benefits of rocker head cover oil breather?

[gazbrownvtr]

What (if any) are the benefits of a oil breather on the rocker head cover? I have a K&N cone fitted and the oil breather pipe is a bit of a loose dodgy fit and think this would be better but is there any performance gain from it?

[samueljonburgess]

non atall just covers the rocker in oil and shit to be honest mate

[Dizzy]

None, thats why race cars run catch tanks.

[Lew_C]

What (if any) are the benefits of a oil breather on the rocker head cover? I have a K&N cone fitted and the oil breather pipe is a bit of a loose dodgy fit and think this would be better but is there any performance gain from it?

I thought it stopped the shite from being re-circulated and burnt off..

[-Alex-]

I thought it stopped the shite from being re-circulated and burnt off..

It does, your not allowed to vent oil vapour into the atmosphere, so you have to make it recirculate round the engine which covers the tb in oil, having the oil catch tank stores the oil vapour - which when cool turns to standard oil, but also stops it going back into the engine.

[Lew_C]

It does, your not allowed to vent oil vapour into the atmosphere, so you have to make it recirculate round the engine which covers the tb in oil, having the oil catch tank stores the oil vapour - which when cool turns to standard oil, but also stops it going back into the engine.

Ah okay got you. So it does actually do something beneficial, not nothing beneficial at all like the rest of the people have said?

Also i asked a garage where they stood on them as my rocker to air filter breather split and I was like could i just get a breather filter for that and they were like yep that's no problem.. nothing wrong with that

[-Alex-]

In theory it's not a problem, it's supposedly illegal to allow it to, but reason why Cit, Pug don't do it, is as mentioned above covers everything in crap if you drive too hard, you drive sensible and it won't be as noticeable, personally catch tanks are ftw, I've seen people just use Red Bull cans before as it was scene to do that at one point :)

[Lew_C]

In theory it's not a problem, it's supposedly illegal to allow it to, but reason why Cit, Pug don't do it, is as mentioned above covers everything in crap if you drive too hard, you drive sensible and it won't be as noticeable, personally catch tanks are ftw, I've seen people just use Red Bull cans before as it was scene to do that at one point :)

Yeah, i had a red-bull can on the bike, was a sound little quick fix to be fair. And old 2 strokers use a lot more oil, had one for the fuel and one for oil lol they leak from everywhere

[atspeedracing]

in standard factory form the oil breathers will vent to the intake system, and burnt through the engines combustion process. which is fine. but not if you are after power increases! afterall, engines run better on air and fuel rather than air fuel and SH*TTY oil vapour! :P

the engines breather system is often a very overlooked part of the engines performance. a correctly designed breather system can INCREASE horsepower!

i often see people with ebay catch tanks... these typically have 2 large feeds coming from the rocker cover or engine, into a pot.. which then has a teeny tiny outlet for a breather on it.... which is a restriction and will cause pressure buildup in the crankcase.

postiive pressure in the crankcase is a bad thing... as much as peopel concentrate on the pistons movement up and down the bore creating power, they often overlook the pressures the other side of the piston, between the bottom of the piston and the sump. there is a very large volume of air in that space that the piston has to move up and down through, any positive pressure in the crankcase makes it harder for the pistons to move up and down, robbing horsepower. a correctly designed breather systems will minimise this crankcase pressure.

some race engines when using dry sump systems will use special seals and actually run the engines crankcase in vacuum.

- colin