How to Swap a K20/K24 into a MR2 Spyder (ZZW30)
The purpose of this is to provide advice on swapping a Honda K20 or K24 into the MR2 Spyder or MRS. This advice is generalized since there are so many different K Series combinations. While we realize the K20Z3 is much cheaper than the K20A2, we highly suggest avoiding the use of this engine and the extra required to make it work will add up to costing more than the higher priced K20A2 and we will not be addressing the necessary changes to make a K20Z3 engine work. This guide will also assume you have the mechanical ability and knowledge to safely remove the current engine from the car and therefore we will skip that part. Our customer below is starting with a standard 1zz with a 5-speed that has the typical oil burning issues.
Oftentimes, it has been seen that many people do not know where to properly empty the coolant from the system. There are two 12mm screws under the front of the car as seen below. Take one out and put a 5-gallon bucket under it. Once this is removed all the coolant will begin to empty. To help expedite the process, take the cap off the coolant overflow bottle in the engine bay.
We recommend leaving the hubs installed as well as the struts. If you unbolt all the control, trailing, and track arms from the hub, and leave the arms attached to the subframe this will save the alignment and will save you money. When you re-attach the crossmember the alignment will be just where you left it before the installation. We recommend starting with the arms towards the front of the car and working your way towards the back.
Once these are unbolted, you can start to remove the axles from the hubs. You will need a 30mm 12-point deep socket (click for an Amazon link). You will also first have to lift the "safety tabs" before removing the axles. To do this use a punch with a hammer to lift them, once they are clear you can use the socket to take the axle nut off.
To remove the axle from the hub, pull the hub away from the car and slide the axles out, allow them to hang, do not remove them from the transmission, if do you the transmission fluid will spill out. You can leave them in and remove the engine with them attached, like in the picture 2 photos above.
When removing the engine components like the slave cylinder, unbolt the 2x 12mm bolts holding the slave cylinder from the transmission and let the cylinder hang. Do not disconnect the hose at the beginning of the swap. You want to avoid letting the brake fluid out of the clutch line because it makes it more difficult when you reassemble and bleed it later. For now, use the mount that it is attached to and hook it around the brake lines on the driver's side of the car.
This is what the car should look like once the engine has been removed (see below). When using the K20 or K24 we can re-use the OEM coolant lines but modifications will have to be done to make them fit. The K20A2 engine has a coolant output that flows straight out of the head and the K24 is slightly angled The fusebox shown against the firewall in this picture is the one that requires the modifications which are outlined in the Plug and Play harness installation directions
Remove all the remaining motor mounts but keep the screws that hold them in place if you're using the Innovative mounts. If you're using the MAP mounts leave the driver's side and passenger side mounts that attach the car installed. Additionally, leave the rear mount that attaches to the bottom of the subframe. At this time, you can install the driver side and passenger side Innovative mounts that attach to the frame of the car. You can see the OEM mount in the picture above on the driver's side. Wait to install all the other mounts.
Now is also a good time to modify the brake booster hard line while you have the room to do so. The OEM brake booster line from the 1zz engine will need to be modified for any K Series engine. You can unbolt the hardline from the firewall and use a pipe cutter to shorten it. We suggest cutting it at the bend. (see the photo before with the arrow pointing where to cut it)
You can see in the finished photo the brake booster hardline terminates pointing straight up. This will allow you to use the OEM Toyota vacuum line once you modify it, we will get to this after the engine is installed.
The only intake manifold that will clear the MR2 Spyder firewall without modification is the PRB manifold from the K20A2 engine. All other OEM Honda intake manifolds will require modification of the firewall to get clearance. As a note, the K24 engine is half an inch higher in height. The RBC manifold will fit with the hammering of the firewall on a K20. With a K24 engine and an RBC, you will end up hitting the firewall and pinching the brake booster hose as well. For all K24 engines, we suggest aftermarket intakes. ALL the skunk2 intakes we have on our site will fit with hammering.
