How to Swap a K20A2 into a MR2 Spyder (ZZW30)
The purpose of this is to provide advice on swapping a K20A2 into the MR2 Spyder or MRS. This advice is not the same for a K24. This guide will also assume you have the mechanical ability and knowledge to safetly remove the current engine from the car and therefore we will skip that part. Our customer is starting with a standard 1zz with a 5 speed that has the typical oil burning issues.
Often times, 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, this will save the alignment and will save you money. When your re-attach the crossmember the alignment will be just where you left it before the install. 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 a Amazon link). You will also first have to lift up 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 engine, 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 clyinder hang. Do not disconnect the hose at the beginning of the swap. You really 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 side of the car.
This is what the car should look like once the engine has been removed (see below). When using the K20A2 we can re-use the OEM coolant lines but modifications will have to be done to make them fit. 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 screw's that hold them in place. At this time, you can install the driver side Innovative mount that attaches to the frame of the car. You can see the OEM mount in the picture above on the driver side. Wait to install all the other mounts.
Now is also a good time to modify the brake booster hardline while you have the room to do so. The OEM brake booster line from the 1zz engine will need to be modified for the K20A2 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 Honda charge harness will need to be modified. 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 to the same gauge that the charge harness wire's are. Cut and remove the Honda end's, 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.
Crimp on the "eye holes". 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 the Mitch's Auto Parts Plug and Play Harness you can also install that now. It is recommended to do it now and use can easliy 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 loose 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 (available for purchase here) of the use of the Honda extension. 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 here. The aftermarket stainless steel lines for the stock MR2 also work. In the particular case we re-used the stock line.
The switch (quick part), first we prepped the new slave cylinder by connecting the extension to the slave and then when we disconnected the old line. When doing so we e quickly capped the leaking end with our thumb. Then when the new slave cylinder was in hand quickly removed our thumbs and screwed in the opposite end of the extension. This minimized the amount of fluid lost and significantly decrease the time it take 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 a "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.
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 a assorted packet of caps from your local auto parts store. There are 2 on the hard coolant line on the side of the head.
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 number's are Gates- K070510, Dayco -5070510 and Goodyear - 4070510. Please remember this will only fit right for a K20A2 without AC.
You are now going to have to modify the transmission selector shaft on the stock Honda transmission. You will do so by removing the counter weight on the transmission. We suggest using a angle grinder with a cutting wheel. Cut the counterweight off where shown in the picture below. The RSX shifter linkage will not fit with this on.
You should now start to install the 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 MAP version and Innovative version, so install them accordingly.
Install the RSX shifter linkage as shown in the picture below. The red/black part will need to be adjust 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 gear's are difficult to engage. Use the double locking nuts once you have adjusted it to the proper length, at this time you should leave them loose. They will react differently one the car is on the ground and you haven't had a chance to drive it.
Notice the screw on the bottom of the transmission linkage...
Also install the rear mount to the transmission. 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. You will re-use the Honda throttle cable mount. Mount the cable of the outside "teeth" but attach it to the black plastic pulley (Cruise Control Pulley). 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.
The end 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 downward 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.
INSTALLING THE ENGINE
Using a engine hoist bring 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 insure 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 your 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 frame of the car align with the 3 on the Innovative Mount or attach the MAP mount to the OEM chassis mount similar to the 2zz swap.. 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. 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 where 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 in 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 is losing the ability to shift while driving. Because Innovative supplies tiny screws to secure the clips, we recommend using much larger clip like the ones that come with the MAP shifter kit. If you did not purchase the MAP kit, you can make some out of a coat hanger wire. They work better for removing if you need to and re-securing, not to mention its much cheaper. Simply cut about 4 inches of 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 on the battery terminal.
In regards to the coolant hose's. You can see the upper hose is about 4 inches to 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.
As for the front or lower coolant hose you can re-use the OEM one but 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 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 K-tune swivel thermostat housing for the K20 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 Ktune 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 into the hub assembly. Its 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. Your going to need to install the crossmember 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 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. Lets the crossmember hang from the mount. Again do not tighten the nut on the end of the bolt. You 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 the all are threading in and then torquing the with a wrench. Once the crossmember is torqued to spec you can go around and tighten all the mount's left loose to spec as well.
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 forgot to put the axles nuts on the new axle. When re-installing the arm's we suggest working from the rear most 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 your working in a small home garage, lower the passenger side of the car and leave the drivers side lifted up. Open your transmission fluid bottle and pour the transmission fluid into the hole where the driver side axles goes. This transmission requires two quarts which can be purchased from our store here. Once the 2 quarts are in the transmission put the drivers side axles into the hole. There is a "c" clip on this axles which for most people gives them some difficultly. If the axles is not seating all the way it push it in as far as you can and then install the other end in the hub like you did on the passenger side. Once the axles is in push 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 drivers 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 with 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. Your almost ready to start the car.
Now connect your laptop or computer to you 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 turn off functions to allow 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 over heating 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 windsheild defroster on, this will insure that the valves for the heating system is open. Failure to do this will leave potential air in the system and only bleed the engine coolant section. Next, head to 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 up and hold them with a coat hange 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 were the pressure release valve is, run this tube into the same bottle or bucket as the heater core tubes. Open both the radiator pressure release vales and the heater core bleeder valves seen in the picture below. You can now start to add coolant into the over flow bottle in the engine bay. Periodically check the hose's 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 time's its 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 which we will talk about next.
This guide is not yet complete. We are working on getting more pictures to finish it. Pleas emails us if any this is unclear, they only way we can make it better is if you give us feedback.
Lastly, we offer many of the parts needed for this swap in a package deal located here.
Total Install time with taking photos 16 hours.