PCV valve needed? (twin cam)

rodney007 · Post by **rodney007** » Tue Oct 04, 2011 6:44 pm

hi, Is the PCV valve necessary?

will hose work or need that special thingy inside

Post by **Alspos** » Tue Oct 11, 2011 7:33 pm

Yes....you will need a PCV valve. Easy to plumb in, will help stop your engine from pressurising and expelling it's oil.

Sargeant_Khan · Post by **Sargeant_Khan** » Tue Oct 11, 2011 9:21 pm

http://www.roadraceengineering.com/inst ... ctions.htm

JAS · Post by **JAS** » Wed Nov 02, 2011 9:57 am

You may need one fitted to get a cert mate. If its an engine transplant you deff need one. I dont have one on my gold car as its just the head thats different and there for not classed as a engine transplant.
But if you are using a EVO or VR4 block you will need a PVC. Also depends on what you tell your cert guy :)

enthuzed · Post by **enthuzed** » Wed Nov 02, 2011 3:20 pm

Why tell them? Besides, the engine number regardless on block will be 4G63****** anyway. It won't alarm anyone unless they really know these cars....

thrash · Post by **thrash** » Wed Nov 02, 2011 8:46 pm

even if they did, what are they gonna do, measure the distance between the bellhousing bolts??

JAS · Post by **JAS** » Thu Nov 03, 2011 7:48 am

Good points guys.
Im sure the guy that cert'ed mine didnt even pull the wheels off it. I had to remind him about the wheel spacers lol

Entaran · Post by **Entaran** » Thu Nov 03, 2011 9:14 am

The twincam evo/vr4 head needs one as it pressurises the oil to over 100psi at idle. Without the valve you will expel a litre or more of oil everytime you drive.

It's your call.

If you don't have it and block it off, crankcase pressure will build up putting unnessecary stress on your head studs and may lead to premature failure of the seal of your HG. Or any other oil seal including the rocker cover seal or cam seals.

And if you think that rocker cover is strong, you have another thing coming.

rodney007 · Post by **rodney007** » Thu Nov 03, 2011 9:26 am

I just connected the pcv pipe down to the port on the intake manifold. then I run the cam cover breather to the catch tank.

OLD FART · Post by **OLD FART** » Thu Nov 03, 2011 1:06 pm

[quote="Entaran"]The twincam evo/vr4 head needs one as it pressurises the oil to over 100psi at idle. Without the valve you will expel a litre or more of oil everytime you drive

wtf 100 psi at idle speed :o :?

Entaran · Post by **Entaran** » Thu Nov 03, 2011 4:28 pm

My recently rebuilt race motor pushes 135psi at cold start, settling to 80psi after 2 minutes, then down to about 24psi at warm idle.

This is why you have breather valves. That's a SHITLOAD of oil pressure.

Have you never acutally hooked up an accurate gauge to a vr4 oilpump? ;)

fugazi · Post by **fugazi** » Thu Nov 03, 2011 5:12 pm

135psi is normal depending on what oil you use...
24psi on a warmed up motor is good, no problem at idle but it should be more like 100psi @7k rpm...

The PCV is for evacuating crankcase-gases, and burn them, at idle/low rpm/mani-vacuum... when manifold pressure gets higher than the valvespring can hold, it closes and the gases goes the other way to the catchcan and filter/turbo primary side.

You don't need the PCV, tecnicaly. But probably for regulations and invarometal shit...

You NEED some type of breather for the crank-case/camcover.

enthuzed · Post by **enthuzed** » Sat Nov 05, 2011 8:18 pm

Entaran wrote:My recently rebuilt race motor pushes 135psi at cold start, settling to 80psi after 2 minutes, then down to about 24psi at warm idle.

This is why you have breather valves. That's a SHITLOAD of oil pressure.

Have you never acutally hooked up an accurate gauge to a vr4 oilpump? ;)

Good rebuilt stock JB starion motor is about 80psi dead cold idle, about 20psi at idle when fully warm, hits the tonne at about 6000 revs.

enthuzed · Post by **enthuzed** » Sat Nov 05, 2011 8:19 pm

Should also mention those figures are with the balance shafts too.

Austarion

PCV valve needed? (twin cam)

PCV valve needed? (twin cam)

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