catch can working???

[jerry]

Hi all I fitted a catch can / cleaned out pipework & intercooler some time ago .
I still get/ have oil in pipework comming off turbo (black sticky /tar like s---)
but nothing much in catch can??
how can I tell if can is working ??

 

[Old.Tony]

The idea behind the catch can is not a bad one, but the problem is that it's trying to catch a vapour. In order to do this, it needs to encourage the oil to change from a vapour (gas) to a liquid. The usual way this happens is through lowering the temperature of the gas, or through condensation on a colder surface.

It's more likely going to happen if the path through the catch can is erratic (but not interrupted). Rather than have the two openings in the top of the can - like they come with by default - run the inlet pipe to within a couple of mm of the bottom of the can, then surround the thing with steel wool. Vapour will strike the metal, causing the oil to condense, eventually causing the vapour (gaseous oil) to pass through liquid oil, thus causing even more oil to condense.

There's a good thread here showing some pics of what I mean in the first post. Another catch can thread here shows an alternative way of doing the same thing.

 

[robmacca]

Hey Tony.....

The D22 Navara that I recently bought had a catch can already on it. It's a Monza (same as the Drift type). When I showed my Cousin the setup (he works for a Filtering Business), he pointed out that it was doing nothing as it didn't have any sort of filtering inside the unit (unlike those links u listed b4 that had people putting Steelwool inside them). So, I ripped off that catch can and installed a Provent 200 unit that came with the filter already inside the unit..... Time will tell how it goes but at least I shouldn't get any oil in the Air intake like b4.....

rob

The idea behind the catch can is not a bad one, but the problem is that it's trying to catch a vapour. In order to do this, it needs to encourage the oil to change from a vapour (gas) to a liquid. The usual way this happens is through lowering the temperature of the gas, or through condensation on a colder surface.

It's more likely going to happen if the path through the catch can is erratic (but not interrupted). Rather than have the two openings in the top of the can - like they come with by default - run the inlet pipe to within a couple of mm of the bottom of the can, then surround the thing with steel wool. Vapour will strike the metal, causing the oil to condense, eventually causing the vapour (gaseous oil) to pass through liquid oil, thus causing even more oil to condense.

There's a good thread here showing some pics of what I mean in the first post. Another catch can thread here shows an alternative way of doing the same thing.

 

[Old.Tony]

You might still get SOME oil in the intake. The catch can isn't perfect.

Those versed in air-conditioning mechanics could dream up a way to catch ALL of the oil (freezing the vapour), but it's overkill. A catch can set up as those threads show will catch a majority of the oil, and that's what's important.

It means that you're still going to have oil lining your intercooler and sitting in the bottom, but it won't accumulate in there anywhere near as quickly as it once did.

Unless, of course, you do a naughty thing and vent the catch can to atmosphere (yes, it's illegal - but like most of these little mods, not easy to detect). If you ARE doing that, ensure that the hose points towards the middle of the car. It will prevent oil from getting onto your tyres or brakes.

 

[joshman]

Actually Tony, I would say that venting the catch canto atmosphere is one of the easier things to ping you on. It's quite apparent to anyone looking under the hood if you've got a blanked off air intake receptacle and an air filter hanging off the side of the catch can. I would definitely advise against venting it to atmo.

Rather some the money on a good quality catch can (provent, etc) or put some effort and though into a home made or modified jobbie.

 

[joshman]

Hey Tony.....

The D22 Navara that I recently bought had a catch can already on it. It's a Monza (same as the Drift type). When I showed my Cousin the setup (he works for a Filtering Business), he pointed out that it was doing nothing as it didn't have any sort of filtering inside the unit (unlike those links u listed b4 that had people putting Steelwool inside them). So, I ripped off that catch can and installed a Provent 200 unit that came with the filter already inside the unit..... Time will tell how it goes but at least I shouldn't get any oil in the Air intake like b4.....

rob

Also, I've got the provent 200 in, and it's caught a heap of oil so far, a lot more than the crappy calibre branded catch can ever did. Also, where'd you mount the provent?

 

[Old.Tony]

I was more thinking "as the vehicle drove past". They're only opening the bonnet if you've already caught their attention by doing something stupid, and if that's the case then hey, what's one more stupid thing in a basket already full?

 

[robmacca]

Also, I've got the provent 200 in, and it's caught a heap of oil so far, a lot more than the crappy calibre branded catch can ever did. Also, where'd you mount the provent?

I had limited space so I just put it in the same spot the old catch can was (see pic) The only other spot was just behind the LHS headlight but this spot is reserved for my 2nd inline fuel filter

PLUS...... also have gotten rid of the K&N Air Filter..... Don't like them, especially in dusty conditions

 

[joffo81]

Can someone please explain to me or even better show me a pic of the inside of their Provent 200 cqatch can. I have one installed and think its working properly but I am not sure what people mean by a filter in the can. Is the filter removable because my provent doesn't seem to have anything removable inside. Is it possible that I have a provent without the filter inside??
Any help would be much appreciated.

 

[tweak'e]

provent have a paper element. havn't got pics on me at the mo of one. tho should be on manufactures site.

 

[joffo81]

Good idea thanks Tweak'e. I just did a websearch and can see the paper element (filter now)! It has an octagonal plastic piece attached to the top of it. I imagine this is what you turn to remove the element.
Thanks for the quick reply.

 

[jerry]

thanks for the info will have to do mods

 

[Connaught]

made my own out of 15cm 90mm pvc storm pipe,

I put a fixed end one one end, a screw cap end on the other, drilled 2 holes in the side and put in 12 mm retic fittings, (one about 2 cm off the bottom sealed cap, one near the top screw cap), sealed the fittings up (i would think any silicone would work - i used some excess aircraft sealant from work) then i bent up a piece of screen mesh to sit in the bottom and then i took my scissors and cut out about 8 pieces of scotch pad to suit and stacked inside the can

then cause i wanted it to blend in with everything in the engine compartment i spray painted it black - its just sitting in there if you didn't know it was there you couldn't pick it

then i got some 12 mm rubber hose (from work) and routed it from the breather - to the can to the inlet

it works a treat, cost me about 12 bucks and an hour or so to whip up (i had some old pvc pipe glue around from previous projects)

 

[Aussie Frontier]

The only thing I would be worried out with the PVC is the heat. I noticed my alloy unit gets pretty hot with the heat under the bonnet and the heated air going through it.

But on the other side of the coin I found some pics of a Provent not sure if its the same you guys used

 

[robmacca]

Looks to be the same one...... having a proper filter element will make a bit difference in my situation....

 

[Connaught]

mines workin a treat, its th 2.5 deisel, got the can over on the left side of the engine bay behind the fuse box, checked it the other day and surprise surprise it was oiley,

heat isn't or doesn't seem to be a problem, even the hoses that are running near the turbo seem to be lovin it (keep in mind i work in aviation and the hoses are aviation grade, hehe)

 

[Converge]

A little of topic, but what size is the PCV hose on the 2.5L YD25's?