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Engine Breathers

PostPosted: Wed Sep 23, 2020 8:16 am
by J J DIKKE
Hello All
Hope some of you have an opinion. I have a standard breather tube from the rear of the cylinder head into a catch tank. How much additional benefit would I achieve by fitting a second breather to the front of the cam cover and / or to the oil filler cap ?

My thoughts are that extra breathing may assist in the reduction of engine smoke. As an amateur am I correct or incorrect ?

Thank you

Re: Engine Breathers

PostPosted: Wed Sep 23, 2020 10:52 am
by jono
Look at a 'Hart Breather' - fitted to front of cam cover. TTR do them (though silly price IMO)

I was more interested in these potentially to reduce oil leaks due to 'normal' blow by - if you have smoke then you probably have something else to investigate

Re: Engine Breathers

PostPosted: Wed Sep 23, 2020 12:36 pm
by J J DIKKE
Hello and thank you for that. I think its a probability that I have something else to investigate regarding the internals of this engine however, I did wonder if additional breathers may reduce pressure and possibly exhaust smoke as a short term improvement. As I say, I am only an amateur at this.

Thank you.

Re: Engine Breathers

PostPosted: Wed Sep 23, 2020 1:22 pm
by sprintsoft
Hi JJ,

It would be helpful to know where exactly is the engine smoke coming from currently?

Thanks
Iain

Re: Engine Breathers

PostPosted: Wed Sep 23, 2020 6:14 pm
by nmauduit
yes, a compression test, possibly a leak-down test, would help know more about the engine condition before embarking into modifications.

Re: Engine Breathers

PostPosted: Tue Sep 29, 2020 1:01 am
by webrest7
I have chosen that route choosing to run a hose from the rear breather to a "T" piece picking up the hose coming from front timing case and then continuing on to a catch tank placed in the front nose.
Everyone will probably have their own preference but this works for me.

Re: Engine Breathers

PostPosted: Tue Sep 29, 2020 1:10 am
by bitsobrits
Air/oil separators (AOS) are relatively inexpensive these days and permit you to vent the crankcase into the airbox while keeping the oil mist in the carbs to a minimum. Running the vent into the airbox via an AOS has the benefit of reducing crankcase pressure which minimizes oil leaks.

As mentioned above, an improved crankcase vent will not appreciably reduce engine smoking out the exhaust pipe as that is more likely caused by worn rings or valve guides.