Stupid PCV question

[FORMONTOYA]

I've gone through 2 OEM PCV (read boost leak) valves in 1500 miles since the car came off jack stands December 05. I'm tired of buying and replacing them even though they are not that expensive. I was going to pull the nipple out of the intake and put a 1/8 BSPT plug in that location and use the nipple from the intake and replace the PCV valve, however, the nipple is a press-in fit so that's out of the question. I just capped off the nipple and used the PCV valve as my nipple to "T" into the vent line going to the intake before a G-2 gas filter (catch can).

My question is why do I have to hog out the PCV valve internals? There shouldn't be a differential pressure type of thing going on, therefore the PCV valve should remain open, shouldn't it?

Below is a half-a$$ drawing of what I propose and if someone can give me a legitimate reason why it should be hogged out, I'll just order a nipple for it.

[DSM4me44]

You can buy just a nipple that will screw right into the place where your pcv valve does.

[No_Skillz]

The setup that you have drawn is basically the same as a PCV removal and no crankcase circulation. With so many reputation bars, I trust you know the consequences of that setup so I won't get too much into it.

With that said, hogging (nice word) out the PCV will not make too much of a difference, other than the fact that if you build crankcase pressure, there is an extra outlet for the pressure.

Again, I trust you know that a closed filter system be used, since I didn't see an aftermarket MAF in your mod list.

[FORMONTOYA]

Originally Posted by No_Skillz

The setup that you have drawn is basically the same as a PCV removal and no crankcase circulation. With so many reputation bars, I trust you know the consequences of that setup so I won't get too much into it.

With that said, hogging (nice word) out the PCV will not make too much of a difference, other than the fact that if you build crankcase pressure, there is an extra outlet for the pressure.

Again, I trust you know that a closed filter system be used, since I didn't see an aftermarket MAF in your mod list.

Yea, I know how it works . Sometimes people have ideas they know WON'T work but throw the idea out there hoping some other dumba$$ will agree with them so they can fu@% things up with confidence. I'm just a little pissed that even an OEM PCV valve can't hold a measly 20psi repetitively and reliably for 1000 miles.

I tried the setup as drawn above and at idle had the slightest of stumbles afterward. Of course under boost it works great, but cruising around it occasionally had a pop between gears. I guess I just needed to vent about the one thing on this car that's pissing me off. I will be looking at McMaster-Carr and other similar places to find a check valve that will do the job and not cost $100.

The one good thing that came from all this is that I found the reason (small leak at oil cap) behind me having to raise my 50Hz slider in DSMLink. However, I do have the best mod for any car, which is a second car until I can gather a few parts to get this done right.

Thanks for NOT telling me to "go for it" and reminding me to use my brain.

[FORMONTOYA]

I've found a list of items from McMaster-Carr needed to get rid of the crappy PCV valve if anyone's interested. It's a soft seal check valve. Max pressure rating of 1000psi, Viton seals, with a cracking pressure of .3psi, good for temps from -20 to +400 degrees F. Also a list of a few fittings needed to put it in the system.


Line Quantity Part Number Description Unit Price Total Price Ships
1 1 Each 7775K63 Brass Spring-Loaded Piston Check Valve 3/8" Nptf Dryseal Male Connections, Viton Seat $19.44 $19.44 today

2 2 Each 44555K134 Brass Double-Barbed Tube Fitting Barbed X NPT Male for 3/8" Tube Id, 3/8" NPT $3.14 $6.28 today

3 1 Each 4860K141 Brass Threaded Pipe Fitting BSPT Male X NPT Female, 1/8" Adapter, 1" Length $3.91 $3.91 today

4 1 Each 44555K149 Brass Double-Barbed Tube Fitting 90 Deg Elbow Barb X Male for 1/4" Tube, 1/8" NPT $1.95 $1.95 today

5 1 Each 44555K118 Brass Double-Barbed Tube Fitting Reducing Coupling for Tube Id 3/8" X 1/4" $1.67 $1.67 today


Merchandise $33.25
Shipping $4.50
Your credit card will be charged $37.75


So, for $40 I should have a well built CCV system on the car that is effectively set up in the stock configuration for maximum pressure ventilation which should last longer than the lousy 7-800 miles that I've gotten out of the previous 2 OEM PCV valves.



