this ? is for a school paper. sohc vs dohc

[breadbox]

Is there an out right reason to swap from SOHC to DOHC?Meaning are there advantages for both or is DOHC just the better way to go.Does SOHC have anything over Duel?

I am thinking just from what it seems to me, DOHC has higher Power potential and better control over timing of the valves.

The paper is on the comparing and contrast of SR20det vs. KA24det but i am trying to decide if i should include the SOHC ka in this paper.

[Fla240sx]

well the DOHC stock has a better flowing head SUPPOSEDLY, and I would agree with this.....

now as far as controlling the valves, they are both camshafts and work on the same principals so that idea is thrown out the window.. however the DOHC version has more valves, more area for air to enter the combustion chamber.......

one reason I see a lot of DOHC swaps is when going KA-T, because their is basically nothing for a SOHC turbo, it makes the DOHC route seem like SR aftermarket lol....... There are some manifolds floating around, but to get everything you want, especially if u want to keep A/C, its best to get one custom made

another thing I think is better for Turbo applications is the fact where the plug wires are on the DOHC, on top of the head; the wires on a SOHC goto the plugs by the exhaust manifold, where they could theoretically absorb massive amounts of heat.........

in N/A applications, race engines for the SOHC are up to atleast 270crank hp..... while for the most part the 240sx world has yet to see a good 200+ crank hp DOHC

I like the simplicity of the SOHC engine better, I like its intake manifold and all related components are easier to access... it has only one camshaft, which makes upgrading that a lot cheaper, Comp Cams makes a cam for the SOHC that is like 120 bucks, cams for the DOHC are 450-550 bucks. on the whole I like the SOHC valvetrain better, although the lifters tend to bind up and make tapping noises when they get debris in them. However a quick dissasemble and cleaning, or swapping to new ones can cure this. I need to clean mine when I put in the new cam... I'm going to go with the Comp Cam cause i'm a cheap *****

also there are a lot more DOHC engines out and about then a 240sx SOHC engine, they were produced from 91-98 while the 240sx KA24E is from 89-90

the early production year KA24E's also had higher compression ratio that wouldn't be AS good for boost if you were wanting to run more PSI.......

some people like the way the KADE looks more too.......

[180weaver]

nice writeup Fla, but I disagree on a couple areas. First of all there are some good aftermarket parts out there for the e, but they are definitely not as plentiful as the de and usually smaller scale, mom and pops type. Also the intake valves on both are equal just the exhaust differs so they both potentially receive the same intake amount just not the amount out although the exhauset ports are much larger than the de.Turbos are limited but full setups are out there. Basically the main reason I remained e was because I love the 240s, it is an engine considered a throwaway so I wanted to see what I could do with it and also I am a n/a junky and the engine has proven itself better for this application than the de

[Fla240sx]

I feel you there, I'm a SOHC N/A junky myself!

you don't need DOHC to make power, **** look at a LSX!

In fact, the only real way to have a good DOHC is for a direct non hydraulic cam on bucket type setup, like a Taurus SHO Yamaha engine, where the cam damn near rides on the valves with no slack or play... this is way more precise and direct then rockers like a SOHC KA or SR20....... also a lot better for higher rpm's.... only thing bad is they need adjustment with shims and make noise like a sewing machine almost.... damn I miss my SHO engine

I had one making 260whp N/A..... 3.2L that would rev to 8k easily... nasty nasty nasty.... makes quick work of Mustangs/LT-1 camaros... all in a god damn Taurus

[deviousKA]

This may help with your paper, your welcome to take any information from my posts and reuse it for that purpose.

zerothread?id=101249

Edit: IDK, but this might help also, depending on how in-depth you want to get with your paper.

zerothread?id=207617

[deviousKA]

Ill have to agree that the yamaha manufactured SHO engine is a damn sweet one.

But might I suggest the yamaha designed toyota 4age, which is a reincarnation of the cosworth BDA, after yamaha purchased the rights. IMHO it is the best inline 4 cylinder that was ever produced.

Though, that ford zetec is a nice plant as well, very similar to BDA/4ag.

[Fla240sx]

I wanted to put my SHO engine backed by a T-5 in the 240sx, but it won't fit without MAJOR body modifications, its too tall and long.. it has one hell of an intake manifold.. If I made a new manifold it would fit, but thats one of the greatest parts of the SHO unless your trying to get power from 5500-9000RPM

one of the only engines I know of with TWO power curves.......

[Fla240sx]

so devious, help out some inquiring minds here

well maybe just one mind

where can I find a solid rocker conversion? do they make any that just bolt in and don't require any machine work? also will ti work on any cam or does it have to be a special grind?

I thought I saw some somewhere but they no longer sold them....

thx I'm kinda interested in this, my lifters are noisy

[180weaver]

you might have better luck with hybridka than I did, but they have a website setup that you send your lifters only to no rockers and they do the solid conversion work for 300 bones. Unfortunately for me they have my lifters and after several emails, and written letters no communication whatsoever, no phone number either, but it seems like a simple drill out, tap and install a bolt that can be locked into place at desired lengths. Heard there was a writeup somewhere on here, if you find out let me know I have been wanting to convert myself. Seems like most any machine shop should be able to do the work, but then you have to make adjustments, guess thats just another reason to get under the hood though right

[shpaintball]

SOHC IS better i have a DE and an E both cars bone stock ...racing them the DE takes the race by a front lip...now my personal opinion is a sohc has less to break ...so in experience you are trying to simplify your motor as much as possible so why not start with a simpler design....4 less valves ...but when you port and polish it its all the same ....the blocks on the cars are the same i have more details but that is a preview of y SOHC is better to me ...just the way i see it in experience tho

[JDM vs. 318]

I don't know my 2.5 SVT DOHC contour motor was pretty nice. Not to say that the SHO car isn't good because that's the only good taurus. Now back to the nissan If you want any torque stick with the KA24DE don't mess with the single cam, too limited.

[JDM vs. 318]

SR20 NO TORQUE/ KA24DE=TORQUEhttp://forums.nicoclub.com/zeropost?cmd=reply&id=2933816#zer...33816#

[Fla240sx]

the contour svt motor is a destroked Duratec 3.0 POS....... with some better flowing heads...

basically you have a ported out run of the mill grandma taxi cab engine

the SHO engine loves to rev a lot higher plus the heads flow tremendous amount of more air then a SVT, forced induction SHO's put out serious horsepower... with a 60-1 compressor and 10psi on stock block/heads/cams most people are putting down 490+whp thats viper killing territory

plus the SHO kicks the SVT's ***... I know from numerous run ins

now take a regular Taurus/Sable etc 3.0 Duratec engine.. found in 96+ 24v cars and put the heads/intake manifold from a SVT contour on that block... then you have something fairly quick for a N/A v6.... track sleeper to boot!we have a video of one tearing up cars that cost 20x as much lol

slap me for going off topic