Those pipes from throttle bodys to rocker cover
- Thread starter MarkTurbo
- Start date
A
AndrewD
Guest
no wonder why you guys have so many broken engines
you just take biits off while not thinking about it
considering it the return line for the cam cover breather, im not suprised
this reduces the pressure in the cam cover and also helps to scavenge excess oil / air mixture to the oil tank
idiots
you just take biits off while not thinking about it
considering it the return line for the cam cover breather, im not suprised
this reduces the pressure in the cam cover and also helps to scavenge excess oil / air mixture to the oil tank
idiots
S
str_motorsport
Guest
norris designs also do that mod ....
anyway i don't like to block the cam cover breather(the one near the oil filler cap) with a blanking plug, but would like to put a breather filter....
what do you think?
anyway i don't like to block the cam cover breather(the one near the oil filler cap) with a blanking plug, but would like to put a breather filter....
what do you think?
J
jiw
Guest
AndrewD said:
As ginga said, it puts oil into the inlet system slowing down air, also obviously this reduces the octane and quality of the fuel which is burnt which causes DET, the pipes at this age have also deteriated and begin to leak when under boost, also why would he want excess crankcase pressure when under boost?
So this has been thought of, also the majority of broken engines have done a lot of miles been hammered and have had extra boost put through them with engine mods, things do break.
Idiot :roll:
The system was designed to work only at vacuum not boost so blocking it off
wont make any difference under boost enough to cause det guys, mine stays as it is
as it is usefull to have the vacuum on crankcase at low rpm
but you are welcome to to set up your engine as you like
Frank
wont make any difference under boost enough to cause det guys, mine stays as it is
as it is usefull to have the vacuum on crankcase at low rpm but you are welcome to to set up your engine as you like
Frank
I have got my rocker off at the mo and the pipework is dry I think you will find that unless your engine is well worn and chucking oil mist and vapours up there is no weakening of mixture and I am about to check if there is a one way valve in the hose if so even more reason not to worry
ps there is also a sequence of baffle plates in the cover which will stop oil
accessing the exit spigot and finally the spigot that feeds the small hose system has a one way check valve which shuts off any vapours /oil mist on boost have just tested it by blowing through it (one mouthfull of crap later!)
anyway thats my take on it now its your decision...
Frank
ps there is also a sequence of baffle plates in the cover which will stop oil
accessing the exit spigot and finally the spigot that feeds the small hose system has a one way check valve which shuts off any vapours /oil mist on boost have just tested it by blowing through it (one mouthfull of crap later!)
anyway thats my take on it now its your decision...
Frank
zia
Active Member
if you actually looked at the rocker cover, there is no way the oil will travel from the head to the breather hose on the the throttle bodies!!! i have taken quite a few inlet mani off and have never seen oil in the those vaccum inlets. oil normally come through from top mount intercooler from stock induction breather hose or turbo comp inlet!!
too true!. jumping to conclusions knowledge but no experience!!!
zia
I've seen oil in the inlets through that pipe, it was caused by xs crankcase pressure due to knackered pistons though but with a high power/boost engine the crank case pressure could be enough to cause the same thing, the one way valve can also fail at high boost and hence pressurises the crankcase further. the mod is only really required on very high power/boost cars and probably wouldn't be of any benefit on a mildy tuned engine.
the biggest culprit for oil in the intake system air intake to turbo, turbo to intercooler and intercooler to inlet manifold is that fact the breather pipe from the rear of the engine goes into the inlet track just before the turbo putting oily breather fumes into the intake and coating it with a thin layer of oil.
You can just disconnect it from the intake but then you get the breather fumes that smells bad getting into the car, best way would be to fit a proper oil seperator (not catch tank) in the system before it goes into the inlet track.
but with a high power/boost engine the crank case pressure could be enough to cause the same thing, the one way valve can also fail at high boost and hence pressurises the crankcase further. the mod is only really required on very high power/boost cars and probably wouldn't be of any benefit on a mildy tuned engine.the biggest culprit for oil in the intake system air intake to turbo, turbo to intercooler and intercooler to inlet manifold is that fact the breather pipe from the rear of the engine goes into the inlet track just before the turbo putting oily breather fumes into the intake and coating it with a thin layer of oil.
You can just disconnect it from the intake but then you get the breather fumes that smells bad getting into the car, best way would be to fit a proper oil seperator (not catch tank) in the system before it goes into the inlet track.
A
AndrewD
Guest
ahahaha how funny, once again believe what you want its your money
J
jiw
Guest
:lol: :lol: Well said
A
ard1ey
Guest
My two cents, as I've just had all this apart - sorry about the long post:
These pipes are purely to scavenge any blow-by or oil vapour which has made its way up into the area above the valves. Inside the rocker cover there is a closed off area which eventually goes to both of the breather connections, and is open to the area inside at certain points. I haven't cut this open personally (yet :twisted: ) but as Frank said I'd expect some sort of baffling in there to act as a seperator to avoid liquid oil going out the breathers.
There has to be a one-way valve between the throttle bodies and the breather, or when you get on boost your engine will start blowing seals left, right and centre - apart from the combustion chambers no part of the engine internals should ever be under pressure. This means on vacuum at part throttle, the system will draw the vapour from inside the rocker cover, through the seperator stuff and into the throttle bodies - if your seperator is in good nick or your vapour is not too oily, there will be no visible residue. Mine happened to have a bit of oil in it, doesn't bother me.
