K SWAP Guide (part 4) The final Installment

K SWAP Guide (part 4) The final Installment

Welcome to the 5th and final installment of our K Swap Guide series, where we have taken Pats old rod knocking Euro R motor out of his car and replaced it with another DC5 K20 (best engine). We have covered:

  • The reason why he blew the old engine.
  • Removing the old engine.
  • Cutting/fitting RBC intake manifold, K-tuned throttle body adapter, and EP3 adjustable pulley.
  • Installing spoon baffled oil pan, 4 piston oil pump, hybrid racing timing chain tensioner, Toda racing timing chain, Circuit Hero lower timing chain guide.
  • Installing ACT lightened flywheel, clutch, Speedfactory detent springs/heavy duty shifter springs, and mating trans back to engine.

All of the above topics have very detailed how to’s, tons of pictures, tips and tricks on how to make the process’ easier, and finally explanations on why you do or don’t need certain parts. The goal of this whole series was to enlighten everyone on what you actually need to get a reliable running K swap in your car, and why I believe if you’re going to do a “cheap” K swap you might as well just do a B series swap. The Links below will take you to each installment of the series thus far.





Jumping right in, We begin with the motor already installed back in the car.


The motor rests in there with only 3 motor mounts, one rear, one drivers side, and one passenger. I have the intake manifold removed to show how you how to hook up the charge harness. Don’t be confused by all the wiring that going on, its easily broken down into three parts.

  1. The main engine harness: This is the harness that should come with your swap, and unlike B series you can actually use the JDM harness that comes with your motor. I wouldn’t recommend getting a motor that doesn’t having the CORRECT matching harness. Unlike B series, K series stuff isn’t as interchangeable and you will end up having sensors that don’t match up, or plugs that need to be repined. The engines main harness is the one that has the ECU plugs on it.
  2. The charge harness: This one will involve making your own wires, because you will need to wire up power to the starter, and alternator. Your motor swap should come with the plugs already for the charge harness, you will just need to splice in power from the battery, and the fuse box. This part can be a bit confusing for people who assume they got a “swap harness” so they are good, when in fact they still have more to wire. This is one of the many things that will make K swaps a little more challenging than a B series swap.
  3. The “swap harness.”: Many companies make these, and they are all a tiny bit different from each other. They all do the same thing though. Basically connecting the dash harness, (so that the cluster works, headlights, and fan), and engine harness. This allows you to still retain all functioning switches inside the car.

The engine harness will be plugged into all sensors on the engine, and it will get run through the firewall behind the dash to meet up with the ECU, and dash harness. It’s very easy to route nicely thought he engine bay, as it is just one big fat chunk of wires.


You can see the rubber grommet from where the harness went though the firewall on the donor car. On Patrick’s car, you can see the large oval hole in the firewall where the A/C went through. Obviously he doesn’t have A/C so I ran the harness through there, this way I don’t have to cut or drill any holes in the firewall and when you install the battery it hides it all (but still keeps it easily accessible, in case you have to access for any sort of diagnostics)

Next is the charge harness.


Above you can see (I’m pointing to it)  It runs off to the passenger side of the car.  This is the part you will be adding, underneath that wire sleeve is the two power wires you will run.

  1. One will run from the alternator to the fuse box.
  2. One will run from the starter to the battery + terminal

The rest of the “charge harness” alternator signal, starter signal, and knock sensor should have all come with your swap. If it didn’t you will need to source a K series charge harness.

As you can see below the charge harness will connect to the engine harness. (I’m pointing to it) Just to clarify… the only thing you will need to wire is the two power wires (they are already a part of the charge harness, they are just cut.) you’re just adding length to each one. Its not that hard, just make sure you use proper gauge (thickness) wire because there is a lot of amps going through them, and you don’t want them to melt.


Finally the swap harness.

Below you can see how it will just connect to the dash harness coming out of the firewall on the drivers side of the car. I then run it along the firewall, threaded behind the brake hardlines ending up going through the same A/C hole in the firewall that I ran the engine harness through.


Seen below, the Swap harness has some plugs that need to stay in the engine bay.

  1. Primary O2 plug (4 wire grey plug)
  2. Temp sensor ( 1 wire for temp gauge on cluster)
  3. Milky white plug (unused. for aftermarket fan/temp sensor.)
  4. Ground (unused. This is to be used in conjunction with the aftermarket fan/temp sensor) you do not need to ground this.


To run these cleanly, I just use electrical tape to piggyback the OEM temp sensor/Aftermarket fan/Aftermarket temp sensor onto the engine harness and run them to where temp sensor is on the engine. In my case it’s near the intake manifold where it bolts to the head. The O2 plug will just run down the firewall in-between the subframe and the firewall to meet up with the O2 sensor under the car (in the header).

