Skylines Downunder NZ Car Club

Technical => Naturally Aspirated => Topic started by: BUC957 on May 18, 2012, 11:38:58 AM

Title: catch cans
Post by: BUC957 on May 18, 2012, 11:38:58 AM
catch can. do i need one? what does it do exactly and how is it hooked up?
Title: catch cans
Post by: BADHAB|T on May 18, 2012, 12:09:04 PM
Unless you have blowby you don't "need" one
The plumbing method varies depending on the type of catch can you buy. They come vented and sealed.
It basically replaces the PCV system in the car
Title: catch cans
Post by: frost.motorsport on May 18, 2012, 12:19:13 PM
*search*

or try these:

http://www.gtr.co.uk/forum/163690-oil-catch-can.html

http://www.gtr.co.uk/forum/164930-r32-gtr-stock-breather-stage-1-1-bar.html
Title: catch cans
Post by: BUC957 on May 18, 2012, 02:44:43 PM
I have a 20 de all that seems to be for turbo's
Title: catch cans
Post by: westybob on May 18, 2012, 03:10:03 PM
If you needed one you would know. They are not a fashion accessory don't bother.
Title: catch cans
Post by: zifzone on May 18, 2012, 03:11:07 PM
Nah fashion accessory would be using a v can or a redbull can :P
Title: catch cans
Post by: BADHAB|T on May 18, 2012, 03:29:51 PM
Quote from: BUC957;599081
I have a 20 de all that seems to be for turbo's


Definitely not a turbo specific thing, you can fit one to any engine :)

This is how mine is set up... I'm only using one because of the front facing plenum - it was in the "too hard basket" to replicate the factory PCV system, so I replaced it with a catch can

(http://i198.photobucket.com/albums/aa19/BADHABIT_R33/My%20R32%20GTS-t/DSCF5218.jpg)
Title: catch cans
Post by: Harley on May 18, 2012, 03:30:39 PM
your catch cans on the wrong side...
Title: catch cans
Post by: BADHAB|T on May 18, 2012, 03:41:34 PM
lol I know it needs moving... but I need DE breather nipples to make that job easier
It doesn't "catch" anything anyway so I'm not too worried about where it is right now :)
Title: catch cans
Post by: Harley on May 18, 2012, 04:08:31 PM
Lucky for some, I Had to install a drain back to the sump on my one!
Title: catch cans
Post by: BADHAB|T on May 18, 2012, 04:11:06 PM
Quote from: Harley;599094
Lucky for some, I Had to install a drain back to the sump on my one!


Because it was filling up fast?
Ouch :(
Title: catch cans
Post by: Harley on May 18, 2012, 04:17:40 PM
Quote from: BADHAB|T;599095
Because it was filling up fast?
Ouch :(


Yeah, i could have put in smaller restrictors into the block lol :)
Title: catch cans
Post by: rrcredline on May 19, 2012, 07:58:12 AM
I have used two of the ones from SuperCheap. Neat little cans. One for the   R32 - RB30DE that I took all the breather plumbing off the top of the engine to have a clean look. The crank case breathing system has been rerouted out of the backs of the cam shaft covers via alloy pipes inside the covers from the splash shields and then to the catch can. Cert required me to plumb the catch can back to the intake. Which I did to get the cert. I noticed the other day however the pipe and fittings that went back to the intake have gone missing....don't know what happened there :>) It's just vents to atmo now.

Used the same Supercheap can on the R33 - RB25DE track car and same clean plumbing system and vent to atmo. This can get about 1/2 a cup full of oil every 3-4 track days as the engine rings are getting tired so a little more blowby then normal.

Worth having on any engine and by not sucking the crank case fumes back into the intake the intake stays nice and clean inside.

Just a note to on the oil restrictors between the block and head. I regret using them since I used the stadard RB25 oil pump on my RB30DE and the engine is not a high RPM application. I am not getting oil flooding in the head in the R33 track car that has factory restrictors so I do not intend to use special restrictors for the RB30DE engine when I build it for the R33. I will rather add the additional head oil drain back to the sump.

Nigel
Title: catch cans
Post by: westybob on May 19, 2012, 07:51:18 PM
Quote from: rrcredline;599128
Just a note to on the oil restrictors between the block and head. I regret using them since I used the stadard RB25 oil pump on my RB30DE and the engine is not a high RPM application. I am not getting oil flooding in the head in the R33 track car that has factory restrictors so I do not intend to use special restrictors for the RB30DE engine when I build it for the R33. I will rather add the additional head oil drain back to the sump.

