scoobymat1

This is a general query, why does an engine breath? and what causes an engine to breath? i'm sure it's a very simple awnser to most of you but i dont have a clue. Hope some of you can let me know.

TopBanana

I think it's because you get some exhaust gasses blowing by the piston rings and you don't want any pressure building up in the crankcase

jasperjarrot

Without a breather dangerous Explosive Gases would build up inside the block

pugoetru

if it didn,t breath it would suffocate

scoobyboy

if it didnt breath it would soon pop every seal and leak oil all over the place.

pugoetru

scoobyboy they do that anyway

hades

When people talk about engine breathing (particularly w.r.t. tuning by "improving the breathing"), they often mean induction and exhaust - i.e. air getting in, and burnt gasses getting out. That's kind of central to the whole way they work. Improving the breathing means that the engine can get more air in more easily, and waste less energy pushing exhaust gasses out, and so makes more power. Admittedly, this phrase tends to be used more when tuning normally aspirated engines.

What most of the guys above are talking about - releasing crankcase pressure etc via the breather hose.

Gary C

Had a crankcase explosion in my escort last month. Pushed a load of oil up the breather and came poring out of the air filter !, well, at least it unblocked it. Breathers are inportant, just a shame they recirc rather than use a catchpot.