I installed 2 oil catch cans end of summer 2022, walnut blasted the intake valves in November 2022.

Before blasting: (Note this replacement new engine has about 30k miles when pics taken)







They looked like this after blasting and scrubbing:







I took intake off yesterday. 13 months later and MAYBE 5000 miles (I can get an exact mileage later) later and the valves looks like this despite 2 catch cans.






The passenger side PCV is the one that collects 95% of the oil, but honestly they haven't helped much at all.

 

Catch cans won't prevent coking of the intake valves. What you need is a water-methanol injection kit.

 

aha....no thanks...more complexity not desired.

 

Oil catch cans were not invented to keep valves clean. That is snake oil that has been pimped and regurgitated by morons who get most of their info from facebook. Oil Catch Can manufacturers have grabbed onto this nonsense and use it as a marketing tool... oil catch cans do A LOT for a motor. The one thing they do NOT do it prevent coking on the valves.

What oil catch cans DO is massively reduce (not eliminate) the amount of blow-by that is making it into the combustion chamber. The reason why this is beneficial is because blow-by is not combustible. The more blow-by that enters the combustion chamber, the poorer the ignition is. On a stock vehicle with a stock tune, it doesn't matter as the cars are designed, manufactured, and tuned to accommodate this. However, when you start modifying the car to bring in MORE air, expel MORE air, increase boost, and advance timing (to create more power), you heat up the combustion. This is why folks who increase boost need cooler spark plugs. When doing this, you also need to ensure the most efficient combustion possible.

Enter the oil catch can. The Oil Catch Can reduces the blow-by that makes it into the combustion chamber and thus allows for more efficient and hotter combustion.

With that said, since no Oil Catch Can eliminates blow-by 100%, the first thing to get fouled up by the blow-by that does make it past the can is the intake valves.

So again... Oil Catch Cans are NOT tools to keep a motor clean and if folks have no intention of tuning the motor for more power, there is no real benefit.

As noted above, the very best way to keep the valves clean is to install an WAI system. That is, a Water/Alcohal Injection (a.k.a. methanol) system.


so, before you come here saying Oil Catch Cans do NOTHING....understand that Oil Catch Cans Do now, and have always, and will always, do exactly what they were designed to do.

 

FB has nothing to do with this. The issue is such that Toyota and Ford now have returned to PORT and direct fuel injection.

You realize the catchcan is is just a very crude filter in the existing PCV system which reroutes those gases/oil right back into the combustion chamber right?

CCs are not intended to eliminate blow by. They are intended to catch the suspended oil coming from the crankcase.

Its a desperate attempt to catch that crap before it coats the intake valves.

My $25 CC arent very good at that.

https://www.roadandtrack.com/car-cul...tch-can-works/

 

I've been wrenching, racing, and tuning cars for 25 years... I know exactly what an OCC is AND what it is not. You are dead *** wrong in your regurgitated assessment that it is "a desperate attempt to catch that crap before it coats the intake valves". That may be what idiots have accepted but that is not why they were invented. That is not why responsible tuners REQUIRE them before tuning and advancing timing, that is not their intended purpose at all. I've explained their purpose, choose to understand it or don't.

Again, the idea that they are supposed to keep the valves clean is snake oil and just one idiot passing along bad information to the next idiot. You are part of the problem.

You clearly bought oil catch cans thinking they would keep your valves clean, which tells me you have NO idea what you are talking about and you need to stop spreading information you have no clue about.

 

Cool study by SAE International in Australia on crankcase oil mist separators from 2019. ATTACHED.

Need to change the title of this thread to SOME OIL CATCHCANS DO NOTHING.

"While a wide array of separators are available in the international market, we restricted our study to those separators readily available in the Australian market. More specifically, we focused on proprietary models used in the Australian market as well as “imitation” models. It was considered important to include such (often unbranded) imitation separators, in order to allow users to undertake cost/benefit assessments."

Some of them had fibrous elements, some were cheapo ones like the 2 generic units I have installed with just stainless-steel wool and some simple baffles, some had wire mesh. None the units they tested were the exact unit found on Amazon/eBay that I have.

