Draining catch can oil? Good or Bad idea.
 

Last week at the track I was getting excessive blowby(common to VW 16V motors and shitty total seal rings) so I'm trying to work on a better catch can setup.

I was running just a block vent but now I will be venting the block AND the valve cover along with an added windage tray.

Do you Honda guys ever drain your catch can oil back into the pan?

Just curious,

Jason

pic of my motor setup for views.
221whp & 217lbs torque at 10psi
http://www.we-todd-did-racing.com/we...ZmQzMXk1NDE%3D

i just drained mine. and no i would never put it back in the car wtf??

Re: (mike93eh)
 

mine drains back into the motor

Re: (Jordo)
 

yeah, don't drain it back into the motor. it's not JUST oil, it's oil and gas and other shit that you wouldn't wanna put into your oil.

Re: (darksol2005)
 

It's contaminated oil.. drain it in your nearest sewer. Watch out for the EPA.

Re: (Nameless RB26)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Nameless RB26 &raquo;</TD></TR><TR><TD CLASS="quote">It's contaminated oil</TD></TR></TABLE>

Drain the can before it overflows and do NOT make it a returnable system.

Re: Draining catch can oil? Good or Bad idea. (vdubspeed)
 

I know some people on here say drain it back into your motor.

I just drain mine b/c I don't want all the crap going back into my motor. It is a pain in the ass espically when your rings are shot and the can fills up after like 8 hard runs. I usually have to drain it once or twice at the track. Otherwise it fills up and comes out of the breather and all over my engine bay.

Re: Draining catch can oil? Good or Bad idea. (underpressure02)
 

The stuff that your oil catch can (the one connected to the back of the block where the OEM PCV system would connect) only carries oil vapor, and the oil seperator can that alot of people are using can safely be drained back into the block.

If however you're tlaking about a real "catch can" that has lines from the radiator overflow, the valve cover, the back of the block etc... than no, I wouldn't run that back into the motor.

The oil seperator can setups are seeing the exact same vapor as what the inside of the motor sees around the rods and crank throws, so if its safe for this stuff to drain down the inside of the block back into the oil pan, there's no reason why it won't be safe for it to drain from the bottom of the oil seperator can back to the oil pan.

Re: Draining catch can oil? Good or Bad idea. (vdubspeed)
 

I have vents from the valve cover and the oem oil separator going into my catch can, and it usually fills with about 90% water vapor. I definitely dont drain it back in.

Re: Draining catch can oil? Good or Bad idea. (Jaker)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jaker &raquo;</TD></TR><TR><TD CLASS="quote">The stuff that your oil catch can (the one connected to the back of the block where the OEM PCV system would connect) only carries oil vapor, and the oil seperator can that alot of people are using can safely be drained back into the block.

If however you're tlaking about a real "catch can" that has lines from the radiator overflow, the valve cover, the back of the block etc... than no, I wouldn't run that back into the motor.

The oil seperator can setups are seeing the exact same vapor as what the inside of the motor sees around the rods and crank throws, so if its safe for this stuff to drain down the inside of the block back into the oil pan, there's no reason why it won't be safe for it to drain from the bottom of the oil seperator can back to the oil pan.</TD></TR></TABLE>

What about the endyn setup. It vents back of block and valve cover... then Ts into the stock pcv breather box hole as a drainback. Think there is any contamination issues to worry about there?

Re: (Nameless RB26)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Nameless RB26 &raquo;</TD></TR><TR><TD CLASS="quote">It's contaminated oil.. drain it in your nearest sewer. Watch out for the EPA.</TD></TR></TABLE> https://honda-tech.com/forums/images...s/emsmileo.gif

Re: Draining catch can oil? Good or Bad idea. (splitime)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by splitime &raquo;</TD></TR><TR><TD CLASS="quote">

What about the endyn setup. It vents back of block and valve cover... then Ts into the stock pcv breather box hole as a drainback. Think there is any contamination issues to worry about there?</TD></TR></TABLE>

Id like to know also since im running the same can. Ive been thinking about draining it, but I dont know where to find any type of fittings to do this job

They are oil vapours with a lot of fuel contamination. The stock PCV system actually allows these vapours to get into the engine and combust them. This is how the oil inside the engine stays clean because heat from the engine will evaporate the fuel inside the oil and prevent contamination.

