Breathers into air box - good idea?

[Borec Senior Member Find all posts View Profile Close Borec]

Hi,

I am thinking about doing diff and transmission breathers, and doing bit of reading about it on the net. There are some good threads about it here on the forum, using kits, or home made stuff. However on another forum I have come across an idea which suggests, tapping tire valve stems into the air box (in the clean section), and connecting the breathers to that.

I rather like the idea, as it solves the issue of any filters, and also it gives me the same height of the breathers as my snorkel.
However is it a good idea technically? I am not too keen to drill holes into my air box to start with, and then any faults in the connections, and in the hoses back to the diffs or trans are potential intakes of unclean air/or worse into the engine.

Another bit I am not sure about is (it might be silly thought, but I have little knowledge when it comes to this), would not the engine try to suck the air out of my diffs and transmission, and thus suck in the oil, or there is not enough pressure for this?
Any input on this would be greatly appreciated

Borec

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

If some level of vacuum is pulled in the airbox then that will be on the breather too. Lower pressure than atmospheric in the diff will allow water past the seals more easily than otherwise. Already we wait for the diff to cool down before a water crossing (or should) and that is to stop the sudden cooling effect of the water and subsequent pressure drop sucking in water.

I haven't and wouldn't. It is easy enough to do the breathers anyway. Cheapest option is to use small fuel filters or you can go for the various kits on the market or use industrial gearbox breathers as I did. I assume you have seen the how to thread? It is very comprehensive.

[Borec Senior Member Find all posts View Profile Close Borec]

If some level of vacuum is pulled in the airbox then that will be on the breather too. Lower pressure than atmospheric in the diff will allow water past the seals more easily than otherwise. Already we wait for the diff to cool down before a water crossing (or should) and that is to stop the sudden cooling effect of the water and subsequent pressure drop sucking in water.

Suspected something like this, however not sure if the level of vacuum actually would have that kind of effect. Would be nice to know exactly, as I would like the breathers to come out higher then engine bay, I know bit academic you might say, if you have water that high, you will have other issues to worry about . But that is why the idea of getting them into air box is appealing to me.

I assume you have seen the how to thread? It is very comprehensive.

Yes I did, if you mean the D4D Auto Transmission Breather thread, that will be my guide once I decide what to do.

I like this kit - and mounting it somewhere on the snorkel ro something
http://www.diffbreathers.com.au/comp-diff-breather.html

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

The only thing I would be wary of is if you have a filter failure you'll be getting
dust etc going into the diff's, transfer case, gear box and engine all in one hit.

Same for a line, if a breather hose gets pulled off under the car then you cpuld
get dust entering the air box as well as the whatever, granted it might not be much
but always better to keep them separated in my opinion.

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

That's an expensive kit. To do the whole lot which in a 120 is four breathers (excluding the fuel tank) you need the fitting for the rear diff (1/4" BSP to 1/4" hose tail) and 1/4" fuel line to the engine bay. The gearbox is 1/4" hosetail joiner and then 1/4" fuel line to the engine bay. The transfer case is 1/8"to 1/4" hosetails to 1/4" hosetail tee (or run both) and then 1/4" fuel hose to the engine bay. In the engine bay make a bracket as I did and then mount little filters or breathers (not the stock ends because they aren't breathers). You could just cable tie them up there too. The front diff requires a 1/4" hosetail joiner and some 1/4" fuel hose. Pretty sure I spent well under $100 to do my 120 and my 150.

Oh and lose about an acre of skin and 4L of blood doing the gearbox.

The 150


The 120

[Borec Senior Member Find all posts View Profile Close Borec]

I guess if I had a filter failure, then I would have other things to worry about, but that is very unlikely, what worries me more are the lines being pulled, and then engine sucking unfiltered air (or whatever).

[Borec Senior Member Find all posts View Profile Close Borec]

Thanks for the info. Ya, the kid is expensive, that is why I am bit reluctant, but what I like about it is that it can be mounted outside (if it ever comes to it) and has only one filter. I have to think about this bit more, if to do the air box trick, or engine bay like you did, or mount it outside somewhere using that kid. Anyway, I have ordered some valve stems on ebay already, just to have a look how that would work out.