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Breather Box - OK to connect to carb air filters?

Discussion in 'Engine & Transmission' started by Woolly, Mar 15, 2016.

  1. Woolly

    Woolly Member

    Messages:
    42
    Location:
    Brisbane
    OK, I have this fear I am about to get even more confused (and a lot of responses) about this issue but have run out of ideas and research is just making things worse. Here is my scenario:

    1972 Kombi, 2055cc Type 1, CB Performance Breather on Alt stand (valve covers not vented). Twin 36 IDF's.

    NOTE 1 : I like my engine set up and happy with the components etc.

    Originally the breather just had a air filter attached to top (on a 3/8 nipple) - result - fine oil mist throughout engine bay. Breather box when cleaned (every 1000 miles at oil change) had putrid yellow mixture of crank case gas, oil , water (I will refer to this as blow by cr*p - BBC - from now on) This obviously makes its way back down the alt stand into the oil as could smell it at oil change - dont think this is good for oil / engine.

    Modification 1 - kept the air filter on top of breather but added a PCV valve to side of the breather and then ran 1/2 inch pipe from this to top of right carb. Reduced the oil mist but still a bit. Reduced BBC in breather box but still a little bit and still a bit of a smell in oil at oil change. Right hand carb air intake / velocity stacks / butterfly all fairly clean. Still not happy the the BBC is getting back into the oil.

    Modification 2 - Running pipe from bottom of breather and top of breather to T piece and then to top of both carbs. Oil mist gone. After 300 miles so far not much BBC in breather box (obviously as it is now being burnt) and carbs both sides nice and clean. Made certain the slope of pipes is such that no BBC can solidify and block the pipes.

    Happy I seem to have fixed a couple of problems - worried I may be creating a much bigger one..........

    NOTE 2: Typically I am only driving short trips as the bus is my everyday drive so I am aware this can create more BBC.

    Now for my question (sorry if you are already asleep) - my concern is dumping the BBC into the carbs. I have seen many many 1000's of pictures and articles that all seem to suggest it is OK to do this (I would say a lot more saying to do it then saying not to do it) but I have this niggling concern that this eventually is going to clog up carbs and cylinders etc?

    I have a preference not to just dump the BBC etc to atmosphere too - I tried this via a pipe from top of breather to top of engine bay and then back down through tin and dumped via air filter fitted to end of pipe - didnt fix the oil mist, after time left BBC on my garage floor and also misted onto muffler that got me worried about it just deciding to ignite.

    If you are still awake can you let me know what you think please? (just about this question, not what you think in general :))
    Thanks
     
  2. grumble

    grumble Well-Known Member

    Messages:
    1,361
    Location:
    Taree
    Unfortunately a lot of people reduce the size of the breather tube and the increase the size of the engine with resultant blowby,during my 45 years in the trade we tried to keep the blowby to a minimum without restricting the hose size most of the later model vehicles went to a PCV valve and fed the blow by into the inlet manifold to be burnt rather than dump it into the atmosphere..
     
  3. vassy69SC

    vassy69SC Active Member

    Messages:
    995
    Location:
    Brisbane
    What you have done with your breather is how mine has been set up for years.
    It is not an issue in my experience (70,000kms on a stroker 2165cc).
    An occasional longer run would improve things also as the engine up to temp helps burn up some of what you are talking about.
    What oil do you run?
     
  4. Woolly

    Woolly Member

    Messages:
    42
    Location:
    Brisbane
    Thanks for the replies guys.
    Yikes - the oil question. :eek:
    Up until recently have been running Penrite HPR30. However along with the change to the breather I also have changed to Penrite HPR15 full synthetic. I know it costs more and you still have to change it at the same frequency (I change oil and filter every 1000 to 1500 miles regardless) but after doing a heap of research and speaking with a number of VW mechanics I thought I would give it a try. So far is running a bit cooler and seems a little quieter (that is probably me just thinking that in reality). Next change going to try Penrite Racing 20 as it has an even higher zinc content.
     
  5. Mellow Yellow 74

    Mellow Yellow 74 Active Member

    Messages:
    847
    Location:
    Sydney
    Why so often?
     
  6. Woolly

    Woolly Member

    Messages:
    42
    Location:
    Brisbane
    Used to be because of the smell of the oil with all the BBC in it. I read a few articles on various sites that once the oil starts to smell it is a sign it wont be doing what it is supposed to do in the engine. Hopefully with the breather mods I can stretch this out a bit. I really dont mind doing it fairly often as figure it certainly cant hurt the engine.
     
  7. Kai

    Kai Well-Known Member

    Messages:
    4,793
    Location:
    Sydney, NSW
    oil lasts a lot longer than 1000miles.... youre wasting money and creating unnecessary waste
     
  8. Mellow Yellow 74

    Mellow Yellow 74 Active Member

    Messages:
    847
    Location:
    Sydney
    I am not sure if smell is a good indicator of oil condition, but if your oil stinks so much you need to change it frequently it sounds like you have a serious problem. I am not familiar with the CB Performance breather but do you still have an oil deflector plate on the alternator stand?
     
  9. Woolly

    Woolly Member

    Messages:
    42
    Location:
    Brisbane
    Yes plate is there. Please understand that I chose to change the oil at that frequency on the basis that it certainly can't hurt the engine. Previous life I was a condition monitoring engineer so have spent a lot of time researching lubrication in a lot of weird and wonderful applications so I do realize how/when/why lubrication breaks down. I know I am being very over cautious but that's my call I guess. On another note, now 500 miles into current configuration/oil and all is sweet. No mist, no smell in oil, breather internals clean, carbs clean so I think I have found a set up I'm happy with. I guess burning the blow by May offset dropping off the 3.5 liters of oil for recycling every 2 to 3 months.....,
     
  10. kombiwhisperer

    kombiwhisperer Member

    Messages:
    146
    Location:
    fraser coast queensland
    Hi Brett, its just the horsepower trying to get out!!!
    Carb breather hoses are fine, add another 90 deg fitting to back of breather box and vent it downstairs where there is a hole in tinware near dipstick. This hose will let air pressure out to stop some of the windage inside, and carb breathers will burn off fumes, all good
    You can try NULON 25/60 street and track oil, been having good results and cheap
     

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