My idea for the ultimate crankcase evac system.....

[ShadowFromHell]

Ive always has issues with PCV systems over the years and have ton a lot of reading on the right way to do it. The info I find always seems to contradict itself. One thing that has always intrigued me is using a exhaust evac kit to get a constant source of vacuum. A electric pump would work too, but I like to keep things simple. In doing the research on using a exhaust evac kit it seemed a lot of 4 banger guys ended up with a setup that pulled to much vacuum and that created a whole new set of problems. So I kind of shelved that idea. I recently bought a turbo neon and want to get a proper system on it. Right now it is running the NA PCV system on one port, and the other port ran to a catch can. It works, but the exhaust evac idea has popped back into my head.

This is what I came up with after a few days of thinking on it. The guys that used a exhaust evac system correctly on a 4cyl always seemed to end up with too much vacuum usually ended up removing the system or added a "bleed" to reduce it. Problem with a bleed is it isn't constant, the amount of vacuum changes with RPM do to the bleed never changing in size. So I started looking for a vacuum regulator and I found some but didn't like the price. Thats when I came up with the DIY regulator in the picture below. It basically works like a ball spring MBC which was my inspiration for this. When the vacuum gets high enough to overcome the spring pressure it opens up and lets air into the system to reduce the amount of vacuum. The bolt alows the pressure on the spring to be adjusted, just like a MBC.

http://i291.photobucket.com/albums/ll308/TurboshadowWA/Vacreg_zpsa6af29fd.jpg

So combining this with a exhaust evac system and a catch can I think is the best way. This should give me the same crankcase vacuum on the freeway as WOT. Ive read a few articles on this and it has been proven putting the crankcase under vacuum will increase HP. Probably not a lot for us, but gains still. Since it is making the engine more efficient it should also increase MPGs. Maybe not alot, but it should. Although it might not even enough to notice. The diagram below shows how I would plumb it in on a 8v, since this is a 8v forum.

http://i291.photobucket.com/albums/ll308/TurboshadowWA/Uevac_zps7a2432d4.jpg

So what do you think? The entire thing is mechanical and once the magic number for vacuum was found it should be able to be left alone. I see this as a great solution to a well argued over problem. No oil in the intake like a normal PCV setup, no blown PCV valves making the car run like crap (been there with my CSX) and it might even raise the HP and MPGs. The best part is I think a guy could build this from scratch for $30-$50. Thats pretty cheap compared to a electric pump, and even the good supra PCV valves are like $12 and they don't do anything for evacuation under boost.

[johnl]

Good thinking. See this link, spendy though -

http://www.summitracing.com/parts/mor-22636/overview/

Your solution is better since it doesn't introduce dirty air to the crankcase, or, at least, the need to filter the air that would be sucked into the valve cover through the relief valve. Although, one could put the summit valve in the same spot, after the catch can, as you do.

[A.J.]

I had a problem with too much vacuum being pulled on my crankcase causing a squeal noise from air being pulled pass the seals. I added a grainger valve to my catch can to regulate the vacuum to 5" HG. I have it routed to the air box so it doesn't pull in dirty air.

[shackwrrr]

Why run a catch can? Anything that ends up in the evac should be vaporized in the exhaust. I've never had any problems with it smoking or fogging. I know my exhaust evac setup was able to keep up with my TIII with broken top rings at 18 psi.

[ShadowFromHell]

The catch can is more of a "just in case". My motor was rebuilt by a previous owner and for the amount of oil I am getting out of the vent I am actually thinking that they may have left out the oil restrictor for the head when it was gone through. Im glad to hear a similar system has worked good for you AJ, but I really dont see a reason to add a filter, even though it would be really easy to add a cheap fuel filter below the vac regulator. Since the regulator is after the catch can, anything it pulls in should be sucked into the exhaust if I am envisioning it right. I like the idea of using a grainger valve. Jusr simpler and they are cheap. No drilling and tapping or anything that way. Do you have any picks of your setup? While I can find the parts to build something like this I am really surprised no one makes a kit to do this. Its so simple and I just do not see any downsides.

[johnl]

The pressure relief valve sold at the above Summit link is supposed to go on the valve cover and it just sucks in air to relieve excess crankcase vacuum that the pump/exhaust unit might create, so . . . .that ought to have some kind of filter on it.

With the exhaust type, if you are running a cat, then the Bernouli/cut pipe should be downstream of the cat to prevent any oil from fouling it/cutting its lifespan.

[turbovanman²]

Why run a catch can? Anything that ends up in the evac should be vaporized in the exhaust. I've never had any problems with it smoking or fogging. I know my exhaust evac setup was able to keep up with my TIII with broken top rings at 18 psi.

How's yours setup?

[shackwrrr]

How's yours setup?

