Have you ever wondered what would happen if you shoe-horned a more powerful engine into your vehicle? It’s a well known fact that many Toyota Hilux and Fortuner 4.0 V6 engines have found their way into Quantums – as they are far stronger than the 2.7 petrol engine the manufacturer offered. Similarly, most tow trucks, whether they look like a Nissan Navara or Ford Ranger, actually have a Lexus V8 under the hood. However, not all engine swaps are to Frankenstein your way to real muscle in your vehicle. 

An engine swap is the process of removing a car’s original engine and replacing it with another engine. This is often neccesitated by engine failure, or to install a different engine, usually one that is bigger and better to make your car more powerful and or economical. Sometimes older engines may have a shortage of spare parts and so a modern replacement may be easier and cheaper to maintain. 

In years gone by, swapping from a petrol engine to a diesel engine for improved fuel economy was a well established practice, but came at the cost of a reduction in performance. Nowadays, there are a compelling number of high efficiency and high performance diesel engines, and combined with the fact that most passenger vehicles nowadays are offered with both petrol and diesel variants, petrol to diesel swaps have become uncommon. Except possibily for the particular application of off-road vehicles, where the high torque at low speed of turbo diesels combined with good fuel economy makes these conversions particularly effective. 

At Start My Car we would not promote swapping your engine since it will definitely void your warranty. However, if your car is already a good couple of years old, and you wish to prolong it’s lifespan even further or if you’re driving an early model Ssangyong that went kaput, and you can no longer find parts for it,we have compiled a guide to 10 aspects people often forget or underestimate when doing a late-model engine swap. 

10 Things to Consider Before Swapping an Engine: 

1. Wiring 

Wiring is always a constant problem for people, no matter the size of project they are undertaking. For those of us who battle to wire a light at wo-way light switch, an engine swap would be a definite no no. Wiring can be very complex and it requires a thorough understanding about amperage, wire gauge, relays, and overall circuits. A perfect example is the electric fan circuit. A lot of people run two wires (power and ground), but the circuit needs to be tied into the cooling system, air conditioning system and the system needs one or two relays. 

2. Cooling Systems 

Cooling systems don’t require an advanced degree in engineering, but many people underestimate the volume of work that goes into it. Mechanical fans will work sufficiently with older engines, but the modern day engines run hotter and require a lot more cooling. Most people fail to consider the specific functionality of the modern engine they are installing, and merely reinstall the mechanical fan (or they hook-up a cheap electric fan) that doesn’t have enough flow. 

3. Headers 

Most of us will know, or at the very least suspect, that the exhaust manifolds are going to need to be modified. Most of us also know of an uncle who has a pipe bender or machining shop that can fabricate an exhaust/header. Although simple in theory, it isn’t until the engine is sitting 

in the engine compartment that we begin to realize how complex the issue can be, and complexity often results in a lot time and money wasted. Steering linkages, spark plugs and wires can really cause some headache when fabricating a header. By the time most people have a good mental image of how the headers need to lay out, they come to the realization that the tubing is going to hit the frame or body, and have to start from scratch again—a common and costly mistake. 

4. Oil Pans and Pick-Up Tubes 

Since most chassis and cross-members are in different locations, oil pan clearances are often present a problem. Although not the hardest part to fabricate, you may need to budget in the building of custom pans and pick-up tubes. With a little luck, you may find an aftermarket oil pan out there, but you should not bank on it!

5. Steering 

Steering linkage can get tricky when trying to figure out how to navigate past the headers and everything else which can be in the way. Aditionally, most people upgrade their suspension and steering systems at the same time as the engine (which is not neccesarilly a bad idea). With the wide variety of aftermarket components available, the combination of parts used can require an odd combination of steering linkage. 

6. Air Conditioning 

Air Conditioning is a creature comfort and not critical to the safety of the vehicle, and consequently, it’s hardly something you will think about when doing an engine swap. But just so you know, late-model engines will often have mounting brackets or bosses for air conditioning compressors. While this can make it convenient, the compressors are usually mounted on the lower sections of the engine. This can create problems when trying to get an engine between the frame rails, which often forces you to mountin the compressor in a different location. In addition to the compressor, a lot of people have problems laying out the system and figuring out where the accumulator/dryer or fixed orifices go. 

7. Fluid Reservoirs 

One commonly overlooked modification is that in general all of the reservoirs need to be changed. The cooling system isn’t a big deal, but the power steering reservoir can be tricky. Packaging gets really tight, especially in the newer engines. If all else fails, a remote mount reservoir may be needed. 

8. Driveshaft 

While a driveshaft doesn’t seem like a big deal, people will sometimes run into problems either measuring the driveshaft or selecting the right yoke or flange. I’m sure every mechanic on this side of town know of someone who has suped up there car, put a blower on it or shoehorned a massive engine into there engine bay, and then, while hammerring their vehicle down the road, have bent the driveshaft or even kicked it out the side of their car. 

9. Fuel Systems 

A bigger engine will need larger and higher-quality fuel lines and better filtration. That’s pretty simple to understand. It’s like saying bigger people have a bigger apetite or that grown ups need to eat more food than children. Where people run into problems is selecting the right fuel pump. Experts recommend that people try and use a factory-style in-tank pump for their daily driver as frame-mounted high-volume pumps vibrate, run hot and usually aren’t designed for extended driving cycles. 

10.Torque Converters 

If the rest of the driveline is staying the same (designed for an early-model engine), sometimes getting a converter with the right flywheel pattern and transmission spline count can be tricky. There are aftermarket “hybrid” converters to solve this problem. 

Summary 

If you are planning to swap your engine, be it for better performance or due to a breakdown, for a non-identical one, be sure to take note of the points above. No issue in insurmountable, and all of the common issues mentioned above can be solved ahead of time with extensive research and forethought for system layouts. An engineering education is not required but practice makes perfect and it helps for novices to seek help from experienced professionals. 

Like everything else today, there is a wealth of information available online, through media such magazines and by good-old face-to-face networking with fundis at car shows. Odds are, you won’t be the first person to do that particular swap. Ofcourse, you could take the easy route out and go to an expert for help, which is what I would do! I would find a competent mechanic and entrust the job to him, which I believe will save you a lot of time, money and headaches in the long run. Lastly, if you do swap your engine out, remember to notify your insurance company and to apply at a motor vehicle registering office for a Request for Police Clearance. After that you will need to take your vehicle to a vehicle clearance unit of the South African Police Service where vehicle will be cleared. 

For some light reading, have a look at this article “33 of the Most Interesting Engine Swaps We've Ever Seen” 

(https://www.roadandtrack.com/car-culture/buying maintenance/g6790/coolest-best-engine-swaps/) 

Keep safe and happy Frankensteining !