removing pcv preather
- Thread starter Gaz gtiR
- Start date
Do you mean the pipework; there isn't actually a breather on it as standard?
The easiest thing is just to buy one of Steve's kits with a plug to replace the PCV and caps to go over all the ports on the manifold; that way all you need to do it pull the pipes off and put the kit on. - This might not be the best picture, but it's the only one I've got to hand. Note the bung in place of the PCV and black caps on all the ports:
If you want to keep the PCV and route the pipework elsewhere, that's a different matter. - There is some logic in keeping it as a way to draw crank case emissions into the cylinders rather than out the other way through the inlet pipework.
The easiest thing is just to buy one of Steve's kits with a plug to replace the PCV and caps to go over all the ports on the manifold; that way all you need to do it pull the pipes off and put the kit on. - This might not be the best picture, but it's the only one I've got to hand. Note the bung in place of the PCV and black caps on all the ports:
If you want to keep the PCV and route the pipework elsewhere, that's a different matter. - There is some logic in keeping it as a way to draw crank case emissions into the cylinders rather than out the other way through the inlet pipework.
which is the best way?? as ive still got all my breather pipes coming off my rocker cover. i want to get rid of them like you have in the pic!
I just basicly need to know hat im removing & & what i need to reconect if i need to? as i dont wnt to be causing problems by doing it wrong!
In retrospect, I'd be tempted to put a catch can between the PCV and the inlet manifold; that way it can draw vapour though and catch any oil blow-by. - As I understand it, it's designed to go that way; fresh air from the induction pipework pulled through to replace any vapour from the crank case... but that also means it can happily splurt it back out into the induction pipework too.
The big black box on the front of the engine is actually an oil/mist seperator. What's meant to happen is that any oil mist condenses-out and drains back to the sump, and any vapour gets drawn-through to be burnt-off.
The PCV its self will stop functioning correctly over time. You can just replace it, but many people find that binning it helps with their various idle problems... and lets face it; the crank vapour doesn't burn nearly as well as a good air/fuel mixture. I've left that bit as is; it might mean that I get a bit more oil in the pipework, but I figure that will give the turbo a bit of additional lubrication and if I see blue smoke I'll know there's a problem.
If the caps aren't available, you can always just loop a length of hose from one port to the next; usually people just use two lengths and connect the two at each end together.
The big black box on the front of the engine is actually an oil/mist seperator. What's meant to happen is that any oil mist condenses-out and drains back to the sump, and any vapour gets drawn-through to be burnt-off.
The PCV its self will stop functioning correctly over time. You can just replace it, but many people find that binning it helps with their various idle problems... and lets face it; the crank vapour doesn't burn nearly as well as a good air/fuel mixture. I've left that bit as is; it might mean that I get a bit more oil in the pipework, but I figure that will give the turbo a bit of additional lubrication and if I see blue smoke I'll know there's a problem.
If the caps aren't available, you can always just loop a length of hose from one port to the next; usually people just use two lengths and connect the two at each end together.
Rite ive just been looking in to this abit more!
am i ok running this set up as follows:
1. get rid of all breather pipes on inlet & loop 1 & 2 - 3 & 4 with vacuem hose like pobody says!
2. leave PCV valve in the rockor cover & run a pipe to a catch tank. or do i get rid of PCV valve & get an open fitting so it eliminates the valve to run the pipe off?
am i ok running this set up as follows:
1. get rid of all breather pipes on inlet & loop 1 & 2 - 3 & 4 with vacuem hose like pobody says!
2. leave PCV valve in the rockor cover & run a pipe to a catch tank. or do i get rid of PCV valve & get an open fitting so it eliminates the valve to run the pipe off?
i can see the logic in using a catch can but blocking the pcv just seems odd. there are 2 exits from the rocker cover so i spose the pressure could still sort it's self out via the hole on the dizzy end of the head. is that the general thinking?
i do see the benefit of not having the intakes pulling the oil vapour in but i think i'd want it to go to a catch can. the main reasons that nissan plumbed it back into the intake system must be so the car is less effort to use day to day with not having to empty the catch can all the time. no chance of fluid leaking on the road if the engine is burning everything that comes out.
but the engine still needs to vent pressure, so is that left to the sump breather/seperator and the right hand rocker vent?
i'm sure that another reason that it's all plumbed back into the intakes is to suck the vapour out rather than just letting it float about in there? much of the extra pressure has to be blowby gasses and these could shorten the life of the oil if they are not vented enough.
or is this all smoke and mirrors and blocking the pcv up is fine and leaving just the right (of rocker cover) and sump open is more than enough for our engine?