Seal material in check valve:

DuPont Dow Viton®
-30°C to 240°C Viton® oil seals feature excellent resistance to petroleum products and solvents. They have good high temperature and low compression set characteristics. They are suited for use with wide chemical exposure situations and for hard vacuum service. petroleum oils, gasoline, transmission fluid

[FORMONTOYA]

I looked at my invoice and noticed I screwed up on line item 2, the tube fittings should have been a female NPT connection instead of the male NPT I ordered. Damn, have to get them local.

[kenamond]

Revive this post when you get it together and working and then again when it lasts 5k miles . I was thinking of doing this sort of thing (non-OEM valve), but didn't do the legwork to track down an adequate valve, so thanks! If it lasts and works great, a tech article would be nice.

[FORMONTOYA]

Originally Posted by kenamond

Revive this post when you get it together and working and then again when it lasts 5k miles . I was thinking of doing this sort of thing (non-OEM valve), but didn't do the legwork to track down an adequate valve, so thanks! If it lasts and works great, a tech article would be nice.

Yea, I planned on something along those lines.

I ordered the parts this morning, so they should arrive hopefully this weekend. I just can't justify $100 for the "other" check valve plus buying the fittings required for installation if I can find a different, less expensive, workable solution. Although it would probably be over a year for me to put 5K miles on the car as it's been on the ground rolling since Dec. 05 and I have less than 1500 miles on it to date since then.

[No_Skillz]

Awesome how this turned from a no brainer question to something that will interest all people frustrated in the PCV (myself included). I'm not familiar Mcmaster-Carr check valves, so I can't wait to see the write up. Keep us posted.

[oldman]

Jim, got pics?

[FORMONTOYA]

I have a scheduled delivery date of 6-7 (Thursday, UPS). McMaster-Carr is out of Atlanta, Ga and I have ordered several items from them and they have always shipped that day if ordered before 2:00pm, the next day if after 2:00pm. I have no doubts I will be installing the setup this weekend and of course I will take pictures along the way and also give a complete parts list and steps required to get the job done. Y'all can expect a write up of sorts Monday (6-12).


edit: added web site: http://www.mcmaster.com/

They are like a super Lowes/Home Depot, they have just about anything you might need for just about any project you might do around the house and then some.

[FORMONTOYA]

I started the install this morning and NOT to my surprise...I needed to get a few things as the initial idea wasn't going together as first anticipated. However, I managed to get everything needed to put this checkvalve into the system.

I installed the system in place of the PCV valve, and thought if I put a G2 filter in line it might help keep the checkvalve and intake manifold cleaner, plus I can see what's going on better.

Setup complete as shown.
The left filter is for the checkvalve side, the right filter goes to the intake snorkel.



After installation I did a quick boost leak test, everything held as I expected it to. Everything appeared to be "good-to-go" so I fired the car up. Immediately I noticed a hissing sound and also my idle RPM was at 1000 when before this install it would idle at ~750rpm. Also I had an idle vacuum reading of 22inHg when normally it's between 18-20inHg, never has it gone higher unless I'm decelerating.

I investigated the source of the hissing sound and concluded it was actually the checkvalve due to air rushing past the seat. One thing that happened is after a couple of minutes I noticed that the G2 filter attached to the checkvalve was starting to collapse to the point it was actually crushing the filter element (left filter), but the hose was holding up fine. And I could actually see oil being "sucked out" of the valve cover. It was also starting to collapse the second filter (right side) but just not as bad.



The car actually ran for about 3-4 minutes before I shut it off. One thing I can say for sure is that this setup definitely evacuated the fumes and then some from the valve cover. During the short amount of time the car sat idling it managed to suck enough oil in the checkvalve filter to saturate about 40% plus of the filter element, and had about a coke caps worth of oil sitting in the bottom.