That sums up the wiring. Due to the differences in aftermarket harnesses I won’t go into detail about what you have to wire inside the car under the dash. There are between 4-9 wires you will to splice and run, again this sounds scary but the directions supplied by the harness manufacture will make everything very easy and usually they will come with connectors you need.

If you’re not going run K pro, or any other aftermarket ECU. You’re going to need to wire in a secondary O2 sensor. This can be more challenging since you will need to re pin ECU plugs. I highly suggest just getting K pro, this will make you life much easier. I have wired secondary O2 sensors in both my brothers K swap and mine, since we both didn’t have K pro at first. Also keep in mind that ONLY K series O2 sensors will work, YOU CAN NOT USE B/D series O2 sensors.


Above you can see the engine is all hooked up in the car.

  • Vacuum line from the brake booster to the intake manifold.
  • Throttle cable (you will need to get the K swap throttle cable bracket, and a gsr throttle cable for this) There are kits with everything you need.
  • The fuel system is easy. Just buy the K swap kit, you can either mount the Fuel Pressure Regulator to the rail or the chassis. There is either Tucked Fuel system kit, or the one we run which just keeps the OEM filter on the firewall.
  • The shifter cables can either be ran through the fire wall, or under the car. Just try to not have the cables ran with tight bends and keep them away from header/exhaust (If this is unavoidable, you can get heat resistant sleeves to put on the cables.) The cables are pretty self explanatory and there are many different ways to run them. (the less bends the better)
  • There are only two grounds necessary, one from the valve cover to the chassis, and the other from the transmission to the chassis.

Bleeding the coolant on K swapped cars can be a bit difficult because the engine is higher that the radiator. This will cause air to get trapped in the head, and can cause your car to overheat once you start to drive it more aggressively. The best way to do it is, Jack up the car as high as possible only int he front. Then bleed it from the head where there temp sensor is. Or get some sort of swirl tank, this will bolt to the head where the water neck outlet is, and will become the highest part of the engine. The air will naturally travel to the highest part of the engine.

Below are just some pictures to help show you different angles, so you can see how it’s all ran.




Keep in mind he does have RDX injectors, so that’s what the extra long piggy back connector wires are coming off each injector.


The old motor. We were able to swap a lot of parts from the old motor to the new one.


Above you can see the differences in the between the RBC/RBB heads, and the PRC/PRB heads. The RBC/RBB head (picture above) has the water neck outlet come off the side of the head. Above you can see how he has the K tuned adapter on it.

And below you can see how the water neck on the PRC/PRB head comes off more of the front of the head. See the black radiator hose coming off the head. (right below the fuel pressure regulator) This is why you have to cut an RBC/RRC manifold if you’re going to use it on a PRC/PRB head. If you notice on Pats old motor he has an RBC manifold that comes stock on the EURO R motor. And you can see how that manifold isn’t cut.


Things can get a bit messy.


I would say that my garage is pretty good sized for a 2 car, but it still gets pretty tight.


I realize that after reading the whole series that you might still be left with some questions, and that I didn’t really go into too much detail about some things. This is mainly because Patrick already had a K swap in his car, so there were things I didn’t need to do. Like cutting out the drivers side mount and install the swap one, go through wiring in complete detail, or go through fueling in complete detail. I feel like the parts I didn’t go over or have pictures of, I at least touched on to give you some sort of guidance.  If I were to type a complete “how to” K swap it would be so long you would lose interest, and it would vary for each different chassis.


Key things to keep in mind if you’re going to get lured in with he affordability of the Euro R swap.

  • The rear mount for the trans is bulky. This makes it hard for a swap header to fit. Patrick was using a K tuned one the whole time he had his old motor, and when he originally went to install the header he was having a hard time getting all the bolts to line up properly in the head. Little did he know that the header was barely hitting the rear trans bracket causing the header to barley not sit flush to the head, thus making it difficult the get all the bolts in. I only noticed this because, this time around he bought a new header and when I went to install it and it didn’t fit. I couldn’t get all the bolts to manually thread in, and I didn’t want to strip out the head. Upon closer inspection I noticed that the header was hitting the trans bracket so much it was not allowing for the header to seat flat against the head. I then tried to install his old header, and quickly ran into the same issue. Although it wasn’t as bad, I was able to almost get the header to completely bolt in. I still didn’t feel comfortable tightening it all the way, again because I didn’t want to strip the head. So I took the old header back off and hit it a few times with a hammer to help gain some clearance. This ended up working and you can barley tell there is a small dent in the header. This is just one thing to keep in mind, especially if you’re having a hard time getting the header to line up. Make sure you can manually thread it all the bolts/nuts for it before you start to tighten it, or you may strip out the head.
  • You must use RBC/RBB specific shifter and cables. Also the way the cables attach to the trans is slightly different (not better or worse just different). RBC/RBB style bolts to the shifter cable bracket on the trans, and the PRB/PRC style just uses clips to hold the cables to the bracket. Remember there are a few different styles of cables (specific to chassis/motor) so make sure you are using the correct ones. Again this is another reason to get a complete swap.
  • The water neck outlet on the head (upper radiator hose). As I mentioned above its different on the Euro R swap, this makes things a little more challenging when trying to run your coolant hoses.

