Catch Tank ----------------------

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--alpina--

--alpina--

Hiya, a quick question on Catch Tanks, are they easy to fit ?? If so what would be the best way to do it? And as theres a carbon canister in the back of the engine does that have to come out in its place i.e. Is it the same sort of thing and is the carbon canister really needed in any way?

Cheers

J
 
Catch tanks are a doddle to fit.
Oil breather from engine breather to tank and tank to engine inlet :)
I've an old photo somewhere
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Cheers guys, so whats said is that the inlet mani pipe that connects to the rocker cover (left side) is blocked off and the catch tank pipe connects to that side on the rocker cover and the (right side - distributor side) another pipe from the catch tank connects there???

Is that correct... Just to confirm my understanding!!

Cheers..

J
 
I once wrote this to help imagine how the PCV system works and what the catch can does:

metaphorically, think of the crankcase as a busy chip shop kitchen, inlet manifold as the extraction fan, the PCV circuit as the kitchen ventilation extraction fan duct and the engine cover breather port as the kitchen window and the catch can as the cold window glass.

if the pcv valve wasn't connected to the inlet vacuum (like turning off the extractor fan), a heavy soup of combustion blowby, water vapour and oil spray/mist just hangs around the crankcase (like the oil fryer emitting loads of steam n oil vapour while cooking chips)
until enough blowby volume slowly pushes the mist to escape via the easiest open path straight out the breather port (dense steam vapour from cooker engulfs the kitchen then flows out the window)
that dense oily watery vapour goes through the cold catch can n condenses most of the water and oil vapour (steam and oil condensing & running down all over the cold kitchen window)

the engine parts (shop customers) won't be happy that all that dense vapour in the crankcase (cooker steam pouring from the kitchen to the customer area) is contaminating the oil and forming acidic conditions n sludge (poisoning n gassing the customer reducing their lifespan)

the pcv valve should normally be connected to the mani vacuum so during idle it sucks fresh air through the breather, in through the crankcase collecting vapour, up through the rocker cover and into the engine to burn. during high boost or blowby, the pcv closes and the excess pressure & vapour goes out the PCV breather port where the catch can collects the oil vapour and either returns filtered air back into the engine inlet or into atmosphere
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Hahahaaaa now thats a well explained idiots guide!!! Having a turbo would you say its mandatory to have one fitted regardless?? Also the carbon cannister thats already fitted,whats the there for?

Cheers pollyp
 
--alpina-- said:
Hahahaaaa now thats a well explained idiots guide!!! Having a turbo would you say its mandatory to have one fitted regardless?? Also the carbon cannister thats already fitted,whats the there for?

Cheers pollyp
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turbo, recommended cos otherwise you'll either coat ur engine bay in oil stain or coat ur entire inlet plumbing, sensors etc in oil stain over time
 
carbon canister both allows air into the fuel tank as the fuel level drops and also collects evapourated fuel vapour from the tank and releases it into the intake during vacuum so it's burnt off rather than simply released into the world (emission control). can be left alone
 
Hi, thanks for your reply back!! All is clear on this! Ill have to be ordering the tank as its on top of list now! Just to clarify on one thing!

The inlet mani pipe that connects to the rocker cover is to be blocked off!! And then the two outlets on the rocker cover goes straight to the tank is that correct?

I know its a simple thing to some etc, i just dont wanna be blocking off pipes that may cause a proplem specially a wrong pipe!!! hahahahahaha.

Cheers

J
 
ok cba to draw but to list afew setups:

catch cans filter oil vapour out the crank vents before it enters the inlet system and are plumbed inbetween one or more of the three crankcase vents.
after air filter / before turbo -> rocker cover,
crankcase -> rocker cover,
rocker cover PCV -> inlet mani.

check the catch can instructions for flow direction cos some are directional working

google catch can install/setup and theres loadsa guides
 
pollyp said:
ok cba
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i,m shocked paul :D
catch cans do bugger all J, they,re just a bit of bling really, how many factory turbo,d cars have you seen with one ? i hav,nt run one for years and i know for a fact that if i start venting oil then there,s a fault/issue somewhere
 
pollyp said:
ok cba to draw but to list afew setups:

catch cans filter oil vapour out the crank vents before it enters the inlet system and are plumbed inbetween one or more of the three crankcase vents.
after air filter / before turbo -> rocker cover,
crankcase -> rocker cover,
rocker cover PCV -> inlet mani.

check the catch can instructions for flow direction cos some are directional working

google catch can install/setup and theres loadsa guides
Click to expand...

