TheSamba.com :: View topic

Wed Aug 27, 2014 2:05 pm

My carbs do not have a breather nipple on top of the covers. How do I vent the crankcase? What do I do with the breather nipple on the oil filler neck?

Wed Aug 27, 2014 2:10 pm

I recently eliminated those vents on the carb filters..

here is how my setup USED to run:

valve cover vents up to either side of a breather box, front of breather box to a T-fitting, one side of T to a bar that connected the carb filters, other side of T to oil filler vent.

Here is how I run it now:

valve cover vents to either side of a breather box, front of breather box to oil filler vent..

Wed Aug 27, 2014 3:18 pm

DO NOT vent the crank case to the air cleaners. The oil mist will cause fouled spark plugs. Put one of these little filters on the oil filler vent. http://vwparts.aircooled.net/Bugpack-Mini-Oil-Breather-p/3052.htm

Wed Aug 27, 2014 4:16 pm

vwracerdave wrote: DO NOT vent the crank case to the air cleaners. The oil mist will cause fouled spark plugs. Put one of these little filters on the oil filler vent. http://vwparts.aircooled.net/Bugpack-Mini-Oil-Breather-p/3052.htm

sorry it's a small pic, but this is how mine was.. I ran it like that from 2002-2008 and never had plug fouling issues... that's how the shop who first built my 1776cc installed it..

edit: they used rubber hose, but after like 4 or 5 years, i replaced it with that orange stuff because the rubber had gotten brittle and i was too broke to buy good stuff..

Wed Aug 27, 2014 8:55 pm

So I don't need a hose to carbs? The mini filter will do?? But then nothing is sucked out of the crankcase? How does a breather box work?

Thu Aug 28, 2014 3:24 am

A length of hose connecting the breather tube to a filter mounted on the firewall is all that's needed. If your engine is in good condition, the small filter clamped onto the breather will work OK.

Thu Aug 28, 2014 4:07 am

That vent going to the air filter is just a clean destination for the crankcase blowby. It is not under vacuum. so If you can find anywhere nice and clean for the fumes to go- your good. They put it to the air cleaner as an emissions control so you wouldn't spray oil mist everywhere.

The little filter traps some of the mist and it drains back into the sump- it also stops the occasional neg pressure in the crankcase from drawing in contaminated when the engine cools down.[img][/img]

Thu Aug 28, 2014 4:49 am

Doing the "Bob Hoover" HVX" mods on the cam bearings changes the amount of oil that goes to the 3/4 side vale cover.

Thu Aug 28, 2014 4:58 am

I vent to the one air cleaner on most of ours - have not had an issue - on Kads, I add a PCV type fitting to the base or top depending on the car and connect the vent hose. I personally dont care for the mini filter stuck on the filler with a real short length of hose - A longer hose like to the firewall as mentioned gives the oil vapor more to condense on and drip back into the case instead of having a mini filter just drip on your engine.

Breather box is great as long as its not sealed from the outside. You need some air movement and a way to allow the crank pressure to bleed off.

Have seen systems that also route to the exhaust, but I have never done that.

Thu Aug 28, 2014 7:14 am

I have a road draft tube with the other vent going to one of my filters and a pump block-off with a breather hose going to the other filter. I have nearly 80,000 miles on the 1776 in my 67, so that little bit of mist doesn't seem to be bothering my engine.

Thu Aug 28, 2014 8:51 am

bugguy1967 wrote: I have a road draft tube with the other vent going to one of my filters and a pump block-off with a breather hose going to the other filter. I have nearly 80,000 miles on the 1776 in my 67, so that little bit of mist doesn't seem to be bothering my engine.
======================================
That's not a "road draft tube"

The tube that ran straight down through the tin work from the filler neck was not "open". At the end of the tube beneath the tin work was a little rubber nipple that had a slice in it at the bottom. That rubber piece was actually a "check valve" that opened up when crankcase pressure became more that the vacuum from the carburator/aircleaner could overcome. That "check valve" let the excess crankcase pressue out that was caused by high rpm or maybe bad rings. (blow by) The stock VW system was basically closed with the the carb./airfilter providing the vacuum for the crankcase pressure even when there was no possitive seal at the pulley. !

Thu Aug 28, 2014 9:25 am

I'm not sure if engine size makes a difference. The original poster did not say what size.
I have a 1641 vented the oil filler to the carb with no ill effect. I have also stuffed a copper pot scrubber "Choreboy" in generator stand to help dissipate the oil mist. The carb and plugs are oil free.

