So in the not so distant past I had issues with blowby and found out that it was my head. So got that all CB'd/HLA'd and no more fogger exhaust. At the same time I opted for the STM 3 port catch can since I had been having issues blowing the dipstick out. Now I remember someone on here at sometime claiming that's a dumb idea - the oil's just gonna travel into the catch can like a river once it "naturally" comes up the dipstick. So that's good, it's doing it's job right?

Well after this last track weekend I can claim that i'm "dumping" about 1 quart PER full session due to this design. So what gives. Is it really better to use the inspection hole rather then a modified dipstick. Or is it a matter of air pressure getting behind the oil in order to "travel up" the dipstick so that's always gonna be the case... Who else has tried both?

 

The inspection hole and the dipstick move a lot of oil. Your better off doing -10 stuff out of both of the existing valvecover ports.

 

I have the dipstick vent. If I wire the dipstick directly through a sealed catch can that has a goodly amount of vacuum, the oil is vacuumed out of the pan. If I tie my dipstick line to the vent off the valve cover, not a problem.

 

That's the thing, it's a vented can with both VC taps and the dipstick so there's no real vac at all, buuut still gets a quart, so it's gotta be the pressure sending it up and out. Hoses from the VC are pretty dry.

 

I tie the VC and the dipstick independently off the catch can, then one line to the catch can. I still get 22.7 psi of vacuum on decel, but it balances out and doesn't hoover the oil. If I were to plumb the dipstick and the VC independently into the catch can, I'd expect a bad time.

Unless this is the way you have it (Tee-d, then Catch can), and I am talking out of my place.

 

if you ever have a dip stick blow out, you'd know how much oil gets pushed out the dipstick. so if you vent at the dipstick, that same oil would go to the catch can. the dip stick go down pretty far, close to the oil level in the pan. so during acceleration, the oil level probably reach the opening of the dip stick.

i have vent at the BS inspection hole before, it did get some oil, but that hole is a lot higher than oil level compare to the dip stick.

CBRD also made me a vent tube that press into the balance shaft port (with BS delete). it did push some oil also and they were going to make some kind of drain back system. but i dropped power and went back to stock motor and turbo. didn't need it anymore.

the first thing you should try is enlarge the two ports on the VC, remove the PCV and run both into open catch can. the VC is the best place to vent because its baffled.

 

So if you haven't seen the STM can it's here:

http://www.streettunedmotorsports.co..._catch_can.htm

So it is coming off of both VC connections, but it adds the 3rd to either breather or dipstick. So....is the breather port more beneficial due to the accel/sitting in oil situation mentioned above. Or wil you still get tons of oil (because you did this already), so you should plug the 3rd hole and stick with the VC ports while securing your dipstick.


Also i'd advise against drain back systems. As good as it sounds every time i've taken oil out of the can it's somewhat milky because it mixes with moisture, which you'd not want back in the block. This was the major issue with Buschur's can when it first came out.

 

since i'm on e85 now, when i drain the catch can, it's 95% water/ethanol and 5% oil.

 

I just put a spring on to keep my dipstick down and run 2x10an off the VC no need to empty the can every session.

 

So your sucking alot of oil out of the pan out of the dipstick? I'm redoing my entire catch can setup at the moment and going with a sealed unit. Would you recommand leaving the dipstick one or it would just suck too much oil out of it?

 

Still debating that.

Idea 1: Plug the dipstick AN and the 3rd port on the can, thus two VC vents to can and atmosphere and be done.

Idea 2: Move the front VC line to the intake (6an weld on bung), add a block breather port line to the 3rd port in it's place - so 3 vents going to atmosphere and 1 vac on the VC.

Idea 3: Seal one of the two top vents of the can, add a 6an bung to the other and create a "sealed" can minus the intake manifold piece maybe.

 

Have you performed a leak down test of the engine? If so what where the results? If not, you might want to consider it. I have always understood blow by as an issue with the rings ability to seal against the cylinder walls, something that the head has basically no effect on. A problem with the head can certainly cause compression problems, but blow by is a bottom end problem.

 

It's not blow by as the VC hoses are barely wet, as stated above it's getting pushed out of the dip stick vent a quart a session.

 

pushed out by what then? Im not sure what a dip stick vent is though so maybe im just not understanding what your actual problem is. I will say in troubleshooting you cannot rule something out unless you have specifically tested it and have a conclusive result from that test.

 

Out of curiosity....for those with oil pressure issues, especially with your dipstick popping out, what max oil psi are you seeing? My DEFI gauges show peek at around 125 psi at the filter on my 2.3L, and I've never had that happen on this build, or even on my stock block.