As an example, I normally run a G2 filter on the vent side going to the intake snorkel and change it every 3 months (~500 miles) and I can barely notice any saturation on the filter element and there is not enough oil settled in it to cover the bottom of a coke cap.

I haven't yet figured out if the new checkvalve just flows to much air or what the deal is. I will have to take an old PCV valve off my shelf and take it to work and see if I can get a flow rating on it.

I've cleaned up a PCV valve so it holds pressure and have it setup in the OEM configuration until I can figure out an alternative. As soon as I was done I fired up the car again and everything was back to normal...ideling at ~750rpm and no hissing with vacuum reading back to the norm of 18-20 inHg.

Maybe I'll go to a smaller checkvalve. I don't know yet.


Back to the drawing board!

[No_Skillz]

The checkvalve is a good idea if you can get it to work, but I don't think the G2 filter is worth the trouble. There is alot of crap that is pulled out of the PCV during idle and it's easiest, and not overly harmful, to just let it go into the intake mani and have the engine burn it away. Otherwise I think you'd have to change that G2 filter every 5 miles or so.

[FORMONTOYA]

I agree about the filter on the checkvalve side probably not being worth the trouble. I just found it strange that the filter on the vent side going to the intake snorkel started to collapse also. I've run one on that side for quite some time without anything like that happening before.

I have been thinking about the amount of oil and saturation of the filter element in the checkvalve side filter and wonder if it might be a design error on my part. If you look at an OEM PCV valve it has a small nipple that sticks out past the threaded portion which protrudes past the inside wall of the valve cover into its "atmosphere" and just sucks up fumes. Whereas my initial configuration has an adapter that screws into the valve cover with no protruding nipple and possibly acts as a vacuum cleaner of sorts sucking up all the oil that's splashed on the inside wall near that area.

Who knows? Maybe the OEM PCV valve has the right amount of restriction and depth in it to correct my initial problems.

Anyway Monday I'll take a PCV valve and see if I can get a reasonably close flow rate out of it to try and find a more suitable checkvalve.

[underradar92]

As for the tube inside the valve cover, you could try to replicate the oem tube then maybe silver solder it in. Once you have an accurate flow number, just plug one of the fittings going to the intake & drill it to match that spec, like a carb jet. I take it you know someone with a flow bench?

[steve]

Originally Posted by FORMONTOYA

I haven't yet figured out if the new checkvalve just flows to much air or what the deal is. I will have to take an old PCV valve off my shelf and take it to work and see if I can get a flow rating on it.

I've cleaned up a PCV valve so it holds pressure and have it setup in the OEM configuration until I can figure out an alternative. As soon as I was done I fired up the car again and everything was back to normal...ideling at ~750rpm and no hissing with vacuum reading back to the norm of 18-20 inHg.

Maybe I'll go to a smaller checkvalve. I don't know yet.


Back to the drawing board.

What you forgot in your plan is that the fuel system is actually set up to account for the air pulled past the PCV, both because the air going in the breather is metered at the MAF as well as the flow rate is controlled by the valve. As you have discovered is you have created a new air bypass just as if you had pulled the BISS screw out.

For grins you could use the PCV and the check valve to solve the big problem of the average valve not keeping boost out of the valve cover.

Your correct that the tube on the threaded end is to keep from sucking oil rather than vapor. You have also discovered that the fuel filters don't flow air very well once the filter paper is full of oil. I found that to happen pretty quickly even when they are on the breather side of the VC. They flow ok when dry but create a restriction to getting fresh air into the VC when they are wet.

Steve

[justin0469]

I don't know, maybe this would be able to aid in your project? The crank vents at the top.

http://all.dejonpowerhouse.com/edit/A-04.htm

[oldman]

Originally Posted by justin0469

I don't know, maybe this would be able to aid in your project? The crank vents at the top.

http://all.dejonpowerhouse.com/edit/A-04.htm

The problem with the setup is that there are no source of fresh air to replace what is being sucked out, the system will certainly relief pressure but will not ventilate fuel mixture which will end up in your oil. Also, high crankcase vacuum will increase oil consumption.