FitFreak's - I have gone overkill on this post. As I have surfed the web and considered a catch can on my previous 2015 car, and now finally installed one on my 2018, three-plus years of thinking about this and I have encountered so much random stuff along the way. Shocking amounts of bad advice, amazing amounts of great advice, and many little helpful morsels of info tucked into posts. I have gotten carried away with this thread and really decided I would attempt to (with the help of others) create the last thread you need to look at if you are on the fence about doing a catch can on a direct injected Honda Fit.

Disclaimer: Do your own research and consider this part of your research. I am not an engineer, I am using my idea of common sense.
Disclaimer #2: I do have a few links in here to other members posts. I have a link to HowStuffWorks - there are many others created by keywords and the fact this site is integrated with Amazon. Those are not me... I am not trying to sell a vacuum .

Nice and simple read about Positive Crankcase Ventilation, also more simply known as PCV. ==>Auto How Stuff Works - PCV

Amazingly educational read: http://www.conceptualpolymer.com/Documents/pcvor.pdf

Simple examples that help new gear-heads learn. Stuff to think about while discussing PCV. (by CyclingFit)

• A rotating engine is sucking air in and pumping air out as long as it is rotating, even without hitting the accelerator. You can imagine setting your engine on a work bench with the exhaust system still attached, and then connecting the crankshaft to an electric motor. If you spin the crankshaft, the engine would be blowing exhaust and sucking in air. If you reached up and opened the butterfly by hand, the motor spinning the crankshaft would not have to work as hard because you would be removing the vacuum in the intake and letting the intake return to atmospheric pressure. I am explaining this to help give you and idea of why there is vacuum in the intake manifold.
• Because an engine is sucking in air, if the butterfly closes or is near closed at idle, there is vacuum inside the intake manifold. This vacuum is drawing more from the crankcase and allowing the PCV emission system to work.
• If you are using the engine to decelerate or possibly to maintain speed while descending a mountain highway, the higher revs while off the throttle will be sucking in tremendous amounts of air, creating much higher vacuum in the intake, thus sucking even more crankcase air. This is why a stick shift car, or a using the CVT paddle shifters may get more benefit from a catch can.
• A closed catch can system means there is not an open air filter on the catch can or in the PCV system. An opening on the PCV system may as well be a leak in the system. Imagine engine vacuum trying to pull bad stuff out of the crankcase, but instead it is just sucking clean air from the little filter you mounted in the PCV system. This means the bad stuff that we may want out of the crankcase will just stay in the crankcase until is blown out instead of sucked out by vacuum.
• So why would someone want that little filter or an open system? Super high revving race cars. Race cars being run at their max have enough blow by that they can have much greater "positive" pressure in the crankcase and it can push the bad stuff out. Race cars do not want to risk anything coming back into the intake side that could take horsepower or change the tune of the car. A race car is more likely to care less about smell under the hood, and more about consistent clean horsepower. Leaving contaminants in the oil is not as big of deal when a race car may get an oil change every time it goes out to race.
• There is more than just oil in the PCV system. There can be fuel that gets by the rings and water created from condensation. A closed system is going to help pull out the fuel vapors and moisture away from your expensive synthetic oil.
• But I keep talking about air being sucked out of the crankcase and vacuum, WHY IS IT CALLED POSITIVE CRANKCASE VENTILATION? There is positive pressure in the crankcase too and it can push stuff out.

Other Fit Freaks systems in use - that I am aware of:
bdcheung - conventional closed system - using stainless steel wool inside the baffle
skatana - conventional closed system
UnFitRick - closed system - mounting requires non factory intake
bigD_2015 - closed system - mounting requires non factory intake
Fitftw15 - closed system - not sure mounting modifications
evilchargerfan - air compressor water/oil separator type (testing a different system after confirming the water and oil separator is too restrictive)
idroveacamry - this system not agreed upon due to how it connects but sharing here for reference if anyone is doing mass research ( POST 26 will explain why this is wrong)

Note: Changes or future ideas for my system are in order with dates at the bottom of this post.

My Install: (with changes along the way - I may update this to only show it's current look, but I think something can be learned by reading my experience)
It seems no two people are buying and installing catch cans in the exact same way. Today mine went on and here is my story.....

