Ok, this is something I have never really seen anyone talk about in length so here it goes.

On a stock car we all know how the crank case gets it ventiation. You have a tube going from the valve cover to the TB to get a vac. source and to help burn off some of the oil vapors coming from the motor, and we have a PCV valve that is looped into the intake manifold.....blah blah blah blah so on and so forth.

Now once you had a forced induciton to the car the PCV system is pretty much worthless since you are pressurizing the intake system of the car. The TB line can not be used or it will pressurize under the valve cover and more times than not the PCV will just pop out of the intake. So what do you do?

I know in ATI's kit they just have you put a breather on the valve cover, plug the TB line, and run a line from the PCV down to the intake side of the blower. Thats all fine and dandy but how good does it work? And the only other problem with that is that it sucks oil all thru the intake system and if you do have a somewhat loose built motor your going to just coat everything in a fine mist of oil....and if you have a blow thru MAF, your going to coat it as well.

Now most drag guys use a header Evac which can create tons of vac., Hardcore road race guys more often than not use a Dry Sump....so they have their problems covered.

So what about us street guys that still want to screw around on the race track? Header evacs suck to much oil to use for 20mins on a road course, dry sumps are pretty pricey and not really needed for the occasional trip to the track.

So here's what I thought up and put on the car. I have a converted LT1 AIR pump being used as a vac. pump and it is pulling from the stock PCV location in the intake (without the valve) there are two breathers in the valve covers with small baffles on them and the TB line is blocked off. So this techincally isn't going to pull a hard vac. on the motor but should keep the crankcase clean, correct?
Some pics of the motor....



Keep in mind this is a brand new motor and I have yet to get into the boost with it, but I got under it to do a second oil change after 150 miles to keep it clean and there is a fine mist of oil all under the front of the car (the vac. pump is mounted under the battery). I'm thinking about putting a catch tank on the car to keep it clean, but is this normal? Should I even have it on the car at all? I do notice if it isn't on I do see some slight smoking from the valve cover breathers once it is warm but nothing major.

Thoughts, ideas, solutions? Normal?

 

I tried using the LT1 air pump, but it wouldn't pull enough vacuum to do anything. Next I plan to try an actual vacuum pump off a Ford or Caddy.. I already have a vented catch bottle to vent the pump to.

Currently, I have breathers in both valve covers, and a check valve on the PCV hose. The PCV mainly works at idle, since at WOT you don't have much vacuum. Seems to work ok, but I still have a small leak on my oil pan.. although I think that is coming from the return line fitting.

Pan-evac systems don't work too good with mufflers, just enough back pressure to make them pull more oil than vacuum.

There is a list of donor cars for the vacuum pumps on my tech page...

 

http://www.turbomustangs.com/forums/...&threadid=6083

there is an option.....he did post an update post and said that the pump pulled 15" of vacuum but that was on the bench and not on the actual motor

maybe give him an email and ask him if he had a chance to put it on the motor yet

 

There was an informative, semi lengthy thread a couple months back. Don't recall if it was here, adv. or tech though. Do a search. BTW, the AIR pump is virtually worthless.

 

Well if the AIR pump is worthless, they (local shop) did something to it to make it work better because it does pull, and it pulls enough to get an oil mist after driving for an hour or so.

 

Hey Anthony

I did a lot of reading on this topic and I concluded based on the opinions of some apparantly informed folks that the LT1 air pump would not be enough of a vaccum. texlurch has a great explanation on the topic, you check it out yet?


my thread on this topic.
http://web.camaross.com/forums/showt...t=vacuum+pumps

telurch excellent page
http://camaroz28.cardomain.com/membe...=199561&page=9

 

I actually tried the F-body AIR pump on mine. I plugged the PCV valve, and hooked the suction side on the pump to the rear of the pass valve cover. I also have a catch/breather tank on the outlet side. When I fired it up, it immediately started smoking out of both tailpipes. I pulled the hose off the valve cover, and hooked a vacuum gauge up, it was only pulling maybe 3" of vacuum. You need around 12 to make any difference. Here is what my hookup looked like:



Ignore the breather on the valve cover, that was removed.

Now, 1LEthumper, on yours you said you still have the breather and PCV hooked up, so you are not pulling a vacuum per say, just sucking the oil and air out of the valve cover.

The whole idea is to create a vacuum in the crankcase, and to do that you need a sealed system. If it is vented, you are just basically pulling some air thru, and with it the oil mist. That is why you run a catch can with a breather on it, and drain it occasionally.

