Heres my senior project paper on a SOHC to DOHC swap give me your opinions or advice if i left anything out.

PS sorry if its hard to read. Im not fixing it so don't bitch.





Joshua Donahue
Senior Project
Mrs. Versace
2006-10-18
The modern gas powered engine can be found in every aspect of today's modern world,
from yard tools, to power generators, and almost every automotible in the world, and while useful
they are prone to failure and need to be either fixed or replace. Although most of problems are easily
remedied,the older the motor gets the closer it is to complete failure at which pont the motor can't run
anymore. Once this happens there are usually two options, you can rebuild the motor using new parts,
and machining the old parts. This is both timeconsuming and expensive, so for most people this is
out of the question. The second option is to replace the motor, by doing a motor swap you replace a
worn out motor with a new or used motor that is in running condition. Some of the benifits that this
offers is the ability to upgrade to a newer year motor or swap in a motor that produces more power than
the stock motor was able to. In this report, there will be a detailed account of the steps that need to
be done to swap a KA24DE motor (2.4L Inline 4 cylinder Dual Cam) into a 1989 Nissan 240sx with
a worn out KA24E (2.4L Inline 4 cylinder Single Cam).

The first and most important step in the entire process is the preperation phase. This is
when all the materials and supplies are collected, and when a workspace is set-up that provides a
clean, well lit, and organized area to work on. To perform the swap from single to dual cam motors
you must have several peices of equipment. A complete garage that has an engine hoist, floor jacks,
and many hand and power tools are needed to do the swap. All of the before mentioned items can
be found at stores such as Sears or Autozone. The car parts that need to be gathered include the
motor itself, a new transmission if the old one isn't used, a newer dual cam engine coil, a dual cam
Mass Airflow Sensor (MAF), a dual cam throttle cable, a new engine harness, and a new Engine
Control Unit (ECU). Once these items are collected and a workspace is prepared then the swap can
begin.

To begin the swap, pull the e-brake to secure the car, and open the hood. There are four
bolts that attach the hood to the car. Remove these then set the hood aside. Disconnect the battery
and set this aside also, now begin to disconnect the old engine harness from the motor. Once all
the harness plugs have been remove go inside the passenger side of the car and above the carpet
behind the dash there is a small yellowish box. This is the ECU, carefully detach the bolts holding
the ECU to the car, and the wiring harness to the ECU, set it aside and go back inside the car to
continue removing the harness. Now depending if the car is a manual or an automatic you will see
between one or two plugs connected into the dash harness, Remove these then go and pull the
harness through the hole in the firewall from the engine side. Once that is done then the body
harness needs to be disconnected from the motor. Unhook the wiring from the alternator, the
starter and from the transmision, make sure there is a oil pan to catch gear oil that will leak
out once the speed sensor (the plug that is bolted in) is removed. Although not a part of the
body harness the grounds should also be unscrewed at this time There is one on the passanger
side that connects to the battery box, and a small one that connects on the drivers side from
the firewall to a bolt above the headers. Disconnect and remove the old coil, as it isn't
compatable with the new engine. Pull the air intake tube off and set aside so the MAF's can
be swapped out. Disconnected and pull the electric fan off, then unbolt the radiator and radiator
hoses, this will drain all the cooling fluid so get a can to catch it in. Pull the radiator and put it
somewhere where it won't be damaged by being stepped on. If desired, the radiator can be
flushed clean to remove rust that has accumulated at this time. Get a floor jack and raise the
car so the exhaust bolts can be reached, remove the exhaust right after the exhaust manifold
and set the other side of the exhaust gently on the ground also remember to save the exhaust
gasket for later use. Next go and unbolt the power steering line from the power steering pump and
the AC lines from the compressor. Since dual cam and single cam AC lines are different the entire
AC system can be removed at this time if desired. At this time the driveshaft should be removed
there are 4 bolts attaching it to the rear end, and two bolts that support it in the middle. Remove
these and slide the driveshaft out of the transmission, making sure not to drop the end that comes
out of the transmission on the ground. Once out put the end of the driveshaft in a plasic bag to
protect it. Since this swap is being peformed on an manual 240sx, the slave cylinder needs to be
disconnected, undo the two bolts and set it aside. Now back in the engine bay disconnect the
fuel lines from the aluminum lines that go into the fuel rail, this is a good time to replace the old fuel
filter if you wish. Now go under the dash on the drivers side of the car and remove the throttle cable,
then disconnect it from the throttle body in the engine compartment, pull the cable out and set aside,
you may also discard it if wished because it isn't used anymore after this. Now go back in the car
and remove the boot covering the shifter, with the rest of the shifter exposed undo the 6 bolts that hold
the shifter on and remove. Failure to removed this can result in a bent shifter so its best to remove it.
Between the motor and the firewall there are two hoses, disconnect these from the firewall. Now
get a second jack or a jack stand and place it under the transmission, with the transmission
securely supported unbolt the crossmember and set it aside. Last thing to undo is the motor mounts,
unbolt them from underneath the car, then get the engine hoist out and set it over the engine
compartment. Make sure that as the motor is lifted out of the car that it doesn't drop on anyone or on
the radiator support because it will crush whatever it lands on. Once the motor has been pulled out then
the swap is halfway finished, take a break because there is still a long way to go.

