Mounting The K
We previously noted the K series is a mirror image of its predecessors. So how to you get it to mount properly? Hasport's solution generally applies to all Honda and Acura chassis. For the Civics EK and ES, Honda simplified the mounting procedure by not welding any mount brackets on the frame. On these models, the frame is pre-drilled where the mounts are bolted to support the stock engine. Hasport makes mount kits with brackets that utilize these holes. Using the kit makes the installation a fairly simple bolt-in procedure for both the left and right sides.
The rear mount and bracket is a little more specialized. The K's rear transmission-attachment points are located on the far left, while the stock D series' is on the far right. For the EK chassis, Hasport created a bracket that attaches to the left side of the cross-member so the transmission mount can be attached.
While the mounting process can be overwhelming, Honda has a ready-made solution for the latest Civic. You can bolt the subframe from the RSX or Civic Si, which have the correct K-motor mounting points, directly to the Civic. Additionally, Hasport recommends replacing the Civic's weaker, lower control arms with those from the RSX or Si, as they will bolt on to the knuckles.
On all other chassis the solution is fairly universal. The brackets are welded to the side rails that attach to the left and right sides of the engine. The right-side bracket, which is where the stock engine's transmission mount connects, hangs out into the engine bay. Because it would interfere with the K's timing chain cover, it's removed and a new bracket is bolted or welded to the frame rail. A mount then connects the new bracket to the K-series engine. On the opposite side, a bracket is made to connect between the K-series transmission and a mount that bolts into the stock bracket. The solution for the rear transmission mount is the same as for the EK.
Electrical
The newest engine controls are more sophisticated than earlier generations. K20-powered cars have a hardwired security device, called an immobilizer. Whenever you try to start the car the ECU pings the key, which contains a uniquely coded chip. If the code is recognized, the ECU will allow the car to start. This is why it's important to use an ECU designed for the K series. Often times you can buy the ECU when you buy your engine. If you get a stock ECU, companies like Hondata enhance it for your specific application. You can also get the programmable K-Pro.
Stock ECUs come with an immobilizer installed, and unless you're swapping into an ES chassis, the immobilizer is a bad thing. However, you can circumvent the immobilizer on Japanese-spec ECUs. On U.S.-spec ECUs, Hondata can reprogram the unit. Another option is adding AEM's EMS Swap Box. The Swap Box features boost control, traction control and individual cylinder trim based on EGT reading. Before you make your final decision, visit AEM and Hondata's Web sites.
It's also important to use either the current Civic Si's or RSX's engine harness. These harnesses contain all the engine connections and two of the three ECU connections, greatly simplifies the process. As a general rule of thumb, use the RSX harness with six-speed engine swaps or the Si with five-speeds. While you're at it, grab the alternator harness, too.
In addition to the problems we've pointed out, some modifications might be necessary depending on your engine choice. It's best to have a Honda Service manual for both the car you own and the car that donated the engine, especially if you're doing it yourself. A misplaced wire can damage your ECU. Depending on the application, you might have to modify the alternator harness. Stuff needs to be lengthened or rerouted to reach the fuse box and battery connections. If you suffer from "which-wire-where-scare," Hasport and other companies can perform the modifications for you.
Swapping into the current-gen Civic is easiest, because the RSX or Civic Si engine harnesses can be modified to plug straight into the Civic's harness. An additional air/fuel ratio sensor relay is added to complete the harness swap. There may be other modifications depending on the Civic's trim level. For other swaps, Hasport still recommends using the Civic Si or RSX engine harness combined with an additional chassis-specific subharness. The subharness will contain the last ECU plug and some other necessities as well as all the connections to the car. With wires finally out of the way, it's time to select either the Hondata-modified K-series ECU or the AEM Swap Box. Decisions. Decisions.
Fuel System
The current-gen Civics' stock fuel system can be used with a little modification by combining the factory hard fuel lines and the RSX fuel line. For the Civic's non-return fuel lines, the fuel pressure regulator is located in the fuel tank and is already conveniently set to the proper fuel pressure for the K-series engine. This is a dead-end-style fuel system where the regulator is before the rail.
For other chassis, a pressure regulator needs to be added. Plumbing the regulator can be done in a number of ways. Those who want to keep the stock fuel rail can route fuel from the filter to the regulator and then out to the return line. Route a second line from the body of the regulator and dead-end it into the fuel rail. You can cut up a stock RSX or Accord fuel line and purchase a set of quick-disconnect fittings to use on your line.
For forced-induction and high-performance applications, Gillespie suggests using an aftermarket fuel rail and routing the fuel from the filter through the rail to the regulator and out the return. This is a looped-style fuel system where the regulator is after the fuel rail. By passing the pump's entire volume of fuel through the rail, you will decrease the likelihood of running lean.