Petrol Engine Breather

Chaps,
My 1978 series 3 petrol has an engine breather.
Looking at the parts manual it looks like someones fitted a cap from the diesel rocker cover and piped it into the air hose/carb inlet port spout.

question: What is the proper 2.25 petrol engine breather?
is it ERC2867 piped to the air inlet pipe
is it 247631 breathing to atmosphere

My oil filler is remote off engine block and not a screw cap in rocker cover job.
I don't have the emissions control system on my engine.

The current breather wire mesh is rather rusty and im concerned its flaking off into my air intake and gumming up the carb.

It depends on the age, you need to decode all the suffix stuff in the parts catalogue on pages 1C-08 to 1C-09 and 1C-11 to 1C-12 (which you may have done), 1C-11 and 1C-12 seem to contradict each other though and I suspect 1C-11 is wrong!

If it were me I'd go for the piped up job as when its all put together right runs well, reduces pollution and the oily smell, makes oil changes less frequent (reduces sludge considerably) and is probably right for your year my 1979 and 1980 ones both seem to have the fully piped set up.

If your gauze is rusty give it a wash in petrol and then good blow through with compressed air to dislodge anything loose, both ways then soak it in oil and shake out the excess before refitting. You're supposed to clean and oil them as a service job.

The first few 6000mile oil changes when mine was to air was quite sludgy, now I've put it all back right I tend to leave it 8-10,000 miles and the oil has a lot less crap in it.

appreciate the reply Dominic, my breather cap didn't have an o-ring in it so I fabricated my own and now its a really good tight fit into rocker cover..with engine running I can feel an ever so slight puff puff coming from breather cap, I guess this is just recirculated and mixed with fresh air going into carb!

muchos

The carb actually sucks a little ( the bypass makes sure it doesn't suck too hard) and pulls the waste gasses and other snot out of the engine into the carb and burns it. If your engine is not knackered you will notice that the choke plate will go a bit black after a while but hopefully not too oily. If you just have a regular breather the gasses make it out a bit slower and that gives time for the snotty stuff to condense on the insides of the engine and eventually end up dissolved in the oil or as sludge in the bottom.