The Chrysler-Plymouth-Dodge 2.5 liter Trans Four engine

The 2.5 liter engine was the final Chrysler engine of its era. With a long stroke and single fuel injector, the 2.5 provided better low end power and more torque than most competitive engines. It was also larger than most engines with similar horsepower.

2.2 liter engines

A 2.2 liter engine with a longer stroke, and balance shafts to offset vibration, the 2.5 was only available with fuel injection. Smoother and quieter than the 2.2, it had more power at the bottom end than its sibling, but was not well suited to high performance.

Development of the 2.2/2.5 liter engines, like that of the slant six, was led by Willem L. Weertman, head of engine design from 1976 to 1987.

The 2.5 did not have many changes in its life; and the engine, fuel system, intake, and exhaust were close to identical in every vehicle it was in (Shadow/Sundance, Daytona, Dakota, Caravan/Voyager, and Spirit/Acclaim, among others).

There may be some confusion with the 2.5 liter AMC engine used in Dodge trucks through the 1990s; the latter had sequential-point fuel injection when used by Dodge.

2.2 and 2.5 liter engine chronology

Repairs 

Most repairs are covered on our central repairs and troubleshooting page. However, we do have a collection of odds and ends on our 2.2/2.5 liter repairs page. Also, one reader noted that the timing belts differ between the 2.2 and 2.5, and byyear, with the earlier engines having a square-notched timing belt.

Note: There is more information on this engine in our 2.2/2.5 page.

2.5 Liter Engine Specifications

Displacement 153 in3 (2500 cm3)
Bore x Stroke 3.44 x 4.09 (87.5 x 104)
Valve System SOHC, 8 valves, roller followers, hydraulic lifters
Construction Cast iron block, aluminum alloy heads,
counter- rotating balance shafts
Compression Ratio 8.9:1
Power (SAE net) 100 bhp @ 4800 rpm
Torque (SAE net) 135 lb-ft @ 2800 rpm
Max. Engine Speed 5950 rpm
Fuel Requirement Unleaded regular, 87 octane
Oil Capacity 4 qt. (3.8L)
Coolant Capacity 9.0 qt. (8.5L)

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