PCV Upgrade for Turbocharged 420As

[VelocitàPaola]

Actually, I've been thinking about the PCV system a lot recently. How do you suggest beefing it up to handle more boost... a 4G63 valve?

 

[1stGenRocks]

Actually, I've been thinking about the PCV system a lot recently. How do you suggest beefing it up to handle more boost... a 4G63 valve?

the 4g63 valves give us issues all the time. seems like the best bet is to just run 2 open breathers or to use a secondary check valve from mcmaster carr inline from the manifold to valve cover.

 

[Talon ESI-T]

the 4G63 guys have issues witht he PCV often? Duplicating that design would have been my first choice. I have a few designs for a catch can that actually fits the design of our engine bays. A check valve would be nessasary and one breather as well to duplicate the vent on the VC that is vented to the intake pipe. Now i have tested the design on the bench and a 2GNT PCV will seal properly in boosted situations so its hard to say we need a different check valve. I have yet to install the setup and test it on my car. Since i have no issues now I am not sure i am going to see any improvement.

Paul, can you split this off since we are on a good topic but deffinitly off the original topic.

Terry

 

[Blitzeclips]

I like all the info. here. I'm still learning about the PVC system and this is definately helpful. Keep it up guys..

Paul, could I request a diagram in reference to the above assembly?

 

[VelocitàPaola]

A diagram of the PCV system?

This is basically how the PCV system is set up, sans the breather hose/filter.

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In the stock system, under vacuum conditions, the PCV valve (a basic one-way check valve) is open... engine vacuum draws fresh air through the breather hose (from the intake) into the crank case, and sucks out blowby (nasty oil/gas mixture that gets by the piston rings) through the PCV hose and valve. The blowby gets pulled into the intake manifold to be burned in the next combustion event. Evidently this reduces emissions significantly...

I've seen some pretty intense discussions about this subject. In the older cars, PCV systems were primitive... they consisted of a simple tube to vent blowby the the atmosphere. Ok... screw the environment, but is that really the best solution for the engine? Maybe not, since the scavenging effect of engine vacuum helps to more efficiently pull blowby out of the crankcase.

The only rational solution I see is to either do an exhaust setup, or something like Terry was talking about, with a catch can connected to some source of vacuum.

 

[VelocitàPaola]

Now i have tested the design on the bench and a 2GNT PCV will seal properly in boosted situations so its hard to say we need a different check valve. I have yet to install the setup and test it on my car. Since i have no issues now I am not sure i am going to see any improvement.

Really? I hooked my PCV valve up to a bicycle pump and it let air through. I even tried blowing through it with my mouth, and it still let air through. Maybe it's just my valve?

Paul, can you split this off since we are on a good topic but deffinitly off the original topic.Terry

Quite true...

 

[FORMONTOYA]

Why don't I link you to a thread I started for the 4G63 guys. It's come a long way from the initial idea.

http://dsmtuners.com/forums/showthread.php?t=229338

 

[Jeff99GS]

Really? I hooked my PCV valve up to a bicycle pump and it let air through. I even tried blowing through it with my mouth, and it still let air through. Maybe it's just my valve?



Quite true...

Mine was doing that too, If the little stopper inside the PCV valve isn't perfectly centered it seems to leak a little. So I set my Air Compressor to 8psi and hooked my pcv to the air line and blasted it with 8 psi....it sealed up great! I think at the lower psi it doesn't seal as well as at 8-10 psi. Those Plastic Valve's aren't exactly precisely machined, so I think it takes a little more pressure to seal properly.

 

[Jeff99GS]

what about using something like this...

BRASS SWING CHECK VALVES

Brass swing check valves are normally installed in a horizontal position and are not spring loaded. Brass body valves with female pipe thread connection are rated at 125 psi. The brass swing disc seats directly against a ground seat in the brass valve body.
1" Brass Swing Check Valve #10BSCV $ 11.25
1-1/4" Brass Swing Check Valve #12BSCV $ 17.00
1-1/2" Brass Swing Check Valve #15BSCV $ 23.35
2" Brass Swing Check Valve #20BSCV $ 34.50

Water Well Accessories


1/2 Swing Check Valve


Product Description
Swing Check Valves Brass Threaded Size Ins.=1/2
150 PSI non-shock WOG. Threaded end

 

[FORMONTOYA]

Mine was doing that too, If the little stopper inside the PCV valve isn't perfectly centered it seems to leak a little. So the I set my Air Compressor to 8psi and hooked my pcv to the air line and it sealed up great! I think at the lower psi it doesn't seal as well as at 8-10 psi. Those Plastic Valve's aren't exactly precisely machined, so I think it takes a little more pressure to seal properly.

It sounds perfect, however, the problem we face on our side is that with the boost-vacuum-boost (of course we're hitting 15-18PSI+) that goes with shifting at WOT is that the plug seat will get buggered up and start to leak fairly quick. I know mine usually doesn't last 1K miles. That's why I started the above linked thread.

 

[FORMONTOYA]

what about using something like this...

