetor; with the Weber (PN P4349300) it jumped to 155@5200 RPM; by comparison the standard Turbo II package reached 174 hp, though presumably the supercharger built up power earlier and more gradually. (Thanks, Marc Medina!)
Chronology (courtesy of Aaron Karpinski, some additions by the Webmaster)
Note: we’ve moved out most of the turbo information to our 2.2 / 2.5 turbo engine page.
| 1981 | This was the first year for the 2.2 liter engines; they were built at Trenton Engine, former home of the big-block V8s. The 2.2 produced 84 horsepower @ 4800 rpm and 111 ft-lbs of torque @ 2800 rpm. The first 2.2 featured a cast iron block with aluminum pistons, overhead camshaft and valves, and an aluminum cylinder head; auxiliary equipment included a two-barrel Holley electronic feedback carburetor, antifreeze-heated intake manifold, and a computer controlled carburetor. The aluminum intake manifold had long, completely separate runners for each cylinder. The new engine was used in a wide variety of cars starting in 1981. |
| 1982 | A slightly different intake manifold with shorter, integrated runners and a larger plenum was used; it still produced 84 horsepower, though the MasterTech News claimed the aluminim manifold provided “a significant improvement in top end horsepower.” The exhaust and intake valves were modified for better airflow. The cam centerline was changed to improve torque; a minor change in the cam sprocket keyway allowed for relocking the cam from 110° to 106° (advancing the cam increased torque without lowering horsepower). TRW exhaust valve seats were used; a new "D" intake manifold was launched as a running change. Stock was added to the block between the cup plugs, below the manifolds. Teacup oil filter. |
| 1983 | The first year for the A511 "G" casting cylinder head, with slightly more air-flow then the older head. Using .030" higher pistons for an increased compression ratio give the engine 94 hp, more than it would have with throttle-body injection. Underhead flat was removed from exhaust valve; a new exhaust manifold was used, flanges were removed from sprockets (running change), low load valve springs were substituted, and an anti drainback valve was added.
This was the first year for the Shelby engine in the Dodge Shelby Charger - the same as the regular engine except for slightly richer carb jets, a .030" milled engine block (raising compression to 9.6:1), increased piston fit clearance, 4°-advanced cam phasing, detonation sensor, chrome-plated valve cover, and a slightly different engine computer, yielding a respectable 107 horsepower, more than the single-carb slant six (albeit with lower torque). The Shelby engine was introduced midyear, and reportedly was developed internally with Carroll Shelby providing general guidance. The A465 five-speed manual replaced the A460 four-speed in most vehicles (the A465 added an overdrive gear, and had an extended case cover to make room). |
| 1984 | Changes to the 2.2 included hardened powdered-metal inserts on top of each rocker arm (where the cam lobe contacted it), reducing friction with the cam, extending the lives of both parts; the valve spring pressure was also reduced. This was in response to a relatively small number of cases where the cam had to be replaced. The carbureted 2.2 liter engine now developed 96 hp @ 5200 rpm. The Shelby engine was carried over from mid-1983, though horespower was now rated at 110 hp @ 5,600 rpm with torque at 129 lb-ft @ 3,600 rpm. It was only available with a five-speed manual, with overall top ger ratio of 2.57:1; it was in the Omni GLH. This was the first year for the TBI (throttle body injection) engine, which hit the non-turbo 2.2’s all-time non-Shelby peak: 99hp @ 5600 rpm, with 121 lb-ft of torque. The Daytona/Laser launched with the TBI 2.2 and the New Yorker was upgraded to one, but the Reliant/Aries/Lebaron had to wait; they still used a carburetor. The head bolts were upgraded from 10mm to 11mm, and the A-525 manual transmission debuted on the Daytona and Laser. This was the first year for the Turbo I engine, which pumped out a V6-beating 142 hp, and was available as an option in a variety of vehicles, allowing Chrysler to limit use of the Mitsubishi 2.6. It featured Chrysler-engineered multi-point fuel injection, and a turbocharger limited to 7psi of boost. This was only the second American front wheel drive vehicle with a turbocharger, after the 1979 Buick Riviera. Accessory changes included a 90 amp Bosch alternator with internal voltage regulator on EFI cars and any fleet vehicles (the voltage regulator was part of the brush holder, mounted on the rear housing); a new aluminum radiator was used with non-air conditioned L-bodies, cutting four pounds and increasing reliability; K, E, and G cars with the 2.2 got new copper/brass radiators, one pound lighter and more durable. Transmission oil coolers could be external or internal, depending on the car. The thermostat was given a better seal when closed. Timing belt flanges were removed, to make cover removal easier, and the PCV system was changed to ease maintenance. The snorkel and retaining clip were also altered for maintenance. Unconfirmed changes include higher load valve springs (both normal and turbocharged engines), stamped rockers, a lightweight crankshaft, oil pump relief raised from 60 to 70 psi, a turbo oil drain boss added to the block, and removed lubrite from the camshaft. (These might have been late or 1985 changes.) |