And the AIR pumps are designed to push air, not pull it, so they are not that efficient. I am still searching for an electric vacuum pump, so don't give up yet!

 

What are the technical reasons for creating a vacuum in the crankcase?

 

The way mine is run, is that it has 2 open breathers in the valve covers, and the vac/AIR pump is pulling from the stock PCV location just thru a fitting. I knew it wasn't going to pull a vac. on the crankcase, I was just trying to help circulate air thru the motor untill I figured out how I was going to do it with out hurting anything. I just figured this would simulate how it would work with the PCV pulling from the intake side of the blower and the valve cover breather that ATI puts in the kits....correct?

The main purpose (correct me if I'm wrong here) is to get the air out of the crankcase letting the pistons move up and down easier so they do not have to fight the air pressure in the crank case as they move up and down. Correct?

What about using a vac. pump off of one of the Mod motor'd Cobras? Also how do you tell whats good and bad as far as Vac. readings go, and should it suck some oil when it does run all the time?

One other question, do you even need one on there or can you just block the PCV and run the 2 breathers and still be fine on a FI car? Granted you'll loose a little bit of power not having the vac. pump but would it do any damage to the motor??

 

No, that is a fallacy. Cuz, as one piston goes up, one is coming down. IF that idea had any merit, which it don't, one piston would offset another. The intent is to remove any pressure to assist/improve compression ring seal.

What about using a vac. pump off of one of the Mod motor'd Cobras? Also how do you tell whats good and bad as far as Vac. readings go, and should it suck some oil when it does run all the time?

Idea is to prevent pressure buildup in crankcase (from ring blowby) when PCV doesn't function, ie at WOT. IOW, picks up where PCV leaves off. BTW, may be fine/ok for drag racing, but I wouldn't recommend a sealed system on the street. That is not the intent.

One other question, do you even need one on there or can you just block the PCV and run the 2 breathers and still be fine on a FI car? Granted you'll loose a little bit of power not having the vac. pump but would it do any damage to the motor??

Wouldn't recommend disabling PCV.

 

Ok...so the only reason to have a vac. pump is to have something working during WOT? Just a question then if you have breathers on a stock motor are you not getting rid of the vac. all together then since you just opened the system?

Also on a FI car, the PCV isn't going to work when its under boost since its a one way valve and when it gets boost, it can't really do much. I can't see the inlet side sucking enough to over power the boost in the intake manifold, right? I know some of the factory turbo cars like DSM's have a PCV system but I'm not sure how they work.

Ok so whats going to be the best bang for the buck setup for a FI car? The way ATI had it set up it just didn't seem right to me. Plus it just blew oil all over the inlet pipes.

 

It will certainly generate less vacuum than a fully sealed system.

Ok so whats going to be the best bang for the buck setup for a FI car? The way ATI had it set up it just didn't seem right to me. Plus it just blew oil all over the inlet pipes.

As noted, I prefer a non sealed system, IOW, more passive. Texlurch has endorsed a more dedicated system that is sealed and obviously draws more. He obviously has had good results, so no way can I state that his is not the better approach. My personal view, is that it is a little extreme for daily street use, that's all. So, now you have a choice, as to how effective you want your system to be. Some experimentation could be conducted to determine if sealed is noticeably more effective than a modified non sealed system, with a restriction in the line, in lieu of the non restricted free flow oem style.

 

http://web.camaross.com/forums/showt...threadid=82357

GOOD Reading.

 

"The oem system is not a sealed system. It draws in metered air from TB. The breather would
replace the TB as a source of incoming fresh air."

Hows this work? The motor can't suck in its own air thru a breather. And I thought that was the hole point of that line was to suck out of that vavle cover.

ok, so then what is a passive system on a FI car?

 

If I understand the ? correctly, the oem system is not intended to hold a given amount of vacuum in the crankcase. The blowby and mist are drawn out the PCV in the cover, and replaced with fresh air from TB or a breather. If too much pressure builds up in the crankcase, it starts pushing out the pcv till the vacuum isn't able to stay ahead. It then closes the one way valve. The pressure then continues to exit out the breather/TB, which is ordinarily, the intended inlet.

If enuf vacuum can be generated in the crankcase, ring seal is improved to the point of diminishing blowby. In reality, the more passive oem style of blowby elimination, with an auxillary pump, is less effective in generating appreciable vacuum, to improve ring seal a noticeable amount, even if it were a full time system, without some form of restriction in the fresh air inlet. For the MOST benefit in ring seal improvement, now we are where Texlurch is at, a fully sealed full time system.

Thanks, Ken. Don't you guys sleep nites?