I have popped the hood three days in a row and thought about the install and here is what I came up with. My goal is to make it one full oil change, or about 7,000 miles before emptying the can. (update: I currently think that with many short trips and a lot of city driving, tests are showing 2,500 miles - look at posts 114, 115, and 116)

Car: 2018 EX CVT
Mileage: 16,245 at time of install.

I purchased the catch can on eBay for $25 . These are obviously cheap in terms of fittings and initial finish, but the finish can be improved. Mine did not come with o-rings / gaskets for the fittings.

How can the finish be improved? Each picture will have an explanation captioned below it. Also, not pictured, I put a small bit of grease on the threads so everything spins apart super smoothly in the future.


This little removable baffle had a shaving left all the way around the threads where it comes apart. It popped off easily and I made sure it didn't leave a sharp edge.



Look closely into the holes and you will see burs left behind and ready to easily break off. I used a hex wrench and wobbled it around in each hole and the excess pieces all came off. I then ran a rag around each side to check for more pieces sticking out.



Here is the large shaving that needed removed. You can also see the small burrs / shavings in the small holes.


Stuff that fell out onto my counter as I improved the fit and finish.
Moving onto the install. Again, captions under each picture...



I noticed a thick aluminum flange on the passenger side of the engine, just above the alternator. This flange already has a hole in it that is tapped with nothing installed in it. The hole is M6x1.00 and my bolt is 12mm long. The little bracket is from the aisle with all the gate hinges and locks at Menard's (home improvement store) The wires going under the bracket are now going over the bracket. I gave a very slight bend to the wires at their crimps. You'll see in later pictures. I ended up using a larger washer that you can see in later pictures. Also I had to open up one of the holes a little bit. You can see the holes are not aligned over each other. I gave a very small tweak by hand to make the can hang perfectly vertical. ABOUT THERE ONLY BEING ONE BOLT.. After tightening everything down, I noticed that no matter how much I move the can, the back of the bracket does not move. I have an M5x0.80mm tap because I was thinking I would drill and tap a new hole in the back. I currently do not see a need for it unless the bracket tries to rotate. If I do tap it, I may switch to M3 and a fender washer this way I leave a lot of material behind.



These two items made me happier than they should. Auto Zone was the only parts store open and nearby, so I purchased needle nose pliers from them. The clamp at the PCV valve is a breeze with these long angled pliers. You will feel like a hero if you own a set. I am also an addict to looking as factory as I can so I purchased two packs of spring clamps. I had to get two packs because there are only two 3/8" clamps in each package.



Closeup - top view Routing design has been changed - Leaving this picture for reference in case you choose this direction. Updates are later in this opening post.





Top view Routing design has been changed - Leaving this picture for reference in case you choose this direction. Updates are later in this opening post.




This angle you can see what I did with the wires and loom going over the bracket. Routing design has been changed - Leaving this picture for reference in case you choose this direction. Updates are later in this opening post.




Clearance to the alternator. More than enough room to remove the lower can to drain and clean. Routing design has been changed - Leaving this picture for reference in case you choose this direction. Updates are later in this opening post.



Adding one more finished picture, this way the post ends with a finished picture! LOL. Routing design has been changed - Leaving this picture for reference in case you choose this direction. Updates are later in this opening post.


Thanks for reading. I'll update the thread when updates are available or if anything changes.

UPDATE: 7/30/2018
I am not an engine engineer but I happen to be surrounded by many of them at work, so I try to inherit some of their better traits... Already it is bothering me that I have hoses that move with the engine, resting on the body under the hood. I just ordered THESE adapters that will allow me use standard pipe thread 90 degree fittings... This will allow me to route the hoses facing more directly at their destinations and it will allow me to take a few inches of hose out of the system. Pictures will be added.

Update: 8/1/2018
Thread adapters arrived. I really did not like that the hoses touched the body. The engine rocks and the body does not. This means moving parts would touch non moving parts.... I am a little frustrated with myself for not patiently waiting for lower profile brass fittings or dropping the big bucks on the super nice black aluminum fittings. I ended up using a bushing to make what the store had larger and fit into the thread adapters. I will likely still order what I want, but spending $10 today was easier than spending $40 for black aluminum fittings.

Except for color clashing, this now looks much smoother... again, making me anxious to get the other low profile black fittings.



Update 8/2/2018:
Okay.... I think after a week of people with posts, chatting with others in PM, and now making what could be my final change. Here is what I have done.

