VR6 Oil Catch Can?

[The_Hawk]

At the moment the vent from my crank goes direct to the intake, I'm also chewing through a little oil and since there are no valves in this direct line I reckon it's a good bet that a solid vacuum on the intake from the crank case isn't helping.

So... I have been looking at a couple of options.

The cheapest is to just put a little filter on the crank vent at let it vent to the atmosphere... cheap, effective... maybe not legal (and oil may drip on things)

Plan B. Catch can from the crank with the other end of the line still running to the intake. Probably the most legal option. What I don't know is how the can works?? Does it turn the vapour into liquid or am I just adding extra space between the crank case and the intake??

Plan C. Catch can from the crank with a filter to vent to the atmosphere.


So who has done what? What's legal? Whats possible? Whats recommended?

[Shteifen]

i would also like to know...
mine uses probably about a litre every....5-6 thousand km.
ive heard a few ppl say euro cars use a bit, but my old GL didnt use a drop in two years. are VR's supposed to? i dont know.

-steve

[Tim]

i would also like to know...
mine uses probably about a litre every....5-6 thousand km.
ive heard a few ppl say euro cars use a bit, but my old GL didnt use a drop in two years. are VR's supposed to? i dont know.

-steve

If you drive her hard thats about right.
Im eventually gonna put a catch can on my VR6. Ive cleaned up my throttle body a few times and its amazing how dirty it can get.

[Shteifen]

ya i guy i work with reckons its had the crap thrashed out of it. i tend to believe him in the morning, cos when i start driving to work the gearbox wines a bit for maybe a hundred metres or so and goes away.

would be nice not to have to check oil every few weeks

-steve

[Shteifen]

do yo know if anyone sells a catch can kit or somethin? or would you just ahve to improvise?

-stve

[The_Hawk]

They are a pretty generic part that you pretty much make up the connections as you go. Shouldn't be too hard...

I'll be looking into it over Christmas while I'm off work, but to be honest, the latest thinking was with only driving around 10,000 km a year, it's not a lot of oil to use up, and oil is cheap as... although as Tim has said, less oil through the throttle body will never be a bad thing

We will see.

[Jarred]

If it was a mk 1, this is what I'd do





Cheers to Tim for pics/idea.

Cheap, easy and it works. Keeps the crap from coming back into the intake. Just make sure you block off where the factory breather goes back into the intake.

Hope this helps.

[The_Hawk]

If it was a mk 1, this is what I'd do


Cheers to Tim for pics/idea.

Cheap, easy and it works. Keeps the crap from coming back into the intake. Just make sure you block off where the factory breather goes back into the intake.

Hope this helps.

Nice work Do you actually catch much oil in that? Would have thought the vapourised oil would just go through the filter.

The only issue I have with that solution is the fumes it could cause. Sames goes even if you get a propper baffled catch can and vent to the atmosphere, although it should be reduced over what you have since the baffles should 'filter' the oil out somewhat.

Plan B is to plumb back into the intake after the catch can to remove the fume problem entirely and still be as close to legal as possible.


Plan B sounds like the better option and is no more expensive than not plumbing it back since it's either get a filter or the appropriate pipe.

[Jarred]

I can't see why plan B wouldn't work. but depending on how the pipes are set up, I geuss that you might still run the ristk of getting oil back through the intake.

With the powerade bottle, it's basically just a cheap catch can. probably not legal in NSW, isn't here really. But it works. oil goes in the bottle, fumes out the top, throught the autobarn special filter. Don't think there's an issue with fumes in the cabin, I don't have any such issues in the audi, which has this setup. I don't use oil really, so my bottle is empty basically, bar some residue.

[The_Hawk]

I can't see why plan B wouldn't work. but depending on how the pipes are set up, I geuss that you might still run the ristk of getting oil back through the intake.

With the powerade bottle, it's basically just a cheap catch can. probably not legal in NSW, isn't here really. But it works. oil goes in the bottle, fumes out the top, throught the autobarn special filter. Don't think there's an issue with fumes in the cabin, I don't have any such issues in the audi, which has this setup. I don't use oil really, so my bottle is empty basically, bar some residue.

I think I use more oil because the intake it just sucking at the crank, your solution (as with any catch can not plumbed back) it's only excess pressure, not a vacuum pulling the fumes out. I assume the valve that is supposed to be in there is such that the normal intake vacuum isn't enough to open the valve, but when the crank gets to a certain pressure point it opens. The question is will a baffled catch can *reduce* the suck through considerably while still allowing for pressure release?

I'll have to experiment a little when I get some parts to play with.

[Jarred]

Ah right I see. I couldn't say. best of luck.

EDIT: I had a brain wave. AutoSpeed always have some good tech articles and DIY stuff. Maybe some of it will help. I just searched an picked a few supposedly relavent articles.

http://autospeed.com/cms/A_1101/article.html

http://autospeed.com/cms/A_110826/article.html

http://autospeed.com/A_110826/cms/article.html

http://autospeed.com/cms/A_1576/article.html

[The_Hawk]

Very nice set of links there

So I want not so much a catch can, but an oil/air sperator

[Oneofthegreats]

For cost effective way, it's hard to beat the powerade bottle!

The rocker cover has a mesh screen inside it to stop alot of oil splash. I've also fitted a hydraulic cam/lifter baffle for this reason too.

It only catch's any residue, or if you really beat on it, it catch's alittle overflow.

If you let the can fill up, it can get alittle fumy, but apart from the blown headgasket incident, it has never filled up past 1/4 in between 10K services.

Also, the Mk3 cabin is probably alittle more sealed than the mk1 too, so I don't think fumes would be any problem.

All car's (don't know the exact year when they were introduced for pollution requirements. think approx 74/75, as the HJ's didn't have any pollution gear in them) should have one of these fitted or a PVC valve equivelant system like the cyclone oil separator's as part of the pollution system.

http://en.wikipedia.org/wiki/PCV_valve

That explain's how they work.

In some performance application's, I've seen a vaccum pump's ran directly from the rocker cover's with a regulator in the crankcase system to create a constant vaccum, which can in some case's increase performance by upto 40hp on a 1000hp engine.

This isn't a cheap excercise either. $1000+



Another old skool tech is to use the pulse air valves off the early MK1's & plumb the rocker cover's breather's directly into the exhaust, creating the same sort of scavanging system. If your engine is in poor health, than it will get smokey!





I still see this system used on alot of car's too & work's extremely well.

On my warm 304 project, I used massive breather's & baffle plates in the rocker cover's. Never blew any oil out holding it at 6500+ for 3 min's & with the race oil I used, it alway's smelt good too!



When getting into the performance side of the crankcase system, it can get very scienctific, as does any part of the 4 stroke engine, so on that note

I'll stick to my powerade bottle's though. Haven't failed me yet!

[The_Hawk]

All car's (don't know the exact year when they were introduced for pollution requirements. think approx 74/75, as the HJ's didn't have any pollution gear in them) should have one of these fitted or a PVC valve equivelant system like the cyclone oil separator's as part of the pollution system.

Yeah, don't think I have that valve anymore since it used to leak and was removed, but I assume the catch can/seperator take the place of that valve anyway, another reason to consider doing something

[rayray086]

Some good info here, I finally understand how the PCV system works.

Just wondering if anyone have since added an oil catch can? Curious to see some setups as well as the amount of reduced oil in the intake.