Pollyp, yeah i understand, no need for some picaso drawing on it etc, am just brushing up on what i know of it which you explained which was clear enough!


frank said:
i,m shocked paul :D
catch cans do bugger all J, they,re just a bit of bling really, how many factory turbo,d cars have you seen with one ? i hav,nt run one for years and i know for a fact that if i start venting oil then there,s a fault/issue somewhere
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Frank, thats a point i understand, am hearing from people that its more than needed if running a Turbo, yet ive not seen any factory fitted Tanks !! maybe as you says they do bugger all or its a money thing etc :)

Oh and what does CBA stand for?

Cheers

J
 
frank said:
i,m shocked paul :D
catch cans do bugger all J, they,re just a bit of bling really, how many factory turbo,d cars have you seen with one ? i hav,nt run one for years and i know for a fact that if i start venting oil then there,s a fault/issue somewhere
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http://oilcatchcan.com/

the principle of the mechanism itself has a purpose:
reduce oil vapours from re-entering the intake,
prevent contamination of all the components thoughout the intake plumbing,
reduce risk of disturbing the combustion mixture under high loads (from either contaminated sensor causing miscalculated AFR or from a small pool of oil entering the chamber),
reduce risk of any abnormal combustion such as knocking or lean-out or too rich,
reduce chances of ECU "pulling back" the mapping (and power) to protect itself when it detects knock IF it has such feature,
reduce risk of lean-out damage or lose power from over-rich AFR if there's no knock sensor

the system basically ensures consistant reliable power so the tuner can push the most out of an engine safely.

when the products are poor quality replicas, poorly designed to not perform well or was installed incorrectly, then it's called bling.

why do motorsport use them while normal domestic NA/turbo cars don't? = cost & ease of maintenance & emissions standards.

on factory cars they simply return the oily PCV vapour straight back into the inlet mani vacuum (after the sensors & throttle) to be burnt.
it's cheap & easy, the user won't have to periodically empty any oil canister for ease of maintenance and oil vapour ain't leaking onto the floor or air.

If there was any chance of the oil causing abnormal combustion, the ECU map would've either been mapped with alot of safety margin (at the cost of performance) and/or the knock sensor would've caused the ECU to pull back the map briefly (at the cost of performance) to save it.

motorsport tuners on the other hand want to tune the MAX performance from that engine setup as close as possible to the edge of failure only to last a specific mean-time-between-failures to have the best advantage to go fastest & win, and don't care for the environment or ease of maintenance with such resources.

chalk & cheese difference in goals & requirements.

another way to see it is like the computer industry.
a standard domestic PC CPU/GPU is hardly running at it's maximum theoretical limit cos the manufacturer intentionally dulled it down within a safety margin to operate reliably under a wide range of conditions & tasks.
custom PC overclockers in comparison are like engine tuners, running the chip under specific conditions (low temps) for lower inteference and manage heat so they can ramp up the voltages and clock speed closer to the edge of failure just to acheive a faster but reasonably reliable clock speed for a specific task.

--alpina-- said:
Oh and what does CBA stand for?
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can't be arsed :p
 
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frank said:
praps members can post a pic of the contents from their "catch" can ? :)
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I just drain mine never photograph it. They take the condensation out the head whilst it's sat. Take oil vapour out of incoming air which is a good thing. You'll get vapour whatever the state of the engine put some paper over the breathers and you'll see
Factory cars don't come with one because its an economy thing to burn it off rather than catch it and bin it

As for "only abit of bling"
Come to modified live and tell the 1000hp car builders that their catch can is pointless
Please photograph their faces :p
 
i guess the millions of diesel drivers have to check their oil level every week with all that oil they,re burning off then :rolleyes: that 10% of owners that actually know where the bonnet-pull and dipstick are of course.
they typically run a c/r of 15:1 and 18psi of boost, so if you are venting oil from the crankcase breather then its usually a sign that your engine is shagged,
i had to fit a can to pass the 1/4 mile scrutineering (to catch the oil if you blow a piston on the start-line) but it,s never actually "caught" any oil tho
 
--alpina-- said:
Very well said !!!!! @h701micra was there alot of oil? And the last time till recent how many miles or months did you had to drain the oil?
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Its caught what seem to be more condensed water. Which is better than it being sat in the top of the engine itself :) whilst running mine has no effect as I haven't connected the outlet of the can to my inlet to vacuum ot through :p although I never made a note of the drains tbh :/
 
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frank said:
i guess the millions of diesel drivers have to check their oil level every week with all that oil they,re burning off then :rolleyes: that 10% of owners that actually know where the bonnet-pull and dipstick are of course.
they typically run a c/r of 15:1 and 18psi of boost, so if you are venting oil from the crankcase breather then its usually a sign that your engine is shagged,
i had to fit a can to pass the 1/4 mile scrutineering (to catch the oil if you blow a piston on the start-line) but it,s never actually "caught" any oil tho
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Yes they should. Its part of weekly maintenance for any car owner to check their oil.

