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setting up oil catch tank


Mint69

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can I not just connect the catch tank up to the Pcv valve without having to cut the base off it? would The catch tank im looking at has steel wool inside it and seems to me like it would act as a pcv valve. my theory was just to run a pipe from the pcv valve to the catch tank then use the otther pipe on the catch tank to run another pipe to the manifold.

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nah you have to cut it as the pcv valve normally actuates when vacuum is applied, and a catch can cant give any vacuum to suck the valve open, and because a catch can is vented to atmosphere, having a hose from the manifold would do nothing as all the vacuum air would be supplied to the manifold via the vented catch can and mess around with the air intake on your car

so either connect pcv valve to manifold where the vacuum will open the valve, or cut pcv valve and pipe to catch can, you will have all sorts of weird problems otherwise

and you can always go buy a new valve, i imagine they would be pretty cheap

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If done properly a sealed catch can it will run fine through the PCV valve.

But yeah if your using a can with a little filter then the PCV has to come out.

This is how I have always set mine up:

singlecatchcansetup.jpg

And I have had best results with the inlet on the can having a tube to near the bottom of the can with holes in the lower 3/4s and the rest of the can packed with stainless steel wool, if both the inlet and outlet are right next to each other I have found that the oil vapor gets sucked straight into the outlet fitting rather than staying in the can which defeats the whole purpose of the can to start with!

dc3revbsect.jpg

But I know most people seem to love having a tiny lil pod filter in there engines bay so feel free to ignore this post if that's the case.

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Whats the reason for having a catch can if you are still hooking it up to your manifold? the oil will still end up going into the car and probably be more of a liquid rather than a vapour if you didnt check it(and you cant seriously say that after every drive you check your catch can)

the reason im running a catch can thats open to atmosphere(and removed the check valve) is because I will not be hooking it into my manifold

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Whats the reason for having a catch can if you are still hooking it up to your manifold? the oil will still end up going into the car and probably be more of a liquid rather than a vapour if you didnt check it(and you cant seriously say that after every drive you check your catch can)

the reason im running a catch can thats open to atmosphere(and removed the check valve) is because I will not be hooking it into my manifold

You didn't understand my earlier post. Catch cans are only for rooted motors. The reason it has a PCV system is to give a flow of fresh air through the crankcase.

The flow of fresh air is essential for removing water and exhaust gasses which otherwise contaminate the oil and make your motor even more rooted.

You'll know your oil is contaminated with water when you can see "mayonaise" on the dipstick or the filler cap. The "mayonaise" is water which has been absorbed by the detergent which is a constituent of the motor oil.

Steve

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Whats the reason for having a catch can if you are still hooking it up to your manifold? the oil will still end up going into the car and probably be more of a liquid rather than a vapour if you didnt check it(and you cant seriously say that after every drive you check your catch can)

the reason im running a catch can thats open to atmosphere(and removed the check valve) is because I will not be hooking it into my manifold

Because if you have a well set up can with stainless wool in it (like in the pic of the red cans I posted earlier) the oil vapor gets separated from the air and stays in the can.

If you set one up with out the tube going down into the stainless wool then yes the oil vapor gets suck straight back out the exit fitting of the can makong it pointless.

Since the thread got a will needed tidy up here is the diagram of how to set up a twin tank system again for anyone interested

dualcatchcansetup.jpg

Edit:

Some dickhead deleted it

Pity they didn't delete you at the same time.

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That dickhead was me :D and I edited your above post too, removing the parts that were intended to wind people up, because we can see that is your intention here.

Keep on topic, he asked a question about how to. We don't need a history lesson through the eyes of Steve on why things are.

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personally i really like readings Steve's tech view on why things work, gives you a real insite as to why and how your doing things, not just doing it cause everyone else is and its sounds like a good idea, but no need to take digs and get angry at each other over different views :lol:

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  • 2 months later...

im gonna bump this thread up cos i need to do it and after reading it like 3 times, im still confused...

Mini engines have heaps of crank case pressure and alot at the top of the head. from factory, let alone when they run at high compression. it has one breather line from the crank case (Filled with stainless baffle) which went god knows where from factory, (can only imagine it went to either the main air filter or to carb inlet manifold) but all ones i see now just have one of those little air filters on them. They also generally have a oulet from top of rocker cover that originally went back to the main air filter (unpressurised)

Now am running sidedraught carb with no vacuum advance or anything, and need to run a catch tank for track use etc, what i want to know really is:

above you seem to be talking about re-using air all be it clean with no oil mist wouldnt it just be better for engine to have fresher air inside it if anything or is there some benifit i am missing? Why have parts of the engine under pressure that dont need to be? also this pcv you are talking about what does that go in between on your escorts etc?

the internal design of catch tanks are generally all the same weather it is for closed loop or open to atmosphere? just the lack of filter i geuss?

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The Positive Crankcase Ventilation valve, or PCV valve, is a one-way valve that ensures continual evacuation of gases from inside a gasoline internal combustion engine's crankcase

As an engine runs, high-pressure gases are contained within the combustion chamber and prevented from passing into the crankcase (containing the crankshaft and other parts) between the side of the piston and the cylinder bore by piston rings which seal against the cylinder. However, some amount of gas always leaks past the piston rings into the crankcase. This amount is very small in a new or properly rebuilt engine, provided that the piston rings and cylinder walls are correctly "broken in", and increases as the engine wears. Scratches on the cylinder walls or piston rings, such as those caused by foreign objects entering the engine, can cause large amounts of leakage. This leaked gas is known as blow-by because the pressure within the cylinders blows it by the piston rings. If this blow-by gas could not escape then pressure would build up within the crankcase.

Before the invention of Crankcase Ventilation in 1928 the engine oil seals were designed to withstand this pressure, oil leaking to the ground was accepted and the dipstick was screwed in. The hydrocarbon rich gas would then diffuse through the oil in the seals into the atmosphere. Subsequently, it became an emissions requirement as well as a functional necessity that the crankcase have a ventilation system. This must maintain the crankcase at slightly less than atmospheric pressure and recycle the blow-by gas back into the engine intake. However, due to the constant circulation of the oil within the engine, along with the high speed movement of the crankshaft, an oil mist is also passed through the PCV system and into the intake. The oil is then either burnt during combustion or settles along the intake tract, causing a gradual build-up of residue inside the inlet path. For this reason many engine tuners choose to replace the PCV system with an oil catch can and breather filter which vents the blow-by gases directly to atmosphere and retains the oil in a small tank (or returns it to the sump), although this technically fails to meet most engine emission legislation

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