What the use of this Valve Cover hose?

[kingearl]

There are two hoses that are connected to the valve cover. I am talking about the one that also is connected to the intake hose. To me it seems to do nothing but drop oil into my intake. It looks like it could damage some things in the MAS and I would like to know why this hose is required.

 

[90tsi]

The one towards the fire wall is the pcv valve, the one going into the intake is just plain stupid. Pull that one out and get a catchcan or breather filter.

 

[larryd]

its an oil pressure relief line I believe.. I cant remember the exact title of it but most people pull the line off the intake cap it, and put a breather filter or catch can on the end coming from the valve cover

 

[NosLaser]

It's simply a crankcase breather line, and it's designed to relieve pressure. It dumps into your intake because it has no-where else to go. If you wanted to be cool (not that any DSM'er would do this because it's not the beaten path and it actually makes horsepower) would be to install a scavenging pump. With a scavenging pump, you could pick up an easy 20+++ HP depending on your current power level.

Regards,

 

[kingearl]

wow, thanks for all the fast replies. Thats great. But I am now pretty interested in the scavenging pump idea. I dont know what that is. Could you give me some basics on this concept? How to do it and such.

 

[pilsner]

i also have a question regarding this issue. could you just remove the hose and let it hang? do you really need the catchcan?

 

[Bohrn]

what I did was install a fuel filter from a Chevy or similar carb V8 car. It cost me less than 2 bucks, installed in 2 min and allows the most harsh of emmision nazis to pass it. I cut the line from the valve cover to the intake pipe, and just put the filter in-line there. Also there is no oily crud in my intake tract/intercooler area.

there is a picture somewhere by one of the regular posters here. Sorry, I lost the link.

also it looks cool, clear plastic with the filter element inside. Perfect fit.

and better yet, no drips or fumes in the air or on your engine.

 

[fast_talon]

You can also make a catch can very easily..

 

[AWDtsimang]

I just did this same cheap ass fuel filter mod last week. I picked up a fram fuel filter for carb'd cars, it came with: fuel filter, 2 hose extensions, and a full compliment of hose clamps. Whole package was like $2.38 or something. If you want to see some pics, look up AWDTerror on DSMt**k.com and I think he's the one who made up the vfaq.

 

[KenTSIII]

You might want to keep the hose connected to the valve cover & intake. W/ it connected the suction from the turbo sucks the extra crank case pressure out of the valvecover... ever notice your dipstick popping out? Try reconnecting the hose & watch how it misteriously doen't pop out anymore. I also use the same fuel filter that is described above.. costs like $1.99 at any auto parts store.. just replace it after it's clogged.

 

[kingearl]

ok, but does anyone know what NOSlazer was talking about with the scavenging pump thing? Any info.

 

[Bohrn]

yea, do tell Mr NOS

 

[97EclipseGSX]

The PCV vale line does the job of this scavenging pump he is talking about. It would only be benificial to have this pump if you were to plug the pcv line (intake side) and put the pump on the side where the pcv valve would go. This will suck air into the crank case through the breather line which will cool the top of head, and will also allow no boost to be leaked through the pcv line.

The only thing I don't get is where would you get a vacuum pump thats gonna be able to withstand our cars underhood temps.

 

[NosLaser]

I was kinda kidding about the scavenging pump. What a scavenging pump does is suck pressure from the tops of the pistons and even from the bottom. The big advantage is unequal pressure is being created on the top and bottom of the pistons, and it causes the rings to rock in the bore. If you hold a plate in your hand, lift one hand up an inch higher than the other, you'll see what the ring is doing on the piston. A scavenge pump will help relieve that pressure and allow the ring to sit square in the bore. However, a svaneging pump on a street car is not the best idea. It increases oil consumtion, runs the risk of locking iup, and all sorts of other problems. While the advantages are big, the possibility for failure outweighs those advantages. Also, the guy who said the line being plumbed into the turbo inlet pipe is acting as a natural scavenging pump, he's absolutely correct. However, again, the advantage of not having oil blown into your turbo outweighs the suction provided. And think about it, of the suction was that great, the stock rubber turbo inlet hose would collapse, so it's already a pretty low pressure area.

Regards,

 

[kingearl]

Then its hope for a lost cause............... Its not nice to play with peoples emotions.

