# Engine Rebuild SOHC vs. DOHC



## Jordy240 (Jul 18, 2005)

Hey dudes,
I have the opprotunity to pick up a 2400 12 Valve SOHC enigne and tranny to match(5 speed) for 100 bucks canadian. I currently have the KA24DE in my car and am wondering if going to a KA24E would have its advantages and disadvantages. My KA24DE needs a rebuild so does the KA24E, the plus is I could rebuild the SOHC and then just shoie it in when the DOHC dies on me. I am wondering the pros and cons to this swap, any help would be greatly asppreciated. Oh yeah and the SOHC has 250,000 KM on it while the DOHC has 313,000 KM on it
I would prefer to rebulid the DOHC instead of the SOHC but that would mean alot of down time and another daily driver, which I dont have. So any help would be great dudes. Thanks and keep on driving.


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## DaCheat (Nov 4, 2004)

Jordy240 said:


> Hey dudes,
> I have the opprotunity to pick up a 2400 12 Valve SOHC enigne and tranny to match(5 speed) for 100 bucks canadian. I currently have the KA24DE in my car and am wondering if going to a KA24E would have its advantages and disadvantages. My KA24DE needs a rebuild so does the KA24E, the plus is I could rebuild the SOHC and then just shoie it in when the DOHC dies on me. I am wondering the pros and cons to this swap, any help would be greatly asppreciated. Oh yeah and the SOHC has 250,000 KM on it while the DOHC has 313,000 KM on it
> I would prefer to rebulid the DOHC instead of the SOHC but that would mean alot of down time and another daily driver, which I dont have. So any help would be great dudes. Thanks and keep on driving.


Not trying to Dog the SOHC KA24E, but personally i don't like it.
Not as much HP or Torque stock, although rebuilding would be cheaper, parts would be harder to find because they are less common.
Try to find a good KA24DE that needs a reuild because you will eventually end up with a better motor in the end, and a pretty much Bulletproof bottom end, and a bullet proof head if built right.
I am seriously considering sticking with my KA instead of a swap, but an RB20DET swap is so tempting i am logically going to end up going on with it, let us know what you decide in the end, we will help you find some sites with performance parts for rebuilding!


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## Jordy240 (Jul 18, 2005)

*Sounds good*

Yeah I like the looks of the DOHC alot better too though. I wana repanit the head on it too. but it needs a rebuild real bad its got alot of klicks on it. and its staring to knock a little around 3000 rpm. so I keep the shifts low and im hoping for the best. I have a buddy at work who put a MOPAR 360 in his 93 240sx so he's got the original engine and tranny for that car that he'll sell me for like 100 bucks. so it looks like a good deal, except the engine is the KA24E. Thatnks for the input, I was kinda wondering what the power potential is like for the two engines. I know the DOHC is better in total. But im wondering if the simplicity of the SOHC would bee better for upogrades and so on. Thanks guys.


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## sunnydet90 (Sep 10, 2004)

Jordy240 said:


> Hey dudes,
> I have the opprotunity to pick up a 2400 12 Valve SOHC enigne and tranny to match(5 speed) for 100 bucks canadian. I currently have the KA24DE in my car and am wondering if going to a KA24E would have its advantages and disadvantages. My KA24DE needs a rebuild so does the KA24E, the plus is I could rebuild the SOHC and then just shoie it in when the DOHC dies on me. I am wondering the pros and cons to this swap, any help would be greatly asppreciated. Oh yeah and the SOHC has 250,000 KM on it while the DOHC has 313,000 KM on it
> I would prefer to rebulid the DOHC instead of the SOHC but that would mean alot of down time and another daily driver, which I dont have. So any help would be great dudes. Thanks and keep on driving.


 well to begin with when it comes to rebuilding a SOHC to DOHC the SOHC is cheaper if your returning to stock components because every rebuild kit for the SOHC is cheaper. but performance wise they are actually around the same and don't believe the whole its hard to find parts for a SOHC KA because thats bullshit. the good thing about the KA is the abililty to use the bottom end parts for both motors they are identical. currently the pistons that are for my SOHC were made for the DOHC. on the S13 chassis the HP is 15 difference but the SOHC puts out equally as much torque as the DOHC. but even though i am a SOHC man by heart and its nearly 4 in the morning in your case i would just find a trashed DOHC and rebuild it because its not worth the hassle of throwing a SOHC with all the wiring which granted isn't that terrible but if your like me then electronic equipment is not exactly your friend. just my 2 cents.


Don


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## Jordy240 (Jul 18, 2005)

*Maybe Im misunderstanding*

Im not sure If i understand completely, are you saying the block is the same for both engines and the only thing that makes it differnet is the way the heads are put together with the DOHC instead of the SOHC. So I coyuld take the block of the SOHC and put a rebuilt head and timing chains and tensioners and the rest of that gear from the DOHC onto the SOHC block???? Thats what I thought you were saying. If this is the case then Im in awesome shape to do this rebuild but if not. then thanks anyways.


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## sunnydet90 (Sep 10, 2004)

Jordy240 said:


> Im not sure If i understand completely, are you saying the block is the same for both engines and the only thing that makes it differnet is the way the heads are put together with the DOHC instead of the SOHC. So I coyuld take the block of the SOHC and put a rebuilt head and timing chains and tensioners and the rest of that gear from the DOHC onto the SOHC block???? Thats what I thought you were saying. If this is the case then Im in awesome shape to do this rebuild but if not. then thanks anyways.


 yes thats what i'm saying but here's the catch. granted these parts will and can bolt up to the the block itself but when you're putting a different head on the KA (in your case going to DOHC on a SOHC motor) its going to raise the compression ratio. how? i can't tell you that one but putting DE pistons that are rated at 9:1 compression in an SOHC motor nets me a full point drop in the compression because of the heads. so needless to say i'll have a 8:1 compression. but like i said in the other post. its easier to just rebuild the motor you have than doing a head swap and whatnot.

Don


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## tyrannix (Jun 12, 2005)

if that happens, you are in great shape for a turbo



sunnydet90 said:


> yes thats what i'm saying but here's the catch. granted these parts will and can bolt up to the the block itself but when you're putting a different head on the KA (in your case going to DOHC on a SOHC motor) its going to raise the compression ratio. how? i can't tell you that one but putting DE pistons that are rated at 9:1 compression in an SOHC motor nets me a full point drop in the compression because of the heads. so needless to say i'll have a 8:1 compression. but like i said in the other post. its easier to just rebuild the motor you have than doing a head swap and whatnot.
> 
> Don


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## thedaddies (Sep 29, 2003)

You have to use the DOHC timing setup. There is more to it than it looks from the get go, but is possible. If you use a SOHC lower with a DOHC upper. You'll have a high compression motor, not lower compression.

The DOHC lower(bottom end) with a SOHC upper(head) will net you lower compression due to the head design.

You'd be happy with either motor is done right. Decide which you really want, and go with. I'm building a SOHC, that's going in a DOHC chassis. Pretty much just need the wiring harness for either one, and fix a few little things on the harness plug. Easily done. The tranny sensors read differently, so you'd have to switch to a SOHC tranny sensor and gauge cluster. I beiieve the tachs read differently as well, but that might not be true. Of course whichever ECU you want depending on which motor, or in my case the AEM EMS.

I think that's it.


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## sunnydet90 (Sep 10, 2004)

thedaddies said:


> If you use a SOHC lower with a DOHC upper. You'll have a high compression motor, not lower compression.


did i not say that?

Don


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