crankcase ventilation

[beetlemandan]

so i've come to the conclusion after getting sick of oil leaks that i have insufficient  crankcase ventilation on my 1641.
 right now i'm running a bugpack oil filler extention vented a bugpack breather box mounted on the shroud just above it, and thats it...

my stock valve cover actually leak, which i've never had happen on other (stock) motors, and the oil pan leaves puddles everywhere (not always a bad thing depending on whose property i'm parked on.)

so i searched thesamba and everyone has a different opinion, which left me with more questions than answers. the setup that was most agreed on was a vent on the fuel pump plate, one on the oil filler and a 3rd on the pass. side valve cover, at the rear of the cover. and as for venting the drivers valve cover, some say that causes the engine to fill that valve cover to fill with oil. and almost everyone agrees not to vent the case fumes into a carb.


so, opinions on this and what to do?

[mitchy965]

extra(uncontrollable) crankcase pressure has to come from some where.perform a leakdown and compression test to verify ring seal.(maybe the bore is worn).good luck

[beetlemandan]

d'oh! forgot to mention my compression is 140+ psi on all cylinders and holds it

[mitchy965]

how does it hold it? is it maybe the check valve in your compression gauge? a leak down test is a little more accurate, but still not a 100%. i reread your post and something struck a note,you stated you have a  oil filler extender? if its got 1 hose barb to a 3/8 hose your acutaly made it smaller than stock!the factory filler/ breather has  always worker well for me (just vented to atmosphere though a filter at the top and the factory draft tube at the bottom.have you got any pics of your current set up??

[beetlemandan]

well, holds like  a healthy engine... be patient, i'm just a lowly  truck-painter type!

my setup looks like this:

http://images.thesamba.com/vw/classifieds/pix/1754941.jpg

except it has a bugpack breather mounted just above the generator backing plate.  i got rid of the factory filler because its impossible to add oil without spilling it, and my tinning doesn't allow for the down tube, and that motor never came with a down tube cause it had the paper air filter. (paper air filter with generator! from factory)

what about adding another vent in the oil cap?

a lot of articles said that if you run the factory downtube without the rubber nipple at the bottom you end up sucking in road grit. and other articles went off that the factory oil fillers are full of rust and drop chunks down into your case.

like i said, there was a ton of conflicting info on "the" setup!

[Randy]

I'm running a similar setup but using a stock style filler. I had to vent to the right side carb to resolve the oil spray. Right or wrong, I think the carb vacuum helps reduce the internal pressure.  Also I agree if you have a small size fitting try to get a larger size.

[mitchy965]

i guess if your engine braking down a long dusty hill in a baja dusty trail it possible to suck in some dirt. but if you think about the size of the tube plus the size of the vent this was min. sizing for stock motors. try adding another vent hose off that filler and see if it helps. imho venting to the air filter housing works the best as far as scavaging but to the detriment of oil vapor fouling your carbs or causing detonation. air filter housings on dual carb acvw just dont lend themselves to that configuration..

[getgeoff]

Are you running an external oil cooler by chance?

[stu817]

I had the same problem with a motor that I had in a buggy I also had the same oil fill tube that you had . It ran great for quite a while no issue with leaking then it developed oil weeping from the same places that you discribed still ran great just didnt like the oil leaking so I tried everything I could to stop it changed the gasskets still leaked added extra venting still leaked asked everyone I knew did compression test it seamed fine (the presure on the gauge should stay at the pressure the cylinder will build up to but this pressure is not remaining in the cylinder it will leak past the rings and valves even in a brand new engine the tester has a valve in it to hold the pressure in the gauge so you know what it got up to this type of test will only tell you that it is a good start but will not source your problem) I was in denial about the motor having a problem. After I tried everthing I could think of and asked everyone i knew i did two things put a gauge on the vent tube to see what pressure I had in the case and also borrowed a leakdown tester ( the correct tool to test for a problem) it turned out I was getting way to much case pressure it was getting past the rings and also getting past the valve guides so I rebuilt the top end decidded to build it bigger went 1835 runs great lots more power no more oil problems and still running the small vent tube.
Vw motors were designed with only the one vent and this works great when parts start wearing out your crank case pressure will get higher and leak I did not want to think that the motor is worn out but this is ussualy the problem.
The only reason that you should ever need extra ventting is if you are raceing or offroading the car were you are overreving the motor and it is getting supper hot and vaporiseing the oil hope this helps and just have it tested before you waste a bunch of time and money like me

[beetlemandan]

yes the motor gets over revved  on a more than regular basis and runs hot no matter how you treat it ( south okanagan in the summer!). and no, there is no oil cooler other than stock.

i'm thinking venting the oil cap now......

what about using the exhaust for sucking oil fumes out like they do on v-8 dragsters?