Let's talk oil breathers/separators

I'm getting into the serious part of building the Cobra for autocross and the occasional Track Night in America. I'd like to replace the hokey PCV valve system, which is currently letting the engine suck down oil, with some sort of an oil catch can/separator.

So far I've found two candidates. First is the Moroso 85486, a metal separator that holds a quart and is designed for use in my year/chassis. It's pricey at $145, but it's also a "known" unit that works. This of course being GRM, I thought there might be a better way, so I found the Jaz 605-375-05, a half quart mini breather usually used on roundy-round cars. It's lighter as it's a plastic and it's cheaper at $84 shipped.

Any reason not to use the Jaz? Any experience with either one or should I be looking somewhere else entirely?

Not sure of your year but have you tried American Muscle. They're my Mustang go to place.

I just bought a JLT one for the SHO. I haven't installed it yet, but after looking at the thing, I'd probably just go with the cheaper option. There's not much to it.

I shelled out some bucks for a Radium catch can. It's nice, anodized billet aluminum, decent filtering media, cool built in dip stick, etc. It probably does the job just as well as the cheap one that you're considering.

Those are two different kinds of catch cans...the Moroso is a suck-through and the Jaz is vent-to-atmosphere.

A suck-through is better emissions-wise and will keep your crankcase and oil cleaner and your crankcase pressure lower, but will leave your intake air slightly less clean than a VTA type, which is bad for emissions, crankcase pressure, and crankcase & oil cleanliness. I don't think the tiny intake cleanliness advantage of a VTA type is worth all the downsides.

I have a similar Moroso unit on my Corolla and it's a nice top-notch unit with a good honeycomb stainless filter medium inside...but they are indeed quite costly.

JEGS sells a cheap unit that looks decent:

http://www.jegs.com/p/JEGS-Performance-Products/JEGS-Air-Oil-Separator/763433/10002/-1

I have seen mason jars with fittings fitted to the lid used and they did a decent job, with some baffling/filter media it would have done even better. I think you just need to decide if you want to use a vacuum or vent type then find one in your price range and it should do what you want, at the end of the day there isnt that much to them.

I have one similar to this:

which I bought on ebay years ago on my RN Truck. I plumbed it in with a couple of PCV valves so that it auto-drains back into the valve cover.

In reply to Dr. Hess:

I've got a similar one on the Jeep with some copper scrubber pads shoved inside for baffling. It's mounted in cool airflow in the front bumper to make it more effective. Works pretty well at catching oil, only downside is the mounting location leads to it collecting a lot of condensed water in the winter.

They sell for like $15, so you can't complain (much). I have mine mounted at the back of the motor up near the firewall. It is higher than the valve cover so gravity will drain it through the extra PCV valve I mounted at the bottom. I've never had to manually drain it.

I put it on when I was having oil loss problems after a rebuild. I thought it was blow-by. Didn't notice any difference. The oil loss problem eventually resolved itself at like 60K miles post rebuild when the rings finally seated. I'm NOT using that machine shop again.

Oil catch cans are very simple devices, I can't imagine paying large sums of money on name brands makes a difference.

I can see where a dipstick, sightglass, and/or drain would make for a more user friendly unit.

NEALSMO wrote: Oil catch cans are very simple devices, I can't imagine paying large sums of money on name brands makes a difference. I can see where a dipstick, sightglass, and/or drain would make for a more user friendly unit.

Most of the difference is that the cheap ones tend to do very little unless modified as they're often un-baffled (so most of the oil vapor just goes right through them).

I'm actually getting ready to purchase some catch cans for my Mustang, as well. I think I'm going to go with the Bob's Auto Sport ones.

I once heard that there were issues using catch cans in below-freezing temperatures? Is that true?

In reply to Dr. Hess:

Can you point me to the $15 ones?!?

Sky_Render wrote: I once heard that there were issues using catch cans in below-freezing temperatures? Is that true?

I've driven in sub-zero temps with mine getting blasted by the cold air stream over the front end. I've had times in that weather where I've had to warm the can up to drain the (frozen) water out of it, but I've never had the lines ice up and stop flowing (I've checked to be sure a few times in that weather).

In reply to Javelin:

Here's the one I stole the hotlinked pic from:

eBay

$15.26 and free shipping. There are many that are the same or different colors.

Its hard to do in most car/engine combos, but if you can mount the can high enough, with the inlet on the bottom and a filter on the top, it will drain back into the crankcase when there is no flow into the can.

Also, check the rules and make sure there isn't a minimum size required. Coolant overflow is generally 1 liter. I don't know whether a puke tank has a minimum.

In reply to Sky_Render:

I use the Bob's Auto Sport ones on my wife's Subaru and my Tacoma and they work fantastic. You can use the universal ones on anything with a pcv valve. I have a video where I did a review on youtube. Just go to youtube and put in review of bobs auto sports air/oil separator and you can see first hand how well they work. I plan on putting one on my miata after I install my cappuccino washer tank as well.

Chris Rummel

rslifkin wrote:

NEALSMO wrote: Oil catch cans are very simple devices, I can't imagine paying large sums of money on name brands makes a difference. I can see where a dipstick, sightglass, and/or drain would make for a more user friendly unit.

Most of the difference is that the cheap ones tend to do very little unless modified as they're often un-baffled (so most of the oil vapor just goes right through them).

And some care about aesthetics, built-in mounting solution with hoses to length and fittings included. A "bolt-in" vs a DIY setup. But you do pay for it.

Dr. Hess wrote: In reply to Javelin: Here's the one I stole the hotlinked pic from: eBay $15.26 and free shipping. There are many that are the same or different colors.

Thanks! For $15 I'm willing to monkey with it and see if I can get it to work.

I have a BMW cyclone type separator. Haven't installed it yet, but it was cheap ($8.50) enough and BMW thought it worked, for whatever that is worth. http://www.ebay.com/itm/New-Pressure-Regulating-Valve-Engine-Oil-Separator-Fit-BMW-E53-X5-11151705237-/281577540268?fits=Make%3ABMW&hash=item418f544aac:g:5lAAAOSwz2lXB3~y&vxp=mtr

I just installed a Moroso on our Mustang. No, they aren't giving them away, but the price/quality ratio is perfectly in line. It's what I would recommend to someone with low to moderate mechanical skill because of its completeness and ease of installation, or to someone that wanted a "no excuses" catch can setup.

Their operation, however, is simple, and can be done with cheaper materials and some skill, and willingness to not have the prettiest thing under your hood. A trip to Home Depot for a small metal paint can, some brass fittings and some hose will get you where you need to go.