good reasons to NOT build up a Sohc?

[MakotoS13]

so im taking the plunge and having one of the dead sohc's i have been given built up. i'm told the sohc sucks but when i ask for evidence to support that i'm disapointed to find no good reason other than dohc parts are easier to find or the dohc has the extra cam so you might get better mileage and what not. dohc has more power potential but if i'm only shooting for 250-300hp right now whats the need for a dohc?

enlighten me.

[chlatboy]

looks better?

[infinitexsound]

thats just stupid............. both are good in my eyes..... i was just at my friends shop, and the sohc car holds a record at laguna seca in the gt3 class.. id build w/ what ever u have... who cares what ppl think..

[Irukandji]

a friend of mine (who is also a mechanic) told me that the sohc ka24e's are more efficient than the dohc ka24de's in a sense that they get better power using the same boost. He even swapped a sohc kat into his s14. At first I thought the idea was idiotic, but his car puts a lot of power to the ground compared to a dohc kat.

i think its worth it...and i experinced far less problems with my sohc than my dohc.

[FRpilot]

^^^ hmm.. only reason i can think of for the sohc being more efficient than a dohc is if the sohc head flows better than the dohc head. but is there proof of this?

[wootwoot]

Shit, if I was going to build a kat I would do it sohc. Less shit to go wrong. I would just build the shit out of the head so I could still rev to 7200ish.
The only reason to not is because there are a lack of parts for it, but its not that bad

[Annoying Eric]

WWW.paeco.com


Thats where i got the parts when i built my sohc high compression

[chmercer]

the only reason people run ka24e motor in gt3 is because it came carbed in the trucks. if they were allowed to run ka24de (or anything else for that matter) that shit would get kicked to the CURB!

but yea dohc, smoother intake exhaust pulses from more ports blah blah but if you just want like 250-300 like you said sohc is quite fair enough

[veilside180sx]

I have a good reason, I don't like competition. haha..j/k

Well you've seen my build Makota, i think the SOHC is worthy of anything thrown at it.

[MakotoS13]

well, there doesn't appear to be any argument as i suspected. i'm doin it. forged pistons, basically stock everything else other than cam. blueprinted/balanced everything, p/p head with pdm racing cam.

it should in theory put out as much as or more power than a stock dohc, then after i rock it NA for a while and make sure its okay i'll put a snail on and shoot for a nice low 13 high 12 in the quarter.

if you can't afford a vette: kill one.

[lilredstiffy]

i wouldnt waste money on it period except for a turbo

even then dohc's are everywhere

[kandyflip445]

The best reason would be that your V8 idea was a lot cooler. lol

I'd go for it. Does the AEM ems work for the SOHC? Just wondering.

[BigVinnie]

SOHC's are just as good as the DOHC's. In my opinion it is more of what resources you can get in order to make your build. I have a DOHC, but I have also built SOHC high revs up to 8800RPM, using the NAPSZ 2.0 and 2.2litre blocks with an 86mm stroke, with siamesed L SERIES internals. I guess it is just what is your perogitive. On any level SOHCS are easier to tune with a single cam, and it doesn't take too much to port the SOHC's to make just as much power as DOHCS. HKS makes dual side draft mani's for the sohc's that you can use to put ITB's, or carburation on. The SOHC is a fun engne to play with.

[BigVinnie]

I'd go for it. Does the AEM ems work for the SOHC? Just wondering.
89-90 SOHCS and 91-93 DOHCS used all the same sensors for both OBD engines. You can use the AEM EMS on the SOHC's but you will need to use the wiring harness from the 91-93DOHC's in order for it to be a plug and play on the SOHC models.

[91CRXsiR]

ive driven both and IMHO the SOHC pulls a bit harder and can take a beating better...

[ryan hagen]

ive driven 3 sohc, 2 were pretty gutless, 1 seemed nice, i ve drven 4 or 5 dohc and all of them pulled harder than the 2 sohc, the one sohc pulled as hard as maybe half the dohc's did, i like the dohc, dont think id switch.

[veilside180sx]

89-90 SOHCS and 91-93 DOHCS used all the same sensors for both OBD engines. You can use the AEM EMS on the SOHC's but you will need to use the wiring harness from the 91-93DOHC's in order for it to be a plug and play on the SOHC models.

I have one and I'm wiring it with the SOHC harness, but wiring up a knock sensor for it. It's a DOHC vehicle BTW though.

[infinitexsound]

well, there doesn't appear to be any argument as i suspected. i'm doin it. forged pistons, basically stock everything else other than cam. blueprinted/balanced everything, p/p head with pdm racing cam.

it should in theory put out as much as or more power than a stock dohc, then after i rock it NA for a while and make sure its okay i'll put a snail on and shoot for a nice low 13 high 12 in the quarter.

if you can't afford a vette: kill one.
ever thought about knife edging the crank?

