I may have problems with my engine breather too at the moment.
Do I get it right when I say a good breather should give a lower than ambient pressure in the crankcase?

My old one gave a higher than ambient pressure in the crankcase and I just tried 2 secondhand breathers doing the same.
Was already worried something else is wrong with the engine, but compression is okay, 9bar left and 10bar on the right. And a look with a scope through the plug holes didn't show signs of bad wear (for as far as I could see something).

That's how I understand it, yes. Unfortunately the one I repaired had a hole in the side of it that I'd not noticed when I did it, and it's continued to piss oil everywhere, so the car's now got a secondhand breather that James Wallace gave me, which I'll rebuild with the proper rubber in it and do a before/after manometer test. I might even be a righ geek and do an MPG comparison test too.

Thanks Russ, just found why my breather don't seem to work... a piston ring in 10pieces. Probably blown because I forgot to take the winter shield of the grill on the way back from the Crapadeuchetropy.

It is me all over, just figured out that I managed 5 major engine failures in the last year and a half (2 professionally & 3 privat)....

(Slightly) off topic : What temperature does the breather get to ? I want to paint mine and wondered if standard rattle can satin black would do or should it be a 'High temperature' formula ?
cheers

I doubt you'd have any problems with normal paint, it doesn't get that hot. I'd take a bit of time to prepare it properly though.

I had mine painted with normal paint, no problem really.

Personally I prefer to have one that is breathing. But we all have our choices, often things happen and you have to try and make do.

A hole in the side is a bit odd...I do check that kind of thing out regularly and go for holes in top or bottom. If I can get way with it.....then maybe both.

If you are having problems with oil being pissed all over the place then I do think there are some other things here. That is OK. Personally wouldnt want to even try it once.... but eventually you will probably want to have a slighly more nomal ride.

As mentioed above, I think I might be woth trying with some new rubber....and no one is going to complain if you give us the results of you manometer test....