Thursday 7 February 2013

Oil breather

Standard build is to remove the crankcase oil breather and replace with a nice GBS cover; I did start a question on oil breather options on RhoCar early in the build - its a hot subject and no clear answer. There is some good discussion out there & a good article here from Burton Power with background information on the breather setup.

My final decision was to leave the crankcase OEM oil separator tank in place along with its outlet pipe which runs along the back of the engine under the coil pack. 

My thinking is: If its ok to run the engine with no crankcase vent, then the OEM separator an breather cant do any harm, and may do some good letting the crankcase breathe.

The breather itself has a vacuum adjusted valve (PCV) which will not function since there is no vacuum connection - however this valve is a: always open at least partly b: will be pushed open before pressure in the crank case would push past the oil to the top of the engine or past the cylinders - so again  - I don't see any harm in leaving this in place. My personal decision & thought process only. (see update at the bottom)

With this in mind I adjusted the old breather pipe which used to run to the OEM intake manifold, with the addition of a nylon 10mm 'T' the same pipe can be used to join the rocker cover breather with the crankcase/oil separator outlet and an air filter thus:

You can see the metal pipe from the crank case breather/oil separator at the bottom of this picture:

All set with the air filter in place - it needed a little self amalgamating tape around the hose to be large enough for the air filter to clamp on completely:

I think thats a reasonably neat solution; the only extra part was the 10mm 'T'

Update - eventually opened up the PCV