[revat619]

My friend use to have a sohc with cams, pulley, jwt ecu, and your other regular bolt ons and that thing pulled HARD. It was definitely faster than my dohc with intake and exhaust, which doesnt do much anyways but still that car was quick. And it put down more hp to the wheels than my dohc as well. Bottom line is, MOST people who tell you to ditch the sohc are talking out of their asses. They know nothing about it. But i've seen it first hand, and its quite doable. I'm sure he'll chime in momentarily to give all the details. :bow:

[JaeTea]

Just turbo it...200whp is pretty easily attainable.

[420sx]

yes. u can get around 220ish with a t28/t3 bottom mount custom welded manifold ic etc blah blah at like 7 psi and u will be ok. no need to touch the block internals. waste of money IMO. it can handle 7 psi so leave it alone. it blows? fuck it. get another one. want more boost? dig in. so it isnt big deal. just do it already!! :D

[veilside180sx]

^I would stick with the forged pistons, it's worth the peace of mind of not having to worry about your ringlands. IMO.

[MakotoS13]

what are the benefits to knife edging the crank?

[zaneithan]

http://www.zilvia.net/f/showthread.php?t=26996&highlight=knife+edged+crank

a 2 second search yielded that, hope it helps

[veilside180sx]

It allows the crank to cut through the oil, to cut down on parasitic drag as it cycles.

[wootwoot]

p.s. the highest hp ka is a sohc at something around 650whp. This might have recently been broken but I still think it holds the record

[theicecreamdan]

My friend use to have a sohc with cams,

that's not fair, he converted to DOHC.

Makoto if you're going to do a single cam, you should do the V8 idea. 5.0 is cheaper than a sohc KA

[jOeHaCk98]

There is a thread on freshalloy, but its pretty old. The thread starter is ADAM HUTCHSON or something like that. He did it, and he regretted it. Power for money he said it wasn't worth it. His shit was well built. You might want to read that thread. I think he wrote it in 2001-2002

[CKAMC]

the cheapest thing you can do? nothing. cheapest way to get turbo? turbo the single! www.ka-t.org and look at jordan gladman's ride. He makes the manifolds and they are pretty good and well that setup with the t3/t4oE 50trim puts out nice power very easy *heck watch some of the vid's and you will see that*. graphs to back it up as well!

[Var]

the only problem with the SOHC IMO is the revs die out. If you build the top end to stay happy until a little bit past 7k then you're in the money. T2 flanged manifold and a GT2871 .86, forged pistons, better rods, head studs, pistons and tune the bitch. If i went as far as changing any of the internals, it would be all the internals and i would shoot for 400hp.

[wootwoot]

^^^^ ew... Come on, t3 flange allright?

[Var]

NEVER!!!!. rather get a T4. I'd have full-race build it for me too.

[MakotoS13]

the cheapest thing you can do? nothing.

its a good thing you told me that. guess i can save a lot of money now.

[CKAMC]

its a good thing you told me that. guess i can save a lot of money now.

yeah like buy a big screen with that money or have a shopping spree at sams club.

[MakotoS13]

i dont evne know what i was thinking. screw this motor. hell, screw the car, im buying something thats cheap to own and screw modifying things too.

[420sx]

lol..... i'll sell you my trycicle

[Var]

220whp is like a waste of time. With a turbo that small it's gonna crap out before redline, so just keep the engine stock. When you're ready to step up to the plate , then do everything. Middle ground is loser shit. Either build the whole system for like 500 bucks, or spend a few thousand and make it sick. t-25 with SMIC and 10psi, open exhaust, and you should have your 220whp. My sr did 214whp with the same, so you should make a lot more with 2.4 liters. Make it a FMIC and 1 bar, and you'll get close to 250whp. IMO it wouldn't be worth buying a t-28 and rebulding the engine just to have the 250whp.

[kandyflip445]

There is a thread on freshalloy, but its pretty old. The thread starter is ADAM HUTCHSON or something like that. He did it, and he regretted it. Power for money he said it wasn't worth it. His shit was well built. You might want to read that thread. I think he wrote it in 2001-2002

That's probably because there wasn't as much support to turbo ANY KA engine back then. He was one of the first to do it to a SOHC and those people usually pay more.

[revat619]

that's not fair, he converted to DOHC.