Thu Aug 28, 2014 1:02 pm

When I had a street car I didn't like those little filters-made a misty oily mess out of the engine compartment with time...but then you can just wipe it around every often and slow that rust on all your chromed goodies :lol:

I used to route to air filter with no problems until I was breaking in a 1915cc years ago. I think the rings were not yet seated and I had excessive cranke case pressure, add that to carb vacuum and it actually sucked/pushed oil from crank case down carburetor :shock: It "hydro locked" instantly. Luckily I did not bend a rod or anything...maybe my long-duration cam helped out. Anyways after that I run a breather box. I run hoses from 1/2 site and oil filler neck to the box.

Fri Aug 29, 2014 4:56 am

andk5591 wrote: I vent to the one air cleaner on most of ours - have not had an issue - on Kads, I add a PCV type fitting to the base or top depending on the car and connect the vent hose. I personally dont care for the mini filter stuck on the filler with a real short length of hose - A longer hose like to the firewall as mentioned gives the oil vapor more to condense on and drip back into the case instead of having a mini filter just drip on your engine.

Breather box is great as long as its not sealed from the outside. You need some air movement and a way to allow the crank pressure to bleed off.

Have seen systems that also route to the exhaust, but I have never done that.

For two years I used a PCV fitting that Aircooled.net sells

http://vwparts.aircooled.net/Universal-Crankcase-Ventilation-Fitting-for-Filter-p/00-8998-00.htm

This was with Kadrons....tap the bottom air filter plate on the passenger side carb and you're good to go. The angle of the piece allows a good fit for the stock diameter breather hose and no interference.

Sat Aug 30, 2014 2:32 pm

hooker wrote: bugguy1967 wrote: I have a road draft tube with the other vent going to one of my filters and a pump block-off with a breather hose going to the other filter. I have nearly 80,000 miles on the 1776 in my 67, so that little bit of mist doesn't seem to be bothering my engine.
======================================
That's not a "road draft tube"

The tube that ran straight down through the tin work from the filler neck was not "open". At the end of the tube beneath the tin work was a little rubber nipple that had a slice in it at the bottom. That rubber piece was actually a "check valve" that opened up when crankcase pressure became more that the vacuum from the carburator/aircleaner could overcome. That "check valve" let the excess crankcase pressue out that was caused by high rpm or maybe bad rings. (blow by) The stock VW system was basically closed with the the carb./airfilter providing the vacuum for the crankcase pressure even when there was no possitive seal at the pulley. !

Wow! Did not know that.

Sat Aug 30, 2014 2:41 pm

VW vented the oil filler to a oil bath air cleaner that kept the oil from entering the carb air stream. The vent system was never intended to suck anything out. It was designed to let excessive crankcase pressure blow out.

Wed Jun 08, 2016 8:45 pm

]

this is how i did mine--the valve covers connect to the breather behind the shroud--any smoke from them disperses thru filters--(still clean af. 3yrs)
the carbs get any pressure from the case equally
any micro oil droplets make it to the carbs--helps my combustion chamber
(like a marvel mystery oil dispensor)
i love it!

Sun Jul 02, 2017 6:19 pm

Ok I put back on the STOCK oil filler with down tube. However, the rubber valve on down tube touched my vintage speed exhaust so I had to take it off. Down tube is wide open now.
The top vent tube is connected to the right carb. Now I've read not to do that so here I am again asking what do I do with top vent hose?
What do I do with bottom of draft tube? What do I connect top vent to?
I don't have any oil leaks since it's connected to carb. But if I disconnect it, I won't have any suction to suck out case pressure.
Should I get a breather box,? Or just run longer hose to top vent hole with small air filter??

Sun Jul 02, 2017 7:43 pm

What are you wanting to do?

Tree hugger wants to save polar bears?
Hotrodder likes to go fast, live for today! ?
Preventing oil drippings on your fancy pants driveway?
Evacuate water vapor to extend engine live and oil change interval?

You CAN choose all of the above, but the system will get very complex :shock:

Sun Jul 02, 2017 8:56 pm

modok wrote: What are you wanting to do?

Tree hugger wants to save polar bears?
Hotrodder likes to go fast, live for today! ?
Preventing oil drippings on your fancy pants driveway?
Evacuate water vapor to extend engine live and oil change interval?

You CAN choose all of the above, but the system will get very complex :shock:

Don't have polar bears where I live, so I'm good there.
I like to go fast.
Bug doesn't leak
And I like changing my oil.

Not sure what I wanna do or if I even need breather box. Just need to know if I can work with what I already have. Never used breather box before.