Nigel

My research and experience with the RB 30 with a high output pump (N1 in my case) tells me that the the head drain doesn't work. Some people think it acts as a sump vent but that is not good either as I think it just blows more oil out the top breathers. If you have a high output pump and run at WOT for extended periods (generally this will happen only on the track) you will need restrictors. I have hydraulic lifters and have two x 1.0mm restrictors.

If you are doing a new engine it is a good idea to drill out the oil return holes to 9.5 or 10mm and relieve the area around the other drains. What solved my excessive oil in the head problems as well as the restrictors was 2 x 20mm breathers from the sump going not to the head but to a catch can. The 30 crank whips up a storm and there is a fair amount comes out of those breathers (and its not blowby as I have done a leak-down test and it was fine).

I have one hose going to the top of the catch can and one to the bottom. As I do not have an extended sump (as really one should have for track work) I fully or slightly over fill the sump and under some conditions oil gets pushed out the breathers so the bottom hose allows it to drain back.

With this arrangement I have been able to complete a full track day without exiting in a cloud of smoke with oil coming out everywhere on top of my engine for the first time in ages.
Title: catch cans
Post by: frost.motorsport on May 21, 2012, 11:35:49 AM
Quote from: westybob;599152
My research and experience with the RB 30 with a high output pump (N1 in my case) tells me that the the head drain doesn't work. Some people think it acts as a sump vent but that is not good either as I think it just blows more oil out the top breathers.


I run a -8 from the front/right of my RB26 sump up to my catch-can.  Works nicely, though I have a Tomei sump baffle which helps stop the oil sloshing up there anyway...

I spent a long time investigating this issue while building my engine and came to the conclusion that the sump vent is the way to go.  

Interested to hear about other peoples experiences on this!
Title: catch cans
Post by: westybob on May 21, 2012, 03:23:28 PM
Quote from: frost.motorsport;599303
I run a -8 from the front/right of my RB26 sump up to my catch-can.  Works nicely, though I have a Tomei sump baffle which helps stop the oil sloshing up there anyway...

I spent a long time investigating this issue while building my engine and came to the conclusion that the sump vent is the way to go.  

Interested to hear about other peoples experiences on this!


I have a Tomei sump baffle as well. People with RB26s have reported that the Mines baffles in the cam covers help too (although I am hoping I have it sorted now).
Title: catch cans
Post by: BUC957 on May 25, 2012, 05:55:40 AM
I have traces of oil going into my pcv hose off my intake cam. pretty sure its going from cam to value. what should i do?
Title: catch cans
Post by: westybob on May 25, 2012, 06:21:50 AM
"Traces"? When you have litres of oil coming out you have a problem! Seriously I don't think you need to do anything unless you are planning to track or drag the car in which case it is time to look at a catch can set up.
Title: catch cans
Post by: BUC957 on May 25, 2012, 02:07:12 PM
Sweet as thanks
Title: catch cans
Post by: jade501 on June 02, 2012, 04:35:10 PM
my mates have got catch cans but none of them drained them back in because of the **** oil thats caught but a catch can i dont now y but when they drain the oil doesnt look prety.. on my 26 i was just going to do hoses into a catch im intersted into y the sump needs a breather and how does in help i got big wigde sump would a breater make a difference ???
Title: catch cans
Post by: BUC957 on August 08, 2012, 10:07:00 AM
hey guys i have a blocked factory pcv and catch can in another car. am looking for a two port with breather port. anyone know where to get one cheap?
Title: catch cans
Post by: xxfr on August 08, 2012, 11:20:17 AM
Quote from: jade501;600096
my mates have got catch cans but none of them drained them back in because of the **** oil thats caught but a catch can i dont now y but when they drain the oil doesnt look prety.. on my 26 i was just going to do hoses into a catch im intersted into y the sump needs a breather and how does in help i got big wigde sump would a breater make a difference ???


The oil collected in a catch can becomes ****, as you have put it, when it gets collected in the can and absorbs moisture. The **** oil is basically oil and water that has mixed.

In a normal situation once the oil gets to the can, the fumes are vented, the oil is as good as what you have in your engine and is a good idea to have it returned to the sump as others here have noted.

As an example, Nismo only made a oil/air separator and returned the oil to the sump via the turbo return line.
Title: catch cans
Post by: gtsr on August 09, 2012, 08:41:36 PM
Quote from: westybob
The 30 crank whips up a storm and there is a fair amount comes out of those breathers (and its not blowby as I have done a leak-down test and it was fine).

I would think it's blowby. Rings should seal the bore at TDC when doing a leak down test.

