Oil Catch Can Information

[fourwheeldrivenavara]

With an oil catch can, I understand that if I bought one, it would most likely arrive as an empty can, therefore be relatively ineffective.

What is the best material to fill the can to "catch" the oil vapors, without adding concerns about it breaking down and entering my engine!

Is there a better solution out there.

I saw a picture of Dave STR's setup and would like something similar. Dave is this effective??

Thanks again.

 

[Dave]

Mine has nothing in it.

Usually empty the catch can every 5000-10,000km's.

My Navara isn't under load that often, I hardly carry anything in the tray.

Mainly used for highway driving, here and there gets a car trailer on the back and a box trailer here and there for dump runs.

The intake side of the turbo is clean and oil free, had the silicon hose off a couple of days ago.

Dave.

 

[Al]

bought one today. gonna fit it and do egr this weekend

 

[Al]

Did anyone place that restrictor that is in the factory hose into the new hose? is it essential as my new hose is slightly larger (5/8 hose). if it must go in there which side of the catch can should it go?

 

[tweak'e]

i left it out with the reasoning that the catch can will be enough restriction.

incidentally does anyone know what the restrictor is for? limited the amount of blowby or an attempt to cut down how much oil gets blown into the intake ??
i wonder how much better these motors would run if the catch can is vented into the air instead of returned to the motor?

 

[Al]

for the record i put it cut it out of the old pipe and put it back into the new one. Mainly becasue on the out side of the catch can the hose had a bit of a curve to it and outting the valve/restrictor thing there holds the hose open wide on that curve. Unlike you tweak1e i haven't got any filter matter in the can, so the catch can would offer little ressistance. the flattening of the hose at teh curve was small and most likely didn't effect the flow but better to be sure i say.

 

[tommy222220_0]

i left it out with the reasoning that the catch can will be enough restriction.

incidentally does anyone know what the restrictor is for? limited the amount of blowby or an attempt to cut down how much oil gets blown into the intake ??

The restrictor actualy helps create vacuum. Think of it like a little venturi. Notice how it is pretty much at the highest point in the tube as well....
Prob wont effect it much, but it's there for a reason.

i wonder how much better these motors would run if the catch can is vented into the air instead of returned to the motor?

If you have a well setup catch can (ie baffled), minimal oil should be passed into the intake. (a small amount is ok because it helps lubricate the head)
Being plumbed into the intake give the PCV the requirec vacuum to operate correctly.

 

[tweak'e]

no PVC on these motors. like a lot of diesels crankcase is vented directly to inlet.
the restrictor doesn't make any real vacuum, if anything it reduces it. hence i think its to reduce flow, especially when air filter is getting dirty and you get more vacuum in the pre turbo intake.

as far as venting to air is concerned, its not the oil (catch can gets most of that) but the EGR that flows into the intake. not only is it pre turbo (heats intake air and replaces air) but if the system is allready pouring in max EGR through the EGR system then the extra EGR could be too much. especially if you have very dirty air filter and sucking in heaps of it.

 

[Al]

so should it be on the inward or outward tube from the catch can? outward is where I have it now.

 

[tweak'e]

i would have the restrictor in between catch can and inlet hose.

 

[matty]

hey guys are the catch cans made especially for one type of make and model or are they all pretty universal, Cheers

Matty

 

[Al]

universal, i just bought one from supercheap (only type they had). but it came with the wrong size fittings so i went to Enzed and bought 2x 5/8 inch fittings + 1 metre of 5/8 fuel hose + 4 hose clamps. Navara fittings are 16mm.

 

[tommy222220_0]

no PVC on these motors. like a lot of diesels crankcase is vented directly to inlet.
the restrictor doesn't make any real vacuum, if anything it reduces it. hence i think its to reduce flow, especially when air filter is getting dirty and you get more vacuum in the pre turbo intake.

PCV = positive crankcase valve/vent (just used for easy identification)

Vacuum doesn't just come from the neg (gauge) pressure in the pre-turbo intake. Its also produced by the airflow past an orifice. my understandin of the the restrictor is; it is there to increase the gas velocity at the highest point in the system (or close to). Therefore because Velocity X pressure is a constant, it reduces the pressure at that particular pont in the system (Vel up - press down). Therefore the air/oil fumes are drawn up to this point, at this point if the oil falls out of suspension it flows down to the inlet/catchcan, and doesn't return to the crankcase.

as far as venting to air is concerned, its not the oil (catch can gets most of that) but the EGR that flows into the intake. not only is it pre turbo (heats intake air and replaces air) but if the system is allready pouring in max EGR through the EGR system then the extra EGR could be too much. especially if you have very dirty air filter and sucking in heaps of it.

Ok, Are your talking about exhaust gas blow-by? (blow by the ring/bore gap, creating postive carankcase pressure then out PCV into intake)
If so, very little should be coming through, because the oil effectively seals the rings and bores upon combustion.
It's more likely the contaminates the oil collects, evaporating.

 

[tweak'e]

sorry i should have said PCV valve. petrols run a valve to regulate the PCV flow. diesels just have a straight open pipe.

with the standard pipe there is no need for oil to fall out of suspension. its all going into the intake regardless. from what i have seen very little "falls out" due to it. never seen it in any other motor.
i think its just a flow restriction, nothing fancy

Ok, Are your talking about exhaust gas blow-by? (blow by the ring/bore gap, creating positive crankcase pressure then out PCV into intake)
If so, very little should be coming through, because the oil effectively seals the rings and bores upon combustion.
It's more likely the contaminates the oil collects, evaporating.

actually it IS exhaust blowby. thats fairly normal for diesels, hence why they have 1/2" breather pipe. with high compression (plus high boost) a fair bit escape past the rings.

welcome to diesels

 

[maddogrc]

just to revive an old topic...

what is everyone running in their catch cans?

i've read its best to run steel scrubbers and not steel wool as it can supposedly come loose and get sucked back into the intake as there are so many small fibres in steel wool.

i've also read some people use nothing at all? and some use special filter elements?

i picked up one brand new from ebay (local guy) for 20 bucks with all fittings except it isn't openable except for the drain plug at the bottom so i'm limited to the steel scrubbers by shoving them in or nothing at all.

what do you all recommend?

cheers

 

[tweak'e]

the best thing to use is a filter.
next best is steel scrubbers, not steel wool.
then open can. open cans get catch bugger all.

patrol4x4 forum has a fair few threads on catch cans. people have used CAV fuel filters, engine oil filters and air compressor filters and all work fairly well.

 

[jap55s]

The restrictor actualy helps create vacuum. Think of it like a little venturi. Notice how it is pretty much at the highest point in the tube as well....
Prob wont effect it much, but it's there for a reason.



If you have a well setup catch can (ie baffled), minimal oil should be passed into the intake. (a small amount is ok because it helps lubricate the head)
Being plumbed into the intake give the PCV the requirec vacuum to operate correctly.

i didnt think diesel engines created a vaccum

 

[2010_Navara_STR]

i didnt think diesel engines created a vaccum

Yeah they don't thats why most have a vaccum pump seperate to supply the brake booster

 

[tommy222220_0]

i didnt think diesel engines created a vaccum

Yeah they don't thats why most have a vaccum pump seperate to supply the brake booster

Bringing a thread back from the darkness, but to clairfy.

Diesels dont create a vacuum after the turbo like petrol cars do, and why they require a vacuum pump to assist the brakes.

But the turbo sucks air through the air filter(restriction) creating less than atmospheric pressure (vacuum) between the filter and turbo.

 

[tweak'e]

correct. tho there is a high vacuum just in front of the turbo. some vehicles have the breather right at the turbo entrance.