If you do not have a functional stock PCV and running a catch can, try to avoid draining the catchcan oil back into the motor. What you are doing basically is preventing the fuel vapours from escaping and allow fuel to contaminate the oil.

Re: (Tony the Tiger)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tony the Tiger &raquo;</TD></TR><TR><TD CLASS="quote">They are oil vapours with a lot of fuel contamination. </TD></TR></TABLE>

How is fuel contamination getting into the crankcase?

Re: (Jaker)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jaker &raquo;</TD></TR><TR><TD CLASS="quote">How is fuel contamination getting into the crankcase?</TD></TR></TABLE>


It's called blow by, and it breaks out down like chewing on doritos.

Do not drain oil into the sewers BTW, oil lube garages have a tank where you can drop off oil and some gas station do also.

Re: (MidShipCivic)
 

If you're getting that much blow-by, you've got more serious problems.

Re: Draining catch can oil? Good or Bad idea. (vdubspeed)
 

All answers found here:

https://honda-tech.com/zerothread?id=1199935

Re: Draining catch can oil? Good or Bad idea. (dasher)
 

After seeing what comes out of my catch can, no way in hell I'd allow it to drain into the block.

Re: (Jaker)
 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jaker &raquo;</TD></TR><TR><TD CLASS="quote">If you're getting that much blow-by, you've got more serious problems.</TD></TR></TABLE>

No, even a motor with almost no leakdown will have blowby. If your car runs rich (especially for any turbo car, A/F's will always be rich under high load), expect even more fuel getting into the crankcase.

Check the official catch can thread in this forum. Awesome info on a bunch of different vent methods.

Re: (Tony the Tiger)
 

You are correct about the blow-by issues on all cars, however like stated above : If someone is draining their catch can after 8 hard runs or every other day etc...I'd say if you are drainging it from being full even once a month - then you've got problems down below...

I've had a catch can on my altima now for a year, and it's only ever gotten a slight oily film on the topof the catch can...never enough to even think about draining...


And for those who want to 'reroute' it back into the engine - I'd say stop being a cheapy and just fill your engine up with new oil...it may be ok, but who he really knows if that oil is good or bad??

But again - if anyone is drainging their can often, somethign def isn't kosher!!

Re: (AceAltima)
 

The amount of oil inside the catchcan will depend on how much power you are pushing (dynamic compression), and pretty much what type of motor it is.

My Camry V6 (single T66) doesn't even get one drop of oil inside the catchcan even after one complete oil change. It will get mucky and that's about it.

My Integra GSR with a fresh motor used to get about half a quart of oil inside the can after 3000 miles or so. The amount of crankcase pressure, the design of the engine, and the amount of RPM the engine is running has a direct impact to how much blowby is "normal". There are more variables, but that's the basic factors.

On Hondas, especially boosted ones, most guys are getting a good amount of oil once in a while I'd say.

Blowby is one thing, but fuel contamination is another. The way the engine runs, air and fuel are always being compressed during the compression stroke. That is when raw fuel will lend to leak past the rings even if there is no apparent blowby. Fuel just thins out the oil at the edges of the rings and always find a way to seep through down to the crankcase. The richer the car runs, the more fuel contamination there is in the oil. The stock PCV system like I said before actually allows the fuel to evaporate from the oil. If there is a catchcan which catches the fuel vapours, draining the catchcan oil back into the engine is pretty much preventing the fuel from getting out of the system https://honda-tech.com/forums/images...es/emsmile.gif