Quote from: xxfr;603459
In a normal situation once the oil gets to the can, the fumes are vented, the oil is as good as what you have in your engine and is a good idea to have it returned to the sump as others here have noted.

Not a good idea if car is in a cold climate. The oil + water / condensation becomes ice and that blocks the return hose, so oil builds up and catchcan fills up.
Title: catch cans
Post by: xxfr on August 09, 2012, 08:56:19 PM
By returning oil straight to sump you won't have any sitting in the can itself so no issues with blockages. The catch can performs the function as an oil/air separator, not an oil collector.
Title: catch cans
Post by: gtsr on August 09, 2012, 09:26:47 PM
What I'm trying to say is the hose that sends oil to the sump from catchcan gets oil sludge buildup over time and that oil sludge buildup attracts water / condensation, which in cold climates turns to ice that blocks that hose. Then oil builds up on top of the ice and fills catchcan.

It's a well known problem and it's suggested to clean out that hose which sends oil to sump every once and a while (rod it out or replace) to prevent this oil sludge buildup from happening.
Title: catch cans
Post by: BADHAB|T on August 09, 2012, 09:30:51 PM
At what temperatures does that happen? Anywhere in NZ? I would have though engine bay temps would soon melt any water that freezes in a hose that runs right next to an engine.... unless the car is in Alaska or something ....?
Title: catch cans
Post by: gtsr on August 09, 2012, 09:48:10 PM
Not sure on temps. Maybe in South Island where it snows?? It happens in snowy or very cold conditions where oiltemps don't get high enough (sludge buildup).
Title: catch cans
Post by: xxfr on August 09, 2012, 10:44:11 PM
Good point gtsr. Sorry I don't have information or experience on that.

On that thought though, I would say the grade of oil being used would come in handy.
Title: catch cans
Post by: AGRORB on August 09, 2012, 11:13:48 PM
If you dont need a catch can, dont fit one. Why fix what isnt broke.

I had one on my old R32 and it was just hassles, the smell of the fumes was nasty too.

If your taking your car to the track a lot, or you have motor mods that make using the factory PCV system impractical, THEN fit one, if not, its just a wanky shiny thing you dont need and wont make your car go, stop or handle better. Far better things to spend money on.
Title: catch cans
Post by: gtsr on August 10, 2012, 02:23:54 AM
Exactly, the factory PCV setup is actually a simple, good design and works in cold climates (direct into intake, no drains from catchcan that could clog) and is a no maintenance (don't have to empty catchcan), emissions friendly / no smell setup (blowby gas is vented into engine where it's burnt off).

Only major problems with factory setup on street or racetrack is the small amount of oil (measured at about a ounce every 10,000kms on the street with turbo charged engine) that gets into intercooler (dropping ability to cool air), and engine (dropping octane of gas which could make engine knock, clogging valves on engine, gets into idle valves, etc). That's where a catchcan comes in handy (to intercept this oil).

The left over blowby gas is then vented into engine where it's burnt off (emissions). But that causes another problem, where the blowby gas spoils the burn inside cylinders. You lose hp due to dirty burn inside cylinders (less oxygen) and with cleaner burn you get more oxygen instead of dirty blowby gas into cylinders hence you get a leaner A/F ratio (more oxygen) which = gain in hp. That's why when you vent catchcan, you have to retune engine, due to engine is running leaner and if have other mods making it run leaner.

Venting catchcan to atmosphere is similar to fitting extractors that extracts the dirty gas from cylinders on exhaust stroke thus gives a cleaner burn inside cylinders when sparkplug is fired (fuel, etc is injected and air enters cylinders before compression stroke, then compression stroke, then fires spark plug). So catchcan needs to be vented on a racecar to atmosphere to get cleaner burn inside cylinders. On road you can't due to emissions, so has to go back into intake.

Quote from: xxfr;603564
Good point gtsr. Sorry I don't have information or experience on that.

Thank you for your kind words. It's ok, we are all learning new things everyday. Think of it as a new thing you have learnt about that setup (how to service that setup, known problems in cold climate). :)

Quote from: xxfr;603564
On that thought though, I would say the grade of oil being used would come in handy.

I agree, that probably would play a role as well. :)
Title: catch cans
Post by: BUC957 on August 10, 2012, 06:21:49 AM
That's well and good and i have learn't more about it, but i still need advice on a cheap effective can with breather port and two inlet's to replace k factory one.
Title: catch cans
Post by: AGRORB on August 10, 2012, 08:31:40 PM
Is it giving you headaches? Honestly, traces of oil in the hoses is nothing, a lot of its probably from vapour anyway.

