Engine swaps are a common thing these days. With all the gas conversion, bad fuel, oil and Dholaikhal parts ruining the original stuff of your 5 year old car, chances are the engine does not perform well nor is efficient as it originally used to be. This is where engine swaps come in, the idea is to replace the tired ol' lawnmower that performs like those buses for a fresher engine. In an ideal budget you'd look for something with low mileage, which is easy for newer generation cars but can be tricky for older cars. Most people go about replacing with an engine of similar specifications, but sometimes owners decide to swap to a different engine entirely, which means everything might not fit the way it did before. Having somebody who has done it before to guide you is the best help you can get in this regard. Otherwise, here is a short-list of problems you might run into or more like the major issues I ran into during my swap.
ENGINE MOUNTS: In some cases you can get away with changing a couple of mounts with a different model car, but in most cases, some cutting, welding and trimming is required for it to fit.
AXLE: If the transmission is also changed, the axles might not fit, but fear not, Dholaikhal surely has something that does.
INTAKE SYSTEM: A stock panel-type box designed for your engine can be sourced, otherwise you could order an intake from abroad that fits your application and if you're on a budget, fabricate an intake yourself with a cone filter. Warning: Fabricated intakes don't usually work as good as OEM pieces.
EXHAUST: In this case, fabricating a custom downpipe is usually a better solution than trying to source the OEM downpipe, better if the flanges, gaskets and the other components are sourced before-hand.
WIRING: This is the most critical aspect ensuring your engine runs and functions the way it is designed, it's best to get it done from a reputed wiring mechanic and check for fault codes after the swap to ensure everything is plugged in properly. While an orange symbol glowing on your dash may add to your headlight decorations, it may be an early sign of a disaster waiting to happen.
SENSORS: Some sensors might not work properly throwing a code and causing malfunctions; in my case, the water temperature sensor and oil pressure switch were damaged and had to be replaced to get rid of the check engine light.
OVERHEATING: This can't be stressed enough, as the water lines were dry for a long time, air clogged into them causes your car to overheat and boil the water resulting in the overflow bottle vomiting steaming hot water. While it may be useful in cold winter morning baths, it's not particularly healthy for your car. Another reason could be the radiator not being able to cope and might need replacement.
BUDGET: This is the single most important aspect to take into account. Your budget will be exceeded no matter how generously you draw it.