V50 mk2 breather system

Due to the original filter / breather system perishing am looking at a different breather system for the mk2. Question. The condensed oil mist off the rockers, is it wise to route back to sump due to possible water vapour ingress? Original thought was use similar set up (2 hoses to “can” from rockers and one hose returning to sump with small cone filter to keep it unpressurised. However is it better to collect such oil mist and dispose of as it builds up, replenishing sump as required or…?

The inside of the rocker covers have a couple of pips cast into them. The thinking being that oil mist condenses on the inside of the cover and then drips off of these ‘pips’ onto strategic parts of the rocker gear. After which I presume it finds its own way back down the cylinder/head stack back into the sump. That being the case, then you might suppose that returning any other vapours to the sump should be acceptable. And if you look at the big block LeMans approach all vapours there return to the sump via that black box with the ball valve. It’s just a case of ensuring you are dealing with the crank case pressure for the return I guess – maybe adopting one of those LeMans breathers?

There’s a link here which talks about the breather system.


Here’s a picture of the breather fitted by a previous owner on my V50 mk2.


I suppose it it all depends on the type of journeys made as to whether there may be a problem with returning the vapours to the sump.Â

Cheers for that. Will have a ponder.

on my v35/monza hybrid i have the two rocker box outlets connected to a brass Y pipe and then vented to the rear mud guard.

As an experiment I re routed the pipe into an open plastic pot and got about 100ml of mayo over 4 weeks of local running. Good case for not returning to the sump i think.

My newer V65TT has a plastic breather tank with inlet manifold negative pressure sucking fumes into carbs and sump return. Sump return was temp disconnected and a plastic pot hooked up to the breather tank outlet. Only oil small amounts of oil in pot

That was my concern. I think this requires a re-think. I have bought one of these and my plan had been to use the drain point in the base to fit a barbed pipe for a hose back to the sump however now that hose and a common from the rockers will go into the can. This mayo can can be drained at suitable junctures - there is a sight glass arrangement to alert to increasing volume. Brackets needed now.

edit: pic not shown - quota reached or something - anyway its this thing…

Sump return’s blocked with bolt on my v35 monza. Over 2000 miles never needed a top up!