Engine plumbing Qs

[blackmav]

I recently bought a GQ Patrol petrol turbo.
Trying to sort a few issues and noticed tonight that the intake manifold is plumbed back into to rocker cover.
Wouldn't this be pressurizing the top of the donk?

[beinthemud]

Blowby
Think of it the other way youll get it

[blackmav]

But the intake manifold is pressurized by the turbo?
A blow by vent would normally be plumbed into the pipe going into the turbo after the air cleaner?

[beinthemud]

But the intake manifold is pressurized by the turbo?
A blow by vent would normally be plumbed into the pipe going into the turbo after the air cleaner?

If its before the turbo then no ,if its after the turbo then farked if i know but boom would of happen or atleast you'd be blowing seal but could be some secret weapon nissan has come up with

[beinthemud]

Does it go hose then turbo or turbo then pipe
Because up to the turbo is sucky sucky after the turbo is blowy blowy

[blackmav]

Have a look at the pic.
The hose is coming out of the intake, therefore blowey blowey

[beinthemud]

You crazy nissan boys coming up with these wackey ideas

[Red Dog 4x4]

Ok looking at the pic and what you have said, then yes it will be pressurizing the motor, it should go from the top of the rocker cover to the turbo intake, but should probly put a catch can in to help stop oil going into the turbo. should just check you have vacunm on the brakes after, even if you disconect the hose and check.

Red Dog

[blackmav]

Hmm.
This car has a miss down low. Related?

[bigcam]

if all fittings are just hose barbs, under boost you will be pressurising the crankcase, this will form a restriction for oil returning to the sump from the turbocharger which will in turn cause it to find its way out of the compressor exhaust seal and into the engine/exhaust making oil smoke..

however....

in the photo the fitting the hose is attached to on the rocker cover looks like a normal nissan PCV (positive crankcase ventilation) valve. essentially a one way valve that allows the inlet manifold to suck blowby gasses out of the rocker cover at all except for boost and 0 vacuum conditions.. if this is the case then the other rocker cover barb should be plumbed in between the air filter and turbocharger intake. (or to atmosphere if you dont care about emmisions.) but this line to the inlet manifold is essentially blocked off under boost so no issue for crankcase being pressurised.

so short story, pull the hose off the fitting on the manifold and pull it out, see if it is a one way valve, if its not then you have issues..

[Red Dog 4x4]

Could be, when dose it start missing and when dose it start making boost? What is happing is it will be making boost into the block so if you change the hose around the bost will probly come on sooner and more boost than now.

Could also be the gaps in the spark pluges gaps so maybe cheack them to.

Red Dog

[blackmav]

so short story, pull the hose off the fitting on the manifold and pull it out, see if it is a one way valve, if its not then you have issues..

Just checked, sneaky little one way valve.
Problem solved, nothing to see here...

[blackmav]

Could be, when dose it start missing and when dose it start making boost? What is happing is it will be making boost into the block so if you change the hose around the bost will probly come on sooner and more boost than now.

Could also be the gaps in the spark pluges gaps so maybe cheack them to.

Red Dog

It misses if you give it a stab off idle, not even a stab but quickish dab.
You can feel it missing through the gears in the lower rev range under load.
What sort of gap should the plugs have?
Petrol only, fuel inj running Autronic copmuter.

[Red Dog 4x4]

There could be some other underlining problem there, but the first thing i would be fixing the plumming first then check the gaps on the plugs then probly a good tune but if it is missing just adove idle could be dirty injectors, possavly.

Red Dog

[beinthemud]

Could be, when dose it start missing and when dose it start making boost? What is happing is it will be making boost into the block so if you change the hose around the bost will probly come on sooner and more boost than now.

Could also be the gaps in the spark pluges gaps so maybe cheack them to.

Red Dog

It misses if you give it a stab off idle, not even a stab but quickish dab.
You can feel it missing through the gears in the lower rev range under load.
What sort of gap should the plugs have?
Petrol only, fuel inj running Autronic copmuter.

Thats Dump get rid of it
Block off the one from the intack then take the stupid one way valve throw that in the bin .Then plumb the line from the rocker cover into a catch can .It could be pressurisng the system and causing it to build up just enough pressure to slow things down but not blow seals