If you are using our Tucked Engine and Charge Harness which was made specifically for this swap in an MR2 Spyder, then you only need to connect the plugs as labeled to the corresponding sensors and attach the power terminal to the labeled locations. You will still need to modify your fusebox as described in the PNP Installation instructions. If you are modifying an OEM harness then you will need to modify it as described below. We receive many emails asking about the modification of this part of the harness, hopefully, this will clear that up. You will need to buy from "eye hole" crimps (we sell them) to the same gauge that the charge harness wires are. Cut and remove the Honda ends, try and leave as much wire as possible, the longer the better. Strip them and prepare them for crimping. The" eye hole" crimps are available here. The RSX charge harness is preferred but the TSX charge harness will work as well. Please note with the TSX harness you will need to swap to the TSX or a K24 knock sensor. Additionally, all K24s will require a K20 crank position sensor.
Crimp-on the "eyeholes". The longer wire runs from the fusebox in the engine bay to the alternator and the shorter wire runs directly from the battery to the starter. Once this is done you can assemble the harness and connect it to the engine. Install the engine in the car with the harness attached to the engine, once the engine is in the car, space will become limited so it is suggested to do it now while the engine is out.
If you are using Mitch's Auto Parts Plug and Play Harness you can also install that now. It is recommended to do it now and use can easily route the wires depending on which harness you purchased. This harness does not connect to the engine yet, run it through the firewall hole into the engine bay if you have AC or the O2 sensor. We suggest running the O2 sensor wire down the driver side of the car under the battery and between the driver frame to the rear of the car.
The last modification that is wise to perform before the engine is in the car is switching the slave cylinder you previously disconnected from the original transmission. It is very important to save yourself the headache of bleeding the entire line by performing these steps as quickly as possible. The less fluid you lose while you switch the slave cylinders, the easier it is to bleed and get the air out. Therefore prep your slave cylinder-like below before disconnecting the line.
The stock MR2 clutch line will work with a small extension or our stainless steel clutch line. Sometimes the small extension is cut when another shop removes the line therefore you will need to buy or make an extension. The extension needs to be approximately 3 inches long and with the standard fitting. You can choose to make one or we sell them on our website (link above). The aftermarket stainless steel lines for the stock MR2 also work but the MAP version listed above has the correct 90-degree bend for the Honda clutch. In this particular case, we re-used the stock line.
For the switch (quick part), first, we prepped the new slave cylinder by connecting the extension or new stainless steel clutch line to the slave, and then when we disconnected the old line. When doing so we quickly capped the leaking end with our thumb. Then when the new slave cylinder was in hand, quickly removed our thumb and screwed in the opposite end of the extension. This minimizes the amount of fluid lost and significantly decreases the time it takes to bleed the system out. We will discuss bleeding the system later when the engine is installed and you have the new slave cylinder mounted.
You will need to purchase an "EP3" pulley, available here. The pulley is used on the EP3 Honda Civic (2001-2003) and the Civic Si 06+. Be sure to install it with the two bolts. You will need these regardless of which K Series you have. If you're using the K24a variant from overseas, please note you will need a new K24 water pump housing, water pump, and engine belt tensioner as the JDM version is greatly different and will not work. (See below pictures)
With the engine out you should consider capping the open hoses you will not need once the engine is installed in the MR2. There are 5 of them. We suggest picking up an assorted packet of caps from your local auto parts store. There are 2 on the hard coolant line on the side of the head. If you're using the K24A engine, you should consider purchasing the K24A2 heater hose (P/N as the K24A version stick out and is oftentimes in the way of many things and has poor positioning for the MR2 Spyder
Another is located on a sensor found on the throttle body which you will not need but would create a vacuum leak. There is also one on the intake manifold near the fuel injectors. (No exact picture)
The 5th one is near the exhaust manifold.
When installing a K20A2 without AC, reference the below picture of the belt configuration, we offer the belt in our store and the correct part numbers are Gates- K070510, Dayco -5070510, and Goodyear - 4070510. Please remember this will only fit right for a K20A2 without AC. If you're using either K Series Engine with AC you can use the OEM MR2 Spyder belt if you're using our EP3 idler pulley previously discussed. Keep in mind because we are re-using the OEM Toyota AC compress, you need a 5 rib belt, not a 6 rib like the Honda used. Position the belt toward the timing cover with the one bare rib on the Honda pulleys towards the outside.
