Breather Box

Discussion in 'Mech Tech' started by james cunliffe, May 17, 2019.

  1. I'm fitting twin carbs and have been advised that the Right Hand air filter to the carb needs to be tapped and breather hose fitted.

    I have a type 4 CJ engine and with the old carbs removed it leaves the small oil breather box outlet above the fan housing with nowhere to go.

    Should I fit a new breather box to the firewall and attach with 13mm hose the small oil breather together with a seperate connection between the new breather box to the top of the Right Hand air filter.

    Thinking of buying the cheap breather box from coolair vw which has three outlets. Any recommendation what to do with the third outlet - vent to outside air
    - drill another hole and connect to rocker covers
    - something else ?

    Thanks for looking
  2. If you use a box, you'll need to empty and clean it at every service, if you just plumb into the filter, direct from outlet, then there's no need for a box.

    I've only ever seen boxes on Cal Look engines running open stacks, nowhere to plumb in the outlet on those.
  3. ^this. Breather boxes just leave you with an oily mess to clean out. Best avoided.
  4. Dubs

    Dubs Sponsor

    And if you just have a box, and no connection to the air filter, you end up with greater crankcase pressure. Best to do as suggested above, and have the pressure sucked out by the carb as VW intended. :thumbsup:
    snotty likes this.
  5. The crankcase breather is just visible in this pic going to the RH carb. The fuel tank breather goes to the LH carb.

    IMG_6723 (Medium).JPG
  6. Hmm, that's interesting I'll have to check where my tank breather goes, I don't think the PO of my Bus has put it to the left hand carb. But the bus does/did have some US emissions stuff fitted, dunno if that changes anything.
  7. Now I know what to do with my fuel tank breather which just hangs loose at the moment.
    What size and type of fitting did you use to connect to the carb.
  8. The fitting and its barb, needs to match the pipe, which needs to match the other end on the 'T', otherwise the pipe won't seal properly on the barb.
  9. I drilled and tapped both filter housings and fitted a ½” elbow similar to this - or you could pay considerably more from Webcon.

    The crankcase breather fits directly into the elbow and the fuel tank breather through the VW adaptor that I removed from the original air-filter – sorry I can’t remember the part number.
  10. Thanks for that info.
    Just another point - what did you do from the t connection at the fuel breather where the metal pipes are 5mm od with the outlet much smaller.
  11. That’s where the VW adaptor came in – it reduces the ½” at the elbow to the 4mm hose from the tank. Look at the parts lists for the standard type 4 carb filter and you’ll find it – probably.
    Last edited: May 18, 2019
  12. Last edited: May 18, 2019
  13. paradox likes this.
  14. Thanks again, just ordered the reducer from VW Heritage.
    77 Westy likes this.
  15. FFF208EC-424E-4C22-A008-161093890275.jpeg

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