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Crossflow breather setup help ???


Boycey

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Hi

My Crossflow engine in my westie seems to fill its oil catch tank up really quickly as i dont think it is plumbed in correctly.

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Im sure it should b taking from to top of the engine and vent to the oil catch tank???  As in its current state im sure it is too low.  I have a burton power alloy rocker cover with no outlet pipes, but i have seen they sell a oil cap with outlet pipe on.

Does anyone else run a crossflow who can help with the plumbing in of it, or is the catch tank positioned to low in the car, so causing a gravity effect. thanks again

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on mine the block breather goes to a fitting on the back of the rocker cover. The rocker cover then breathes through a burtons cap with breather take off, to the catch tank.

The other connection on the tank has a breather filter on it.

Also make sure your fuel pump blanking plate has the horizontal baffle on it, which stops the cam flicking oil up the pipe.

Also helps to get the tank as high as possible.

hth

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ah cool yes that sounds more like it. This is how it has been when i bought it.

Could you please put some pics on here for me.

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My block and rocker vents go into a t-pieceand that goes to the tank.  The second fitting on the tank has a breather on it.  Tank is mounted as high as possible up the passenger footwell.  Catches some oil but not too bad for filling up quickly.
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Your catch tank is too low.

When I first had my crossflow, it used to fill the catch tank with oil.

Vent from the block and rocker cover, join high level into a Y piece and plumb to catch tank (mounted on scuttle)

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From my understanding the Catch tank has to be as high as possible.This is what i did to my xflow, soz for the low res piccy. took on a phone, but you get the idea. Now if i could only get the dam thing started :-)

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Cool thanks for all the response, bits are on there way. I will more the tank this week and plumb it in.

Now just my mirrors to sort out

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  • 2 years later...

Sorry to bump an old(ish) thread, but I've just started to look at my Crossflow setup and amusingly, my oil catch tank consists of an old Mobil1 bottle wedged between the body and chassis, with a single tube feeding it.  I emptied the container and it was about 1/3rd full (no idea when it was last emptied).  As the bottle is showing its age (and appears to be a half-rsed attempt at catching the oil) I am looking to do it the proper way.

 

Am I correct in saying that the catch tank should have 1 inlet (from the block, same as the current tube), and 2 outlets (1 to small filter to vent to air, and 1 to return on the rocker cover (not present at the moment)) ?  And the catch tank needs to be plumbed in as high as possible?

 

How would I go about adding the 2nd outlet (to rocker cover)?

 

edit: would http://www.ebay.co.uk/itm/300865315430 fit the description?

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The way it's done on mine is the catch tank has one inlet from the rocker cover and an outlet with a breather on it. Then the block breather pipe is plumbed into a second fitting on the rocker cover.

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My set up is NOW.....lol...crankcase to rocker cover, oil filler cap vent to catch tank, then catch tank venting to atmosphere near ground.

And.....hey presto ! It works !!!! :)

Because of gauze in oil filler cap, getting virtually no oil in catch tank........at last.

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You lot are not helping  :d

 

My rocker cover has no outlets, only the filler cap.  The hose going into the Mobil1 container is somewhere halfway up on the engine (underneath the twin 40s).  I don't know what the crankcase is, but it sounds like that's where my hose is connected to at the moment already.  Maybe there is no right or wrong way?

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Yes the crankcase breather is under the carbs.

 

You should be able to vent both crankcase breather and cam cover breather direct into a catch tank. Quite common to use an old bottle as a catch tank.

 

However if your engine breaths a bit heavy (and a lot of xflows do) it is common to direct the crankcase breather into the rocker cover (you need to drill and tap the rocker cover) which allows the oil to be caught in the rocker cover and drained back to the sump with the air going into the catch tank with maybe a little oil mist.

 

With xflows, unless you have forged pistons then if you rev above 6k you will get blow by and excessive pressure in the crankcase.

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Cheers Pete.  The Burton guide prefers the 1st option

 

To eliminate any charge contamination and subsequent power loss, most highly modified engines should vent via an isolated catch tank, which will also act as a collector for any oil lost. These tanks should have a minimum 1 litre capacity, 2 top inlet connections (1 crankcase vent and 1 valve/cam cover vent), a sight gauge (to indicate the level of any oil inside) and a bottom plug or tap to allow the oil to be drained off when necessary.

To avoid frequent inspection and draining of the oil level in the catch tank, an automatic drain back into the sump can be improvised as shown. The vent outlet can be recirculated through the intake system or left to vent to atmosphere via a suitable filter, the latter being the more popular option.

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Q, been through this too many times to count now, it's a tricky one to get right! Are you wet or dry sump? Feel free to PM me and we can chat through on t'telephone.

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I think I've got it all figured out  :yes:   First need to collect some parts (and now my exhaust has fallen off, that takes priority) before I start messing about with the oily bits.  I figure if it was good enough for the past 1000s of miles, it will be good for the next 100s of miles still ;)

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