If you remove this pipework (I did, it was in the way of some bolts) you still have the right-hand breather connection to the inlet pipe which will do exactly the same job - scavenge vapour from the rocker cover. This is also the vacuum connection to the oil seperator which only deals with the blow-by gases in the crankcase, the liquid oil should be seperated out and return to the crankcase, any vapour returns to the inlet tract and is burnt in the engine (and covers your turbo and intercooler ). If you remove the inlet pipe connection and run it to a catch tank thats open to atmosphere the vacuum won't be there to draw out any unwanted gases - you may also get an oily smell as the system is no longer sealed, but no oil will get back to your intake system.
Another way might be to run the vacuum connection to the intake pipe through another (more efficient :?: )seperator to get rid of any residual oil mist in the drawn out gases. This is what I'm going to look at doing, as I do have oily gunge and I don't like having the system open - just my preference.
AndrewD - there are many members on here who do have the ability to look at an engine and decide whether changes to a system that Nissan put on are worth doing. People don't always just look at a mod that a tuner does and go "Hey, that looks cool! Off come the pipes". I don't have any problem talking over another point of view, but if you're going to call me an idiot I'll invite you, as friendly as possible, to fook off
Anyone got a spare rocker cover they fancy sacrificing to find out exactly whats under that closed off section :?:
Thats it, any different ideas how it's supposed to work :?: Shows over, thank you for coming
These pipes are purely to scavenge any blow-by or oil vapour which has made its way up into the area above the valves. Inside the rocker cover there is a closed off area which eventually goes to both of the breather connections, and is open to the area inside at certain points. I haven't cut this open personally (yet :twisted: ) but as Frank said I'd expect some sort of baffling in there to act as a seperator to avoid liquid oil going out the breathers.
There has to be a one-way valve between the throttle bodies and the breather, or when you get on boost your engine will start blowing seals left, right and centre - apart from the combustion chambers no part of the engine internals should ever be under pressure. This means on vacuum at part throttle, the system will draw the vapour from inside the rocker cover, through the seperator stuff and into the throttle bodies - if your seperator is in good nick or your vapour is not too oily, there will be no visible residue. Mine happened to have a bit of oil in it, doesn't bother me.
If you remove this pipework (I did, it was in the way of some bolts) you still have the right-hand breather connection to the inlet pipe which will do exactly the same job - scavenge vapour from the rocker cover. This is also the vacuum connection to the oil seperator which only deals with the blow-by gases in the crankcase, the liquid oil should be seperated out and return to the crankcase, any vapour returns to the inlet tract and is burnt in the engine (and covers your turbo and intercooler
). If you remove the inlet pipe connection and run it to a catch tank thats open to atmosphere the vacuum won't be there to draw out any unwanted gases - you may also get an oily smell as the system is no longer sealed, but no oil will get back to your intake system.Another way might be to run the vacuum connection to the intake pipe through another (more efficient :?: )seperator to get rid of any residual oil mist in the drawn out gases. This is what I'm going to look at doing, as I do have oily gunge and I don't like having the system open - just my preference.
AndrewD - there are many members on here who do have the ability to look at an engine and decide whether changes to a system that Nissan put on are worth doing. People don't always just look at a mod that a tuner does and go "Hey, that looks cool! Off come the pipes". I don't have any problem talking over another point of view, but if you're going to call me an idiot I'll invite you, as friendly as possible, to fook off
Anyone got a spare rocker cover they fancy sacrificing to find out exactly whats under that closed off section :?:
Thats it, any different ideas how it's supposed to work :?: Shows over, thank you for coming
coxie
New Member
the reason i know it is better to do it and remove them is it reduces the risk of oil in the throttle bodies and therefore reduces the risk of lowering the octane rating of fuel which intern will produce det. how do i know this....because my best mate of years is a mechanic at middlehursts nissan in st helens.he has spoke to several people in the skyline race bay there and all have said just remove them.
8) :twisted:
Dooie Pop Pop
New Member
so which would be better then? to plug the rear left breather and rely on a catch tank only?Coxie said:
how do i know this....because my best mate of years is a mechanic at middlehursts nissan in st helens.he has spoke to several people in the skyline race bay there and all have said just remove them.
or to let it vent to atmosphere for peace of mind?
I've been speaking to a mate of mine who does ZVH re-builds and conversions on the Fords,and he recommends removing the Ford breather system to his customers as on the rollers he has seen gains of upto 24bhp with it removed :shock: (this is in his experience) So make of this what you will The worst ingestion of oil is the one from the right hand pipe that chucks it
upstream of your turbo inlet, think this is the main one to cure first ,ie catch tank, as for the left hand pipe the baffle system and check valve stop oil inlet on mine on boost which is only time I would be concerned have spoken to an
engine builder about this to who builds one or two high power cars he confirmed what I had been saying the only time you need to worry is IF YOUR CHECK VALVE DONT WORK as there is not enough vacuum to pull oil
from an isolated chamber into the inlet on idle, anyway hey ho whatever
upstream of your turbo inlet, think this is the main one to cure first ,ie catch tank, as for the left hand pipe the baffle system and check valve stop oil inlet on mine on boost which is only time I would be concerned have spoken to an
engine builder about this to who builds one or two high power cars he confirmed what I had been saying the only time you need to worry is IF YOUR CHECK VALVE DONT WORK as there is not enough vacuum to pull oil
from an isolated chamber into the inlet on idle, anyway hey ho whatever