How Vtec Works
#11
Registered User
Originally Posted by FitzyS2k,Aug 11 2010, 05:28 AM
isn't there 12 roller rockers per side. for each cylinder theres 2 outer ones connected to the valves and then theres the middle one too. i'll have to look at my manual.
#14
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x4
Also:
1 & 2 are the non vtec rockers.
3 is the vtec rocker.
Note: the vtec rocker isn't a real rocker as it's not in direct contact with the valves
Only when the pins locks the 3 together it operates the valves via the other 2 rockers but it is driven by the vtec cam lobe.
There is a spring behind the pins pushing them into non-vtec position unlocking the individual rockers unless the oil pushes them the other way, locking it all into 1 big rocker.
The non vtec cam lobes are not the same btw.
So in non vtec mode the valves don't open the same hight, maybe also not the same time but that's not specified in this drawing.
#15
Originally Posted by SpitfireS,Aug 11 2010, 10:45 AM
x4
Also:
1 & 2 are the non vtec rockers.
3 is the vtec rocker.
Note: the vtec rocker isn't a real rocker as it's not in direct contact with the valves
Only when the pin locks the 3 together it operates the valves via the other 2 rockers driven by the vtec cam lobe.
#16
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Oil feed goes through the rocker shaft - its hollow.
Look at the cut-away of the rocker shaft of the intake valves.
(right above the spark plug)
You'll see a hole.
That is where the oil comes out and pushes the pins into the vtec position.
On all 8 rockers, 4 intake, 4 exhaust (or 8x3 = 24) at the same time.
You could - in theory - operate vtec on the intake seperately from the exhaust but you'll need 2 solenoids and a seperate oil system per rocker shaft.
IOW a totally different head design.
It would be a nice project though.
IF I had millions in the bank and a workshop to my disposal 24/7
Look at the cut-away of the rocker shaft of the intake valves.
(right above the spark plug)
You'll see a hole.
That is where the oil comes out and pushes the pins into the vtec position.
On all 8 rockers, 4 intake, 4 exhaust (or 8x3 = 24) at the same time.
You could - in theory - operate vtec on the intake seperately from the exhaust but you'll need 2 solenoids and a seperate oil system per rocker shaft.
IOW a totally different head design.
It would be a nice project though.
IF I had millions in the bank and a workshop to my disposal 24/7
#17
Originally Posted by SpitfireS,Aug 11 2010, 11:08 AM
Oil feed goes through the rocker shaft - its hollow.
Look at the cut-away of the rocker shaft of the intake valves.
(right above the spark plug)
You'll see a hole.
That is where the oil comes out and pushes the pins into the vtec position.
On all 8 rockers, 4 intake, 4 exhaust (or 8x3 = 24) at the same time.
You could - in theory - operate vtec on the intake seperately from the exhaust but you'll need 2 solenoids and a seperate oil system per rocker shaft.
IOW a totally different head design.
It would be a nice project though.
IF I had millions in the bank and a workshop to my disposal 24/7
Look at the cut-away of the rocker shaft of the intake valves.
(right above the spark plug)
You'll see a hole.
That is where the oil comes out and pushes the pins into the vtec position.
On all 8 rockers, 4 intake, 4 exhaust (or 8x3 = 24) at the same time.
You could - in theory - operate vtec on the intake seperately from the exhaust but you'll need 2 solenoids and a seperate oil system per rocker shaft.
IOW a totally different head design.
It would be a nice project though.
IF I had millions in the bank and a workshop to my disposal 24/7
#18
Registered User
Originally Posted by SpitfireS,Aug 11 2010, 11:08 AM
Oil feed goes through the rocker shaft - its hollow.
Look at the cut-away of the rocker shaft of the intake valves.
(right above the spark plug)
You'll see a hole.
That is where the oil comes out and pushes the pins into the vtec position.
On all 8 rockers, 4 intake, 4 exhaust (or 8x3 = 24) at the same time.
You could - in theory - operate vtec on the intake seperately from the exhaust but you'll need 2 solenoids and a seperate oil system per rocker shaft.
IOW a totally different head design.
It would be a nice project though.
IF I had millions in the bank and a workshop to my disposal 24/7
Look at the cut-away of the rocker shaft of the intake valves.
(right above the spark plug)
You'll see a hole.
That is where the oil comes out and pushes the pins into the vtec position.
On all 8 rockers, 4 intake, 4 exhaust (or 8x3 = 24) at the same time.
You could - in theory - operate vtec on the intake seperately from the exhaust but you'll need 2 solenoids and a seperate oil system per rocker shaft.
IOW a totally different head design.
It would be a nice project though.
IF I had millions in the bank and a workshop to my disposal 24/7
#20
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ChefJ Posted on Aug 11 2010, 11:34 PM
In the picture they slide from the left (non-vtec) to the right (vtec).
If you stand next to your front left wheel and look at the intake, the intake pins slide form the left to the right.
Btw.. in the blue/white cut-through picture they are in vtec mode.
The pins have the same lenght as the width of the rockers they are in.
(I hope that makes sense)
Dark blue pin is shorter than the light blue pin.
Same diameter though.
P.S.
Part #A is symmetrical (a circle).
Part #B is symmetrical (a square).
This does not mean (IMO) part #A and part #B are the same.
So in this picture help how can you tell which way the pin slides?
If you stand next to your front left wheel and look at the intake, the intake pins slide form the left to the right.
Btw.. in the blue/white cut-through picture they are in vtec mode.
I don't have a pin infront of me but I thought they were symmetrical?
(I hope that makes sense)
Dark blue pin is shorter than the light blue pin.
Same diameter though.
P.S.
Part #A is symmetrical (a circle).
Part #B is symmetrical (a square).
This does not mean (IMO) part #A and part #B are the same.