Rocker cover/crank breathers??

[singleton]

Hello all just wondered if anyone could clarify something for me. I have had 3 1098cc engines and have various parts knocking about, one of the three rocker covers has a breather elbow the others do not, I have one block with no crankcase breather, one with a breather pipe and a later one with the cylinder for the later breather set up, question is what should I use, there muddled up! If you have a crankcase breather do you not need the rocker to have one? If I run the late type emission system can I just have a rocker with no breather?

[IslipMinor]

The later 1098 engines had a 'closed circuit' crankcase breathing system, which was the best for keeping fumes and the oil inside the engine, by maintaining a small vacuum in the crankcase. The fumes are ingested via the inlet manifold and the oil stays in the sump (almost?).

For that you need 4 parts:

Plain rocker cover - no breather connection
PCV screwed into the inlet manifold - this valve limits the amount of vacuum that can be created
Front tappet chest cover with flame trap/oil separator
Hose to connect between the tappet cover and the PCV

Unless the engine has very worn bores and high levels of blow-by, this set-up works very well, especially at keeping the oil inside the engine!

[bmcecosse]

2nd vote for closed breathing - whether by that system, or a more simple 'home brew' system. The essentials are the same - slight negative pressure in the crankcase.