On the spirit it was run directly from the nipple on the front of the block to the check valve at the exhaust evac.

[R/T]

Mmmmkay;

Sportbikes that rev to 16,000 RPM don't use a PCV system, just a vent hose from valve cover to the airbox.

So why do our cars need them??

[zin]

Lots of reasons, but the one that pops to mind 1st is that we're turbo'd, and anything other than air that you put through a turbo generally isn't good for it!

Other reasons: removes moisture and air from your oil, and therefore reduces sludge build up and improves oiling, pulls contaminates from the crankcase before they diffuse into the oil, extending it's life and the engine's, keeps you from having to smell oily blow-by, and most important, more HP.

Lower pressure in the crankcase means less "wind resistance" to the moving parts, and creating a higher pressure differential between the top and bottom of the rings causes them to seal better, reducing the blow-by problem and maintaining a higher HP level.

Oh, and it reduces emissions without costing any real HP.

Mike

[OmniLuvr]

i like the idea, but i think your regulator is in the wrong spot. i didnt look up john l's link, but i believe the regulator should have its own port on the valve cover, and the catch can (i think you should have it) to exhaust evac should have its own port, kind of like a reversed fuel system.

so the evac should be pulling the crankcase into a vacuum the whole time, once it reaches maximum desired vacuum, the regultor opens up letting fresh (and hopefully clean) air in. the vacuum gauge could be right after the regulator to monitor?

at least this is how i picture it?

EDIT: im kind of slow today, yours would totally work, but the other way is how we setup my friends 1800 hp race car with mechanical vacuum pump, so i had a mental block...

but maybe you could have an orifice with a filter on it so you do get "some" fresh air in there?

[johnl]

What! You didn't read MY link!? I am SO offended.

Seriously, a related point - poor oil drainage from the valve cover presents a windage loss in many engines. Maybe good for the cam/followers, but . . . .

With that in mind, pulling vacuum from the crankcase instead of the valve cover will help evacuate oil, pulling it down to the crankcase from the valve cover. Or, pulling a vacuum at the valve cover might be a dumb idea because it would tend to hold oil in the valve cover and impair oil drain back.

[ShadowFromHell]

Mmmmkay;

Sportbikes that rev to 16,000 RPM don't use a PCV system, just a vent hose from valve cover to the airbox.

So why do our cars need them??

Why do we do we replace factory airbox's? Why do we turn up the boost? Why are 3" exhaust systems so common? Because there are gains to be had. Because the bean counters and EPA control a large part of how cars are built. We don't have to listen to them, and can make out cars perform better. PVC systems are a emissions creation, I don't know when exactly they became common place but before them "blow by" tubes were used that hung under the car and were slash cut so at speed the created a vacuum. Now, the EPA doesn't want those fumes getting out of our engines so they have to be ingested to get rid of them. I don't live in a area that has pollution problems so we dont have emissions testing here so I can do things like this. I am currently running my car with the factory PCV setup, and a vent. This is probably adequate and will work fine. But if I am going to redo the system to work better, I want it to work the BEST. I also like to tinker and have 85% of the stuff laying around to do this.

OmniLuvr I don't think it is going to matter where the "regulator" or vacuum relief is. If you think of the whole system as a sealed tank, it shouldn't matter if the regulator is opposite of the "fill port" or right next to it. At least the way I am imagining it. This way also keeps me from having to pull the valve cover to drill and tap it. I do like the idea of pulling from the pan, maybe down the road if I have it off I will add a port and tie it into the system or just pull from their entirely. I could tee into the turbo drain and while the 90+ turbo 8v's did that, I would be afraid of it causing problems or sucking up a bunch of oil.

[Reaper1]

You can pull a vacuum on the crankcase from the valve cover. You just need to have a balance tube between the crankcase and the head so that the oil drain-back issue (that was brought up by John) doesn't happen. The most popular place to do this for 8V engines in the block is where the mechanical fuel pump would have been, you can put a fitting there, then run a tube to the valve cover to balance the pressure between the two. Doing this alone will also help oil drainback.

[ShadowFromHell]

After digging around on McMaster-Carr I found this. Should make for a perfect relief valve. All that has to be done is to put it in line! Comes from the factory able to go from 0-27hg. Cant beat it, and I don't think I could make one as cheap as they sell them. Would be nice if I had some idea of where to get one locally though lol.

http://www.mcmaster.com/#standard-relief-valves/=md71ub

[johnl]

Be careful, those valves appear to go the wrong direction, they release internal pressure, not vacuum, for pressure vessels.

As for the sportbikes, most of those pcv systems are controlled by reed valves that create crankcase vacuum; I cured all of the oil leaks on my Norton 750 Commando by installing a crankcase reed valve; 180* crank that creates powerful 750cc pulses of vacuum; probably sucks dirt into itself now, LOL.