You are now going to have to modify the transmission selector shaft on the stock Acura RSX Type S transmission. You will do so by removing the counterweight on the transmission. We suggest using an angle grinder with a cutting wheel. Cut the counterweight off as shown in the picture below. The shifter linkage will not fit with this one. For the 06+ Civic SI transmission or the RSX transmission, you can purchase the MAP adapter, and install instructions are located here. If your using the Innovative version see the instructions below.
You should now start to install your mounts on the engine and transmission. Install the transmission mount, you can re-use the studs on the transmission. There is no need to remove them. Mounts differ between the MAP version and the Innovative version, so install them accordingly. Do Not install the front mount yet if you have the MAP version. (There is no front mount with the Innovative kit)
Install the Innovative RSX shifter linkage as shown in the picture below. The red/black part will need to be adjusted once the car is on the ground. Turning this part will change the throw when you shift the gears if you find one or two gears are difficult to engage. Use the double locking nuts once you have adjusted them to the proper length, at this time you should leave them loose. They will react differently once the car is on the ground and you haven't had a chance to drive it. And again if using the new MAP adapter, follow these instructions.
Notice the screw on the bottom of the transmission linkage...
Also install the rear mount to the transmission for the Innovative kit, not for the MAP kit. If you are using the Innovative Mounts this mount is VERY important to leave loose. We suggest not even putting the nut on the bolt. This is the most difficult mount to install and this is the reason why we suggest leaving the mounts loose. (Pictured is the Innovative Mount below)
This is a good time to install your header. Attach the header and do not forget the gasket.
Lastly wheel or move the engine under the car as we get ready to install it. Connect the throttle cable to the throttle body. Please note, if you're using a Skunk2 throttle body you will need to drill the hole that holds the cable slightly bigger, do so before installing it onto your engine. You will also need to cut/bend/weld the Skunk2 throttle cable bracket to fit in the MR2 Spyder (15 min job). You will re-use the Honda throttle cable mount if you're using the stock K20A2 throttle body. If you have a K24, chances are it came with an electronic throttle body and it will need to be replaced with a mechanical one. Lastly, please note that different intake manifolds have different bolt patterns therefore a PRB throttle body will not mount to RBC and vice-versa without the use of the Skunk2 adapters.
Mount the cable of the outside "teeth" but attach it to the black plastic pulley (Cruise Control Pulley) if using the OEM K20A2 throttle body. Doing this with the engine already installed is difficult because there is little room to hold the throttle cable open in the position needed to attach the cable. If you are using an aftermarket throttle body, nearly all of them have a hole too small for the Toyota cable, you will need to remove the throttle wheel and drill the hole out to something slightly bigger with a drill press as previously mentioned.
The result should look like the below picture.
You will need to adjust the length of the cable and there should be very little tension. We test the length by resting a finger on it. The cable should bend down due to the weight of the finger but not move the throttle pulley. No modification should be needed. You might want to unhook the Toyota cable from the hooks along the firewall to give you more length. You can reconnect them easily once the engine is installed.
It is also recommended that you route the fuel line and attach it at this time. This can also be done later if you like. We suggest using the MAP fuel line and the OEM tends to be slightly too short and tight for the K20 and will not work for the K24.
INSTALLING THE ENGINE
Using an engine hoist brings the engine into the car from the bottom. If you do not have a hoist for the car make sure the car's lowest point is approximately 22 inches from the ground, this will ensure you have enough clearance to bring the engine in and out of the bottom of the car. We install the driver-side mount first. Just slide the main bolt through the urethane mount when it is aligned while the engine is on the "picker." Put the nut on the end of the bolt but leave it loose until all 3 or 4 mounts depending on which kit you are using are installed.
