DoctorQ

Looking to tap into the vast TMS tech knowledge base with a question regarding PCV blow-by in our 3V Mod Motors. I’m getting ready to install an oil separator in-line between PCV valve and intake. Appears to be a valuable mod to separate/extract blow-by oil and prevent re-entry into the intake. However, I recently discussed my plans with an associate who is a certified mechanic (granted.. a Chrysler mechanic). He suggested not to add the oil separator as ‘some’ of the blow-by oil vapor is actually beneficial. I found this hard to believe, but he explained that in many designs, the oil vapor is beneficial for top-half lubrication. So, here I am ready to rock on the oil separator mod, and get this bit of information. Question to my TMS brethren: does this theory hold water? Does the 3V motor actually see top-half lubrication benefit from the oil vapor escaping past the PCV valve… and would installing a separator actually be detrimental? Thx

wallace

lnteresting....

05YellowGT

wallace

well lets see.... the ford guys did design the new engine this way and after all they're the tech's, maybe i trust these guys.
wait a minute..... they're also the same guys that gave us a 50pds, 2 pice driveshaft. seriously, i dunno. but correct me if i've read wrong, but it seems to be a f/i thing not many n/a guys are collecting much blow by in their catchcans.

anthony05gt

I don't know of anything in the intake tract that needs lubrication. In the old days lead in gasoline used to keep the valves lubricated and was especially great for 2 stroke engines.

Sharky

When I installed my delete plate kit, I could not find anything beneficial about that much oil going into my intake.

n8rfastback

this is an ongoing debate with every car someone wants to mod.... ive seen this discussion on about 3 forums now...

the ultimate answer is, how good does it look to you?

there will be no performance gains, and no noticable difference in the engine whatsoever....

all i know is, the techs designed it that way because why?... your top half needs ventilation, and oil is going to blow by out of it.. so where else to put it than the intake tract.

and..... all aftermarket intakes retain the use of it. so i will leave it and not use up more of my engine bay than necessary.... plus you have to deal with draining the catch can regularly, and they leak too.

thats my opinion

metroplex

The upper cylinder area does need some lubrication to prevent excessive ring wear. That is why you are NOT supposed to keep using E-85. You're supposed to alternate between E-85 and regular gas, because regular gas contains additives along with to help lubricate the UC area. GM powertrain engineers have found that excessive E-85 use tears up the engine quite badly.

A good reason to use a quality separator (not an air compressor inline filter like Steeda is selling) is to prevent oil from caking the intercooler on a supercharger (Lightning, 03-04 Cobra, GT500). On a naturally aspirated application, it will coat the insides of the intake manifold with some oil but it won't cause anything to fail. I have a 27 year old Ford 302 that is a daily driver and the blowby from the PCV hasn't caused anything to fail yet.

Some engines DO come from the factory with a separator, like Ford/Mazda's 2.3L DOHC Duratec. There is a special assembly custom-fitted to the engine block that separates the oil and allows it to drain back into the block automatically. I believe they do this to reduce emissions.

anthony05gt

Another good reason for an oil separator is the maf and throttle body areas need to be kept clean. I've had to clean out a couple of air to air intercoolers with brakleen for guys before. That's quite common.

94tbird

Blow by oil vapor is NOT beneficial to performance in any way nor is it beneficial to the motor in any way.

The system is designed the way it is to enhance the emmissions of the vehicle by burning off the vapor in the combustion chamber.

By allowing the oil to follow this course you are reducing your octane rating of the gas, therefore making it more prone to pinging and knock.

Now on a N/A vehicle its not anywhere near as bad as it is on a FI car. on a FI car that degredation of your octane rating, especially at high RPM is not a good thing and can cause problems.

Some people suffer from this more than others.

And you do not need to drain them regularly if you get a proper sized one. if you go with the steeda one you will be emptying it every night to 2 days. they fill that quick. gonig with the stefs unit #5128, i have not had to drain it yet in over 4 months.

There wont be seat of the pants performance gains but your engine will run cleaner and that is a good thing. it also prevents fouling of the plugs and injectors if the car sits for a while

Torch_Vert

Do you have photos of your Stef's unit installed?

I've been looking add something to do this, but haven't found one that looks good to me yet (I show the car now and then)

GT John

Here is a pretty good read.

http://www.misterfixit.com/blow-by.htm


http://www.bobistheoilguy.com/blowby.html

GRAYPNY

Pictures of mine~

kevinb120

Bingo! They do it that way as there really isn't anywhere else for it to go, and adding an oil separator to a normal production car would freak 'normal' people out. Pretty much every car has this setup in some shape or form. It probably has no long-term effects for the vehicle as designed in stock trim and is withing an 'acceptable' level of contamination for a production car. I probably wouldn't worry about it for a mildly modified vehicle, but for FI or if you are really going to wring it out in the tune and hi-po mods like cams and what-not where the tune can be pushing the limits if its fouled in any way, I would definitely get one.

MTAS

"Aftermarket intakes"....do you mean a CAI? The tube that goes from the CAI to the passenger side cam cover is a vacuum. It's the driver's side cam cover (that has nothing connected to the CAI) that pukes oil into the intake manifold.

GT John

The hose that goes from the CAI to the passenger side valve cover is the intake air for the crankcase ventilation system. This is where the air comes from that is sucked up through the crankcase, through the pvc and into the the intake.

This is why when at WOT and there is lttle to know vacuum that pressure in the crankcase can build up to a point where oil will be forced out of the engine through whatever path it can find.

All high powered cars use either a vacuum pump or some other sort of scavenging system to keep the crankcase under a vacuum.

I have seen cars running 800hp push the oil dip stick right out of the tube from so much pressure being built up in the crankcase.

In the event that the pvc should fail, oil will be forced out of the passenger side hose, due to pressure build up in the crankcase, and into the throttle body and then into the intake.

It will be one big mess to clean up.

Its pretty well illustrated in the Ford Mustang Service Manual.

http://www.dragstuff.com/techarticles/vacuum-pumps.html

metroplex

Actually, burning engine oil contributes to added emissions levels, which is why many ULEV and near zero emissions vehicles all have oil separators (such as the Ford/Mazda 2.3L DOHC I4 Duratec) to prevent engine oil from being burned.

The MAF sensor is so far upstream that any contamination from the oil blowby is unlikely unless your rings are so worn out that there's enough blowby to make Exxon Mobil rich.

Mongoose

I have a Stef on mine after seeing an intake with over half cup of oil in it. Send me a PM with your E address and I'll send photos. I am not computer literate and do not know how to post here.

classj

Depends. I have not reached the point where I think it is excessive yet.

Truthfully, they run these engines for thousands of miles prior to releasing them. Sometimes a problem will slip through, but usually things of this nature are done for a reason.

Overall, I do subscribe to the thought that a minute amount of oil vapor can possibly be benificial.

People have been running upper cyl lubricants for years. Usually they go in the fuel. But they actually used to sell a system that injected it right into the intake.

Marval Mystery oil is a big one. I never quite went that far. But it is not rare at all.

metroplex

I agree. If the engineers thought an oil separator was absolutely critical, they would have installed one as they do in many production vehicles. Volkswagen has a factory/production oil separator that looks similar to the ones used in the Ford 2.3 engines. The Steeda separator is an air compressor inline filter, just like many of the aftermarket "filters" for Ford modular V8s.

The production separators are usually made of Zytel nylon and are generally designed to release the trapped oil back into the engine system. In addition, many of them cost upwards of $200 or more and are used after thousands of man-hours of testing.