The following is based on my personal swap that I completed in the fall of last year.
As with all motor swaps, make sure you have all the tools needed for the job, prior to starting. Nothing is worse than having to make multiple trips to the autoparts store for various sockets, torque wrenches, electrical tape, etc.
With that said, I made 2 runs. One for more electrical tape, and one for power steering fluid.
Prep Work
-Prior to doing anything with the car and old KA24DE, I made sure the new engine was ready for installation. That included a resurfaced flywheel, new clutch, drained fluids, all the things that make life easier. Heres a shot of the engine seperated from the transmission, prior to installing the new clutch. It is VERY important to make sure you get the correct throw out bearing.
The throwout bearing for a 93 and up KA24DE WILL NOT FIT on an SR tranny. Nor is it in fact, the stock replacement. According to Autozone, Advance, and Central Auto, the stock KA24DE throw out bearing that they list, is not the right one. I had to cross reference the part number on my old SR and KA engine, and it came up with the stock 89-90 KA24E engine instead. So for those looking to use a KA throw out bearing, you have to use a KA24E throw out, or make sure you cross reference your old one, or you WILL get the wrong part at the parts store.
Im saying this in light of every thread I found searching pointed to the 95 KA24DE throwout, which is wrong.
Removing KA24DE Engine
I'm not going to go into much detail here, as the engine pull is by far the most documented area of 240sx motor swaps. The same rings true for the SR20DE as it does for the DET. That means you can swap the AC over if you so choose. Just make sure to keep it out of the way, as to not interfere with the installation. I chose to remove the engine and transmission as one piece. Make sure all wiring is disconnected, all hoses, and anything else hampering the engine from being taken out.
Note: Watch the power steering lines. If your careful, its no big deal. If your paranoid about destroying them, simply remove them, making sure to note the way they go back on.
Here is a shot of the removed KA.
Engine Bay Prep
Take the time now to degrease and tidy up the engine bay. It pays off well in the end.
Before:
After:
Now its time for the install. I had one other friend help me guide the engine in. Make sure to have the engine tilted at roughly a 45 degree angle, and slide it in. It took me about 10 minutes to get it situationed on the motor mounts, and bolted on. I hear horror stories about people not being able to line it up. Just take your time, be careful of the power steering lines if they are still on the car, and bolt it up.
It should look something like this.
When Swapping an SR20DE S13 engine into a S13 KA24DE body:
-Motor mounts are identical, just like the SR20DET, no brainer there.
- Lower SR20DE, and KA24DE harness's (The ones that connect to the tranny) are identical.
- Use the Upper KA 24DE Harness, with the SR20DE ecu.
---- In order to make that work you need to do the following:
2. On the SR20DE engine, there are 2 plugs near the injectors. There are 2 ground wires on the stock SR20DE wire harness in this area, to help you understand what I'm talking about. Its the 2 plugs for the Idle Air Control, and FICD device. You will utilize only one of these plugs, the one with 4 connectors in it.
--- On the KA harness, locate the following color wires near the fuel injectors.
1. Blue/ Red Stripe
2. Blue/ Green Stripe
3. Light Green
4. Black/ Yellow stripe.
You will take those wires, and insert them into the plug in the following order. This is looking at it from the top, with the clip facing north.
1 2
3 4
Plug the newly modified harness plug into the SR20DE engine, wrapping up any bare wires you have incurred along the way, they are not needed.
3. The TPS sensor. The KA and SR use different TPS's, with different amount of connectors in the plugs. Its a 3 vs 4 prong design. Using the SR20DE plug, insert the following color wires from the KA harness into it.
1. Black
2. White ( this one is a large white wire, you'll see it, its bigger than the others )
3. Green/ Red stripe
Looking at the TPS, running from up to down, wire it as such into the SR20DE plug
1
2
3
-- Plug that into the TPS, wrapping up any other miscellanous wires not used in this operation.
-- The harness will now extend across the front of the engine, giving you JUST enough room to plug the distributor wire into the distributor. If you would like to clean up the wiring, you would need to extend the wires just a tad so you can route them cleaner. Not needed however.
- The power steering plug plugs right in, since its the KA harness, along with the MAF. What I did with the Ignition coil was kinda trick.
- Instead of using the supplied SR20DE ignition coil, which mounts closer to the firewall than the KA24DE, I use the KA24DE ignition coil on my SR20DE engine. Since its mounted in the same spot as the KA motor, the KA harness plugs in perfect to it. Thus, instant ignition. I'm unsure of what voltage it puts out, but I'm sure its as good, if not better than the stock SR20DE coil.
--
Oxygen Sensor-- I used the SR20DE oxygen sensor, cut off the connector, which has 3 wires on it, and soldered on the KA24DE connector, which has one wire. 2 of the Oxygen sensor wires will not be used, they are there to heat it up, a power and ground. You only need to use the sending wire, which is the White wire.
The only other plugs that will not be plugged in at this point, is one plug near the coolant temp, and sending unit. Its not needed, either cut the plug out, and wrap up the wires, or leave it.
Also, on the back of the engine, the KA has a bunch of EGR air bypass yada yada emissions/ EGR electronic things. That translates into a few plugs on the back of your engine that will just sit there. They are out of eyesight, so I just let them be. If it bothers you, cut the plugs out, cover up the wires, and clean it up more.
At this point, your almost there.
--
Coolant temp Sensors
-- You need to swap both of the coolant sensors out of the KA, and into the SR. This will give you the stock temp guage reading, and let the ecu know whats up with the engine temp. Let it be known, the car will run without even plugging in the coolant sensors. I doubt your gas milage would appreciate that however.
Once the sensors are swapped, simply plug them into the KA harness, done.
Sidenotes about the Swap:
The stock radiator fan will fit, but just barely with the way I routed my intake and radiator hose. I used a KA radiator, so I had to have a custom hose running across my engine to the radiator. If you chose to go this route and reuse the KA radiator:
I purchased a heater hose from a neon 2.0L to use as the top radiator hose, since im using the KA radiator. Trimmed to fit, worked well. You can use a stock KA24DE radiator hose on the bottom radiator fitting, elimanating the need for crazy custom bent ones. If you use an SR20DE radiator, yours will look a lot cleaner.
I connected the vacuum line to master cylinder with a 3/8 fitting, since mine was cut on the SR.
I used the stock KA24DE ignition coil, in the OEM location, with my SR20DE coil plug. Since I used the KA harness, plug and play.
I checked all the grounds and dodads, filled up the radiator, filled up the tranny, and installed the SR20DE ecu.
Double check all of your wiring, fluids, make sure everything is connected. It should look something like this.
At this point, your done. Start it up, let it come up to temp. Make sure your coolant temp guage comes up to normal specifications, set your idle and timing, and your ready to enjoy your newly swapped SR20DE.
