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Discussion Starter #1
whats up guys ive been completely puzzled after reading through a million catch can threads. i want to run two -an lines from the valve cover , block fitting where the black box is/was , and run all three to a vented baffled catch can , however it seems everyone drains back to the block using the drain on the can . personally i don't want that crap going back into my motor.

so could i run a set up as follows vc ports to catch can plus block to catch can , drain to ground (when it gets full) .

ive seen everyone or what it seems like everyone drains to the block , which is what i don't want to do.

is my set up ideal and also safe? i don't care about having to drain the can out .

please no uneducated answers , im looking for facts as to whether this would be a correct or incorrect set up and exactly why .
 

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i weld a fitting and attached a 17mm hose to the factory blackbox vented to the floor behind the block..i did not see it spill any oil..

i have another 2 12mm fitting on the valve cover without connecting any hose..so far it is dry..
 

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The factory black box is a very good catch can, it just lacks the capacity to handle vastly increased blow by that you will see with a big HP increase over stock.

Before emissions where an issue breathers where just a tube that directed blow by to the ground. They deposited oil mist into the air and onto the road surface in a careless and irresponsible manner. Legislation to stop this was probably the very first automotive emissions law and for good reason.

The hole in the side of the block is not a vent, it is a return. That is why it is connected to the bottom rather than the top of the black box.

What you are describing as crap is oil and water mixed together. There is always some water in the crankcase and it soon builds up in the oil. Heat drives it out on longer trips. While it does no good at all, it is inevitable and does no real harm.

After all, oxygen in the air burnt with hydrocarbon fuel equals pretty much 100% carbon dioxide and water
 

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I'm pretty sure he was intending on having no drain back, but have it fill a container as opposed to having it leak into/onto the air/ground. There are plenty of catch cans like this; they have a little valve at the bottom to empty it when it gets full.
 

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Discussion Starter #8
ok so what you guys are saying is have the can drain back rather then fill up to prevent oil loss?

assuming im using a good quality baffled catch can , with the drain going back into the block , is that adequate ventilation for a high horse power vitara build ?

my thoughts are other than breathing easier than the stock set up or leaving a filter on just the vc nipple ,what does the can actually do then other that provide a space for the oil to collect and drain and provide ventilation ? in that configuration you guys stated above is it in fact getting the gases out of the oil or just simply providing a collecting place and returning it .

i was thinking about building my own catch set up out of some steel or aluminum to mount in place of the battery/fuse box when i finish my wire tuck. Is it correct in my understanding that the baffles just keep the filter dry/ stop the oil from splashing out of the can ? ive seen thread upon thread about catch cans but ive never seen a set up with no drain back and just having the block vented to the cc as in my original idea (on a dseries), but when i went to the dark side(dsm's) that seemed to be the general set up.

sorry this is a long post im just looking for correct answers and theory's here
 

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The prime purpose of a breather system is to vent blow by gasses out of the crankcase eventually to atmosphere or back to the inlet system so as to prevent pressure build up that will:-
1) blow oil seals causing leaks.
2) blow oil back up past the rings.
3) work against cylinder pressure.

The second purpose of modern systems is to separate oil mist from the blow by before the gas vents to atmosphere or the inlet system.

A big volume well designed can allows the blow by gasses room to slow down so the oil drops can be separated out, but the blow by still has to be sent somewhere, either to atmosphere via a filter or to the exhaust via a slash cut or to the inlet air duct before the turbo.
 

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Discussion Starter #10
so in other words the purpose of the can is to condense the oil mist while letting the gases that in the mist escape, thus draining the actual oil back into the block .
 

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you got it.

you want big hoses vs. small hoses, from the valve cover, to the catch can. More area for the gases/oil to slow down and collect.

I also have a few stainless steel 'kitchen scrubbies" stuffed into my can to give the oil mist something to collect on.
 

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Discussion Starter #13
so is there a need for baffling or should i just stuff my can a bit if i decide to weld up my own ?? the norm seems -10 an vc to cc and cc to block -12 is that correct?
 

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To do it right you need baffles.

-10 and -12 sounds plenty big enough.
 

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Discussion Starter #16
now by baffling would peices of angled metal or aluminum welded in side the can above the inlets suffice ? and sometype of screen or mesh at the bottom or is that over kill
 

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For crying out loud, just how far do you want the spoon feed to go.
 

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In my turbo build, I take off the stock oil breather (pcv valve) and remove the little valve, I weld a fitting for a 19mm hose that goes directly to the catch can, and the hose from the valve cover directly to the catch can too.... (remember to block off the hole in the intake from the old pcv valve hose).
I running like this for 250 miles without trouble... Later I'll check the can and see if it is full... But I don't think so... My engine oil level stays the same...
 

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Discussion Starter #19
i was not asking to be spoon fed , i was simply asking for theory and advice . As there is set ups that work and others that do not. i stated my thoughts on the set up that i thought would work best ,and i was informed that oil loss could be a problem and ive made my decision . thanks for the help
 

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I would prefer to just drain my catch can out every few weeks, because I personally wouldnt want that milky brown ish.. to get back in my engine to begin with..
 
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