Next, install the passenger side mount. Start by bolting in the two bolts to the mount on the engine block. From there raise, lower, and move the engine until the 3 holes in the frame of the car aligned with the 3 on the Innovative Mount. If you're using the MAP mounts you should have left in the urethane mount on the frame, therefore you will use the 6061 aluminum bridge mount, this should be installed on the frame mount by re-using the OEM Toyota bolt, do not tighten it and it will need to swing. The new version 3 mount has a centering hole. This hole should accommodate a stand Philips screwdriver. Put it through the hole and use it to line up to the MAP K24 timing mount, this mount will be required for all K24 swaps. If you have K20, you will not be able to use the centering hole. We suggest using a metal dowel to help alight the holes. Once aligned put the factory bolts you saved in but again do not tighten them, you will want to have movement until you install the last mount, otherwise you will have a hard time getting the final mount installed if you're using the Innovative Mounts. At this point, we suggest working on the cooling hoses as you will be able to pivot the engine if you need more room when working on the lower/front coolant hose. It is not recommended to install the rear mount at this time.
Now that the engine is installed, we are going to go back to that brake booster vacuum line. Take the original brake booster line off the 1zz. Your going to need to cut it approximately were shown in the pictures. You need to form a long straight tube with a 90 bend in it.
Once you have the line installed re-use the OEM Toyota clips to retain the hose.
Install the shifter cables, make sure you test that you have them installed on the correct side before securing them. Simply connect them and have another person attempt to shifter gear and double-check that the arms are moving in the correct direction and there are no binds. If the arms move in the right direction but do not fall into gear that is okay we will adjust that later. Also do not forget to use the clips supplied with your shifter linkage kit to secure the lines, failure to do so, may result in losing the ability to shift while driving. If you purchased the Innovative version, we recommend using something else like a cut-up coat hanger than the tiny screws to secure the clips. They work better for removing if you need to and re-securing, not to mention it's much cheaper. Simply cut about 4 inches of a coat hanger and bend it to a "U" once you feed both ends into the holes with the upper part securing it bend the ends to secure the coat hanger from coming out.
You can now connect the wires from the charge harness you prepared earlier. As mentioned, the longer wire goes to the fusebox and the short one will go to the battery terminal. Fusebox to Alternator and Starter to Battery.
In regards to the coolant hoses. You can see the upper hose is about 4 inches too long. We are going to cut 4 inches in the middle and you will need to purchase a male-to-male connector which is available in our store, here. Once you cut the 4 inches out you can connect the two and see it lines up much better. (For K24, the procedure is the same just adjust the length to the different coolant housing)
As for the front or lower coolant hose you can re-use the OEM or use the Dayco hose (part number 72122 hose b) for a perfect fit. For a K24 as well as the K20, it is recommended you use the swivel thermostat in the link below if you want to re-use the OEM hose which can be cut to the right length. If you re-use the OEM you will need to cut approximately 3 inches off. I suggest you mount the hose in the car and mark where it needs to be cut rather than just measuring 3 inches and cutting, once you have the engine installed. As you can see in the first picture the OEM thermostat housing comes off in a direction that will not allow the OEM hose to connect, so we recommend purchasing the swivel thermostat housing for the K swap as this will allow the thermostat to point in a direction that the hose will connect and pictures further below.
(Before with stock thermostat housing)
(Cut hose and Swivel Thermostat Housing)
With the main cooling hose attached connect the remaining hose next to the cylinder head on the black hard line. Also, make sure at this time you re-install the screw you removed to drain the coolant near the front underside of the car. Once this is done you can begin to put coolant in the car.
At this point in the swap, we recommend installing the axles. First, start with the passenger side. Side on the axles to the intermediate shaft and then again pull the hub away from the car and insert it into the hub assembly. It's close but it will fit and go in this way.
Now if you are doing this swap in your garage and do not have a long funnel and hose to fill the transmission, there is a quick way of doing it. You're going to need to install the crossmember on all the passenger side suspension and passenger rear wheel before doing so. So first you will need to install the last motor mount on the crossmember this one fits very tight naturally. Wiggle it on and use a rubber mallet to align it and put the 4 OEM bolts into it to secure it. Once this mount is on and torqued to spec you can install it on the corresponding mount that comes off the bellhousing that you already put in there before putting the engine in the car. Let the crossmember hang from the mount. Again do not tighten the nut on the end of the bolt. Use the metal dowel to align the 4 holes of the crossmember. This is why you left all the mounts loose. Chances are you will have to push and pull a bit to get these holes to line up. I suggest installing the 4 bolts for the crossmember by hand one at a time until they all are threading in and then torquing the with a wrench. Once the cross member is torqued to spec you can go around and tighten all the mount's left loose to spec as well and now install the MAP front mount, do this first before the rear mount.
