Catch Can Full
 

Hi Z Friends,

this is my my first post on here and I’ve searched for this issue but haven’t come up with anything. My 04 Z is strictly track, I bought it this way. Caged with bolt ons. It came with a plastic generic oil catch can and it seems after every race my catch can is completely full, sometimes to the point that it’s spitting out of the breather. It’s a messy situation and was wondering if anyone know what could be causing this. One friend told me could be crankcase pressure? I’m not sure.

thanks!

Where do you race in mass?

Is the catch can vented or still attached to the plenum?

Crankcase pressure would be from the rings as you know, I would do a dry/wet compression test. I believe 185 psi is the target. I had one way down at 85 dry/115 wet once...

Dry is dry. Just compression test it.

Wet test is when you drip a little bit of oil onto the piston rings and do it again to see if the oil seals the ring gaps.

Also that hose is probably for the PVC boss that goes into your intake. You can delete it to help prevent crank case pressure or plug it back in. It's mostly for emissions. I'm running mine vented with my turbo kit. It's up to you.

Wet is to test the piston rings and cylander walls.

If you do a wet test and you gain compression over a dry, you are having pressure escape past your rings. Because the oil will seal those gaps increasing pressure.

If it's the same as a dry test or with in a couple psi your rings and cylinders are sealed properly and aren't letting pressure to enter your crank case.

Edit: also shows for valve seal and head gasket leaks but most the time it really shows if your cylander is worn or not sealing.

Say my seals, head gaskets, cylinders are all good.. then what do you think the culprit of an overfilling catch can would be?

thanks for the info by the way!

Could be a number of things, some Z owners literally chase that down for years. But it's not just to Nissan, it plagues all sorts of different cars. Many cars see this in boost. Some people find a solution, some never do.

I'd start with putting a small pod filter on the open hose behind the intake. Then do a leak down and see what we get before we explore the rabbit hole.

First thing I'd check before doing all the compression testing b.s. would be to check the pcv valve. Dude has this chepo c.c. vented, so he may have removed the pcv guts. That's typical for someone who might vent to the atmosphere.

I'd still comp test. Its always good to know the condition and health of your motor.

Its not THAT hard. Just annoying to pull the plugs and coil packs. But not that bad.

If the guts in the pcv are missing, it's wide open and the vacuum via intake is going to town. Crank case ventilation would have nothing to do with misfires.

Vacuum via intake is what positive crank case ventilation is all about. On the drivers side fresh air is drawn through a connection on the intake pipe then into the crank case, though the passenger side valve cover, then through the pcv valve and finally into the lower collector. The lower collector or intake plenum pulls this air in through the crank case via the intake pipe.

Makes sense now!

I also forgot to mention that the Z was turbo’d by the previous owner.. so it would make sense for them to have gutted the PCV. Obviously the catch can oil fills under load, so there’s no real way to test it until I have a track day. Ugh

I guess I’ll have to check that out and maybe run another compression test.

Just pull your pcv valve out and look. You'll be able to see right through it.

Alright so I checked my pcv, it still has its guts and it seems as if it’s opening and closing fine.

But it when I went to take a pic of a pipe coming off the intake that I plugged I found another one that is not plugged at all.. tell me what you think..

https://cimg6.ibsrv.net/gimg/my350z....d5c774885.jpeg
https://cimg7.ibsrv.net/gimg/my350z....6abc77f6e.jpeg

Under advanced reply, there is a sub section called manage attachments. Click that bar and add or delete photos. Just note only do 3 or so at a time. When you try to upload multiple it usually times out and does nothing. When they are done uploading you can do 3 more and so on per reply.

Or if you have a 3rd party hosting web site you use. The yellow icon with the black mountain above your rely is a img link and post the link in between those. But photobucket does not work.

Shame it's not the pcv.
I've tucked my engine bay but do not remember these. Sorry. Best guess is the previous owner bypassed the coolant.
If you search online, you will find a nissan site that will give you access to all the field service manuals for nissan/infiniti. That's what I would do next.

You’re right thanks man

I’m assuming I should just plug the intake side.. lol
https://cimg1.ibsrv.net/gimg/my350z....8454722ae.jpeg

IIRC, that coolant nipple ran a hose to the throttle body. It reads right there on the fsm it's to the upper collector but I don't think so. If it is to the upper collector, plug it for sure & this might be why mucho oil in the c.c. but if it's to the throttle body, it won't make a difference but then again you're in the northeast. No coolant to the t.b. might be an issue in the freezing-ass cold.
You might want to go through everything you can on that car and anything that doesn't look oem, figure out what it is using the fsm, looking for hack jobs that need some tlc.

Yes that is a coolant line to warm to throttle body in cold states to keep it from being frozen.

Let me know next time you hit NHMS or Thompson! With what clubs do you run with? on weekends?

I would do a compression test for sure... do it on a warm motor. If old owner boosted the car I wouldn't be surprised if there was a ring issue.. Hopefully not. I had this issue on a boosted engine and it haunted me. Idk I would do a compression test for sure. I would do a leak down as well!!!

How large of a catch can are we talkin here... Add some pictures, so we don't have to keep fishing for information to help you

And your oil level is where when this happens? What have you noticed about the oil level over time?

Oh man definitely do a compression test to put this to bed. I don't think there is any plumbing mistake that would result in that. Wouldn't hurt to take photos of the whole setup for peace of mind
​​

That's the c.c.? I see a small filter off to the side. IDK, maybe I'm missing something here but it looks to me like there's one hose going to it and that's it?