Its not a sign of the engine being shagged at all. Much like the crank creates a vapour of oil at the bottom end the cams create a similar vapour in the top in a much more confined space. This vapour has to go somewhere and usually its the inlet where a vacuum draws it out. A catch can does it by swirling it out in a similar manner air is swirled out of water in coolant lines. Like a Renault 5 GTfor example.

It stands to reason that the condensed oil is then caught in a can... were not expecting litres. Unless of course your cams don't create a vapour of oil... by that point you've bigger problems?

They don't just catch oil. Fuel vapour that's gets past the piston rings on high mileage engines is recirculated in the same principle. Add that to water condensation in the head and you've plenty of crap to get rid of. Majority being condensated water, @pollyp was around I'm sure when I drained mine last

If it was all a fad then why do people's inlets gunk up if it was only air entering the engine? Anyone here could check their inlet and see what I mean. Horrible black gunk in the inlet tract

A good read for anyone who doesn't understand what a catch can does :)
oilcatchcan.com
 
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Researched this a lot and it also helps keep the oil better for a little longer to as the chap the engines trying to burn can't get back into the oil and just keep recirculating , there's been engines that get there insides caked with all that unburnt oil sat at the top of the engine also the air filter has a filter that gets caked in oil an that meant not all the oil will get out to be burn have a look you'll see its got a scourer looking pad where the crank breather enters the air box
 
truck+micra matt said:
have a look you'll see its got a scourer looking pad where the crank breather enters the air box
Click to expand...

if you tie a plastic bag to that crankcase breather that runs to the felt pad and drive the car you will see that its under vacuum conditions tho matt (so flowing the wrong way for oil ingestion)
hopefully some of the members who run catch cans will post a pic of the contents then ? (@Skinner_87 @SuperUno @pollyp spring to mind)
 
Interesting topic, so all this oily water as Superuno mentioned he saw in his catch tank would have been emulsified into the oil complete then?

J
 
I'll try take a piccy of mine someday frank, very busy with work at the mo.

the breather port between the rocker cover and the intake plumbing is freely open two-way and the flow changes depending on the amount of crankcase pressure affected by inlet vacuum and blowby.

the internal passages of the rocker cover allows some of the vapour to condense on the cooler outer cover and drain back down the drain hole while the remaining vapour flows out the breather under positive crankcase pressure (especially under high boost or high blowby).

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before I fitted a catch can, all of the turbo impeller, IC, GTIR MAF used to get coated in oil vapour after awhile and affected the AFR.
I've plumbed mine between the rocker and turbo inlet to protect those parts from oil deposits during high boost and it kept em cleaner for longer.

the vapours come out of the breather mostly during high boost cos thats when the inlet +ve pressure shuts the PCV and the increased combustion pressure causes more blowby and with those two combinations, all that built up positive crankcase pressure has to go somewhere of least resistance ie, out the rocker cover side breather...through my catch can and back into the turbo inlet.

during normal public driving the car ain't boosting for long periods so only a little bit of vapour would be collected.

during normal driving its mostly off boost under high manifold vacuum.
this opens the 1-way PCV, and creates a -ve crankcase pressure to "suck" the aerated oil vapour out the crankcase, it first passes through a wire mesh at the lower front of the block to catch & condense most of the large oil droplets, up the front pipe in through the rocker cover, through the PCV and down into the inlet mani where the vapour would most likely condense at the bottom of the very cool manifold (thats why you'll always see a damp oil patch at the bottom of the mani when you remove the throttle body).
meanwhile fresh air from the air filter flows through the catch can, into the rocker breather port, past the cams, down the timing chain cover and into the crankcase to replace the -ve pressure.

what I should also do tbh is also fit a catch can between the PCV and the inlet mani vacuum where most of the oil vapour flows to, I'd be able to catch more vapours from entering the engine.

Andy, perhaps that's why that evo we saw at cadwell had that 3-tank catch can unit, to capture vapour from the 3 crankcase ports and guarantee absolutely no oil vapour enters the inlet system?
 
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--alpina-- said:
Interesting topic, so all this oily water as Superuno mentioned he saw in his catch tank would have been emulsified into the oil complete then?