Start to attach the track, tow, and trailing arms on the passenger side of the car to the hub assemble and install the wheel. Also do not forget to put the axle nuts on the new axle. When re-installing the arm's we suggest working from the rearmost bar to the front most. The very front one may require you to push the spindle or hub forward while pushing the bolt through the holes, this is normal. Tighten them to spec after all are installed.
Now since you are working in a small home garage, lower the passenger side of the car and leave the driver's side lifted. Open your transmission fluid bottle and pour the transmission fluid into the hole where the driver-side axle goes. This transmission requires two quarts which can be purchased from our store here. Once the 2 quarts are in the transmission put the driver's side axles into the hole. There is a "c" clip on this axle which for most people gives them some difficulty. If the axles are not seating all the way push it in as far as you can and then install the other end in the hub as you did on the passenger side. Once the axles are in pushing the hub forcefully toward the middle of the car. This force will usually push the "c" clip into position and allow for the axles to fully seat in the transmission. You can now attach the track, tow, and trailing arms to the hub on the driver's side. Again do not forget to install the axle nuts and torque them to spec.
Now you can start to install the exhaust system using the configuration you purchased. Many options are available here. Our customer chose the PPE header and PPE High Flow cat with a stock muffler.
Put your wideband sensor in the hole closest to the header for a proper reading. ( Do not confuse it with a narrow band sensor)
Do not forget to add oil if you have not done so already. You can also connect the battery. To assemble the positive terminal of the battery attach the new lead you made from the charge harness to the other OEM positive lead by the nut and bolts on the top, simply tighten them and attach it to the battery. You are almost ready to start the car.
Now connect your laptop or computer to your Hondata after you have installed K manager, you will also need to plug in the rest of the engine harness to the Plug and Play harness and the Hondata unit. You will need to make certain changes in Hondata like turning off functions to allow the operation of the Honda ECU to the Toyota system.
BLEEDING THE SYSTEM
For the K series, this is one of the most frustrating parts of the swap. The K series engine sit's in the engine bay higher than the stock Toyota engines, therefore it is a habit that small air bubbles get trapped in the engine and create overheating issues. Luckily the K20A2 is one of the easiest to bleed. To start, on the HVAC control turn the temperature control to full heat and put the windshield defroster on, this will ensure that the valves for the heating system are open. Failure to do this will leave potential air in the system and only bleed the engine coolant section. Next, head under the hood and remove all the plastic covers. You will need to access the heater core bleeding tubes and the radiator. Unwind the tube attached to the heater core bleeding valve and raise them and hold them with a coat hanger that is hooked on the hood latch. You want to be able to visualize the air/fluid as it escapes. Put the open end of the tubes into a bottle or bucket to collect overflow.
You will also need to attach a tube to the nipple on the side of the radiator where the pressure release valve is and run this tube into the same bottle or bucket as the heater core tubes. Open both the radiator pressure release valves and the heater core bleeder valves seen in the picture below. You can now start to add coolant into the overflow bottle in the engine bay. Periodically check the hoses in the front of the car and look for fluid to occupy the hoses. Once you see fluid in the hoses in the front of the car we are ready to start the car and bleed it further to get rid of excess air trapped in the system.
Many times it's hard to get all of the air out of the system. We have used multiple items to help push the air out. Most frequently we find purchasing a Motive pressure bleeder to be very useful in more than one way. You can put coolant in the pressure bleeder and attach it to either the radiator or the heater core bleeder valve and open another valve. The pressure bleeder will force coolant into the system and carry the air out. You can also use this for bleeding your brakes and the clutch line.
