# SOHC to DOHC swap



## 93blackSER (Feb 1, 2003)

does anyone know how difficult of a swap this is? i am in the process of purchasing a 1989 240sx 5spd fastback and i want the DOHC engine. however, this was too good of a deal to pass up. $900 with 4 new tires, new rotors, pads, and calipers at all corners, new clutch with pressure plate and throw-out bearing, engine with 70k on it, new battery, and new struts. it also has very little rust, all in places that will be removed anyways. but back to the point, i want to build a DOHC in my garage and drop it in, but i was wondering what kind of extra parts are needed. from what i have before, i would need the DOHC power steering lines and i would also need the ECU and wiring harness. anything else i'm forgetting? or any other things i should know? and lastly, would it be easier to skip the ECU and run a full engine management unit? i want to use one eventually anyways. thanks in advance.


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## blueboost (Jul 25, 2002)

I believe you mean you wanna swap the KA for the SR20 engine right? this has been covered in detail many times.. do a search for specifics, but check here, click the INSTALL FAQ option and then from there you can see all the questions listed on the left in aqua.

http://srswap.com/


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## OmegaManEX (Oct 4, 2002)

^^ nope 

he has the KA24E in his 1989 240 , so i guess he want to drop in the newer KA24DE which is DOHC

heres about nissan engines::
http://www.freshalloy.com/site/features/tech/engines/home.shtml


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## nx2000 (Jan 24, 2003)

It is an easy sap. you would need the following

DOHC of course

DOCH guage cluster or the tach of of the cluster or aftermarket tach. The SOHC uses 12V signal and the DOHC uses 16v. Everything will work EXCEPT the tach. Besides, the DOHC clsuter has a check engine light

FULL engine wiring harness (need all DOHC electronics)
DOHC ECU

I was going to do this swap...got frustrated and gave up. It was my first one though. And it wasnt a matter of NEEDING an ew engine, I WANTEd one. Now I NEED an engine so I have ot be patient My first real swap will be an RB20, but with help this time to guide me through. I hear you can use the swap guide for wiring from www.srswap.com. Just wouldnt be for an SR20

www.nissaninfinitclub.net Hsa WAY more info on ALL available swaps

http://community.webshots.com/user/carsinc DOHC swap in progress

http://www.nissaninfiniticlub.net/forums/showthread.php?s=&threadid=22857&highlight=DOHC+swap


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## drift240sxdragqueen (Oct 23, 2002)

u gotta do all the things u would on the SR swap but u get no turbo


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## joerc240sx (Jan 19, 2003)

Its so close your better off staying with what you got, or swaping to another engine completly (SR or RB)


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## 93blackSER (Feb 1, 2003)

ok, another question. will the head off of the DOHC bolt on to the block of the SOHC? i think that would simplify things a little anyways.


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## nx2000 (Jan 24, 2003)

93blackSER said:


> *ok, another question. will the head off of the DOHC bolt on to the block of the SOHC? i think that would simplify things a little anyways. *


NO


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## blueboost (Jul 25, 2002)

i don't see any reason not to get the SR at that point then.


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## 93blackSER (Feb 1, 2003)

becuz the SR is highly over-rated in my opinion. and dont even think about starting a KA vs. SR debate in my thread either. i am entitled to my opinion and that is it.


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## nx2000 (Jan 24, 2003)

93blackSER said:


> *becuz the SR is highly over-rated in my opinion. and dont even think about starting a KA vs. SR debate in my thread either. i am entitled to my opinion and that is it. *


AMEN. I am glad I am not the only one. There are SO many choices...why go SR. It is the most expesive one save the RB25 and RB26. You start with more HP on an RB20 annd you start with a little less on a CA, but the price difference is enormous. You can get a CA front clip for what most people sell incomplete SR's. Same with RB20. And while turboing your KA is the most expensive, it is the easiet because you already have the motor. And replacement motors are easy to come by. You can go ghetto (or custom ) and get KA-T for under a G. Or buy a kit for 2500(on ebay sometimes) to 3500. Dont get me wrong, it is a good motor, but played out and expensive.


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## 93blackSER (Feb 1, 2003)

i know exactly what you mean man. the only reason SR's are so expenive is becuz everyone wants one. they arent completely worth the money. dont get me wrong, they arent bad engines, but there are better ones. if i were to do a swap to some JDM engine, it would be the CA18DET too, which i'm considering. i found the engine with ECU and harness for a grand plus shipping. and i can do the swap myself. so you figure with the engine and shipping, a FMIC, and an exhaust, i'm doing burnouts with my CA around you and your SR that isnt even installed yet and i'll have spent less cash. sounds like a good plan to me.