J
Click to expand...

combustion produces some water vapour in the blowby. couple this watery blowby with the splashed aerated oil vapour flowing out the crankcase vents and into any catch can, that's why there's an oily and watery mixture
 
pollyp said:
combustion produces some water vapour in the blowby. couple this watery blowby with the splashed aerated oil vapour flowing out the crankcase vents and into any catch can, that's why there's an oily and watery mixture
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Did I drain mine when you were around last? Or am I thinking of Rob?
 
truck+micra matt said:
Though the case was under pressure meaning it would blow rather than suck and that's how the felt pad gets closed up ?
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that pipe is the fresh air inlet for the pcv system matt, so that filtered air goes in and the crankcase fumes are passed through the oil separator system under the cam cover ^ in pauls pics, then the vacuum in the inlet mani draws out the fumes and burns them (when there is high manifold vacuum, ie, during idle and low throttle)
at higher throttle there is no vacuum in the mani, and the pcv system is barely working, so it does,nt affect horsepower

quotes from wiki
"pcv quickly became standard equipment on all vehicles worldwide because of its benefits not only in emissions reduction but also in engine cleanliness and oil lifespan "
"the air circulates around the interior of the engine picking up and clearing away combustion byproduct gasses, including a large amount of water vapour"

removing/bypassing the pcv system and fitting a catch tank will mean that there is no circulation and a lot of the combustion byproduct gasses and water vapour is allowed to contaminate the oil (like when you get mayonnaise inside the cam cover when running short journeys
burning this oil/water off at low throttle does,nt harm the engine at all, and modern cars have very long service intervals as a result
 
pollyp said:
Andy, perhaps that's why that evo we saw at cadwell had that 3-tank catch can unit, to capture vapour from the 3 crankcase ports and guarantee absolutely no oil vapour enters the inlet system?
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I know from getting the regs for my car they have to use a minimum 2 litre unit... but that was 3 and would agree with what you're saying. They were in excess of 800bhp so no room for any errors
 
frank said:
removing/bypassing the pcv system and fitting a catch tank will mean that there is no circulation and a lot of the combustion byproduct gasses and water vapour is allowed to contaminate the oil (like when you get mayonnaise inside the cam cover when running short journeys
burning this oil/water off at low throttle does,nt harm the engine at all, and modern cars have very long service intervals as a result
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Sorry but I completely disagree, my catch can has had nothing but positive effects, and the draining of oil laden liquid proves that
Instead of it entering the engine and contaminating the clean air, its caught in a can and the clean air is put back in the inlet stream... that is the only difference from a PCV unit and a catch can being fitted. Cleaner air = more power as a result. Maybe not so on low powered engines but definitely the case higher up the chain and highly boosted engines
Complete removal of the PCV system may cause those issues, but fitting a catch can wont, as the system is still complete
Modern engines are built to completely different specifications than the engines of old. Tolerances and materials these days are so far advanced.
 
Plus depending on the design, a catch can is meant to be fitted to 'intercept' the existing crankcase pcv circuit to help filter out any oil particles from travelling further down rather than to 'replace or bypass' it.

During WOT in a NA, yes the mani is under minimal vacuum so won't be sucking much vapour up from the crank but the crankcase itself will be under more blowby depending on how worn the rings are, so the positive pressure flows freely out the open breather port along with any aerated oil vapour that's escaped
 
pollyp said:
Plus depending on the design, a catch can is meant to be fitted to 'intercept' the existing crankcase pcv circuit to help filter out any oil particles from travelling further down rather than to 'replace or bypass' it.

During WOT in a NA, yes the mani is under minimal vacuum so won't be sucking much vapour up from the crank but the crankcase itself will be under more blowby depending on how worn the rings are, so the positive pressure flows freely out the open breather port along with any aerated oil vapour that's escaped
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i agree paul, which is why i say a catch can on a healthy engine is teats-on-a-bull/counter productive (ie, no oil scrubbing)
 
frank said:
none of these members are running the pcv system andy http://www.micra.org.uk/threads/oil-catch-tank-fitting.60220/#post-678546
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Doesn't matter what engine it is. They're all fitted with a breather system on to head in the inlet tract.
What you're stuck on is only expecting oil through the cylinder for some reason... where water is more likely than oil in all cases. If you're going to tell me no oil comes out of the upper breather ports then go to the back of the class. Have you never looked inside the pipes from an engine that's had them on? Clean right up until the breather comes in where its gunked up. Inlets are gunked. Best hidey place is under the tb butterfly. Its not me trying to convince you of an opinion. Its me telling you the facts.. it happens. And removing that gunk from any engine is positive in every respect
NA or turbo you'll get it as no engine stays in vacuum under throttle there's still air flow enough to create a circuit. Boost just adds to that and also magnifies blowby effects. The crankcase vents through the timing cover. A rather large open hole where because heat rises.. hot oil aerated oil can rise. As @pollyp pic of the cam cover showed There's no way for it to be 'counter productive' unless it been fitted very incorrectly especially as Paul research proved otherwise