SETTING UP YOUR HONDATA FOR FIRST START
Lastly, you will need to make adjustments to the Hondata or whichever ECU you're using for engine management. This particular swap used a Hondata. Upon purchase of Hondata, you should also receive a small sub-harness that is rainbow-colored. This sub-harness is used for any additional inputs you may purchase like gauges or sensors, because the MAP plug and play harness does not have a wideband function due to Hondata recommending that it be wired directly to the ECU, you should opt for an after AFR gauge and sensor, we have them available here. Be very careful when wiring any input to the wires, there are 2 black wires in this sub-harness which are for grounds, if you wire direct power to these you will damage the ECU and Hondata. It is suggested you use these grounds for your sensors and it will minimize distortion of the signal.
To install your gauge or sensor follow the directions it comes with and on the signal, wire remember which color you used and its position on the sub-harness as you will need to specify which one when you program it.
To program the sensor you will need a window-based computer with K manager download on it. You will start with downloading your calibration, save a copy of it and from here you have something to work with. You will have to connect the USB cable from the ECU to the computer to do this. The "Lightning Bolt" is what activates the link between the computer and the Hondata ECU. Click it to send/read/ or pull information from the ECU.
You will need to navigate over to parameters and make a few adjustments to the setting before you can start the car, this is why the OEM Honda ECU will not work in the car. Some factory settings need to be adjusted to make it work with the Toyota system.
Using the Parameters tab, You can enter/calibrate the following items:
- Wideband Gauge: Parameters Tab-> Analog Inputs->Select Model and calibrate the offset until the gauge value is accurate to read what the Hondata value shows. This will be important for data logging and tuning of the car.
- Narrowband Sensor: Parameters Tab->Closed Loop-> check box: Disable P1167/Diable P0134/Disable P0135 ( If you're using a wideband selected it under the "Closed Loop Tab" under "Closed Loop Operation") otherwise click Disabled (Open Loop)
- Fuel Injectors: Parameters-> Fuel Injectors: Enter the size of your injectors. (OE RSX Type S Injectors are 310cc and MDX injectors are 410cc)
- Adjusting Idle: Parameters->Idle: if your using a throttle body without an idle air control valve disable it here. Otherwise, leave this tab as it is.
- MAP Sensor selectors: Parameters-> MAP: Select "stock Sensor unless you have upgraded for turbo applications. NOTE using a sensor other than stock will require calibration.
- MISC controls: Parameters -> Misc: Be sure to un-check "Immobilizer enabled" and under speed sensor click normal speed sensor if you're using an RSX transmission, if you're using a Civic SI transmission, click No speed sensor (if you need an explanation as to why or what to know how to run one please email us) If you're using AC, then also refer to the install and programming instruction for this tab as there are additional changes that will need it to be made.
- Multiplexer: Parameters-> Multiplexer/Digital Output: Select Multiplexer and click "Disabled".
- Setting engine fan activating temp: Parameters-> Protection: Under the overheating protection section adjust the "Force radiator fan on at" part to make sure the fans kick on at your desired temperature, we recommend anywhere between 180-185. Also, set the "Overheating temperature" to 205, this will give you a warning before damage could be caused to your engine. Make sure that "Illuminate the MIL" and "Generate P0217 overheating error code" are both checked. In the event, that the car starts to overheat this will provide a warning because the temperature reaches a level that could damage the engine.
- Calibrating the TPS: Parameters-Throttle: With the car connected and the ignition turned to the on position, activate the "Lightning Bolt" and make sure the car is connected, this is a real-time scaling and reading so you must have a direct connection with power. Click "Read" at the "Minimum reading" to scale the TPS at 0% throttle. Next press the throttle to the floor and click "Read" next to the "Maximum reading" I suggest doing it back and forth a couple of times to make sure you get it right.
Once you have calibrated these settings you will need to upload the calibration to the ECU by clicking the "Up arrow" and leave the ignition on, the car and ECU both need power and the connection to be on for this to work. Once the green loading bar is finished your car should now start.
******Keep in mind we are not liable for any damages caused, if you do not feel comfortable making these changes because of the risk of engine and ECU damage is possible to take this to a professional. This does not bypass the car needing a tune as well, this will allow you to start the car to bleed it and transport it to the dyno for tuning.*****
Welcome to the club...
Total Install time with taking photos 16 hours.