"The worst separators [CC3- empty settling chamber and cyclone] were 12 times and 20 times worse than the best filter [CF1.2 CF1.2 is Flashlube-branded product] based on quality factor, respectively."


Cyclone:



"On the other hand, all catch can-type separators and the cyclone imposed high resistance to air flow in the system, coupled with low capture efficiency, which resulted in a poor quality factor for both types of devices."

Looks we need to upgrade to better quality CCs because the type of can makes a huge difference in capture. MANN+HUMMEL . Not cheap at $200 but with replaceable filter.

https://www.westernfilters.net.au/ma...ro-3931070793/

Looks like the multistage filter in my air compressor setup.

 

Any update to this discussion? Would love to hear more about if I need a CC for my stage 2. If so, which side of pcv if not both?

 

Comes down to this, if youre gonna install one or 2, dont bother with a cheapo generic unit like I have. They dont do much at all. The SAE research data proves that there are vast differences in effectiveness.

Get the best unit you can preferably with a filter like Mann sells. I dont know who makes the best option.

Understand that you will still need to do walnut blasting every 30-60k miles.

 

walnut blasting isn’t an issue for me. Find it fun and meditative to put work into the car.

however, this isn’t the first time I’ve heard about the blow by issue. I believe Lou @ protype r, a respected tuner on here, has mentioned something about this for tuned cars. Something about lowering the octane and reducing the risk of detonation or something like that.

 

All cars have PCV systems, the problem is the direct injection (DI) that doesnt let gasoline run over the intake valves. Doesnt have anything to do with tuning or octane.

This is a universal DI issue. his is why some manufacturers are going back to DI with PORT Injection.

Cool, get a walnut blaster machine...I'm about to buy one even though I have a massive compressor blah blah blah..... This Ford dude endorsed this $400 machine


This is worth watching too. His CC did not solve his carbon buildup.

 

I think we can all agree here that catch cans don't do much for carbon build up. The only way to truly help with that issue is methanol or port injection. You'll need something to "wash" the valves constantly for them to stay clean.

The importance of a catch can isn't with cleanliness, it is for reducing detonation. On a modified/tuned vehicle, you want to reduce as much lower octane "fuel" as possible. Vaporized oil can cause detonation and knock, problems that can be catastrophic to an engine. Any oil the CC collects is oil that isn't going into the cylinders and isn't potentially causing issues. Saying CC's do nothing is disingenuous. It's like complaining that JetDry doesn't clean your dishes. That isn't it's main purpose. Unfortunately, it seems there has been a lot of advertising saying they keep your valves clean, which muddies the waters even more for their real job, helping prevent detonation.

You are right with getting a quality CC, though. Cheap ones definitely don't collect the oil vapor that a quality CC will collect.

 

Even the cheap ones help a little but you do introduce multiple additional points for vacuum leaks.

Maybe a MANN type CC with a filter that really separates oil/water from gases would be great but. Not sure why this isnt more common place. Ive only see baffled units.

 

An oil separator of adequate size will do the job

 

 

Does the N14 have a fully internal PCV channel in the head like the N18?
I mean the pictures certainly make it look that way - that would explain the two small lumps in the intake port, and why the catch can is doing virtually nothing.

Yes some people use catch cans for reducing carbon buildup. Yes some people use catch cans for reducing oil in the charge air and its effect on octane/knock resistance.

The internet loves the Mann Provent. I have a Man Provent 200, and I removed it from my E30 after finding oil in my turbo inlet after a short time of running it. I don't think it does a good job filtering because the 'filter' is on the inlet from the valve cover, so the oil needs to pass through this filter to get to either the bottom and drain, or the outlet to the intake. I don't understand why it is designed this way.
I've seen people install them 'Wrong' so that the filter is inline with the intake and drilling out the check valve so it will flow that direction, so that the air has to travel up and through the filter to get to the inlet ( Like Post 2 here: https://forum.ih8mud.com/threads/pro...estion.588697/ )
The 200 is also bigger than it looks.

Yes Scotty Kilmer is a crackhead.

 

I think its all mostly a waste of time because my valves on my 2 gas turbo GDI cars, Mini and Japanese, still get filthy even with the baffled CCs installed.

They just aren't very good filters it appears.