I have now added stainless steel wool (amazon will try to make that a link, it is not my link) to my system. A lot of it.... All of this research has told me there has to be something to cause agitation in the flow of air and help 'catch' the oil. As it is caught it can grow into a full drop and move to the bottom of the can because of gravity. This is pretty much the definition of coalescing. I also changed the routing, which may startle some people, but I really believe this is a super great move by me. Update: Also learned that that the scowling pads act as baffles to prevent liquid from splashing inside the can. Very important as it fills up.

If you have been following what I have done:
>> Most startling thing someone may notice is that I have air going into what some people see as the exit.
>> The hose with air leaving the can is now on the top. I really only did this to give me plenty of space between that fitting and the washer fluid reservoir. The hole on top of these shares the exact same chamber as the hole that has the plug in it.
>> The reason I am bringing air out of this side of the can is because this side has the baffles. I am using the baffles to help ensure I don't let any steel scowling pad out of the can if a piece were to become dislodged. It is held inside with a small amount of compression, so no moving or vibrating pieces should dislodge.
>> I have completely filled the can with the scowling pads that are shown in the pictures. This required two pads.
>> Why is the can full of wool? Because I didn't want air to simply fly across the top of the pads. I am hopeful this forces air through them. They are very coarse so they will not cause resistance.

As usual, captions are under each photo.



The 3 pack of scrubbing pads, $2 at Target.



Two scowling pads = Full Can!



Moved the intake manifold hose to the top of the can. Some cans are labeled in a way that makes this the "IN" side. I am using it as an out.



Picture take to document clearance to the washer fluid reservoir. Also the hoses are lightly zip tied together to give them more support.



A view to show the amount of clearance for the non factory items.

I am hopeful I can call the system complete. I will end up buying or borrowing a vacuum and pressure gauge to make sure I am not risking anything in the long term. I blew through the factory pcv hose and it had the same or more restriction.

11/12/2018 - First long-term test is complete at about 2,300 miles. Click here to jump to posts 114,115, & 116

The following results are from posts later in this thread. Many of them will contain pictures of the quantities.

 

nice mounting location for the catch can

 

 

nice install!

 

Very nice install. So what size is the bolt that you use near the flange? Stopping at the hardware store this morning to get the hose and angle bracket.

 

Just confirmed that it is M6x1.00 and 12mm length. Because it is only one bolt doing all the work, I would recommend you grab one that is hardened. (preferably 9.8 or 10.9 metric hardness) I will likely switch mine out a regular bolt so that it's not the only hex head I see in the engine bay. Long term, I will likely cut the back hole off the bracket, also for cosmetics.

 

catch can users .... I'd like to put something out there .... if all of us could do weekly or monthly checks or check every X amt of miles driven, how much oil is collected in the catch cans .... as a squad, we could get an idea of how much oil collects in X amount of time/miles driven.

I'll be sharing the amount mine catches, on the next tank of gas ... so far, after 1 week, mine looks like this:




(when I dump it, I will measure how many ML came out ... I promise)

 

I like this and it would be totally fine right here in this thread.

It would be cool to know:
A. Year
B. Mileage
C. Transmission
D. Type of separator (Cheap Baffled Can - Cheap Baffled with xxxx media - compressor water/oil separator - etc... )
E. Picture or picture with measurement of what you caught trying to make a pass through your engine.
F. Optional opinion of your driving style (low revs - normal driver - every road is a race track)

 

I have a suspicion that the manual transmission drivers are going to pull considerably more oil into their cans. Every shift momentarily closes the throttle body. Every time the butterfly is closed and the engine is used for slowing down there should be way more vacuum being pulled on the system.

A CVT in Sport Mode or heavy use of the paddles would be close to the same as above in terms of slowing down, but probably not the same in terms of up-shifts.

Just another two cents... thanks for playing along. I am excited to add longevity to a car that I like so much.

 

2018 EX CVT - 90% cruising highway miles
1024 miles on the odometer (catch can installed at ~900 miles)
Amazon catch can with stainless steel wool in the baffle
It's collected some, but not enough to really measure. I'd say ~2.5ml

 

bdcheung - Do you know where you got your bracket? Sorry if you shared this already in a previous post. It looks higher quality...

and thanks, I knew I was missing one in my list above.

 

I cannibalized it from a set of curtain rod hangers. I think it's IKEA.