Put it all back to stock, delete the c.c.. Hose to intake pipe from valve cover on driver side and hose from pcv valve to the lower collector on passenger side and see what happens.

The burning of some oil might not be associated with ring seal. I think that shitty c.c. is getting filled up and the overflows getting dumped into the plenum.

That's a vented catch can with the Breather filter removed no? Nothing wrong with that if that's the case

Nothing wrong with that assuming there's another hose hidden somewhere. All I see is one hose.

I have one line coming from my PCV valve down below the engine. A vented catch can is the same concept except it catches the stuff coming out which is usually just a few drops a week depending on driving style. Only reason I don't run a vented catch can is I don't want it to ever add any restriction to my PCV system under boost.

If you're boosted and you are running a non-vented catch can there is nowhere for the pressure to go. If you're NA then the plenum will still be creating a vacuum (venturi affect) under WOT so you can run a non-vented one to avoid any crankcase odors from making their way into the cabin to reap the benefits of having a crankcase under vacuum (less foaming, less windage, less oil being burned through the rings, less likelihood of oil leaks from main seals etc)

I've never seen a c.c. with one hose, not on a vq at least. A line, assuming you mean hose, traveling from the pcv down below your engine would make it pretty difficult for the crank case to ventilate, no?
No vacuum at wot on this here n/a vq.
Guys tend to vent to the atmosphere when fi'd because they end up with oil in their pipes. If it was necessary to vent w/fi then there would be a lot of pricey german and jap. imports smelling like lawn mowers.
I'd dump that c.c., put it back to oem then see if anything changes for the better. If not, the guy you bought the car from lied. That's the engine he boosted and busted.

The hose I run is short and causes much less restriction than any vented catch can would. I have to side against going back to OEM, because the oil will be burned at an unknown rate without the catch can to monitor how much is being displaced.

Quite frankly (my apologies). You're not at a full understanding of the whole system, or what the venturi effect is/does. Please let me know if you think I'm incorrect here, but here's what's going on:

At WOT your crankcase will still be under vacuum due to the venturi effect occurring in the lower plenum. I agree, your plenum is not under vacuum. The gold colored baffle plate on your lower plenum causes a vacuum to be drawn when air rushes by it. Even though your plenum is not under vacuum, the section below the gold baffle plate is.

Similar to how a non gravity-fed airbrush works. Also why a car sounds like a helicopter if just one window is open in the back; the window pulls a vacuum on the cabin, which then collapses before being evacuated again. This happens a few times per second which is the sound we hear.


https://cimg9.ibsrv.net/gimg/my350z....aa061e12cd.png


The oil in the FI guys pipes is due to crankcase pressure blowing out their turbo seals. OEM manufacturers vent their PCV systems pre-turbo and have a check valve. This is what people miss when they have their turbo seals blow out on our cars. They only do the check valve on their brake booster but forget to vent the PCV system; or don't know any better.

When a OEM FI car is under vacuum the PCV flow is: crankcase>intake manifold (like ours).
When their car is under boost the PCV flow is: crankcase>pre-turbo>intake manifold


https://cimg8.ibsrv.net/gimg/my350z....329726bb8d.jpg


I think you're right about your last statement involving that engine being busted though. It only makes sense unfortunately.

Your getting off topic here bra. I appreciate all the drawings but I wasn't looking to get into semantics regarding pcv systems and oil catch cans and I certainly don't need to be "at a full understanding", or at least what you believe to be a full understanding of the pcv system.
The oil in the pipes of the fi guys is not due to turbo seals blowing out. I was actually thinking about what I read a couple months back from oldman350z and it was regarding superchargers, the pcv system and preventing oil from getting into the intercooler piping.
All b.s. aside, if you have a catch can and it's vented, you no longer have a positive crankcase ventilation system so ditch the can, put a filter on both the valve covers and call it a day or, with all the oil that's being caught, pull the dipstick and extend the hose that was going to the catch can and shove it into the dip stick opening. Recycling.

You just gave him terrible advice again. Recycling will not work. That would pressurize the crankcase. You should look at the "schemantics" some more before you try to advise someone.


​​​​lol honest mistake; thought schematic was misspelled

Ah...I was joking guy. Guess you didn't get that. Recycling, all the while he's burning oil a'plenty.
Sounds like your panties are getting stuck in the crack there bud. I haven't given any bad advice yet. It's actually where anyone with a little common sense would start, where the problem is most obvious and work from there, now piss off:bowrofl:
​Schemantics?:thumbup:

It's a schematic

Driver side to intake pipe where the pcv system draws fresh, metered air.

Both of the valve covers usually vent back into the intake just before the throttle body. They're connected in front and a tube goes from the back of the drivers side one to the bottom of the intake pipe

Gonna try to unsubscribe from this thread. Yosip buddy, you're making my nutz itch something fierce.
Both valve covers do not usually vent back into the intake. The passenger side runs from the pcv valve to the lower collector and the crank case draws air via the driver side valve cover to intake pipe.
fbomb, get a fsm and follow that before you end up getting some truly bad advice.
Yep. First time I unsub'd. VQ out !!!

SCDA events
 

I am registered with the SCDA... usually Thompson and Palmer. I'm planning Club Motorsports this year as well.

I don’t see how bringing it back to stock would help.. by creating vacuum to the driver side valve cover?