Oil Blow Back into my Turbo..........

[Weq]

both of the hoses here have been routed back to the intake arm.. the one from the head and valve cover.. i guess because the manifold having boost at some times rather then vacuum this is why it was done this way

Yes this is exactly right. It means under boost, this valve cannot vent AT ALL. So u plumb it into a negitive pressure which is pre-turbo. This helps! We are lucky with our honda engines, PCV isnt really a big issue. Some engines, ala Nissans will fill your entire intake system with oil in no time. Mainly because they run a little more clearance in the rings..

Once again, this is all normal engine operation.

Ideal setup;

Catch can, everything plumbed from engine to catch can too intake OR exhaust. Use a slash-cut valve in the exhaust to stimulate a low pressure system and pull the air/vapours out of the engine

Acceptable setup, vent everything to atmosphere. Use a filter to be safe. You wont get accelerated contamination of oil by water.. This is false.

Unacceptable setup, One way valve closing this under boost. Not letting the engine vent under boost. This will increase crank case pressure and cause accelerated wear on ur rings, guides and other seals.

[aaronng]

wow.

It is NOT a one way valve. is it a HOLE. Nothing more. Sometimes the engine needs to inhale air, sometimes it needs to expell air. This is a relief port. SIMPLE. It is common practice to plumb 2 or 3 extra ports into the valve cover, with baffles, to improve engine health and breathing.

I was referring to the PCV valve at the block. Not the hole at the rocker cover.

[Weq]

i knew it was a one way valve. and the whole idea of the system is to suck oily vapours out of the crank case.

i can't see how its going to suck vapours out if theres no vacuum applied to the system (which is what the diagrams show in that link that was posted for a turbo setup). essentially its letting the crank case breathe but its not pushing/pulling the vapours into the catch can. the only momentum is from the movement of the crank.

This is assuming that piston rings and valve guides seal 100%. This is totally incorrect. Its a breathing motion. And engine breaths. In and out. Engine breaking will cause inhale, boost or lots of compression strokes will blead air from the cylinders into the crank case. That is a very very very simple explanation of how the engine breaths.

There needs to be some sort of vacuum in the crankcase for the system to work and if the pipe from the manifold is not used then theres no way that the case is going to be vented properly.

I'll have to pull my PCV valve out and have a look at the little guy. I might put an air compressor on the end and pump it up to 10 psi and see if it will hold pressure.

If the check valve for the brake boost can hold pressure then theres no reason why the pcv valve van't hold the same pressure. if the pcv valve doesn't hold pressure then i'll just use a check valve from the brake booster setup in its place and just put a breather on the top of the valve cover. at least that way there will be vacuum in the system at some stage.

[Weq]

I was referring to the PCV valve at the block. Not the hole at the rocker cover.

The OP asked if it was normal that oil was building up in the intake tract. Its not caused by the PVC valve. the PVC emptys directly into the intake manifold. You will notice this when u take the intake manifold off, it will be very oily and gunky. Same with the throttle body and this is why u need to clean these parts more often when shitty oil is used. It breaks down and contaminates everything.

The PVC valve is actually attached to the STOCk oil catch can. This is a little black box located under the intake manifold. The implemetation is a little raw, but it gets the job done ALONG with the breather in the valve cover.

[Limbo]

limbo can you draw up / or have a diagram of how this system works compared to the stock PCV system ? Interesting to compare.

This is the setup i used from http://www.beesandgoats.com/boostfaq/g2icturbo.html#PCV
This setup mimics the stock setup PCV system. The inlet to the PCV system is in the pre-turbo intake pipe. A 90* fitting (a bulkhead fitting would work, or a bent piece of metal tube) with the opening facing towards the filter will allow incoming air to flow into the system. The air then flows into the valve cover, into the crankcase, and then out of the PCV valve port which now has a simple plastic 90* barbed fitting (no PCV valve). From the PCV port the air flows into the side of the catch can and out of the top of the can. Air then flows back to the pre-turbo intake pipe. For the PCV system outlet another 90* fitting is placed with its opening facing the turbo.
This routing sets up a closed circuit system with pressure being exerted on one end and vacuum on the other.



This is another alternative (breather which is illegal but its your choice)
This routing is a little simpler than the one above. The valve cover fitting has a breather filter on it. Air flows through the crankcase and out of the PCV port which now has a plastic 90* barbed fitting in it (no PCV valve). From the PCV port, the air flows into the side of the catch can and out of the top of the can. Air then flows back to the pre-turbo intake pipe. A 90* fitting is not required here because air flowing across the opening of the fitting in the intake pipe will draw air out in the direction of air flow (the same reason water comes out the top of a straw when it is submerged in a glass of water and you blow across the top of it).
This routing is not a closed circuit system with the only drive for the system being provided by vacuum.




The problem when a turbocharger is added is that the intake pipe and intake manifold become pressurized. If the fitting on the valve cover is still connected to the pressurized intake pipe it will pressurize the crankcase too. At the same time, the PCV valve will close when pressure is exerted on the top half of the valve, sealing the crankcase. If no modifications are made to the system a pressurized and sealed crankcase will occur when the boost kicks in, this is the worst possible time to have a sealed and pressurized crankcase.
There are quite a few different opinions on how to plumb the PCV system for a turbo application. As long as the crankcase is not being pressurized by the intake charge pressure and the crankcase has some way to vent pressure you'll be in good shape. Probably the worst thing you can do is to add a valve cover breather filter to the fitting on the valve cover and retain the plumbing for the stock PCV valve. This would force the crankcase to vent through the valve cover breather filter. Many of the popular turbo PCV options include the use of a catch can. The catch can has internal baffling that separates out more oil vapor from the system. This is important because oil vapor effectively lowers the octane rating of the gas you are using, making detonation more likely. The catch can of choice is the Moroso Dry Sump Breather Tank Moroso part# 85470. The catch can needs to have 2 fittings on it. One is provided by way of a port on the side of the can. The other must be added by inserting a grommet into the top of the can (Help! PCV Grommet # 42048 for a Ford Econoline Van), and then a barbed fitting into the grommet. See picture below.


Hope that helps.

[Lukezen27]

Surely I can just add a catch can between the pre-turbo intake and rocker cover?

[aaronng]

Surely I can just add a catch can between the pre-turbo intake and rocker cover?

Of course you can.

[[ricer]]

Surely I can just add a catch can between the pre-turbo intake and rocker cover?

sure can!

[Lukezen27]

Of course you can.

Sweet

Now we have that sorted...

What's the best type/brand for this job?

Thanks Guys

Luke

[Limbo]

any brand is fine. Its just a can to let oil vapours go into

[aaronng]

Sweet

Now we have that sorted...

What's the best type/brand for this job?

Thanks Guys

Luke

Any. Put steel wool into bottom to give the oil vapour a surface to condensate on. I'd spend the money on good tubing and connectors/clamps.

[fatboyz39]

one vote for lipton ice tea bottle. it cheap and does work. lol