And like the video states, if they freeze youre in trouble.

 

I think it's a fact of life even if you spend a lot of effort closing off the internal ports like Lou did here ( https://www.northamericanmotoring.co...arbon-fix.html ) AND have a robust catch can setup that flows adequately, actually captures oil, and can hold/contain sufficient oil that it doesn't overflow or puke under cornering...

No idea if there are any long term negatives to blocking these ports.

Strong agree on WMI not being worth the squeeze.

 

BLOCK PORTS is CRAZY! These damn Mini's already leak everywhere they can, dont encourage it. Crankcase pressure has to be relieved in a controlled fashion.

 

I will throw in my two cents. I use an Elite Engineering E2 catch can on my Mini. Why? It is a very popular choice over in the Camaro communities, and LS world. What I really liked about them is on their website, they have a very detailed description of what their catch can does. They also have a spec sheet of it torn apart and detailed of what it does. Not like an Amazon catch can that is just a can with two ports. I don't believe I needed to get the E2, but I got it for a good price second hand, so that is what I put on there. It has done a great job and I am very happy with it. I used to have a Moroso on the Mini, but switched it for this one. The Moroso was on the car when I got it, and I knew I wanted an Elite Engineering one, so when I stumbled across it, I got it. Although there was nothing wrong with the Moroso and it catching the extra oil (and I have it on one of my Camaros), I knew I wanted the Elite because they stood behind their product. I can't tell you that it 100% eliminates the carbon build up because I run methanol injection as well, but I do feel better with it being on there. https://www.eliteengineeringusa.com/

Another product that I like, is the Improved Racing. They just came out with a new catch can that is pretty nice. They as well have a detailed view of what their catch can does. They also have the ability to change the top to a vented filter, PCV restriction valve, and they have a small size which would be great for our engine bay. https://www.improvedracing.com/ccs-o...separator.html

For the freezing portion in that video. I find that very strange. I don't live in a super cold climate, but I have NEVER heard of that. I know it would be discussed in the LS community from people that daily drive their cars in snow and what not if it were a huge issue. I am sure that it could happen, but not very often. I would think that you would have to neglect it for a very long period of time. As in, never emptying it out. I check my can every 1,000 miles and it barely gets 1/4 of the way full. That would have to fill up completely to block all the ports. At that point, what is the point of having one? Since when it is warm, it would just be sucking in that fluid. And it can't be the lines freezing, because without a can, what is in the stock lines?

 

Scotty Kilmer is getting nuttier and nuttier as the years progress. How that dude doesnt have even a measly scissor lift is a testament to how peculiar he is.

He knows "everything".

 

Freezing happens. Happened to one of my buddies. He lost quarts of oil on the highway in the dead of winter.

https://www.mcnallyelectronics.com/K...nths_b_12.html

 

Scroll to minute 6

 

From Lou's thread, here's a post about the N18 PCV system, screenshotted the 'N13-N18 Technical Training' document that's out on the internet somewhere:

https://www.northamericanmotoring.co...ml#post4673291

For the curious, here are all the number labels:
Depending on year/market, the N18 may have a third PCV port on the side of the inlet pipe, which has a check valve to only allow air to enter the crankcase. It also may have heaters for both PCV ports on the inlet pipe (on other chassis, this was sometimes tied to a cold climate option)

N14 I know has a second hose that is often deleted. I don't know much about it though.

On the N18, blocking the ports in the head probably helps the oil buildup a lot if you have a catch can. Otherwise, the only time oil vapour even goes to to the catch can is when you're making boost.

Edit:
Actually post 8 in that same thread has a torn-down N18 valve cover, so the differences are visible:

https://www.northamericanmotoring.co...ml#post3895220

 

Yeah, like I said, I know that it could happen as there is water in it. But, it seems like it is coming down to lack of maintenance. I check mine every 1k miles, sometimes 500 just because. And yeah, in the winter I usually do get more condensation. Another reason for me to check it often. When I hit that mark, I will check the oil, and it takes me another 5 minutes tops to spin off the can and then empty and clean it out. The link you posted said to drain it often, and the video said the same thing. I wouldn't say that freezing should be a reason to be afraid to get one like that other video you posted. But, just my two cents! lol