Oil Catch Can - is it needed?

[Jhoude19]

So after doing some research, it seems these motors are "notorious" for oil blow by. So I ordered a Oil Catch can and will be installing it this week as well as doing a review, and install guide. But I was wondering if there is anyone with real world experience with these motors and running catch cans.

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[Mkcagle]

Never heard of this being an issue. Do you have any source information?

 

[Jhoude19]

Never heard of this being an issue. Do you have any source information?

just from research online, my other project cars are all turbo'd so im used to blow by issues. I decided to do some reading up on it for these motors and found some people having some issues. granted most are on the older 3.6 in the jk systems but that's why I was asking if anyone had any issues with these newer designed motors.

 

[PyrPatriot]

Interested

 

[jrf]

Newer ones still can blow oil while parked on steep inclines. I've watched it on the JLs but honestly haven't had a chance to see if the JTs do it too. Would assume so. The catch can kits are very expensive for what they are. I'd like to see someone come out with a reasonable kit.

example on JL


example of steep hill...and no that's not all tire smoke

 

[Jhoude19]

Newer ones still can drain oil while parked on steep inclines. I've watched it on the JLs but honestly haven't had a chance to see if the JTs do it too. Would assume so. The catch can kits are very expensive for what they are. I'd like to see someone come out with a reasonable kit.

example on JL

I actually ended up purhacing a mishimoto can and did a write up and video on it.

 

[ShadowsPapa]

There should always be a vacuum in the crankcase. To me any blowby means abnormal - needs attention.
Turbo changes things as you are increasing the combustion chamber pressures quite a bit (and why some engines blow when adding turbo and no other mods)
Drag racers use vacuum pumps to keep a vacuum in the crankcase. Aids ring sealing, etc.

One test we always used to do to check engine physical health was to measure the vacuum in the crankcase.
Pressure = bad.
Vacuum = good.

Interesting to hear there's any issue at all that way in a normally aspirated engine.

 

[Bowerss2]

Catch cans are not needed in any modern, stock engine. They are nothing more than a vapor/oil separator. If you don't have one with internal baffles/filter/screen/etc then they are REALLY pointless, the majority of the oil and muck will stay suspension and just go through to the intake anyway. If you have enough blow by that you need one on a stock engine, they you have a serious problem with that motor.

If you do want a catch can, just to have something else to maintain, or because it makes you feel better please under no circumstances have it vent to atmosphere. It must be routed through the intake and under vacuum. Otherwise it will be doing more harm than good. Having a vacuum to scavenge the crank case vapors is a good thing.

As for the above video, yes no more smoking, really not much of a problem, but if you are actually driving on those extreme angles, then yes install one. Same reason I installed one on my 700hp blown corvette, its an edge case.


TLDR/
If you need one, you will KNOW you need one also/and; I will never change peoples mind on this, or CAIs, or anything else, but there ya go.

 

[ShadowsPapa]

Catch cans are not needed in any modern, stock engine. They are nothing more than a vapor/oil separator. If you don't have one with internal baffles/filter/screen/etc then they are REALLY pointless, the majority of the oil and muck will stay suspension and just go through to the intake anyway. If you have enough blow by that you need one on a stock engine, they you have a serious problem with that motor.

If you do want a catch can, just to have something else to maintain, or because it makes you feel better please under no circumstances have it vent to atmosphere. It must be routed through the intake and under vacuum. Otherwise it will be doing more harm than good. Having a vacuum to scavenge the crank case vapors is a good thing.

As for the above video, yes no more smoking, really not much of a problem, but if you are actually driving on those extreme angles, then yes install one. Same reason I installed one on my 700hp blown corvette, its an edge case.


TLDR/
If you need one, you will KNOW you need one also/and; I will never change peoples mind on this, or CAIs, or anything else, but there ya go.

Exactly. Like I was saying - if you need one there's a problem, of course running extreme angles or a blown engine, perhaps, yeah.
There's a lot of marketing out there, a lot of bad info, and of course - "he has one and he's cool" helps sell them.

 

[Renegade]

I’ve experienced it once while attempting an extreme climb. I was at an approximately 60 degree angle for several minutes, while trying to climb a ledge. Oil made its way to the intake, and I started blowing smoke from the tailpipe. It continued for several minutes, even after backing down. I may put one on it at some point, but I also don’t think it’s causing any damage to do that every once in a while.

 

[ShadowsPapa]

I’ve experienced it once while attempting an extreme climb. I was at an approximately 60 degree angle for several minutes, while trying to climb a ledge. Oil made its way to the intake, and I started blowing smoke from the tailpipe. It continued for several minutes, even after backing down. I may put one on it at some point, but I also don’t think it’s causing any damage to do that every once in a while.

Depending on engine design, it can be drain-back to the pan - if the oil up top can't get to the drain holes in heads and the valley, it accumulates. There's times that some of us run our cars so hard there's so much oil up top on the heads and such we can make the oil light flicker and smoke out the tail because of the oil accumulation around the valve stems.

 

[FL Handle Guy]

If you have direct injection a catch can will help. Direct injection sprays fuel into the cylinder and any oil that may blow by can build up on the top of the valves. If you don't have direct injection (port injection like our 3.6L gladiators or both port and direct) it will mix with the air being drawn into the cylinder and will clean the valves as it is drawn in.

Watch this video


Read this article and you will get a better grasp.
https://www.autoguide.com/auto-news...a-problem-with-direct-injection-engines-.html

 

[Jhoude19]

update, just over a month after installing the catch can, with roughly 1000 miles. drained the can for the first time.

 

[JCJL]

what catch can are you guys using

 

[Jhoude19]

what catch can are you guys using

mishimoto catch can

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