Venting Oil Filler Tank with Webers

[Donald T]

What is the best way to vent the oil filler tank when using Webers?

[Peter Graham]

• You may vent it to the ground through the sheet metal;
• you can plumb it through the top of the passenger's side air filter (if you are using K&N and the Like) with a little ingenuity; or
• you can modify stock air cleaners to fit Weber carbs and use stock fitting.

Do not stick it into the pipe stub sticking out of the chassis (carb preheat) or you will have fumes in the cabin (seen in photo right edge just above the chassis/motor mount).

Peter

[Donald T]

Thank you Peter,
Nice solution! Do you know which/where/size part (90 degree fitting source) that needs to go into the top of the Weber air filter top? Should be a simple aftermarket part but it looks like DYI is only way to do it. Hose diameter would also be helpful.

[Peter Graham]

Hose is the standard Porsche vent hose (could not find it here on Pelican: Google p/n: 616.107.795.01); fitting OD should be 25mm (~1").

I believe I used electrical conduit with brazed 90*/brazed into air cleaner top (destroys chrome finish; JB Weld could be an alternative.). It was rather inelegant since I had to wrap the fitting with electrical tape to make up the difference to the vent hose (hence the milky oil on top of the cleaner in the photo). Memory is fuzzy: I converted back to stock Solexes many years back.

Peter

[djdsc]

Draft tube.

If you want to be elegant, source the 356 parts for factory draft tube set-up.

[Donald T]

Peter,
Thanks for the photo. I was able to fashion a similar solution using PVC from ACE hardware ($1.50) and some 1" radiator hose from Pep Boys ($10).

[cbrauck]

I just used a mini K&N type filter for mine.

[RRC715]

I just have an additional filter for the tank.

[Peter Graham]

I tried a K&N filter for awhile: it left an oily mess in its general location.


Perhaps using the longer tube will help. Make sure the tube stays sloped back to the oil filler can or you'll have oil drops (if not mist) wherever the filter hangs.

I have since gone back to OE Solex carbs/air filters with stock venting for better performance, gas mileage and reduced carburetor noise. I did drill the air cleaner bases so that any oil from the breather does not puddle.


Peter

[MichaelB]

The claim is that venting it through a engine bay located filter causes oil mist to get sucked into the fan shroud and then contaminating the oil cooler within, causing a heat concern. I have driven with the K&N filter for a lot of miles with no oil residue or buildup found, ever. But I get it, and respect those that may have more blow-by out of their engine and have seen oil mist.

Venting into the air filter is not the choice of some respected 356/912 engine builders yet venting to a vent tube through the sheet metal & out the bottom seems to be a generally accepted practice.

I say to each their own. It all works depending on your preference.