[ShadowFromHell]

Because of the way their website is setup I cant direct link to the one I want. But, it looks like a grangier valve but can be adjusted from 0-27hg and its $12 bucks. There is alot on there that are for pressure, I am sure most of them would make great MBC's. I appreciate the thought though. The main difference it seems between the vacuum and pressure ones is the vacuum ones have the relief holes on the top, and the pressure on the side.

On the pressure differential thing... could I tee into my turbo oil return? Or would that cause other issues. I like the idea of equalizing the two. Really, a guy could run a hose from the pan to VC, and then pull the vacuum from the middle of that and block everything else off really.

[johnl]

I tried taking vacuum off the fuel pump block off plate on a T1 block. Maybe there is too much windage there, it pulled too much oil into the exhaust so I rotated my 90* elbow to point up and then threw a gravity drain back loop into the hose by running it up above under the AC bracket and then back down. That fixed it. I used 3/4" hose but an even larger diameter hose, or a catch can, would be better too so as to lower the velocity of the crankcase vapors being pulled but space/routing/bend radius may not allow it. Of course, the less blow by on boost, the tighter your ring seal, the less volume of crankcase vapors pulled, and the less oil that will travel with them.

[OmniLuvr]

I tried taking vacuum off the fuel pump block off plate on a T1 block. Maybe there is too much windage there

one of the oil drain ports from the head drains over that area, it is designed to lube the carb fuel pump...

[johnl]

Well . . . . . THAT explains it. Thanks. You are the DUDE.

[thedon809]

El duderino.

[zin]

But, does the Dude abide?...

(might be more apropos in the Movie Quotes thread..)

Mike

[Reaper1]

Uh oh...here goes another thread! LOL

In all seriousness, I don't think I remember Ed saying to pull the vacuum from that area, but just to use it for the balance tube. If I mis-spoke before, I apologize.

[86Shelby]

I found the one he was looking at. Here is the description from the website:
Vacuum and Pressure Adjustable Brass Relief Valves

Use with vacuum and air
Temp. Range: -15° to +250° F

Protect against excess vacuum and pressure with one valve. Adjust set vacuum and set pressure within the ranges. Body is brass. Valves exhaust to the atmosphere; vent is on the top. Pipe connection is NPT male. Valve with 1/4 pipe size has a Type 440C stainless steel seal. Valves with 3/8 and 3/4 pipe size have a Buna-N seal.
Pipe
Size Pressure
Range, psi Vacuum
Range, Hg Ht. Each
1/4 0-20 0-27" 1 3/4" 48935K25 $7.53
3/8 0-20 0-27" 2 1/16" 48935K35 12.61
3/4 0-20 0-27" 2 3/4" 48935K45 26.13

[ShadowFromHell]

For the cross over tube, I think may soldering a nipple on to the dipstick tube might be a good solution. But does anyone have any thoughts on using the turbo drain back though? I know chrysler did it from the factory but am still afraid it may mess with things.

[moparman76_69]

http://www.grainger.com/Grainger/CDI-CONTROL-DEVICES-Adjustable-Relief-Valve-6D915?Pid=search

Seems to be the same part. It has a reversible poppet so it can be used as a pressure or vacuum relief valve. If it performs the same function as the moroso part, it's only 1/10th the price.

[Reaper1]

For the cross over tube, I think may soldering a nipple on to the dipstick tube might be a good solution. But does anyone have any thoughts on using the turbo drain back though? I know chrysler did it from the factory but am still afraid it may mess with things.

I'm pretty sure you are talking about the PCV drain tube that was used on the VNT's and the TI's. It wasn't meant to be a pressure balance tube.

[ShadowFromHell]

I am. its been a LONG time since I have seen one that was hooked up 100% stock. Were they just used for drain purposes or tied into the PCV system? Also... I see you are in everett.... You better be coming to the ellensburg meet next month!

[cordes]

Uh oh...here goes another thread! LOL

In all seriousness, I don't think I remember Ed saying to pull the vacuum from that area, but just to use it for the balance tube. If I mis-spoke before, I apologize.

Is the stock vent not enough? I know the smaller of the "drain holes" is supposed to be a pressure equalization type deal.

[Reaper1]

I am. its been a LONG time since I have seen one that was hooked up 100% stock. Were they just used for drain purposes or tied into the PCV system? Also... I see you are in everett.... You better be coming to the ellensburg meet next month!

I am most definitely going to try to be there! I hope the pass is open so I can get there!


Is the stock vent not enough? I know the smaller of the "drain holes" is supposed to be a pressure equalization type deal.

Can anyone find and post the 1990 TIV and the TI vacuum diagram?