I don't remember if I posted this ever here as it was years ago that I did this. This is about making a better performing catch can at a much cheaper cost (~$30). It is better in function and looks (you can't see it). The key to performance is a very significant surface area. I went nuts and even installed a small transmission cooler in the path leading into it but feel that's probably overkill. I used to condense large amounts of water vapor it was so efficient.

I have this old picture when I first started messing with making a better catch can. The picture shows the basic body with an air compressor catch can next to it for comparison. A piece of 4" PVC, closed end cap and a screw-on drain cover on the other end make up the body. The screening is a few pieces of window screen to put in first at the top below the outlet fitting (on the closed end) to act as a chunk filter. I originally used coarse steel wool as a coalescing material but was leery of sucking in bits of steel. Some changes I made: I painted it flat black, used stainless steel Chore Boys in place of the steel wool plus I added a petcock so I didn't have to unscrew the drain. It is mounted on my GTO in front of the driver's wheel out of sight. It can be put anywhere within reason

Crankcase air enters the bottom via a 3/8" rubber gas tubing and is pulled through to the top through a very torturous path and then out condensing the vapor efficiently. The fittings were just screwed into plain drilled holes with the threads cutting themselves. Then they were taken back out and pipe sealant put onto the threads. I guarantee it works better than every high dollar unit out there plus the bonus of the hidden location.

 

So, if I read that correctly, the bottom connection would go to the ls6 valley cover (or equivalent) and the top would go to the intake manifold?

 

love to see this inside and also how it's connected on your motor!! well done!!

 

May work but is ugly as sin!

 

For what they are, and what is entailed in their manufacturing process, catch cans are quite overpriced. So it's cool to see a home-brew solution for a much more favorable price.

However, how can you guarantee that yours works better?

And what, exactly, is keeping any of the high dollar units from being mounted equally as hidden as yours? Why is out of sight listed as a bonus for your catch can? If anything, it should count against your catch can because being out of sight is a requirement, whereas you don't HAVE to hide the high dollar units.

I'm not trying to bash on your creation. I love homemade solutions. I just want to know what qualities you to guarantee that yours is superior to the high dollar units.

 

I would place the inlet up higher on the can, unless you drain it often.

 

If the car was up on a lift and you looked at the right place you may see it but it is flat black. It is invisible from any other angle.

Think about what they do. Effectiveness is about temperature, velocity and surface area. This is multiple times that in every department. It is cooler, air moves much slower though it, and it has a huge mesh surface area to coalesce oil vapor. Hiding can be done with the others too but I guess if you pay a lot for a can you want to see something for it. IMHO is preferable not to add stuff as an engine bay is cluttered enough looking. I removed my plastic FRCs for the same reason.

I agree is could hold more if it was higher but even at that height it holds more than the smaller ones. Besides the larger diameter that square on the cap is hollow and holds an ounce itself. Between oil changes the level is acceptable.

 

How did you install the mesh screen? Is it just sitting on top of the 4" PVC pipe, and then you install the top cap?

I'm going to build one of these. It sounds like it would work well, and I'm so far over my build budget, it's not even funny. I don't care what it looks like, as it will be hidden somewhere out of sight.

 

The cap was glued on and then the aluminum screening is just slightly oversized which holds it in place and is pushed up to where you want it. The mesh Chore Boys are below the screening all the way to the bottom. The mesh makes a torturous path that makes the micro-droplets which want to go straight collide into something to which they "stick".

For those wanting something "prettier" the same concept can be built out of anything but size matters for function and thus you may want to hide it anyways. The usual car "catch can" uses the change to the mildly larger volume of the can to slightly slow down the air and some use a small amount of coalescing material to try to get the oil micro-droplets to fall out. If you look them up the really good coalescing filters for air systems cost $300-$400 up to thousands of dollars for big ones. It should also be noted that the oil vapor concentration in a crankcase is much greater than a pneumatic air system.

 

You're not going to get any cheaper than the plastic
sump style fuel filter. You could paint it black with
some plastic paint and it'd pretty much "go away".

 

I wasn't trying to bust your ***** about it, I was merely asking if you had empirical evidence of your can being more efficient than the more expensive offerings.

Do you have to wash the stainless filter media? Does oil sludge build up in the media?

Also, is there a point of diminishing returns for how slowly air travels through your, or any other, catch can?

I might just box in and seal a section of my truck frame for a catch can. Just have some SS braided line plugged into AN bulkhead fittings, and a easy on/off drain... All built into a ~14" closed off section of frame between the motor mounts. Trucks make this sort of **** pretty easy.

Hmm...

 

She ain't going to be winning no beauty contest, but as long as it functions the way you want it to, then that's all that matters.

 

I like the ingenuity.. there is always room for new ideas!

I agree that it is bananas how much some charge for catch cans, especially passive systems that 'just sit there'. like you have constructed.

it is true you can pretty much put anything in an existing pcv return system and be granted with some level of oil catching.

-but this is a bit much no?
"I guarantee it works better than every high dollar unit out there"

 

I still need to pick your brain on which of your three catch cans would work best on my setup.

 

Another question for the OP -- Are you running anything on the fresh air side (throttle body to valve cover)? I have seen a lot of dual catch can setups, and I wonder if it's overkill for street cars. But, on the flip side, I don't want oil in my new FAST 102 or my Mamo heads...

So, I might build two of the PVC contraptions ...

 

the clean side contamination is easy to notice. and not consistent across the platforms.

i wouldn't throw money at it until you know it exists.

also if you give the crankcase pressure somewhere to go, it wont blow backwards out the clean side.

 

I just pulled my throttle off over the weekend, and I've got oil in my brand new fast 102 pooling right at the PCV inlet. Anxiously awaiting your "guaranteed not to let any oil through" PCV catch can

Question - will this can also change crank case pressure vs the LS6 valley cover going to the intake? For better or for worse if it does?

 

sending pm darth.

 

Mine works great. 240K+miles 5.3, LS6 valley cover/PCV. I catch a few ounces during each OCI. See oil inside? Spin the jar off, empty, spin it back on. Works as good as any design.

 

Original design was plastic PB jar-which got sucked flat from the vacuum, of course.