David@MMS

I have had several guys use two passenger valve covers (like the copo car does) in order to get two massive ports.

keep in mind we can support 1200hp with a single port (my 12an adapter).

http://www.mightymousesolutions.com/...a-02d6fe2ab2d3

rio95

How do u come up with your HP ratings? Do u have crankcase pressure data to compare a stock setup to what the OP has?

double06

Well the number 6 would make sense for up to 500-600 hp as that is what comes with our cars to begin with. The 3/8 plastic line going up to accordion thing from the oil tank. The PCV valley cover hole we have like mentioned above really does not flow much since it is just an 1/8 inch hole.

David@MMS

it is a mathematical calculation mixed with years of experience with these variables

-max allowable pressure
-length of hose
-max crank hp
-cyl leakage %

Michael_D

I experimented with the valley vent..... Epic fail. I converted the vacuum line to -6AN by threading a 1/4" brass nipple into the plate and removed the orifice. After about 100 miles of street tuning, I had to remove the MSD because it was rubbing. Well, found the EE catch can completely full of oil, as well as the intake manifold and cyl ports. So..., completely removing the restriction is not a good idea with this EE can set up between the intake and valley vent. There is an oriface in the valley plate outlet tube that I had to remove. Damn if I didn't take a measurement of the orifice. It was not 1/8" though. Much smaller. Closer to 1/16". I'm going to fit a set screw into the brass nipple and drill a hole in it. I'm deliberating just how big of a hole I go with. I'm thinking of going 1/8". I'm pretty surprised the baffle system in the valley plate will allow so much oil mist to pass. It's quite elaborate.

I was pissed that I had to pull the intake, but it worked out for the best after all.

In retrospect, I should have just gone with one of these MM cans. I probably will eventually.

double06

According to something I read, the hole is 1/10 of an inch 2.5 mm.

David@MMS

I cannot state enough, that the valley plate is a BAD place to vent from.

Excellent idea! Ready when you are.

Michael_D

My experiment failed because I removed all restrictions from the valley connection, NOT because I used it.

It is a pet peeve of mine to cherry pick words to support an argument or position. I in no way implied the valley is a bad place to vent from.

David@MMS

there was no cherry picking sir, additionally i have no argument or position, only friendly guidance.

with the restriction in place it is a bad place to vent from
with the restriction removed it is a bad place to vent from

all times it is a bad place to vent from, no matter who tries it is or what they do. nothing personal about it.

in stock application it is the pcv return, not a crankcase vent.

so unless you are using it as part of pcv control, it is useless.

Michael_D

Whatever........

How can you say that it's a PVC "return", and not a crankcase vent, when the intake manifold is under a vacuum under most operating conditions?

Dan_the_C5_Man

Thanks for the pics and feedback MD - as I read through the thread, I was thinking, "hmm, maybe open up that orifice in the valley cover", and sure enough, you did it and saved myself and others the trouble.

One of the reasons I didn't want to pull from the valve cover is I (assumed) the oil misting / baffling would be inferior as compared to the valley cover.

David@MMS

Because I have measured the flow personally, and it is a platform and system I have been working with for 17 years. Not only is it's contribution to crankcase pressure ventilation negligible, it is also unreliable.

No reason to get upset. Just trying to save some good people here their time and hard earned money. Good luck to you.

Michael_D

With my .125" "orifice" fit into the valley vent tube, I still pulled significant oil. I replaced it with one that has a .090" hole. Normal amount of oil collected after numerous WOT pulls dialing in the MAF and VE tables. But now I collected water. About three ounces after about a dozen pulls to 7200. Ambient air temps were about 50 deg F, and it's been raining.... Hopefully, it's just condensation and not a blown head gasket.

I'm not upset, and believe it or not, I appreciate your input. I've been building engines for better than 30 years, but I learned a long time ago I don't know what I don't know - so I pay attention and ask questions. I just don't get how you can say the valley vent is useless, when I obviously was able to pull plenty of vapor from that port; too much in fact.

And as I've stated a couple times already, I will eventually add one of your cans. I will not, however, eliminate the valley vent unless I can fully understand your position.

Apocolipse

Valley cover vent is great for cars driving around town. It does its job when the manifold is under vac and fresh air is circulating through the engine - which is an emissions requirement and for oil life. At WOT on a stock engine most of the crank pressure (unfortunately) will go out through the valve covers and into the intake accordian (reverse of pcv's general direction). The valley cover fitting now sees only ATM pressure as the manifold is no longer vac in which reduces measured flow even more.

By blocking this vent the overall alibity to remove crankcase pressure is not greatly reduced (under WOT). However, you do remove pcv system functionalty (which not everyone cares about). You then allow for only 1 point of venting and 1 point of control to worry about oil coming through, hence why MM designed the system this way. The valve cover line size is increased from stock to allow greater hp cars to vent appropriately without blowing seals and catches oil mist that may accumulate.

If you so choose - you can keep the stock valey cover line going to the throttlebody but you will create another point of possible oil entrance (as you have noticed). This would pi$$ a customer of MM off because they would be getting oil in their manifold even after buying their product (and I am sure asking for money back).

GM tried by putting baffles on the valey cover and controlling flow via hole size. By controlling internal pressure on a high hp build with appropriately sized valve cover vents, the stock pcv location should not consume more oil than a stock powered engine does.

In all of this...it is your decision if you want to run both venting options. Just understand MM wants to control a single point of entry to ensure a dry manifold instead of relying on GM's design alongside their product.