What to Pay Attention to When Doing Modern Engine Swaps

Jul 22, 2011

The team at Modern Muscle, a hot rod shop located in Oswego, Illinois, compiled this helpful list of the top 10 things people commonly forget or underestimate when doing a late-model engine swap.

“Over the years we have seen the same problems over and over in our shop and heard about them around the country when it comes to people doing engine swaps,” says Justin Meyers, the shop’s vice president. “That’s why we thought it was important to get this list out there to help all of those builders in the future avoid common pitfalls of taking on a modern engine swap.”

Here are the Top 10 things you should be paying attention to in order to have a successful late-model engine swap.

1. Wiring Wiring is a constant problem for builders, no matter what size project they are taking on, but especially in modern engine swaps. “This is probably the biggest single issue we see,” Meyers said. “Wiring can be very complex and it requires a lot of 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 aren’t tricky, but many builders underestimate the volume of work that goes into building them. “Mechanical fans will work [fine] with older engines, but today’s engines run hotter and require a lot more cooling,” Meyers said. “Most people just don’t think about the specific functionality of the modern engine they are installing and reinstall the mechanical fan or hook up a cheap electric fan that doesn’t have enough flow.”

3. Headers Most builders know or have a good idea that the exhaust manifolds are going to need to be modified.  According to Meyers, many builders don’t realize how complex of an issue it’s going to be until the engine is sitting in the engine compartment, and they quickly get in over their heads. “Steering linkage, spark plugs and wires can really cause some headache when fabricating a header,” he said. “By the time most people have a good mental image of how the headers need to be laid out, they come to the realization that the tubing is going to hit the frame or body, and have to start from scratch again, [which is] a common and costly mistake.”

4. Oil Pans and Pick Up Tubes Since most chassis and crossmembers are in different locations, oil pan clearances are often a problem. Luckily with the wide variety of aftermarket oil pans out there, you rarely have to build custom pans and pick-up tubes. It takes a little more effort to find exactly the right fit.

5. Steering Steering linkage can get tricky when trying to figure out how to navigate past the headers and around everything, said Meyers. In addition to that, many people upgrade their suspension and steering systems at the same time as the engine. With the wide variety of aftermarket components available, sometimes the combination of parts used can require an odd combination of steering linkage.

6. Air Conditioning Late-model engines usually 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, which can create problems when trying to get an engine between the frame rails. Because of this, it’s often necessary to mount the compressor in a different location.

7. Fluid Reservoirs One commonly overlooked modification is that most reservoirs need to be changed, said Meyers. “The cooling system isn’t a big deal but the power steering reservoir can be tricky for people,” he said. “Packaging gets really tight and sometimes a remote mount reservoir is needed.”

8. Driveshafts Builders will sometimes run into problems either measuring the driveshaft or selecting the right yoke or flange. “Once and a while, we run into a problem where people don’t tell the driveshaft shop that they put a blower on the car and it has 800 horsepower, so, they will bend the driveshaft or kick it out the side of the car when they hammer it,” said Meyers.

9. Fuel Systems Most builders know they need larger and higher quality fuel lines and better filtration, but they tend to run into problems when selecting the right fuel pump. “We usually recommend people try and use a factory style in tank pump for their daily driver,” Meyers said.  “Frame-mounted high-volume pumps vibrate, run hot and usually aren’t designed for extended driving cycles so failure and cabin noise can be a problem.”

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.   A lot of the issues mentioned above can be solved ahead of time with extensive research and forethought for system layouts. Don’t be afraid to go to an expert for help when it’s needed. It will save you a lot of time, money and headaches in the long run.

Located about one hour outside of Chicago, Modern Muscle is a hot rod shop that provides a variety of services from complete restorations, high-performance engine building, performance computer tuning and more. For more information on the shop, visit www.modern-muscle.com.