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## nx2000 (Jan 24, 2003)

93blackSER said:


> *i know exactly what you mean man. the only reason SR's are so expenive is becuz everyone wants one. they arent completely worth the money. dont get me wrong, they arent bad engines, but there are better ones. if i were to do a swap to some JDM engine, it would be the CA18DET too, which i'm considering. i found the engine with ECU and harness for a grand plus shipping. and i can do the swap myself. so you figure with the engine and shipping, a FMIC, and an exhaust, i'm doing burnouts with my CA around you and your SR that isnt even installed yet and i'll have spent less cash. sounds like a good plan to me. *


there is a CA on ebay I am/was eyeing. 350 plus shipping. FWD with cut harness and no ECu. I can most likely get the wring/electroni for 4-500. Maybe even with ECU and the RWD 5spd for 125. I was on the verge of buying an SR. Only because I was going to win it hceap off ebay. I lost and didnt bother rebidding. i want my 240 running and would take ANYTHING. Nut it didnt work out, so I am "stuck" with the RB20


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## 93blackSER (Feb 1, 2003)

haha. i'm going to find a KA24DE someplace with harness and ECU and build it and then drop it in. build all the internals and valve train and everything so it'll be all ready for a turbo.


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## L.Williams (Jun 23, 2003)

It would be easier to just sell the engine thats in there and buy a dohc one from like a 91+ 240 from a junkyard, then use the extra mone to rebuild it and there you go, much more reliable and easy


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## 93blackSER (Feb 1, 2003)

yeah, that was the plan pretty much. except the junkyard part. the DOHC will be built before i even pull the SOHC out. kinda doesnt make sense to drop it in and then have to pull it again to build it.


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## joerc240sx (Jan 19, 2003)

I dont feel the SR is over rated. i wanted to either build my KA 2 year ago or swap to the SR. the SR made more sense and it wasnt because all the mags, they didnt even talk about the 240 (wish they still didnt). it was because it would get me 240+ hp for less then it would cost to rebuild my KA and go turbo. I dont like the CA bacause you'er going to get an engine thats seat for sevral years, and would most likely need a rebuild. and any RB swap would cost more then 3k to make it work, unless you owned your own shop. looking back i wish i would have done the swap, and not built my KA.


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## nx2000 (Jan 24, 2003)

Are you kidding me??? Like SR's dont sit for years too. You can do the RB20 for less than 3K. I am currently at 1836, That is front clip and shipped. Fluids ran me cant remember. It was a little over 25 probably. Syntheitc oil, coolant, windshield wiper, power steering, and brake. Cant find the tranny fluid I want yet. Boost gauge was 30 shipped. I may get some more misc guages for like 15 shipped (cheap ones, but if they serve their purpose, who cares..better than nothing). Electirc fans...depends if you want one or tweo and what CFM you want. I am looking to get a dual fan that is doing 2780CFM. 300 off ebay shipped unless I can find them cheaper local. Not needed, but extra precaution. I dont NEED a turbo timer or BOV to get it running. Special emphasis on need. Will I get them...yes. 

1836-front clip shipped
50-fluids 
30-boost gauge
15=misc guages
300-dual electric fans
100-misc shit ( spark plugs, oil filter, etc...just in case..maybe more if more comes up)
500 install (help, learn, and tools)

so far that is 2831 and can get me running. SR20 that is just hitting the tip of getting the front clip....MAYBE shipped you find a good deal

Did I miss anything to get running. And dont mention NON essentials like 3in piping...etc. ONly things that are NEEDED to run...noy run super boost

RB25 would be maybe 1400 more. Custom driveshaft and of course more for the clip. 

KA-T is very good too. IF you take care of the engine and know what abuse it has taken, you can turbo it. You dont even know what the SR has been through. Shit ven my RB20. I dont know where it has been. Hopefully it wil start up...LOL How they drove it. You KNOW how you drive your ka. How well you maintained it. If you want boost.....you can get a manifold for the KA for under 350. decent T3 for under 350. Intercooler for mad cheap from the junkyard. Piping couple hundred. Misc oil lines and whatever from teh hardware store for cheap and a S-AFC. That is some decent boost right there. If you are on a budget...custom...cough ghetto cough is the way to go. You have many options. explore them all. Dont get an SR over an RB because parts are "more available"...you still pay a premium on those same parts. RB and CA parts are there. Most people dont search and use that lame ass excuse. And alot of shops are begiining to stockpile RB parts the same way shops are stocking RB parts


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## bizzy b (Apr 13, 2003)

i agree. my KA was rebuilt not long before it i bought the car from an old lady, so, given proper fuel and tuning, i trust it to hold up to 300hp turbo duty just fine. however, if i were going to swap it i wouldn't go with an SR20, simply because it's not the best engine you could get for the money. you can drop in the RB20 for a lot less and have the same power, an iron block and NO disadvantages. or get the CA for wicked cheap. granted, the CA doesn't have as much power, but with the money you saved you could have it pumping out 400hp by the time you get the SR into your car. obviously the RB25 is king of the 240SX swaps, but it's more expensive than an SR20, so arguing for it isn't part of my point.


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