Way to check butte fly valves
Way to check butte fly valves
i was just wondering if there was a way to check if my butterfly valves are opening properly. the car jsut doesn't seem to run right all the time.
THe butterfly are normally open (spring tension)Looking at the rear of the engine,driver side, you will see a small U shaped hose and a harness. Thats the swirl contro solenoid. If you disconnect the harness they will remain in the open position.
Other than that, is to remove the intake manifold and force them to close and to open. Or if you have a extremelly small hand, you can squezze it at and try to close them.
Other than that, is to remove the intake manifold and force them to close and to open. Or if you have a extremelly small hand, you can squezze it at and try to close them.
Ive never looked in the service manual. But I trust my eyes. When I removed my secondary butterflies they stayed closed unless I pushed the actuator down to open them. Im not saying that is how they are when the engine turns on and the solenoid creates a vacuum in the line, but the spring keeps them closed which would lead me to believe they stay closed till higher RPMs. Also the function of teh valves is to restrict the flow of air at lower RPMs to increase the velocity of the intake charge creating more torque for the lowend, this also would lead me to believe they stay closed when not under vacuum.
remove them
from 240sx.org
Will the removal of secondary butterfly increase power?
Solution:
You can feel the power from 4000 rpm on. The idle is a little bumpy, However there is at least 6 hourse power gain you can feel!
MohammedEmail: [email protected]
How to:
Kevin Akita wrote:
> Hey all,>> I've been reading the list for a while and finally decided to de-lurk with> a couple of questions: Forgive my ignorance, but I've seen a couple of> references to removing the secondary butterfly and I was wondering how one> goes about doing this? The FAQ suggests that it gives a slight hp boost,> but what exactly does removing the butterfly do?>> Kevin> 92 240SX SE Coupe
hehehehe, guess I'll get this one guys, as I removed mine on my intake last night !!(aren't you guys just so lucky ?.....)
Anway, in order to do this, you have to remove the intake tract, or at least the upper section (our intake has 2 parts to it....an upper and a lower. Mine is completely off on my project motor, but I still removed it in 2 pieces for simplicity of removal.)
The butterfly on the twin cam motors, is basically a long machined shaft that has flat sections machined out in the ports, which have flat plates screwed into. This mechanism is controlled by engine vacuum by a small port like canister bolted onto the firewall side of the intake, and controls the amount the butterfly opens or closes due to engine vacuum. (stomp on it, vacuum goes down, butterfly's open up or go horizontal, to allow full air flow.) At idle, and part throttle, itcloses up the intake, to keep velocity higher (smaller area) to keep the torque factor high.
REMOVAL:
First you have to remove the injector rail, and all the other top end attachments....throttle cable etc.... and remove the upper intake tract. NOTE: you will need a new intake gasket kit...so be warned.
Once you get your upper intake tract off, you have to remove the c-clip that retains the entire assembly on....and then remove the vacuum actuator. Next, in the middle of number 2 and 3 cylinder, there's a set-scew that keep the entire tract in position. Remove this phillips screw.
Next, you have to use a fine phillips screwdriver, and lightly "tap" the end with as mall mallet to break free the loctite type material on the tiny little butterfly screws...and remove each one. (2 per butterfly.) Next is the difficult part...as I found it somewhat tuff to remove. I lubed it well, and sanded the shaft....but it took some grunt, and tiny grinding of the shaft to physically pull it out.(I bent it a little as I tapped to get the screws out....it's pretty easy to bend this long shaft.)
The shaft pulled out in one long (about 14" long) piece. It's hooped after you remove it...so don't be planning to reuse it.
NOTE: Since there's a horizontally bored hole from cylinder to cylinder, you might have to reseal up the holes with either welding or epoxy.
IS IT WORTH IT ? I don't know....... but for my application (turbo) I don't want it there.
good luck......don
from 240sx.org
Will the removal of secondary butterfly increase power?
Solution:
You can feel the power from 4000 rpm on. The idle is a little bumpy, However there is at least 6 hourse power gain you can feel!