| 1985 | Chrysler sold the Shelby engine as an option in any Charger or Turismo with a 5 speed manual transmission. The new 287 head replaced the 455 heads on carbureted engines; it was similar but had a new a/c compressor mount. There was a new seal ring gasket (exhaust donut). Other changes included the A590 (solid mount a/c) bosses on block and head, oil management block (running change), improved intake valve surface, lightweight connecting rod (running change), high temp timing belt, 11 mm head bolts (running change), integral water box on bottom of intake manifold, better anti-drainback valve (running change), oil pump relief back down to 60 psi, 8 bolt flywheel (late change), material added to head and block at oil transfer hole, .94 rotor oil pump (late change) |
| 1986 | The first year for the A515 "fast burn" cylinder head and notched "fast burn" pistons, designed to decrease emissions; power output was the same for all but the TBI, which dropped slightly to 97 horsepoewr. The 2.5 liter engine was launched; it used the same cylinder head as the 2.2, with standard single point throttle body injection, a taller block, and balance shafts in the oil pan. The 2.5 TBI pumped out 100hp @ 4800rpm, and always would. Other changes: low tension ring package, heater bypass moved to water pump, thicker head gasket (running change), new valve cover with curtain to prevent oil splashing, new 175# valve spring on all engines, 2 mm longer valves (both intake and exhaust), exhaust guide materials changed to a medium phosphorus iron, rocker pad surface finish improved, cam plug instead of lip seal in rear, better rod caps, crank drilled for N body (rear wheel drive), common dipstick and tube. |
| 1987 | A modified longitudinal-mount 2.2 is used in the Dakota pickup - carbureted; and the A520 five speed manual comes out. |
| 1988 | All Chrysler four-cylinder engines now have fuel injection. The 2.2 TBI dropped to 93 hp, with no explanation; it would stay at this level until the end. Roller rocker camshafts were adopted in all 2.2 and 2.5 engines and a single engine computer (with two boards) replaced the dual setup. |
| 1989 | The new common block was used for turbo, standard, and 2.5 liter engines, saving money and giving base engines a stronger block; it included stronger main bearing supports and caps, thick cylinder walls, balance shafts (only used on the 2.5 and late turbo 2.2) and cross drilling between the cylinders. Throttle body injected engines got a new injector and higher fuel pressure. Cam drive sprockets and belt were changed to a quieter design. |
| 1990 | A single board computer arrives. Shelby's VNT engine becomes factory production. An acoustical stamped steel valve cover, with a single-piece gasket, cut noise and, in theory, leaks; powered metal intake and exhaust guides improved lubrication; increased piston wrist pin bore surface area increased connecting rod-to-wrist pin support; 2.5 engines had increased wrist pin stiffness; and a new water pump impeller shaft seal and bearings were used. |
| 1993 | Export 2.5 liter MPI engine produced with 106 hp. 2.0 liter engine, destined to replace the 2.2, enters production in the brand-new 1995 Neon. Mexico gets a multiple-port injection 2.5 with 106 horsepower, while the US gets a multiple-port injection 2.5 flexible-fuel engine that runs on ethanol. |
| 1994 | 2.5 MPI drops to 103 hp. 2.2 TBI drops to 92 hp in its final year. The 2.0 liter “Neon engine” is unveiled; it has some of the same dimensions as the 2.2 in order to reduce tooling costs. The base 2.0 produces 132 hp and 129 lb-ft of torque (a dual cam version goes to 150 hp). |
| 1995 | The 2.2 and 2.5 finally leave production; minivans switch to the new 2.4 liter version of the Neon engine, rated at 150 hp, while the Dodge Dakota switches to a 2.5 liter AMC engine producing 125 hp. From shelbycsx.com: “Chrysler licensed First Auto Works (FAW) of Changchun, People's Republic of China, to build the 2.2L for the Chinese market. FAW began production in 1990, and the engine was still in production there as of July 2000.” |
| 2002 | The end of the 2.0 and 2.4 engines is announced, with both being replaced by a "joint effort" engine lineup (“World Engine” initially designed by Hyundai, and substantially redesigned by both Chrysler and Mitsubishi. Coincidentally, the turbocharged version of the 2.4 also appears; and the AMC 2.5 liter engine drops out. |
| 2005 | The last Neon is built, and the 2.0 engines are relegated to export PT Cruisers. |
| 2007 | BMW drops the Neon-based 1.6 liter engine from their Mini. |
| 2010 | The last PT Cruiser is built, and with it the 2.4 liter four-cylinder engine is eliminated. The last traces of the 2.2 design disappear with it. The World Engines were given a new lease on life, and may be adopted by Fiat for its larger vehicles. |
1987 Slider Cam specs (courtesy Ed Treijs)
| 2.2 Standard | 2.2 Turbo | 2.5 TBI | |
|---|---|---|---|
| Intake opens (BTDC) | 16 | 10 | 12 |
| Intake closes (ABDC) | 48 | 50 | 52 |
| Exhaust opens (BTDC) | 52 | 50 | 48 |
| Exhaust closes (ABDC) | 12 | 10 | 16 |
| Valve overlap | 28 | 20 | 28 |
| Intake duration | 244 | 240 | 240* |
| Exhaust duration | 244 | 240 | 240 |
* This might be a typo in the official guide; it might be 244.
Common repairs
Most repairs are covered on our repairs and troubleshooting page. However, we have a collection of odds and ends on our 2.2/2.5 liter repairs page.
See our interview with engine designer Pete Hagenbuch, which covers the 2.2 and other topics; and our interview with head of engine design Willem Weertman, which also covers the 2.2.
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