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Oil Separators

3K views 25 replies 13 participants last post by  marichardson 
#1 ·
I've seen a lot of info on these things and have witnessed the oil residue on a friends mustang that has one but my question to any of you engineers out there is do you truly think they are worth it? Do you think that by adding the catch can you create an area of low pressure that may be sucking in oil that under a normal setup wouldn't be allowed to happen with just the hose being there? It seems odd that this would get past a mess of true car engineers at Ford and not make it's way onto the production line if it truly would cause havoc on an engine designed to go in a performance style car. Thoughts?
 
#3 ·
from what I understand the engineers are aware of the "blow-by" issues. Their mass production fix is to have the oil/moisture sucked back into the intake and burned. To run any sort of factory catch can would mean someone emptying it regularly, or risking even more issues.

I will say on my Dads Mini Cooper S (supercharged) it has helped alot. On forced induction cars (turbo, supercharged) the pressure is greater for that blow-by, and it ends up coating intake tracts, intercoolers, and everything else down stream. with the mini, every 1-2,000 miles we empty a watery oily mixture. it fills up quicker with short trips in the winter. With my buddies SRT jeep (6.1L hemi) he empties his every 3,000 miles with an oil change, and there is always about 3oz of oil in there (Hemis are known to do that).

I am interested to hear others thoughts, anyone that has a non-supercharged car what kind of fluid amounts do you see?
 
#5 ·
Do a little research on the Ecoboost vehicles. They are having a major carbon/oil sludge issue because of this.

I have heard that there are dealerships that claim adding a catch can voids a warranty. I talked to my local dealership and they not only recommended them but advised that when they change your oil, they would also clean out the catch can.

IMHO, (NOTE my opinion only), they are worth it especially if you are boosted or do a lot of higher speed driving.
 
#6 ·
Do a little research on the Ecoboost vehicles. They are having a major carbon/oil sludge issue because of this.
One of the big reasons eco-boost vehicles have sludge/carbon build up is the direct injection. In standard setups, fuel sprays on the valves effectively cleaning them (through additives in fuel). With Direct injection the fuel goes right into the cylinder. So any blow-by hits the valves and stays there! until a manual cleaning procedure is done. High end makers are wising up to this, adding a second injection point where it used to be, to spray the valves and keep them clean.
 
#7 ·
I empty my catch can every time I change my oil, approximately 2,500 miles or so. it's usually 1/2 full.
 
#9 ·
I also got the song and dance from a service advisor that a catch can was "tampering with emissions equipment". So, I unplug my JLT catch can when going to the dealership for service, and put the original straight tube in. It takes only a minute or two. No problem for me to clean out the can...
 
#13 ·
I've never been a fan of boosted engines. The boost produces power, no denying that. And if it's power you are after, go for it, as long as you are aware of the downside.

Normally aspirated engines tend to live longer than boosted ones because there is less strain on components.

Nothing wrong with that if power is more important than long engine life to the buyer.

The writing is on the wall. Because of ever increasing federal mpg requirements we will be seeing more of small displacement engines with added boost through turbocharging. The MPG gains will be when the driver is off the boost.

I went a bit off topic here, but seems to me there is now more of a need for an oil separator as more boosted engines get on the street.
 
#14 ·
The writing is on the wall. Because of ever increasing federal mpg requirements we will be seeing more of small displacement engines with added boost through turbocharging.
Only if ignoring the coming political change, consumer demand for high displacement engines, and cheaper gas.
:grin2:
 
#20 ·
First, the oil going into the intake has nothing to do with "blow by". If your engine had blow by you would have bigger problems than oil getting into the intake.

"Blow by is the result of bad piston rings, specifically the oil ring. The term "blow by" is from the oil "blowing by" the ring(s) and into the crankcase. Rings that seal good don't have blow by.

If you have blow by and it's bad you would have a lot of oil getting into the intake.

Assuming an engine is healthy the oil going through the PCV system under normal conditions is from oil that gets whipped around in the crankcase and forms a mist that gets sucked into the PCV system. It's normal.

Before PCV systems engines had what was referred to as "road draft tubes". These tubes would attach IIRC somewhere near the intake and go down the back of the block, at least on Ford V8's that had them. So what happens in that system vs PCV types is the crankcase gasses and oil would vent to the atmosphere vs being recycled through the engine. It was easy to tell a car that had bad rings or "to much blow by" because they would at a minimum "blow" smoke out of the road draft tube when stopped. If the blow by was really bad they would smoke while running down the road. Those tubes would drip oil and on tired engines they would leave puddles everywhere they parked or stopped.

A simple way to check for blow by is to pull the PCV valve out of the valve cover and if smoke comes out of the hole there's blow by. On a really tight engine there shouldn't be any smoke. If your buying a used car it's a good way to check the health of the engine, do it cold and hot.

As far as any oil catch devices, there are cars even back in the 50, 60, 70's etc that ran 100, 200, 300k miles without them and didn't have problems. With today's oils and fuels it's doubtful if they're "needed" if they weren't back then.

But marketers being what they are they will try and create the need. Companies create a product and also a need, it's not always the other way around, in fact it's usually not.

My suggestion if your going to get one is to make sure it has enough baffles or some means to prevent the air from going straight thru and pulling any oil along with it. Even though by the time the oil gets that far it won't be in a mist and should "drop" out of the air I would want one that would help it do so.
 
#21 ·
Mine catches so little that it's easily absorbed into a paper towel, which I just toss in the trash...

Yeah, I know an avid environmentalist type would say I'm polluting, but this is less oil than I see in the form of leaks in any supermarket parking lot.
 
#22 ·
3116Bullitt08, While what you say is generally, especially for n/a engines you are overlooking how adding Boost paying in the role. When you add Boost to an engine, you increase the pressure being "forced" into the combustion chamber. This extra pressure can force a little more "blow-by". Not enough to indicate internal problem but enough to cause additional pressure through the PCV system. If you add Boost, you must have something to catch this additional vapor. This is just one of the by-products of adding boost to a engine.

Ford did not account for this with their ecoboost so the additional vapors are going into the intake causing carbon build-up on the valves.

Even with the 4.6 3v engines, there are a lot of people who found carbon/sludge on the "Motion Plates" in the intake. This is also caused by the oil vapors from the PCV system.
 
#23 ·
3116Bullitt08, While what you say is generally, especially for n/a engines you are overlooking how adding Boost paying in the role. When you add Boost to an engine, you increase the pressure being "forced" into the combustion chamber. This extra pressure can force a little more "blow-by". Not enough to indicate internal problem but enough to cause additional pressure through the PCV system. If you add Boost, you must have something to catch this additional vapor. This is just one of the by-products of adding boost to a engine.

Ford did not account for this with their ecoboost so the additional vapors are going into the intake causing carbon build-up on the valves.

Even with the 4.6 3v engines, there are a lot of people who found carbon/sludge on the "Motion Plates" in the intake. This is also caused by the oil vapors from the PCV system.
I didn't overlook it because I felt it goes without saying what happens when you add a huffer or a turbo. Plus oil is a lubricant to both IIRC and when it's introduced upstream of the intake it doesn't have anywhere to go but into the intake.

Apparently Ford didn't/doesn't feel it's an issue or they would have increased the ring tension to compensate for blow by or they don't because the added tension would increase wear to the point of shortening the life of the rings.

In case you weren't aware Ford built an F150 eco and drove the **** out of it in a variety of ways and tore it down rebuilt it and drove it some more. IIRC after one tear down with over 100k miles the engine didn't show oil deposits, the front side of the valves were extremely clean. The rebuilds involved gasket replacement so as to monitor wear over a long period of time.

What people do and how they maintain there's including the type of fuel and oil can make a big difference. Back in the '70's 351c's began having excessive oil deposits/sludge build up, turns out that Quaker State changed there oil and because IIRC how clevelands water was routed the paraffin turned into a solid in the top part of the engine creating sludge.

I did address oil on the valves in my reference to road draft tubes. ALL ENGINES will suck, in the case of PCV systems, oil into the intake because some amount of oil mist from the whipping of oil by the crankshaft in the pan. The dripping oil, crankcase gasses and eventual smoke and excessive oil dripping from poorly maintained or from engines ran hard led to the invention of the PCV system. That didn't or hasn't changed what goes on inside the engine.

3V don't operate any differently than any other engine and 1 extra valve doesn't change anything. I'm not aware of any engines failing prematurely because of oil deposits. I wonder if the issue isn't the 3V but more about how hard some of those engines are run because of the cars they're in? Run a 302 hard and you'll start blowing oil out of the pan gaskets. Run a 3V hard at higher RPM's and it goes without saying that the oil is going to get pulled up by the crank far more than a grocery getter therefore more oil gets sucked into the PCV system. High RPM is why Boss 302's came with windage trays to help keep oil from being whipped around by the crank robbing HP and kept from getting sucked into the PCV system excessively.

These engines, 3V, just like the ones from days long past will and have run 100k miles many times over without any issues if maintained regularly without adding any catch cans.

I put one on my car for 1, because I don't drive it much and 2, I got it for less than a c note at a show.

Excessive carbon on the front side of the valve and intake runner comes from reversion during overlap which can be exacerbated by changing cams with more overlap. Not Ford's problem.

Ford isn't going to and shouldn't do anything because run of the mill engines don't have issues. Put a huffer on a car not designed for one and your on your own, even if Ford warranties it, it's not for excess oil in the intake.

Do 500's have an oil consumption problem, at least ones that aren't run hard?

Again people will sell you anything.

Are catch cans a need? Never have been, probably not now either.

If anything there was a "need" before todays oils and cleaner burning fuel and computers. If anything it makes more sense to put it on an old piece of iron even with todays oils and fuel.

Will it give some people peace of mind? Probably.

If your getting much more than a tiny bit between OCI you probably have other issues so in that case it could be an early warning system.
 
#24 ·
Good points made above. My separator can only gets emptied before oil changes now. Never catches much probably because I very rarely go full throttle to redline. I am a believer in windage trays, made sure one was installed when I had the 360 in my old '77 Dodge truck rebuilt. In a ideal world, a dry sump would be nice, especially as cornering ability is improved.
 
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