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Catch Can

Started by _rorym_ , Oct 11 2008 02:53 PM

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149 replies to this topic

#126 _Westie_

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Posted 14 July 2009 - 03:20 PM

The breather line looks a little on the small side, how does it compare with the system you replaced?

I would consider drilling out the breather location on the rocker cover just behind the filler cap and running a second breather line to the catch can. If you do drill out the second breather then make sure you fit a baffle inside the rocker cover.

The breather line 90 degree fitting is the same part that fits into the cover, so I assume that the hose which fits over it is also the same diameter.

I have read abit in this thread and the other catch can thread about having steel wool or something like that inside the can...what will this do?...and is this what the "off the shelf" units have?

I'm starting to think that a larger can is what needs to happen (atleast thats what CAMS wants - 3 litres), but I dont want to simply bandaid the issue of holding the oil somewhere else, when it should really be in the motor.

Cheers for your thoughts, they are all good :clap:

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#127 _Squarepants_

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Posted 14 July 2009 - 05:34 PM

Westie, the steel wool is just a filter medium. It's there just as extra surface area for the air/vapour to pass through in hope the oil vapour will collect in it and drip out. I can't say if this is the most effective way of doing it, but I thought I'd try it and it seemed to work ok for me. Took a bit of messing around to set up the canister like this though. I'll try and get around to posting some detailed pics of it's insides. If anything I should have made it bigger.
I think most (if not all) off the shelf units are just open canisters with nothing inside.

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#128 rodomo

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Posted 14 July 2009 - 05:40 PM

This is the set-up on the Bombadoor. Bargain basement, home made, scrap heap challenge brand. (Don't laugh!) It's capacity is about 2 litres and has no steel wool or such inside, just an empty vessel.

The car has done about 250 laps around Sandown (anti-clockwise) and Calder (clockwise) and every time I've opened the tap to drain it, it has been dry.

The 2 hoses will give you an idea about ls2lxhatch's comments.

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#129 rodomo

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Posted 14 July 2009 - 05:59 PM

This is the text that accompanies the pic from my thread.

"The catch can was fabricated. The plastic fittings came from the Bunnings garden department ($12 all up) and the hose was $3 a metre. The wire inside the hose is mig wire that I wound around a big screwdriver and pulled through the hose to stop it from collapsing. I mounted the catch can higher than the rocker cover so that any oil would collect in the hose, hopefully, and drain back before it got to the can. The plan here is that the "catch can" relieves pressure rather than catch oil. The coiled wire might help to catch the oil droplets, let it drain back, and let the pressure pass over?"

The fittings and hose are 19mm.

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#130 Statler

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Posted 14 July 2009 - 06:03 PM

OMG!
At first glance i thought....Christ! Rob has airconditioned the engine! lol

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#131 fatslr

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Posted 14 July 2009 - 08:20 PM

Thanks "Litre 8"
The catch cans in your link look better than any i have seen on evil bay will definately be looking at purchasing one once i actually get a job again :blink:

bit skint after a lap of Oz.

Thanks Rodomo for pics and i agree with your theory regarding height of inlet to catch can being higher than rocker covers to minimise actual oil transfer and just allow for vapour .

This is why i am chasing pics of setups would be nice to see a coupla V8s as i am struggling to see a spot with "height" in my engine bay?

Garth

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#132 rodomo

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Posted 14 July 2009 - 08:22 PM

Running the hoses higher, then lower to the can would probably work the same.

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#133 _Westie_

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Posted 15 July 2009 - 01:05 PM

Thanks Rodomo and ls2lxhatch, great to get some pics and logical explinations to the problems at hand. I like the idea of the two hoses, adding another at the front. I also like to idea of the higher hose position, and basically I am understanding the whole oil/air/pressure process alot better, so thanks.

My last question is about my catch can in the pics above, the shiny one that is, which I dont know the brand. When you take the air filter off, there is approx a 1 inch cylinder running straight down to almost the bottom of the outer can, maybe 2cm from the bottom. So when the oil enters the outer can at the top, it runs down and starts filling up the space. When the oil reaches the cylinder, and more oil and air pushes into the outer can, this will start to pressurise. My thoughts are that if this continued, then the outer can will try and relieve it's pressure, and therefore push oil/air/water up the inner tube with some force. Hence the amount of oil over everything on that side of the engine.

Hence my question.....why would someone sell or make a can like this? Why not simply an open space, where the air vents out the top, and the oil/water sits at the bottom.

Anyone got any clues to this? Seems bizarr to me.

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#134 TerrA LX

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Posted 15 July 2009 - 11:24 PM

...why would someone sell or make a can like this? Why not simply an open space, where the air vents out the top, and the oil/water sits at the bottom.

Anyone got any clues to this?

Easy, a fool and his money are easily parted and there is a fool born every day.

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#135 _Squarepants_

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Posted 16 July 2009 - 05:32 PM

I think the idea would be to empty it regularly and not let it fill up that much. It would have to get pretty full to throw oil all over the engine bay.
The tube is to create a change in direction of the gas flow which helps to throw heavier particles (oil) out of it.
I would prolly rather that design than an empty canister.

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#136 _The Baron_

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Posted 16 July 2009 - 05:50 PM

Great info guys, very interesting!

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#137 _gh20_

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Posted 18 July 2009 - 11:52 AM

Have a look at some old Group C cars. We run a return bypass back to the sump on ours as they did in the day, works fine.
I believe that Les Small was the inventer of the pipe cleaner fix

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#138 _82911_

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Posted 18 July 2009 - 09:48 PM

ahem.... Smokey Yunick did it in the 50's so it was not a new idea in group c.

