x-flow breather

[stu999]

If catch tanks are filling up easily, i would say they are overfilled with oil.

Nope. Nothing to do with (incorrect) oil level, and everything to do with driving hard/fast starts. This *might* explain why YMMV...

I purchased my Westy with the understanding it had a fecked engine (cooling probs -typical Xflow as it turned out, and smoking hard on acceleration). It had already had 2 rebuilds (including replacement block the second time). It had the original downdraft carb on it, and the block breather was plumbed into the manifold.

A 'drag' start, especially if it included a corner almost immediately (Curborough for instance) was met with HUGE clouds of smoke, as engine oil was fed straight back into the wrong side of the pistons...

Sorted the breathing as described above, and problem solved.

Interestingly, VX XE's suffer from a very similar problem, (main breather also at rear of block) if the cam cover is not modified...

[itguy]

Nope. Nothing to do with (incorrect) oil level, and everything to do with driving hard/fast starts.

Are you suggesting I drive like a grandad?  

[stu999]

   

[cidersurfer]

I like Stu's idea, my catchtank was nearly always full 'cos I drove the A*** off it 'til I broke it

[fordy]

So if i changed mine to be the norm, block to rocker, rocker to catch - where on the rocker would the plumbing go??

And how far does the 'block pipe in' have to be apart from the 'out to catch tank pipe' ??

thanks

Chris

[Redcar]

I was once told a reason for losing the oil from the breather was piston blowby (oval bores, knakered rings etc) and since the engine had just been built i was worried that the machining was the problem. talking to the engine machinist put my mind at rest since the bores don't seal 100% until the engine has run in. and he was right I do not get any oil come out of the breather no matter how hard the engine is run. the only plumbing is crank breather to catch tank to atmosphere (and there is enougfh oil in the engine, in case anyone wonders)

so maybe the engines that are run in are geting piston blowby

who knows!?

[stu999]

So if i changed mine to be the norm, block to rocker, rocker to catch - where on the rocker would the plumbing go??

And how far does the 'block pipe in' have to be apart from the 'out to catch tank pipe' ??

thanks

Chris

Chris - normally an extra pipe is needed on the rocker cover. I brazed an extra pipe on mine, others have used the type of oil filler caps with a pipe built in, etc, etc.

The pipes in/out of the rocker cover do not have to be too far apart though as long as they are not connected...

Redcar - some of it is piston blowby, and will also vary from engine to engine. These engines are now old skool, piston sealing and block design have come a long way since. Older engines do like to have plenty of breathers, and the bigger the better. High compressions, and high revs will increase the need no end. With the above mentioned simple mod, it will pretty much cure oil being thrown out.

HTH Stu.

[7SE]

If you have an alloy rocker cover, you can tap it 1/4" BSP and screw an oil or airline fixing in and push on a hose.  Or you can use a filler cap with a tube moulded in it.

If you have a steel rocker you can obviously use a breather cap, or braze a fixing on, or drill a hole and push a threaded fixing on and screw a nut on from the back to hold it in place.

I have a tap that peeps can borrow if they want to modify an alloy rocker cover.  I also have a spare alloy rocker cover which has the requisite fixings, filler cap at the front.  Offers are invited

HTH

If you are running a breather from crank to tank, make sure that the pipe/hose runs vertically to the height of the rocker cover before dropping back down into a catch tank.  This will cause most of the oil blown out to run back down into the crankcase.

[Redcar]

Yes i have the vertical pipe, also i had a aluminium insert made to fit the alloy rocker cover so that i could fit the standard ford breather cap.

and as i said have not had any oil come out for years

just realised how many 15!!

[Toby Mack]

I am with all those guys who run a breather straight from the block to the catch tank. My rocker cover breather vents straight down the back of the engine.

My catch tank melted and fell off (it was an old coke bottle....) and I have never bothered to replace it as the oil loss is minimal- I get more out of the top of the dipstick tube!

and I certainly have a bit of a blow by problem with my engine. More smoke out of the breather than the exhaust when running hard

Oh, and no-one I have met has accused me of driving like a granny. Lunatic is the word more often used............

Do all you guys with breathing problems have baffles on the oil pump blanking plate? Just a thought as I would love to know why some people have such a problem.

btw. my rocker cover is alloy and the breather fitting is a push in plastic fitting with a rubber grommit. a bit like the sort of thing you see on vacuum takeoffs on production cars.