Makoto if you're going to do a single cam, you should do the V8 idea. 5.0 is cheaper than a sohc KA


hahaha, sorry. i meant CAM. I'm so used to saying cams i just typed it without thinking. :p

[SochBAT]

http://www.zilvia.net/f/showthread.php?t=89252
BAM! There have been a plethora of parts for SOHCs, its just that no one brings them to light. SCCA have built up a GT3 KAE and have it posted somewhere. Google up SCCA KA24E. And IIRC, SOHC KA-Ts have been up to 600hp already, while DOHCs are barely hitting them now. But lemme dig up more info to back that bold claim.

[Irukandji]

errr i liked my sohc better than my dohc :-(

[veilside180sx]

p.s. the highest hp ka is a sohc at something around 650whp. This might have recently been broken but I still think it holds the record

Ventura racing set the record for a SOHC at 703 rwhp that it had in their drag Toyota Starlet. It hit the wall their second time at the track. The first night they ran an 8.1 et and smacked it the second time going back for 7's.

[wootwoot]

I keep thinking about ditching my current car and picking up a 1989-1990 thats really clean and just drive it while I have the engine in my garage on a stand getting built up. 703whp is fun.. Anyone want to buy my car?

[Irukandji]

703whp??? wtf do u drive???

[SochBAT]

Anyone that wants to ditch their sohcs, give me the engine!!! i'll put it to GREAT use.

[NemeGuero]

plethora is a new word for you isn't it soch?

[SochBAT]

Plethora (pleth·o·ra): n.

1. A superabundance; an excess.

Its the power of SEARCHING that allows me to back up my statement.

Hehe, im a friendlyguy. Sorry for lashing. +1 for Nemeeeeeee!

[NemeGuero]

I wasn't arguing how you used it, I know what it means. Just noting the frequency with which you use it.

that is all,
have a nice day.

[veilside180sx]

Plethora makes me think of Steve Martin's "Three Amigos". haha.

[chlatboy]

single cams are cool. I just done like it as much since its takin up space in my front yard!!.

[Tygma]

Single cams suck. I swapped out my single for my dual. I rocked a single cam for a bout a year then it died and i've been rocking my dual cam for about a year as well. Dohc owns, by far. Way more torque, power.. w/e. It just feels better. I plan on going SR20det in the future, coz any modding to this motor outside of simple bolt ons just doesnt seem worth it to me.

[Var]

stock vs stock, yes it's obvious. You havent been paying attention to the thread have you?

[veilside180sx]

To counter the SOHC suck comment. I've driven lots of both and every 240 I've wound up owning has had them in it. I prefer to drive them, the torque comes on stronger and sooner in general.

In fact I'm swapping my SOHC into a DOHC chassis. It's all personal preference with what you like.

[DriftGirl]

It's cheaper (in the short term) to build power w/a SOHC.

With an SR you have to fork out 1200 - 2k from the start.

With a SOHC you can build it as slow or fast as your pockets will allow. In the end it will come out the same....but its the journey that counts right? ;)

[drift freaq]

enough talk about little 4 cylinders. drop a 6 in and be done :P :rofl:

[420sx]

shheeeeeeiiiiit. fucka 6 cylinder. drop in v8 biach.


i took a ride in my friends freshly built 302, layed out 450 on the dyno without the nitrous, lets just say he blew out the third gear haha. and it sounded real damn good. i'd still put an ls1 in the s-chassis

[drift freaq]

shheeeeeeiiiiit. fucka 6 cylinder. drop in v8 biach.


i took a ride in my friends freshly built 302, layed out 450 on the dyno without the nitrous, lets just say he blew out the third gear haha. and it sounded real damn good. i'd still put an ls1 in the s-chassis
oh damn!!

hehehhehehe, my lips are sealed.

[BigVinnie]

All I can say is a Callaway Small block V8, it fits in a 240 easier than a VG V6 turbo.
On another note I like 4 bangers for gas mileage. The sohc defenitely has it's advantages when you can get your hands on solid lifters with adjustable lashing.

[drift freaq]

All I can say is a Callaway Small block V8, it fits in a 240 easier than a VG V6 turbo.
On another note I like 4 bangers for gas mileage. The sohc defenitely has it's advantages when you can get your hands on solid lifters with adjustable lashing.
well when I was talking 6 cylinders I was not talking VG. VG's are heavy and not that great. Can we say RB? Ok. As far as V8's go , like I said before my lips are sealed!! I can get the same mileage out of a 6 that our 4 cylinders give as well. The SOHC engine has rocker arms the DOHC KA does not. The SR has rockers , the RB does not. I prefer not having rockers.

[wootwoot]

RB?....pft. VQ is where its at now.

[drift freaq]

RB?....pft. VQ is where its at now.

sssssshhhhhh, keep your mouth shut. VQ? I did not hear anyone say VQ!