Save yourself the hassle n money n keep it stock and tbh, if your car has that much blow-by, you dont need a catch can....

You need a rebuild.
Title: catch cans
Post by: gtsr on August 10, 2012, 09:12:10 PM
Best way is make your own catch tank. Below should give you an idea on how it should be designed if recirculate blowby like factory setup (emissions).

Be aware that most cheap intercept oil type catch tanks don't have a baffle plate to separate oil (oil can go back into intake). They are more show than function.

Some pull them apart and fit a baffle plate at top of catchtank, between fittings (oil / blowby enters catch tank and oil hits baffle plate and oil drops to bottom of catch tank. Then blowby goes under baffle plate and up, out the other fitting on catch tank) -

http://www.skylineowners.com/forum/showthread.php?t=170465

Edit: The baffle plate in link above has holes in it for blowby to go through, but should be a small piece of metal at top of catch tank, so blowby + oil has to do 90 degree or more turns thus separating oil from blowby.

If want to run catch tank similar to photo in Badhabit's post (vents gasses to engine bay), this catch tank in link below has no baffles or filter material inside, but does have a breather filter on top and two inlets (one from each camcover) and is cheap, 2 litre -

http://www.ebay.com/itm/2L-2-LITRE-ALUMINIUM-POLISHED-ROUND-OIL-CATCH-CAN-TANK-WITH-BREATHER-FILTER-/330658330734?pt=AU_Car_Parts_Accessories&hash=item4cfcc5b86e

Can buy it in NZ -

http://www.drivenperformance.co.nz/scripts/prodView.asp?idproduct=1443

Probably would need to replace 12mm, 15mm barbed fittings supplied with above catch tank with 16mm OD barbed fittings or AN fittings + adaptors, as stock breathers are 16.5mm OD and use 16mm ID hose. But probably are getting a smell in engine bay, as mentioned by AGRORB.

I think with over 2000cc engine it has to be 2 litres minimum for catch tank, so above catch tank should work. Probably would need to cut top off, fit baffle plate, weld back together if use for venting blowby gasses into intake (emissions). But be aware that some cheap catch tanks use thin metal, so might be difficult to weld back together.
Title: catch cans
Post by: westybob on August 10, 2012, 11:11:29 PM
I may be able to sell you a catch can - I have three and am using 2 on my car.

If you don't have major blowby you should retain the PCV valve in its stock configuration ( I have one of those too if you don't)

Then you need a catch can which you can open - some have tops and bottoms that screw on or you can cut the top off fit the baffles and weld it back on.

You don't want a breather. Apart from being illegal (unless you have a cert and a log book etc) you will get nasty fumes in the car.

So you want 2 16mm outlets and seal the top . Combine the 2 cam cover breather hoses and run them into one side of the catch can. Use the other as an outlet and run it into the inlet pipe. Weld a fitting on if necessary.

This is for your car with a small amount of blowby. For a track car pumping litres of oil out the top it will be different.
Title: catch cans
Post by: gtsr on August 10, 2012, 11:48:00 PM
Best to keep PCV, especially if idling alot in traffic. Catchcan is on exhaust side to catch oil at higher rpm.

This is a cheap custom catch tank for CA18DET, but same design with baffle plate in middle and at top -

http://www.turbophile.com/technical/diy_catch_can.html

Instead of using filter as shown in above link, reroute back into intake via adaptor, AN fitting, 16mm ID hose that clamps onto 16.5mm hardpiping that goes to intake (on turbo engine).
Title: catch cans
Post by: BUC957 on August 12, 2012, 12:45:43 PM
Quote from: BUC957;603457
###hey guys i have a blocked factory pcv and catch can in another car.### am looking for a two port with breather port. anyone know where to get one cheap?


As stated its in another car not my skyline. to replace the system the intake manifold and everything associated bar the turbo has to be removed. I'm trying to eliminate the possible need to do again in the future with an aftermarket can and sdu up.

need two inlet ports and a breather.
Title: catch cans
Post by: westybob on August 12, 2012, 02:12:01 PM
$40 posted.
Height about 200mm without breather diameter 80mm without fittings.
Has two outlets, sightglass, fixing bracket drain on bottom and (blue) screw top.
I'll throw in the Moroso breather which fits in the top with a rubber seal.
Top and bottom come off so you can just fill it with stainless scrubbers if you want.
The marks are where the label was but its aluminium so it will polish up if you're keen.
(http://i1232.photobucket.com/albums/ff369/bobrr/2012-08-12155455.jpg)