Alternative Oil Breathers
Alternative Oil Breathers
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Discussion

GV

Original Poster:

2,366 posts

254 months

Friday 11th April 2008
quotequote all
Since swapping to Carbs from Efi the pipe used for the oild breather is no longer required. The new one from the air filter has a kink in it defeating the obect of passing air into the rocker cover - is there an alterntive. I've seen a baffle type knocking around. What would happen if I left the breather pipe off I wonder?

rev-erend

21,623 posts

314 months

Friday 11th April 2008
quotequote all
I think you could have the oil breather from the rocker cover go into a catch bottle but don't block it up otherwise the engine will suffer pumping losses and possible pressurise the engine causing oil leaks.

adam quantrill

11,679 posts

272 months

Friday 11th April 2008
quotequote all
The input of breather 'air' into the inlet puts the crankcase under negative pressure (w.r.t. atmospheric) which tends to keep the oil inside.

When you start getting blowby (e.g. the piston rings getting a bit worn, or cracked) the pressure will rise, and you need all the scavenging you can get, or the oil will seep out of every available seal.

So my advice is to get the oil breather venting into the carb inlet, preferably under vacuum...

GV

Original Poster:

2,366 posts

254 months

Friday 11th April 2008
quotequote all
adam quantrill said:
The input of breather 'air' into the inlet puts the crankcase under negative pressure (w.r.t. atmospheric) which tends to keep the oil inside.

When you start getting blowby (e.g. the piston rings getting a bit worn, or cracked) the pressure will rise, and you need all the scavenging you can get, or the oil will seep out of every available seal.

So my advice is to get the oil breather venting into the carb inlet, preferably under vacuum...
Adam - do you still have the SE Dash for sale?