Engine swap

An engine swap is the process of removing a car's original engine and replacing it with another.

This is done either because of failure, or to install a different engine, or to usually one that is more modern and so more efficient, this may make it more powerful and or economical. Older engines may have a shortage of spare parts and so a modern replacement may be more easily and cheaply maintained. Swapping to a diesel engine for improved fuel economy is a long established practice, with modern high efficiency and torque diesel engines this does not necessarily mean a reduction in performance associated with older diesel engine swaps. For the particular application of off-road vehicles the high torque at low speed of turbo diesels combined with good fuel economy makes these conversions particularly effective. Older non-electronic fuel injection diesels were well known for their reliability especially in wet conditions.

An engine swap can either be to another engine intended to work in the car by the manufacturer, or one totally different. The former is much simpler than the latter. Fitting an engine into a car that was never intended to accept it may require much work and money; modifying the car to fit the engine, modifying the engine to fit the car, and building custom engine mounts and transmission bellhousing adaptors to interface them along with a custom built driveshaft. Some small businesses build conversion kits for engine swaps, such as the Fiat Twin cam into a Morris Minor or similar.

Swapping the engine may have implications on the cars safety, performance, handling and reliability. The new engine may be lighter or heavier than the existing one which affects the amount of weight over the nearest axle and the overall weight of the car - this can adversely affect the car's ride, handling and braking ability. Existing brakes, transmission and suspension components may be inadequate to handle the increased weight and/or power of the new engine with either upgrades being required or premature wear and failure being likely.

Insurance companies may charge more or even refuse to insure a vehicle that has been fitted with a different engine to its initial configuration.

A common anecdote among tuners in the United States is that the easiest way to make a car faster is to drop in a General Motors small block engine as used in the Corvette. The Chevrolet Vega (and its Astre, Monza, and Skyhawk sisters) is a candidate for a small block swap; some have also seen big blocks, also. Chevrolet engines have been used in such cars as Toyota Supras, BMWs, RX-7s, Mazda Miatas, Jaguar sedans, Datsun 240s, 260s, and 280Zs, Corvairs, and others.

In the Honda world, engine swaps include the Civic Si (B16A), The Civic Type R (B16B), Integra GSR(B18C), and the Integra Type R (B18C5) engines. More recently, swapping larger displacement Honda engines (such as the J-series V6) has become more popular. Swapping any of these motors into a lightweight 88-00 Honda Civic chassis can achieve greater performance.

Chrysler made many turbocharged vehicles in the 1980s, and these engines share much in common with the naturally aspirated ones. It is quite common to obtain an engine from a vehicle such as a Dodge Daytona and swap it into a Dodge Aries. The Mopar Performance arm even offered a kit to upgrade the Dodge Daytona to rear wheel drive with a Mopar V8.

Engine swaps are also somewhat common within the Volkswagen tuning scene, often placing Type 2 (Bus), Type 3, and Type 4 (Squareback) engines in the Type 1 (Beetle). Water-cooled engines, such as the GTI 16-valve four, VR6, or 1.8 T are commonly swapped into the Mark II GTI, Jetta, and Corrado. Less common is the swap into a Mark 1 Golf or Cabriolet, giving an amazing power-to-weight ratio, even with minimally modified powerplants. Porsche engines are also very popular one of the most popular is to take the engine from a Porsche 911 super 1600.

In jurisdictions such as California, with strict, arbitrary smog rules, it may not be possible to register a late-model vehicle with an engine swap, even if it can be proven to produce less pollution than the original engine (owing to "visual inspection" rules).

In the Super GT racing series, engine swaps can be considered a way of life for the upper tier GT500 cars, most of which are provided with specially modified racing engines from the manufacturers. GT500 class rules themselves allow for any engine to be swapped into a car as long as it is from the same manufacturer. Notable examples include Toyota swapping in highly tuned 4-cylinder engines originally from the Toyota Celica into their Toyota Supra GT500 race cars.

British sports cars (such as MGs and Triumphs) from the late 1960s and early 1970s were attractive light-weight cars that had excellent suspensions, but were known for troublesome electrical systems, barely adequate power levels and unreliability. It is popular to take one of these classic sports cars and add a more powerful engine. The all-aluminum 215 cu in (3,520 cc) Buick and Oldsmobile V8 engines are a traditional choice for these cars. Swapping an MGB all-iron 1.8L 4-cylinder engine and 4-speed transmission for a Buick 215 V8 and a modern 5-speed transmission actually improves both cornering and acceleration because it reduces the overall weight of the car by about 40 lb (18 kg). Power is approximately doubled; torque increases even more. Derivatives of that classic General Motors engine, the 3.5L, 3.9L, and 4.2L Rover V8s are also frequently used. (The original Buick and Oldsmobile, the Rover, and the related Morgan-licensed V8, are bolt-ins.) Although more recent narrow sixty-degree Ford and GM V6 engines are more compact, they usually don't equal the Rover engine's power-to-weight ratio. They can, however, be very cost effective and an easier fit, notably the Chevrolet 3.4L. The cast iron block Ford 302 (5.0L) V8 in particular results in spectacular power-to-weight ratios for straight-line acceleration. With aluminium heads, intake, and water pump fitted, the Ford 302 only adds about 40 lb (18 kg) to the front of an MGB, and is substantially more powerful and lighter weight than an MGC or TR6 iron-block six-cylinder. An aluminium 302 performance block is available that weighs 60 lb (27 kg) less than the common iron version, as is displacements of 331 and 347 ci, but they are significantly more expensive. The Nissan SR20DET is an all-aluminium fuel-injected DOHC turbocharged 4-cylinder. This compact engine, along with the very compact, light, and powerful Mazda 13B rotary engine, have both been transplanted into too many different cars to list.