BRASS SWING CHECK VALVES

Brass swing check valves are normally installed in a horizontal position and are not spring loaded. Brass body valves with female pipe thread connection are rated at 125 psi. The brass swing disc seats directly against a ground seat in the brass valve body.
1" Brass Swing Check Valve #10BSCV $ 11.25
1-1/4" Brass Swing Check Valve #12BSCV $ 17.00
1-1/2" Brass Swing Check Valve #15BSCV $ 23.35
2" Brass Swing Check Valve #20BSCV $ 34.50

Water Well Accessories


1/2 Swing Check Valve


Product Description
Swing Check Valves Brass Threaded Size Ins.=1/2
150 PSI non-shock WOG. Threaded end

You're on the right track. Look at this link and at the end we have found check valves for less than $10.

http://dsmtuners.com/forums/showthread.php?t=229338

 

[Blitzeclips]

So it's basically the opposite of a crank breather.. well, for the most part..

I still fail to see a reason of revision...

 

[VelocitàPaola]

Because, the check valve rarely operates as expected under boost... especially under high boost, the valve can fail, causing a vacuum leak. Ever wonder why the 4G63 guys have their oil dipsticks shoot out of the tube? Bad PCV valves under high boost.

I have a few ideas on the subject... I'll make a few sketches and post them.

 

[Blitzeclips]

I found this.

http://www.turbophile.com/technical/diy_catch_can.html

Seems pretty informative. Or am I reffering to the wrong assembly?

 

[VelocitàPaola]

I have several problems with that design... Mainly that it incorporates a breather filter, so that you don't retain the advantages of vacuum scavenging at all. Also, he recommends simply plumbing the outlet to the sump - well, blowby isn't just oil, and I wouldn't want it mixing with my $20 worth of fresh oil.

 

[Blitzeclips]

Well post some of your sketches! Designs too! I need another project sometime soon. Atleast before we install our megasquirts, that way it's one less problem to worry about..

 

[VelocitàPaola]

Ok... here's my idea of the perfect solution. It seems to solve all the problems associated with stock PCVs, catchcans, and aftermarket check valves. It's basically a two piece, cast or welded catchcan.

So, blowby comes in through the tube on the left. A baffle in the center of the canister stops any liquids from getting flung into the outlet. On the other side, we have a one way check valve pressed into the upper piece of the can. The check valve is a ball/spring style, seated in oil resistant Vitron for an air tight seal. Under vacuum, however, it opens, allowing air to flow, and blowby to be sucked into the catchcan.

There is a drain plug on the bottom so you can periodically empty the catchcan. The thing is designed in two pieces, so you can take it apart for cleaning or parts replacement. Also, above the check valve, there is a simple valve to control how much air is being sucked through the device. I added this because apparently, aftermarket check valves flow too much, and can cause some problems as far as idle air speed, and unmetered air entering the combustion chamber (in 4G63s).

The main thing I like about this, is that it keeps the PCV system closed. That is, there is NO breather filter on this, so we still benefit from the scavenging effects of vacuum. Obviously, not everyone will be able to cast or weld their own, but if you're creative, you should be able to make something comparable using simple plumbing fittings.

 

[Focker420]

Was checking around and i like the concept idea of the sketch above, But i found this searching around the howell site.

"When using Total Seal Rings be sure to disable the PVC system. The Total Seal Rings reduce blow so much, that the PVC system can begin to scavenge oil from the crankcase and cause oil consumption. Disable your PVC system."

This is the link http://www.howellautomotive.com/index.asp?PageAction=VIEWPROD&ProdID=192

Tell me what you think if you could just cap off the pcv entirely and just minamize the amount of blow by.

Hope it wouldn't blow your seals out....

 

[VelocitàPaola]

Sure... disable your PCV system if you've got Total Seal Gapless Rings - but only if you've got Gapless rings. Total Seal also makes other rings that aren't gapless, so the PCV system is still something you'd want to have. Plus, if you're using any other type of ring set, keep the PCV system.

 

[4UH8ERS]

The main thing I like about this, is that it keeps the PCV system closed. That is, there is NO breather filter on this, so we still benefit from the scavenging effects of vacuum. Obviously, not everyone will be able to cast or weld their own, but if you're creative, you should be able to make something comparable using simple plumbing fittings.

Well Paul, simply sell some on you website =). I have a gapless ring so i wouldn't use it, but I was just thinking if you could make a few until you figure the best way to make it. (time and cost effectiveness/quality of course) I'm sure you could sell a lot to the 420a and 4g63 community.

Anyway we love your ideas and reasoning behind them, keep it coming.

 

[Focker420]

Just an idea but what if you just incorporated a second pcv valve and routed the 2nd pcv valve to the intake manifold, Im assuming that it would decreace the amount of pvc pressure, especially when under boost, and less blow by from the lower pressure in the valve cover.

The only thing that complacates the set up is i think there would be an increase in the air coming to the manifold at idle and might cause it to run rich, but if i am running the MSnS then i should be able to adjust the enrichments.

Is this right and would it work?

 

[VelocitàPaola]

Nope, the pressure would be equal all around. For now, your best bet is upgrading to a better valve, and maybe using a sealed catchcan.

 

[Focker420]

Ya the pressure would be equal but wouldn't it still be less than if u had only 1 pcv?