Few other random things to keep in mind:

  • Each swap header is a slightly different length. This makes swapping headers a little difficult since you will have to change the exhaust piping length where it meets the header.
  • Keep in mind that it is possible to run a half sized radiator without issue. However, if you’re going to be tracking the car I would highly recommend a full size.
  • DO NOT get the cheapest entry level swap axles! They will break, or wear out way prematurely.
  • You will most likely need to trim a little bit out of the under side skeleton of your hood to gain some clearance for the intake manifold vacuum port to the brake booster. If you don’t do this you will make an ugly dent in your hood.
  • There are companies now making complete swap harness’ so you don’t even need to make a charge harness. The down side is they are very expensive.
  • Patrick isn’t running a heater core (hes running his shifter cables though where the hole for the heater core was). There are plugs to plug up the thermostat where the water pipe comes out of, and a plug to thread into the head that blocks the outlet to the heater core.
  • As I have stated in just about every installment of the series… DO NOT DO A CHEAP K SWAP.

I hope you were able to read the whole series, and hopefully some of my info will be helpful to you. Please don’t be discouraged from doing a K swap. Its tons of fun and when kept somewhat stock can provide years of trouble free fun. I just really want to drive home the fact of not doing it cheaply.

Below is the Final product: Patrick’s completely running, and cleaned up car. While his car was in my garage not only did we do all the K swap stuff, but I also installed ARP extended studs, and PCI spherical front compliance and spherical front lower control arm bushings. His car was previously tuned here in Las Vegas, but now he lives in Oregon and plans to get this new setup tuned at SpeedFactory.


Here is the spec list of his car:


  • 2006 JDM DC5 K20A Type R stock
  • Spoon sports baffled oil pan
  • 4 Piston racing oil pump
  • Hybrid racing timing chain tensioner
  • Toda racing timing chain
  • Circuit hero lower timing chain guide
  • RBC intake manifold
  • K-tuned adjustable EP3 pulley
  • RDX injectors
  • Hondata Version 4
  • Walboro 255lph fuel pump
  • Karcepts Fuel rail
  • Aem fuel pressure regulator
  • Spoon sports magnetic drain plug
  • Speedfactory racing muffler
  • 3 inch piping header back


  • Euro R trans with OEM LSD
  • Insane shaft 500 hp axles
  • ACT lightened flywheel
  • ACT heavy duty 6 puck sprung clutch
  • Speedfactory detent springs
  • Speed factory heavy duty shift selector springs
  • K-tuned OEM shifter cables
  • Oem TSX shifter
  • RCREW shifter plate
  • Spoon sports magnetic trans plug


  • CSF full size radiator
  • K-tuned radiator hoses
  • OEM thermostat
  • Mishimoto single slim fan


  • Tein Mono sport
  • Hardrace front and rear camber kit
  • Custom SS brake lines all around
  • PCI RTA bushings
  • ASR subframe brace
  • ASR 25mm hollow sway bar
  • Beaks lower tie bar
  • Password JDM rear strut bar and trunk brace
  • PCI front compliance bushings
  • PCI front LCA bushings


  • ITR caliper mini cooper rotor up front
  • Alethia motorsports rotor shims
  • Hawk HP+ front and rear pads
  • EP3 rear rotors and calipers


  • Rays Gramlight 57dr 15×8 +28
  • Maxxis RC-1 225/45 tires
  • ARP extended studs
  • Project Kics R40 extended neo chrome lug nuts


  • Spoon sports duckbill wing
  • Bride seat
  • Crow harness
  • Buddy club rails
  • JDM cluster
  • JDM tail lights
  • JDM turn signal
  • Mugen pedals
  • Circuit one shift knob


Working on cars can be a very rewarding process, and I enjoy it more than someone should. To say that im excited about seeing his car start up would be an understatement. Anytime you’re working on cars it can be hard to see the light at the end of the tunnel, but breaking it down into segments made it much easier for me to tackle. This whole entire process was extremely enjoyable, and being able to take a non running car and make it run is a feeling that can only truly be appreciated by someone that knows the feeling.

Sadly our story with Pats car pretty much ends here. You see he lives in Oregon, and since I’m in Vegas there wont really be an opportunity to do any sort of follow up article. IF you live in the Pacific Northwest, keep your eyes peeled for his car at your local track. I know once it dries up, he plans to hit as many track days as possible.




Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: