Catch cans, & Air oil separators

[cdlamb]

https://www.youtube.com/watch?v=Yop5vnYQ1Pc

Has anyone installed, & had good results installing a catch can?

Do they do anything beneficial, & can it be proven through engine oil analysis results.

I am considering installing the one above that can be viewed on youtube for a 2018 F150 3.5 EcoBoost.

I have submitted 3 samples for analysis & seeing fuel dilution issues, & thinking a catch can may help.

Has anyone completed oil analysis prior to, and after catch can installation to see if there is any advantages to oil life when using one of these.

Calvin

 

[BMWTurboDzl]

They generally perform as described however the usefulness with regards to today's engines is hotly debated.

A catch can will not prevent fuel dilution, it's designed to prevent oil vapor (blow-by) from traveling to the intake tract where it will condense out onto the back of the intake valves.

 

[StevieC]

I installed one on my 2018 Highlander and it caught quite a bit of oil in the begining and then what seemed like barely anything thereafter. Not sure if it was still seating the rings as it was new (most likely) or it was just an anomaly. I also have one installed on my cousins GDI Hyundai Veloster and it catches I would say about 1/8th of a quart between oil changes at 3K miles (5,000km).

Since I still have the one I used on the Highlander I'm going to install it on my Caravan as an experiment to see what it catches. Not because it needs it.

My threads on the subject:
https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4863602/1
https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4873504/1

 

[FlyPenFly]

At least on BMW and Audi engines with DI + turbos, it makes no difference.

I believe the intake build up is supposedly almost entirely from combustion blow by.

 

[SnowDrifter]

I have a catch can on mine. I capture 2oz or so of oil every 3k miles. I also have no EGR


Can still see bare metal on my intake

 

[Kawiguy454]

Very simply the catch can precipitate fluids from the EGR vapors so that they dont end up baked on the valves as someone said. This benefit is mostly for DI engines and non DI engines have fuel with detergents hitting the valves to keep them clean. I believe some Euro vehicle DI engines have additional fuel injectors positioned in the intake tract that spray fuel often enough to keep the valves clean. I read somewhere that the engineers have come up with a way to phase the valves in such a way that on DI engines a small amount of the injected fuel is allowed to reverse onto the valves just before they close to help keep things clean. My catch can picks up a few ounces regularly enough ...dump that into a fry pan and heat it until it turns into gunky carbon mess. Do you want that going into your engine?

 

[Linctex]

Originally Posted by Kawiguy454
. I read somewhere that the engineers have come up with a way to phase the valves in such a way that on DI engines a small amount of the injected fuel is allowed to reverse onto the valves just before they close to help keep things clean.



It would have to be very, very late in the intake stroke (very, very early in the compression stroke) - an event completely separate from the normal injection event

 

[StevieC]

Originally Posted by Kawiguy454
Very simply the catch can precipitate fluids from the EGR vapors so that they dont end up baked on the valves as someone said. This benefit is mostly for DI engines and non DI engines have fuel with detergents hitting the valves to keep them clean. I believe some Euro vehicle DI engines have additional fuel injectors positioned in the intake tract that spray fuel often enough to keep the valves clean. I read somewhere that the engineers have come up with a way to phase the valves in such a way that on DI engines a small amount of the injected fuel is allowed to reverse onto the valves just before they close to help keep things clean. My catch can picks up a few ounces regularly enough ...dump that into a fry pan and heat it until it turns into gunky carbon mess. Do you want that going into your engine?

Some OE's are using a dual PFI / DI setup and others are using specific valve temperatures and a combination of firing the injector a short burst while the valve is in the open/opening position or just before closing completely to create a mild washing effect and then firing the rest of the fuel later on after the valve is closed. Ford/Mazda seem to have excellent control of this. Toyota is using a dual setup like in their D4-S series engines. Hyundai/Kia has opted for GDI only and seems to be out of the woods on it now versus their Gen 1 vehicles which had big issues initially with valve gunk. I think oil is part of the equation as well helping it not to form in the first place but I don't think it's the sole answer along with a catch can but every part helps where the design might have slight flaws.

 

[ka9mnx]

I've heard pro's and con's on catch cans. Mostly con's. I thought about installing one but after a lot of research decided it wouldn't make much difference in the final outcome.

 

[StevieC]

ka9mnx, what con could there be about catching oil and allowing the crank case gases to be vented back into the engine thereafter? I could understand venting to the atmosphere.

Just curious is all.

 

[badtlc]

Originally Posted by StevieC
ka9mnx, what con could there be about catching oil and allowing the crank case gases to be vented back into the engine thereafter? I could understand venting to the atmosphere.

Just curious is all.


They remove gunk but they don't prevent intake valve deposits. There is still enough that gets by that it doesn't even appear catch cans slow down the process. So the con is if you are trying to reduce intake valve deposits, you just waste your money.

Catch cans are for the extreme tuners who need to get the octane rating of the A/F mixture as high as possible for peak output. The vapors caught by the catch can reduce the overall mixture octane rating. By reducing with a catch can you can

 

[StevieC]

I disagree with that... We installed the can on the GDI Veloster my cousin had to have cleaned under warranty and it drastically reduced the crud on her valves from needing it again and shortly thereafter we started the GDI cleaner through the intake but since the can was in place we just left it. And yes we looked at the valves on her car after installing it as we were trying to come up with a solution to keep the valve problem at bay. There are videos online showing a reduction in valve crud with these cans as well.

I think in some cases where they do a good job managing the valve temperatures, proper oil composition, proper ventilation in the crankcase and have valve overlap with the fuel injection to create back washing etc. it's not needed but what is the harm in adding it in case any of this falls short?

 

[IndyFan]

Another possible benefit of a catch can is specific to the FCA 3.6 Pentastar. Supposedly (I've seen it in YouTube videos, but have not experienced it in my Jeep) at extreme angles, oil gets into the cylinders in a big way and causes massive smoking as it burns, and in some cases, has caused engine damage. Mashimoto has made a catch can for the 3.6 that allegedly cures this issue.

I'll wait and see if this is validated, and if it is, I'll be adding one to my 3.6. I climbed a 33 degree incline in my Jeep that hit 35 for a short bit, but never saw the burning oil and the engine ran perfectly, so I think the angle where this occurs is certainly steeper than that. I don't intend to go any steeper, as 35 degrees is pretty hairy, but you never know. There might be a situation off-road where you have no choice, especially in places like Moab, Utah.

 

[StevieC]

Originally Posted by IndyFan
Another possible benefit of a catch can is specific to the FCA 3.6 Pentastar. Supposedly (I've seen it in YouTube videos, but have not experienced it in my Jeep) at extreme angles, oil gets into the cylinders in a big way and causes massive smoking as it burns, and in some cases, has caused engine damage. Mashimoto has made a catch can for the 3.6 that allegedly cures this issue.

I'll wait and see if this is validated, and if it is, I'll be adding one to my 3.6. I climbed a 33 degree incline in my Jeep that hit 35 for a short bit, but never saw the burning oil and the engine ran perfectly, so I think the angle where this occurs is certainly steeper than that. I don't intend to go any steeper, as 35 degrees is pretty hairy, but you never know. There might be a situation off-road where you have no choice, especially in places like Moab, Utah.


Indy, thanks for sharing that... We live near an escarpment that has some pretty steep access roads and I haven't encountered it with my own PentaStar or my dad's when I drove that one going up those grades but I can see how it can happen with the PCV oil separator being cam driven so if the head is flooded with oil and you tip it the right way it would spew it out the short hose going right into the plennum.

I still have mine from the Highlander so I will put it on the Caravan and see what it catches. (For fun) but now maybe in case of this ?!?

You would have to be tipped sideways toward the PCV oil seperator on the heads cam for it to happen but it is possible with it's design if you hit it just right especially with how much oil floods these heads as per Chrysler's design.
This would be a problem for the jeeps rock crawling I'm sure.

 

[IndyFan]

Here is the video. They show a clip where their Jeep was smoking terribly and sounded like it was ready to hydrolock the engine.

https://youtu.be/pzlP-ezGAMo

 

[StevieC]

Yup that's what happened...

 

[StevieC]

I put the catch can on today over what would be a lunch period between conference calls today because I was bored. Was quite easy on the Caravan and took 20 minutes. 1/2" hose worked great, no need to modify the OE system. I did take the boot on the one end of the plastic line that feeds the intake so I could shove the return hose in the one end and then the input hose on the can over top of the plastic piece going to the camshaft PCV.

This way if I have to take it in for warranty and I want to hide the can I can put it back to OEM within minutes and without tools.

Warmed it up and booted it on the highway to red line to make sure flow was ok. Only a few drips of oil in the can so far, return hose is dry after the test drive.

I'll take pictures when I go to check it for the first time.