 

Updated my thread. Will record milage and driving conditions. I tow my trailer too so mine may be worse than all ya'lls I recon! Either way, its installed like Cyclingfits setup, and mine says "Oil Catch Can" on it too haha! No CEL lights or codes. Engine runs and idles fine.

Cheers!

 

 

YMMV but for me, the point is readily apparent when I look in my catch can and see a puddle of fluid that did not get pulled into my intake manifold and, subsequently, splattered all over my intake valves.

 

Has anyone considered just routing the hose to dump into the air intake BEFORE the air filter, so the air filter catches all the oil?

That's how my old jeep does it from the factory. You get an oil spot on your air filter, but it accomplishes the same thing, and if you replace the air filter as often as you should, shouldn't be a big deal.

I could see myself forgetting about or putting off emptying the catch can for a few... years... and eventually sucking a whole bunch of oil in all at once.

 

Hi Dave - it is okay if you, "don't get it," and it is okay if you don't get what I am about to say, but I want to say it for you, and others that may feel the same way.

>>My personal life rule about engineers and where I develop my respect for engineers - in most cases... Many engineers could build a better car, a stronger bridge, a faster airplane, a better paint, or a more durable widget. But what makes engineers special, is that they work inside the restraints and balance of: LAW, MONEY, AVAILABLE SPACE, TIME, AND SCIENCE.

>>This is not a problem that is likely to effect the car while it is still under warranty, this is a key reason Honda engineering is not going to care quite as much. Long term reputation then? Other cars in this class will suffer from the same issues, so it will not be like Honda stands out with an issue.

>>Why not fix this issue at Honda? Business decisions are telling them it is not a big enough issue. How many of these cars will be on the road with 150,000 miles? Or more like, how many do they want on the road with 150,000 miles? If they fixed this issue, would they create other issues? Would they create an oil separator that would be more likely to fail and cause a bad reputation for unneeded parts? Remember, saving 5 cents on a part is a big deal in the automotive world. Imagine adding $15 to their cost? If they make two million Fits, and they spend $15 on this fix, that is $30,000,000 dollars they would spend to make a very small percentage of high mileage owners happy.

>>This is an issue that is created by direct injection, direct injection is needed as automakers push hard for fuel economy to make the EPA happy, or make their own company happy because of CAFE Standards or trying to build CAFE Credits <-- do your own research here, it's an amazing topic. Companies will do crazy things just to sell other vehicles in their line up... How much compact car junk did Chevy sell to offset the CAFE numbers and push Suburbans out the door in the 1990's and 2000's, I bet a lot.

>>This issue will probably only result in degradation of car performance for most people. Slightly less HP, slightly less MPG's.

>>If someone plans to keep their car only through warranty, or for sure less than 100,000, this is probably a waste of time and money unless they plan to use it as a sales pitch when they sell off their Fit, hopefully to someone that appreciates their efforts.

If you made it this far, thank you for your time.

 

My previous Jeeps: MJ, two XJ's, and a ZJ, all with 4.0L engines did just as you say..... The quick answer is that you do not want oil on that side of the MAF Mass Air Flow sensor. Oil on the MAF is bad. Over oiled air filters like a soaked K&N, are bad. Still keeping it simple.... It throws off the reading, dirties or ruins the MAF. The Jeep does not have a MAF.

Thanks!

 

DaveGee

I say this with the utmost respect... I dont have any doubt that Honda (and lets just throw in TOYOTA) engineers know what they are doing. I also equally have no doubt that "design flaws" happen, and I wholeheartedly feel that the pcv dumping oil into the intake manifold onto our valves is .... IMO .... a design flaw

I have another car, that feel victim to what we here are all trying to prevent ... oil collecting on the valves and in the intake manifold. my other car has a 3rd gen prius motor in it, without question the prius is popular and reliable engine .... but it has .... design flaws.


its alot to read, but if interested ... here is the hell that I went through:

https://www.clublexus.com/forums/ct-...tart-up-2.html






credits go to the guru's over at the prius forums, those damn tree huggers know their stuff:
https://priuschat.com/threads/oil-ca...-knock.179588/

 

TL;DR to my above posts .... I genuinely feel that had I installed a catch can as of day 1, my motor would not have had a HG leak

and to our awesome OP .... THANK YOU ... for stepping up and taking ownership on this topic, this is huge!