MohammedEmail: [email protected]
How to:
Kevin Akita wrote:
> Hey all,>> I've been reading the list for a while and finally decided to de-lurk with> a couple of questions: Forgive my ignorance, but I've seen a couple of> references to removing the secondary butterfly and I was wondering how one> goes about doing this? The FAQ suggests that it gives a slight hp boost,> but what exactly does removing the butterfly do?>> Kevin> 92 240SX SE Coupe
hehehehe, guess I'll get this one guys, as I removed mine on my intake last night !!(aren't you guys just so lucky ?.....)
Anway, in order to do this, you have to remove the intake tract, or at least the upper section (our intake has 2 parts to it....an upper and a lower. Mine is completely off on my project motor, but I still removed it in 2 pieces for simplicity of removal.)
The butterfly on the twin cam motors, is basically a long machined shaft that has flat sections machined out in the ports, which have flat plates screwed into. This mechanism is controlled by engine vacuum by a small port like canister bolted onto the firewall side of the intake, and controls the amount the butterfly opens or closes due to engine vacuum. (stomp on it, vacuum goes down, butterfly's open up or go horizontal, to allow full air flow.) At idle, and part throttle, itcloses up the intake, to keep velocity higher (smaller area) to keep the torque factor high.
REMOVAL:
First you have to remove the injector rail, and all the other top end attachments....throttle cable etc.... and remove the upper intake tract. NOTE: you will need a new intake gasket kit...so be warned.
Once you get your upper intake tract off, you have to remove the c-clip that retains the entire assembly on....and then remove the vacuum actuator. Next, in the middle of number 2 and 3 cylinder, there's a set-scew that keep the entire tract in position. Remove this phillips screw.
Next, you have to use a fine phillips screwdriver, and lightly "tap" the end with as mall mallet to break free the loctite type material on the tiny little butterfly screws...and remove each one. (2 per butterfly.) Next is the difficult part...as I found it somewhat tuff to remove. I lubed it well, and sanded the shaft....but it took some grunt, and tiny grinding of the shaft to physically pull it out.(I bent it a little as I tapped to get the screws out....it's pretty easy to bend this long shaft.)
The shaft pulled out in one long (about 14" long) piece. It's hooped after you remove it...so don't be planning to reuse it.
NOTE: Since there's a horizontally bored hole from cylinder to cylinder, you might have to reseal up the holes with either welding or epoxy.
IS IT WORTH IT ? I don't know....... but for my application (turbo) I don't want it there.
good luck......don
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sleepyRPS13
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I don't call it secondary butterflys. Is suppose to be "air restrictor"
No, you don't need them if you warm up your car before you drive.(90 seconds will do, longer for cold weather).
I quote from my previous post:
"It is not secondnary butterfly, and dont' work like secondary butterfly. Thus, it will NOT cause anything(power loss). It will not lean your car . It will not cause any bad idle. And it will NOT destroy the engine any much faster . And there's nothing related to the "intake restrictor".
When the S.V.C valve close (engaged), it restrict your intake manifold with a small pass through hole at the corner. This increase the velocity of your air, thus promote better fuel vaporization, and producing swirl air effect in your combustion chamber. Primary, this is to improve fuel consumption and increase stability of engine condition, especially when you start your engine in the morning.(cold engine) (and for emission reason too)
S.V.C valve open (dis-engaged) when:1. Water temperature below 35C /95F2. Engine RPM above 1400
So you can see, is pertty much a useless design. Since I have a turbo, I don't want it there
I didn't remove the rod because I dont want to deal with the leak when rod is gone. "
No, you don't need them if you warm up your car before you drive.(90 seconds will do, longer for cold weather).
I quote from my previous post:
"It is not secondnary butterfly, and dont' work like secondary butterfly. Thus, it will NOT cause anything(power loss). It will not lean your car . It will not cause any bad idle. And it will NOT destroy the engine any much faster . And there's nothing related to the "intake restrictor".
When the S.V.C valve close (engaged), it restrict your intake manifold with a small pass through hole at the corner. This increase the velocity of your air, thus promote better fuel vaporization, and producing swirl air effect in your combustion chamber. Primary, this is to improve fuel consumption and increase stability of engine condition, especially when you start your engine in the morning.(cold engine) (and for emission reason too)
S.V.C valve open (dis-engaged) when:1. Water temperature below 35C /95F2. Engine RPM above 1400
So you can see, is pertty much a useless design. Since I have a turbo, I don't want it there
I didn't remove the rod because I dont want to deal with the leak when rod is gone. "