Alright its time to install the new motor into the Nissan, start by jacking the new motor up and
positioning it over the engine bay. Again making sure not to crush anything slide the motor in and
work it so that motor mounts will go into their slots. Once they fall into place, reinstall and tighten the
bolts. Since now is the most conveinant time for it the shifter plate should be reinstalled but leave the
shifter out so you can refill the transmission with gear oil later. Using a jack lift the transmission until
you can reinstall the transmission crossmember. Tighten all these bolts so they don't come lose later.
Now slide the driveshaft back into transmission and secure it in place by installing the two bolts
connected to the carrier bearing. Now the rest of the driveshaft can be reconnected, tighten the bolts
because a loose bolt now can mean a wreck later. Slide under the transmission and attach the speed
sensor and the other plugs on the body harness that go to the starter, alternator and transmission.
At this time gear oil can be added from inside the car, about 3 small containers of 80w should be
enough. Install the shifter then cover with the shifter boot to cover the hole in the floorboard. Reinstall
the slave cylinder back onto the transmission and tighten. The final thing that needs to be done under
the car is the exhaust. Using the old gasket or a new one if the old one broke reattach the cataytic
converter back onto the exhaust manifold.

Back in the engine compartment the radiator is ready to be installed. Carefully so as not to
damage the fins, slide the radiator into the bracket and rebolt on. Attach the upper and lower radiator
hose, then connect the heater hoses behind the engine back into the firewall, at this point the cooling
system should be refilled with a mixture of water and antifreeze. Attach the electric fan onto the
radiator and plug it back in. With that the cooling system is installed and good to go. Go back inside
the car and thread the throttle cable through the firewall. Once its though attach one side of it onto
the accelerator pedal and the other end onto the throttle body. Now the fuel lines can be installed,
make sure that the lines are installed on the correct side of the fuel rail or else the engine won't work.
The power steering lines can be reattached if the log for the lines to go through is present. If not then
the car will be without power steering unto the log can be found, or new lines can be obtained. The
AC lines can't be reused because they don't line up on the compressor. Install the coil on the side of
the master cylinder is on, then reattach it back into the distributer. Looking at the throttle body there are
several tubes that need to be dealt with. The three small ones should be plugged and the two that are
slightly larger need to be jumped together, the very large one connects into the intake tube. Now take
the intake tube and intall it onto the throttle body, make sure the dual cam MAF is used not the old
single cam one. The final thing that needs to be done is the harness, this is just plug and go for almost
the entire thing. The only plug that won't match up are the plugs under the dash, to fix this just cut the
two white plugs and splice the wires together matching them by color. Don't worry if a couple wires
don't match, because these wires aren't used for anything other than diagnostics. Now connect the
new ECU back into the harness and try starting the car. If it doesn't start immediately don't worry
the new motor needs time for fuel to be delivered.

This completes the motor swap for the Nissan 240sx from single to dual cam. While the
steps taken may vary from vehicle to vehicle, the concept is the same, and budget permitting any
motor can be swapped into any car from mild swaps such as this one to wild swaps to V8's into
originally 4 cylinder cars. With motor swaps a cars useful life can be extended to an almost never
ending point. Well that completes this motor transplant, happy swapping.