[wootwoot]

VQ30! I said it!

[drift freaq]

VQ30! I said it!
man, loose lips sink battleships!!

[RBS14]

I prefer not having rockers.


AMEN.



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[veilside180sx]

It's a whopping $300 conversion to eliminate the rocker arms for solid lifters.

[ledzeppelin240]

"It allows the crank to cut through the oil, to cut down on parasitic drag as it cycles."


That is completely wrong. Your crankshaft should not run in your oil otherwise your crankcase is overfilled and you are aerating your oil. And for obvious reasons this is wrong.

SOHC owns...

[MakotoS13]

It's cheaper (in the short term) to build power w/a SOHC.

in the short term? it either is or it isn't. sohc's have been owning dohc motors for ages. the general concensus appears to be that sohc's respond very well to mods, are inherently less complex than the dohc variants, and people are literally giving them away.

my builder quoted me 1100 if i use oem parts. i'm thinking forged internals and a cam. so like 2 grand for a very dependable 300rwhp and a torque munster? its the only thing that seems to make any sense.

[kandyflip445]

Why the hell was she comparing a SOHC to a SR anyways? :wtf:

[veilside180sx]

"It allows the crank to cut through the oil, to cut down on parasitic drag as it cycles."


That is completely wrong. Your crankshaft should not run in your oil otherwise your crankcase is overfilled and you are aerating your oil. And for obvious reasons this is wrong.



I didn't complete what I had written, so I was half wrong. This is taken from a motorcycle crank shop. foxperformanceengines.com The reciprocating mass inside a motorcycle spins at twice the rate most cars do I'll take his word for it.

Q: Why knife edge?

A: Aerodynamics. That crank is spinning around faster than humans can comprehend. essentially it is a spinning wing doing it's best to slice through the air and all the oil that is being thrown around inside your motor.

[MakotoS13]

Why the hell was she comparing a SOHC to a SR anyways? :wtf:

believe me when i say you're better off askin a barn door why its red. :rofl:

[RBS14]

The only reason sohc's have "been owning dohcs for ages" is because they are older. So people have had longer to mess with them. In addition, the people who are building them (oldschool L series builders/tuners) stick to sohcs because they are more familiar with datsun/nissan sohc engines, and not dohc engines. If they were familiar with dohc's, the gnarliest ka's would be dohcs. They are both great engines, but when you look at the specs, and from an engineering standpoint, the dohc wins.


However now I really wish i has a sohc because then cam(s) wouldn't cost me damn near $600!

[wootwoot]

250 dollars for cam after core =)

I heard in Japan land people are importing sohc's and putting them into their 180sx's and Silvia's. USDM Yo!

[tastyratz]

dohc head flows better than sohc head.
dohc engine has a knock sensor and sohc does not factory.
dohc has more parts available for it for cheaper than sohc.
Dohc engines are newer and not as old/tired
Dohc gets better gas mileage

however.
sohc has lower compression than dohc making it more suited for boost
sohc engines are cheaper and more common (usually free!)
knock sensor from a dohc works if you just weld a threaded rod onto the block
cam (not cams) is cheaper. (keep your eyes out for a new colt cams tri-flow cam for the sohc. I will have some dynos up in the next few weeks to show people some big gains) p.s. fyi colt cams makes the cams that pdm resells.
its probabbly already in your car
its just about the same damn engine and responds very well
its simpler more complex


FYI to who said you need a different harness is WRONG. I have an aem ems on my sohc and its FRIGGIN GREAT! I didnt do crap to my harness either you dont need to.

[wootwoot]

I love to hear stuff from people who KNOW that it isnt in actuallity a supperior engine but they know the benefits of both set ups. Every single engine in existence has pluses and minuses, hell, everything in LIFE does. Some of you need glasses or something though I swear

[infinitexsound]

so we dropped in a nismo ka24de into the a tube chassis the other day, took it to dyno.... anyways its not running right but still its one bad ass motor...... the de back fired and blew a hole in the sheetmetal intake mani..... preferably 16 valve is great no ones knocking extra valves...

the sohc is great also.... holds a record @ laguna seca in gt3 class i believe... and also keeps up with a 700hp viper... and its only at 260hp w/ restriction..... 315hp without i believe...great motors love the torque and love the fact that when their well built can do well on the track...

about knife edging.. basically it lightens up the crank and cuts thru oil faster...

[sideview_180sx]

when www.hybridka.com has a roller rocker kit for sohc i'd go for it, since you can rock a big frigging cam, whether NA or turbo. shit I'm dohc and i'd do it just to flip it on ppl.