 

[2-0turbo]

Originally posted by NosLaser
I was kinda kidding about the scavenging pump. What a scavenging pump does is suck pressure from the tops of the pistons and even from the bottom. The big advantage is unequal pressure is being created on the top and bottom of the pistons, and it causes the rings to rock in the bore. If you hold a plate in your hand, lift one hand up an inch higher than the other, you'll see what the ring is doing on the piston. A scavenge pump will help relieve that pressure and allow the ring to sit square in the bore. However, a svaneging pump on a street car is not the best idea. It increases oil consumtion, runs the risk of locking iup, and all sorts of other problems. While the advantages are big, the possibility for failure outweighs those advantages. Also, the guy who said the line being plumbed into the turbo inlet pipe is acting as a natural scavenging pump, he's absolutely correct. However, again, the advantage of not having oil blown into your turbo outweighs the suction provided. And think about it, of the suction was that great, the stock rubber turbo inlet hose would collapse, so it's already a pretty low pressure area.

Regards,

Actually, a scavenging pump create a vacuum on the BOTTOM side of the pistons. I don't quite see why this would increase oil consumption???

As soon as I can relocate my battery to rear of my car, I am installing a scavenging pump--just like you describe. I have sourced it from a mid-90's F-body. They all come with them stock, from the factory. The PCV valve only applies vacuum to the crankcase when manifold vacuum is present. Under boost, that "check-valve" feature of the PCV valve kicks in and doesn't allow boost pressure to enter the crankcase. But, the crankcase assumes ambient pressure or actually some positive pressure due to blow-by. Hence the reason the dipstick pops out.

My buddies who race a 9-second mustang run an engine driven vacuum pump on their car. Their engine builder claims (if memory serves me) almost 50 HP from the almost 18" HG vacuum it generates. This is on an 800 HP engine. I think the pump I have (electric driven) will only generate 10" HG, but it is worth a try I think. I'll post results once I have them.

 

[NosLaser]

...Actually, a scavenging pump create a vacuum on the BOTTOM side of the pistons. I don't quite see why this would increase oil consumption???...

Yes, it creates vacuum on the bottom of the pistons. Look at my post again. I simply said there is unequal pressure on the top and the bottom of the piston. I didn't specify where the vacuum came from. It's still not a good idea for a daily driven street car.

Regards,

 

[Laser0385]

Old thread but anyways, would it be more beneficial to install two in-line fuel filters just to keep more oil out of there? Thanks, Jake.

 

[echo]

i don't think you would need to install 2 of them. it's not like gallons of oil are flowing through there. it's just oil vapor being spit out from the crank case. it then gets settles in low areas and forms oil. i would just get one. though it wouldn't hurt (i don't think it would help either) anything to get 2....

 

[doug]

Originally posted by pilsner
could you just remove the hose and let it hang?

Yes, absolutely. I used to have the fuel filter on there until I got tired of changing it-- now I just let it hang. You can also do the same thing with the PCV hose-- cap the intake manifold where it goes and let it hang too, or plug it into a catch can.

Originally posted by pilsner
do you really need the catchcan?

No, but it's a better solution than just spraying oil droplets all under the car. I don't have one yet, but I'm gonna get one someday...

 

[racerboy13]

Is it posibile that the reason excessive oil is coming out of the breather hose is due to blow-by?

 

[peregrine]

Originally posted by NosLaser
It's simply a crankcase breather line, and it's designed to relieve pressure. It dumps into your intake because it has no-where else to go. If you wanted to be cool (not that any DSM'er would do this because it's not the beaten path and it actually makes horsepower) would be to install a scavenging pump. With a scavenging pump, you could pick up an easy 20+++ HP depending on your current power level.

Regards,

aslan, what do you think of running a hose from the crankcase to the exhaust like the v8 guys do for scavenging? it would be easy to do and would make your rings seal better. i think about tapping that side hole and making it bigger to connect to my exhaust somewhere underneath. and please, no off color comments about my friends a fresh perspective is always nice.

 

[NosLaser]

Sure, you could do that if you don't mind blowing oil smoke out of your exhaust. Then again, you'll already be blowing all that black smoke from the nitrous so what does it matter, right?

Regards,

 

[wishIhadaturbo]

You could do that, all you would need is a check valve. Either the positive or the negative pulses of the exhaust creates a vacumn. I remember that kind of setup was on my Ford EXP. Come to think of it, my old GTA had it too. That is really a good idea. Try it out and let us know

Will

 

[Defiant]

Originally posted by 97EclipseGSX
The only thing I don't get is where would you get a vacuum pump thats gonna be able to withstand our cars underhood temps.

You already have one in there, to run the power brakes under boost conditions.