 
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pollyp said:
the crankcase itself will be under more blowby depending on how worn the rings are, so the positive pressure flows freely out the open breather port along with any aerated oil vapour that's escaped
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The crankcase vents through the huge hole at the bottom of the timing chain cover....
Its not wholly reliant on piston rings being worn. That's where we expect fuel vapour blowby in the catch can. Hopefully none on a healthy engine

If your expecting oil to travel to the catch can from the crankcase into cylinder its also got to bypass the valve stem seals to get into the breather system... by which point the engine is in need of a rebuild

But I think everyone has forgotten or just didnt know the timing cover being the vapor vent for crankcase oil vapour
 
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Simple Diagram
Red - Oil
Green - Blow-by Vapour
Blue - Water
Arrows indicate flow. Nothing flows upward through the cylinders. I thought this was simple stuff?
Crankcase ventilation.png
 
Nice simple illustrations & explanation there. we should get engineeringexplained off ytube in here :p
An engine is a three dimensional puzzle and the flows are dynamically changing to various driving states. I'll try to draw a pic on what I know someday.
 
pollyp said:
Nice simple illustrations & explanation there. we should get engineeringexplained off ytube in here :p
An engine is a three dimensional puzzle and the flows are dynamically changing to various driving states. I'll try to draw a pic on what I know someday.
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I'll send him a message and see what happens :p
I know the flow around the breathers changes during vacuum and boost but I dont know which way etc. I just understand the basic principle of the crankcase breather system :)

Here's his official site
http://www.howdoesacarwork.com/
 
pollyp said:
fab.
and I'll sketch some 3D pics of the plumbing
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Look forward to it Paul :)
I'm gonna go drain my can real quick, if theres anything to drain today, see what's what :) post a photo where necessary
 
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righteo I'll photo mine too. since on mine I'm basically using a motorcycle oil filter, the captured oil vapour is probably soaked into the filter medium itself and ends up being like those oiled K&N air filters so won't see much from the top opening
 
pollyp said:
righteo I'll photo mine too. since on mine I'm basically using a motorcycle oil filter, the captured oil vapour is probably soaked into the filter medium itself and ends up being like those oiled K&N air filters so won't see much from the top opening
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It'll be good for comparison :)
I know the liquid that comes out of my can smells like a swamp. I made Rob smell it last time. He wasnt pleased :p
 
this is inside my oil filter diy catch can.

the outer holes with some slight residue are where the oily vapours from the rocker cover breather port would enter during boost and the centre hole is where the filtered air returns into the turbo inlet. during off-boost it'll flow the other way

DSC09514.JPG
DSC09515.JPG
DSC09516.JPG
 
I use a simple home made catch can an all I've had out of its is a bit of water. I don't bother with the pcv valve as I'm running ITB's.

Engine breathing is very simple, its amazing how many people get confused by it.
 
h701micra said:
Doesn't matter what engine it is. They're all fitted with a breather system on to head in the inlet tract.
What you're stuck on is only expecting oil through the cylinder for some reason... where water is more likely than oil in all cases. If you're going to tell me no oil comes out of the upper breather ports then go to the back of the class. Have you never looked inside the pipes from an engine that's had them on? Clean right up until the breather comes in where its gunked up. Inlets are gunked. Best hidey place is under the tb butterfly. Its not me trying to convince you of an opinion. Its me telling you the facts.. it happens. And removing that gunk from any engine is positive in every respect
NA or turbo you'll get it as no engine stays in vacuum under throttle there's still air flow enough to create a circuit. Boost just adds to that and also magnifies blowby effects. The crankcase vents through the timing cover. A rather large open hole where because heat rises.. hot oil aerated oil can rise. As @pollyp pic of the cam cover showed There's no way for it to be 'counter productive' unless it been fitted very incorrectly especially as Paul research proved otherwise

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you obviously hav,nt studied a CG pcv system andy, paul is right the pcv draws crankcase fumes only from the mesh and front rubber pipe that is fitted between the exh mani and g/box (not from the head or chain area) then it travels along the sealed galleries/oil separator under the cam cover
removing the pcv like most of the members have done looses that oil separation function and as a result the oil mist from the crank case is vented to the catch can
this oil is probably what you guy,s are collecting in your cans, oil that should be in the engine
P8160065.JPG
 
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