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#139 _rorym_

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Posted 27 July 2009 - 04:59 PM

OK..Update time.
The combination of the restricted lifters and the breathers to the top of the rocker covers fixed the excess oil inn the catch can problem. As previously stated by Greg/82911 about draining condensation from the can after every outing..on this i can not EMPHASISE enough...after 5 runs..3 on Sat and 2 on Sunday at Wheels on Wide Bay the catch can was half full...1.5 litres..of crystal clean water!..not a drop of oil...at all..well..as small amount of milky sludge on top...so for anyone thinking sump drain back...think again.
I left the HV pump in..but am seeing something else weird now...
Cold..good pressure...40psi...slight blip....up she goes..70psi..

get it fully hot...idle 30psi...rev it...up to 60 psi...
Do a run..back to pits..slow down immediately at end of run...blip it...idles at 25psi...doesnt move on the blip..
wait about 30/40 secs at idle...blip it again....flicks back up to 50/60psi..
This one has me stuffed..only thing I can think of is the presuure relief valve is slow to come back into place..??
Never loses pressure completely..just sits solid at 25psi for 30 plus secs at the end of a run then is fine again.??
Any ideas?..Shim the relief valve up a bit on the pump maybe?
R

Edited by rorym, 27 July 2009 - 05:01 PM.

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#140 Stedz_lc

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Posted 27 July 2009 - 11:42 PM

As for draining to the sump and condensation...................
If you have a permanent drain to the sump from the catch can then there is no problem. The oil blown by the breathers just returns to the sump. IT IS ONLY IF YOU LET THE ENGINE COOL OR SIT OVERNIGHT THAT THE CONDENSATION FORMS IN THE PUKE CAN. It is the heating of the air in the can and exposure to atmosphere that condenses the water vapour out of the air and it falls to the base of the can to mix with the oil.
If you don't run a return line, then you MUST drain your can after every session.

I dunno how to do a quote but that is a quote from greg (82911) on previous page So im guessin thats the answer to the condensation and returnin it!

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#141 _rorym_

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Posted 29 July 2009 - 05:36 PM

I am serious...I was shocked with the amount of condensation over night..if you dont have the ability to drain your catchcan overnight or have it plumbed straight back to the sump I would be changing it yesterday...

Maybe I am just getting paranoid over the oil pressure...it never drops below 25 psi...and std idle psi is way lower than that.
R

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#142 Stedz_lc

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Posted 29 July 2009 - 11:35 PM

Now you have me confused, im going thru havin mine catch can and over plfow made atm to suit the car, the way greg put it i can return it but your sayin bad move hrm!

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#143 _rorym_

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Posted 30 July 2009 - 05:37 PM

Now you have me confused, im going thru havin mine catch can and over plfow made atm to suit the car, the way greg put it i can return it but your sayin bad move hrm!

It can return...as long as you have a drain on it and religiously drain it after every meeting ..preferably late at night....but a lot dont have the drain...so all the moisture is just circulating in the engine....they are the ones I was saying to look at their system...
R

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#144 _Bomber Watson_

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Posted 30 July 2009 - 07:51 PM

I would think the return to the sump 1/2" up the side with a bung in the bottom would be a good idea yes??

Cheers.

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#145 _rorym_

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Posted 01 August 2009 - 05:56 PM

Maybe..but as I said..I was shocked to see 1.5L of clear water come out of the can..scary actually.
R

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#146 TerrA LX

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Posted 01 August 2009 - 07:19 PM

What is even scarier is that if you did not have a catch can I doubt there would be 1.5L of water in the sump.

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#147 _rorym_

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Posted 01 August 2009 - 07:53 PM

So where is it coming from?
R

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#148 _the gts_

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Posted 16 August 2009 - 06:58 AM

Would these help

Click Here

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#149 _ass308_

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Posted 16 August 2009 - 06:26 PM

i have been following this thread with interest.i still dont know really what im going to end up with.this is what i have atm.its a bursons brake fluid bottle.2 hoses in,to it,and holes

drilled in the lid,no filter.i get a very slight oily residue under the bonnet atm.at no time has oil ever pooled in the can.no water either.no pcv valve,and a sealed oil cap.standard

covers,and a 355.motor has been dynoed and had 500km driving on it.sometimes at the lights i get vapour comeing out from under the bonnet,so it is breathing

the bottle is left of the radiator

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#150 _Gunmetal LH_

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Posted 31 August 2009 - 10:31 PM

Had a play with a mates 6cyl VC Commodore, after his air filter kept getting WET with oil, he bought a filler cap with a dome and an outlet. That now goes to the air filter to burn any excess gases coming out of the engine instead of the plastic outlet halfway along the rocker cover. The inside of the new cap had a ring of mesh inside it. (filter?) We blocked off the old vent outlet hole with a cork (don't laugh, it fit perfectly!) Ran a tube from the new cap up to a plastic peanut butter jar (crunchy- of course) sitting just behind the suspension tower with an elbow and a tube that went to the bottom of the jar and a bundle of steel wool in the bottom. Put an outlet that only just went down past the lid so it didn't suck up anything, and another tube back to the air filter. Worked killer! The jar being above the engine got bugger-all in it, just a little bit of black poo in there. When he wants to drain it out, just unscrew the jar from the lid and pour it out.

No more soaked air filter and the plugs stayed clean. No need for a sight glass or tube- the jar is clear. Cost? -2 metres off the garden hose, a tube of super-glue and some 'bits' from the shed.

Don't know how this would go on a proper race car being under much higher G's with oil being 'sloshed' around? I bet no-one else would have a 'Kraft' brand catch can though...