ka24e -> ka24de

Information on the naturally-aspirated KA24E and KA24DE engines.
dvs240
Posts: 31
Joined: Wed Jul 09, 2003 1:54 am

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Hey guys, soon I will be doing a KA24de swap into my 89 240sx fastback se. I need to know exactly ALL the parts needed for the swap. I'm trying to keep downtime to a minimum because it's my daily driver. I want to retain power steering but all the other creature comforts can go. I know I need..

MotorTransmissionECUMAFWiring harnessclutch/flywheelalternatorTachometerPower steering lines

anything i'm missing here?


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dabum
Posts: 118
Joined: Sun Nov 23, 2003 4:36 pm

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http://www.zilvia.net/faqs/archive/SOHCtoDOHC.asp

i swear there are amillion threads about this..

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Importroller
Posts: 1135
Joined: Sat Oct 26, 2002 10:12 am
Car: G35 and 07 Altima 3.5 6spd
Location: san diego
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I may also be doing this swap soon. thanks for the info

gumby
Posts: 994
Joined: Wed Oct 15, 2003 6:53 pm
Car: '89 240sx sohc

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95 DOHC into 90

Mechanically it all bolts up no problems.Here are the main differences:

Mechanical:Power steering - different between SOHC (pass. side) and DOHC (driver side). To swap, you need the DOHC power steering lines, reservoir, and hoses.Intake - different shape, so can't swap thatThrottle cable - SOHC too short to reach DOHC throttle body best to get a DOHC cable.A/C is a different compressor entirely, though in about the same position. To make a DOHC compressor work with a SOHC system, you'll need to have a specialty shop custom fit the DOHC lines to your SOHC system. No, the DOHC lines do not just bolt to the firewall fittings, they are different sizes. Also, SOHC systems used R12 refrigerant, now illegal. You'll need to convert to R134, which means a system flush and new drier.Ignition - I understand the '91-'94(?) sytems use a different coil, but not entirely sure. The '95+ systems don't have an external coil, so not an issue there.

Electrical - SOHC systems and DOHC systems are somewhat different in the wire routing, primarily the power/fuse wiring for the ECU (at least for the '95 vs '90 systems), but also some sensors and inputs for the OBD, tach, speedo. It's not really a big deal if 1) you have the FSM (wiring diagrams) for both the SOHC and donor DOHC systems, and 2) you can read and understand the wiring diagrams. Then its a matter of identifying the differences, and cutting/splicing the DOHC harness to match the SOHC systems. The harness plugs that connect to the engine room and dashboard harnesses are different, so you have to cut to SOHC plugs and splice them into the DOHC harness. Takes a little time and you have to do it right, but like I said, not bad if you have a bit of understanding about how electrical systems work.

Also, you need a DOHC tach as the SOHC tach will not work.

Obviously you also need the DOHC computer.

You may have to change the transmission harness a bit to make it mate up, but that's minor (for the '95, I had to wire in the 2nd O2 sensor and crankshaft position sensor, no big deal).


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