i do see the benefit of not having the intakes pulling the oil vapour in but i think i'd want it to go to a catch can. the main reasons that nissan plumbed it back into the intake system must be so the car is less effort to use day to day with not having to empty the catch can all the time. no chance of fluid leaking on the road if the engine is burning everything that comes out.
but the engine still needs to vent pressure, so is that left to the sump breather/seperator and the right hand rocker vent?
i'm sure that another reason that it's all plumbed back into the intakes is to suck the vapour out rather than just letting it float about in there? much of the extra pressure has to be blowby gasses and these could shorten the life of the oil if they are not vented enough.
or is this all smoke and mirrors and blocking the pcv up is fine and leaving just the right (of rocker cover) and sump open is more than enough for our engine?
Really it's just about emissions. - If you suck the crank case emissions in to the intake manifold and burn them off you can meet the regulations. If you just have a catch can that vents to atmosphere you probably can't.
As long as one of the ventilation ports on the rocker cover still goes somewhere any vapour (and oil mist) is getting out. - I don't use a catch can for the same reason; I'd prefer to just drain the oil back into the sump than to collect it. However, if you collect it you get an early warning that there's something amiss when lots of oil comes out.
As long as one of the ventilation ports on the rocker cover still goes somewhere any vapour (and oil mist) is getting out. - I don't use a catch can for the same reason; I'd prefer to just drain the oil back into the sump than to collect it. However, if you collect it you get an early warning that there's something amiss when lots of oil comes out.
There are augments for and against keeping the positive crankcase ventilation valve (PCV valve), it's not "just" about emissions. In part removing the PCV Valve was a simple solution to help remove any possible vacuum leaks in the breather system due to cracked or poorly fitting PCV pipe work or a faulty, worn or clogged up PCV valve. Amongst other things vacuum leaks can be related to the high idle speed problems often found in the GTiR’s SR20, thus removing this possible cause of a leak would often result in stabilising or correcting this problem.
Another part of the augment is weather vacuum actually needs to be applied to the crankcase to relive pressure, numerous older engines were designed just to vent to atmosphere and that system worked very well. The powers that be decided that all these emissions venting to atmosphere was not a good thing, so the PCV valve system was designed as a way of lowering emissions. The PCV valve system is not the only way to apply vacuum to the crank case, as George says, you could have a pipe and catch tank system running from the T junction at the rear of the engine to the inlet pipe of your compressor.
Oh and before anyone ask's, I'm not making the stainless PCV valve bungs anymore as I don't have the time or materials to make them at the moment.
Another part of the augment is weather vacuum actually needs to be applied to the crankcase to relive pressure, numerous older engines were designed just to vent to atmosphere and that system worked very well. The powers that be decided that all these emissions venting to atmosphere was not a good thing, so the PCV valve system was designed as a way of lowering emissions. The PCV valve system is not the only way to apply vacuum to the crank case, as George says, you could have a pipe and catch tank system running from the T junction at the rear of the engine to the inlet pipe of your compressor.
Oh and before anyone ask's, I'm not making the stainless PCV valve bungs anymore as I don't have the time or materials to make them at the moment.
ok cool, i think i understand a bit better now, thanks!
i think i'll dump the pcv funtion by just plugging the hose that goes from it, and put some bungs on the inlets. stick a catch can on the t connection and have the intake still sucking any gasses.
is it possible to plumb a catch can back into the sump breather on the front next to the turbo? or is this too high pressure to allow oil to flow back to the sump?
i think i'll dump the pcv funtion by just plugging the hose that goes from it, and put some bungs on the inlets. stick a catch can on the t connection and have the intake still sucking any gasses.
is it possible to plumb a catch can back into the sump breather on the front next to the turbo? or is this too high pressure to allow oil to flow back to the sump?
That's where most people put it; there's no pressure in it really so you can just put a breather filter on the can.
If you don't care about bling, there's no requirement to buy a fancy fabricated can; and old biscuit tin (or beer can) with the hoses stuck in it will do the job.
If you don't care about bling, there's no requirement to buy a fancy fabricated can; and old biscuit tin (or beer can) with the hoses stuck in it will do the job.
rite ive just done this today.
ive bunged the back of the rocker cover off.
looped the inlet 1&2 -3&4 with vacuem hose.
still got original oil seporator fitted above turbo.
put the breather hose from T peice on the right of the rocker to a catch can (old oil bottle for now)
is this right??
ive bunged the back of the rocker cover off.
looped the inlet 1&2 -3&4 with vacuem hose.
still got original oil seporator fitted above turbo.
put the breather hose from T peice on the right of the rocker to a catch can (old oil bottle for now)
is this right??