Pimperish1 wrote: ↑

Fri May 04, 2018 11:51 pm

Any idea on the efficiency of the catch cans? Without the baffle I know for sure it can't be 100% (oil caught). But with the baffle I'm curious how much will get by to satisfy the lubrication requirements for the valve guides. Given the trace amounts of oil in the "blue" hose my guess is the gases routed through the PCV valve are primarily responsible for this lubrication. I don't want to scrub too much oil and end up harming my engine. Thoughts?

The catch cans I am running have diffusers that trap the excess oil while allowing the rest of the oil laden air through to the intake. I change my oil every 5k miles. I check my cans and oil level every 2.5k miles. I collect about 1/2 cup from both cans. It's weird but I seem to collect more from Bank 1 than Bank 2 for some reason. I don't think I am trapping too much, but honestly I don't know how much oil is required for proper lubrication. I'm still having to add fresh oil, about 1-1/2 quarts every oil change. Based on this observation I feel that I am still getting plenty of lubrication. I've decided to leave the other blow by hoses alone for now, mainly because I don't want to compromise the operation of the PCV lines by tying them in together.

Well now I see the purpose. If you let this oil go back in it seems like it could cause problems with the MAF, Throttle body and all sorts of intake things. Does the 3.7 V6 have this issue with blow-by?

AlabamaDan wrote: ↑

Thu Jun 21, 2018 9:12 pm

Well now I see the purpose. If you let this oil go back in it seems like it could cause problems with the MAF, Throttle body and all sorts of intake things. Does the 3.7 V6 have this issue with blow-by?

To my knowledge, no...mainly because the 5.6 is a DI engine. Maybe the V6 guys can elaborate more on that.

The MAF sensor should be unaffected. It is upstream of the PCV/catch can outlet into the intake. The throttle body & plate might get a little coating of oil, but if your engine is well maintained, you shouldn't actually see any significant amount of oil anywhere... unless you install a container to catch it.

With regards to other engines in the Nissan family, I think it's a crapshoot although I would say it trended with the newer generations and squeezing more power out of the engine block. The VQ35DE had consumption issues as well as the VK45DE, although I didn't think it was as rampant in the VQ37VHR.
I am also curious what the 3.7 owners are seeing, because I haven't personally owned any vehicles with that engine.

Here's my catch can installation:
https://1drv.ms/u/s!Ai70ZJT51I9XgeUkenAccXRkEAfEig
https://1drv.ms/u/s!Ai70ZJT51I9XgeUjzmiPbAswp9fUmA
Give it up to a minute for the pic to come into focus. Thanks.

Off topic here, but can anyone explain how to add an avatar? I went on "edit avatar" but it doesn't allow me to do anything. Thanks.
https://1drv.ms/u/s!Ai70ZJT51I9XgeUlKOvvkXDN7JuzwQ

Gr8Coupe wrote: ↑

Sat Jun 23, 2018 5:34 am

Off topic here, but can anyone explain how to add an avatar? I went on "edit avatar" but it doesn't allow me to do anything. Thanks.
https://1drv.ms/u/s!Ai70ZJT51I9XgeUlKOvvkXDN7JuzwQ

Apparently something is off in the system.
I saw this thread in the general forums: how-customize-avatar-t620619.html

EdBwoy wrote: ↑

Sat Jun 23, 2018 1:44 pm

Gr8Coupe wrote: ↑

Sat Jun 23, 2018 5:34 am

Off topic here, but can anyone explain how to add an avatar? I went on "edit avatar" but it doesn't allow me to do anything. Thanks.
https://1drv.ms/u/s!Ai70ZJT51I9XgeUlKOvvkXDN7JuzwQ

Apparently something is off in the system.
I saw this thread in the general forums: how-customize-avatar-t620619.html

It's fixed. You can add an avatar now.

Can someone confirm that the DIRECTION of the air and oil flow. ... does it move from the lower area under the intake to the upper spot above or near the top of the engine??

JimSim20 wrote: ↑

Sun Dec 06, 2020 8:43 pm

Can someone confirm that the DIRECTION of the air and oil flow. ... does it move from the lower area under the intake to the upper spot above or near the top of the engine??

The PCV air exits the engine from the valve cover to the intake manifold.

The first few minutes of this video might help

JimSim20 wrote: ↑

Sun Dec 06, 2020 8:43 pm

Can someone confirm that the DIRECTION of the air and oil flow. ... does it move from the lower area under the intake to the upper spot above or near the top of the engine??

Yes it flows from the crankcase to the intake. I did a write up here:
post6746876.html#p6746872

Thanks EdBwoy for the detailed explanation of how the air flows and the system in general, well done. I guess in my mind the main benefit of a catch can is too slow down the buildup of carbon on the back of the valves. I don't know if anyone will notice a performance improvement when driving with the catch cans. I got the cans and placed them at the back near the fire wall but haven't installed the hose yet. Installed them is probably more effort than it's worth in reality but maybe others that are using them can offer some benefits from having used them on their cars. Thanks again though.

You're welcome Jim, I am glad the video answered your question with some level of clarity. Earlier in the thread there was also some uncertainty as to what function the other tubes and ports around the valve cover served. I hope those were answered as well.

Regarding the benefits of catch cans to our cars, I think the intention is definitely good, although at this point, I will not be installing them in my own car.
However, if I see a question for which I have the answer, and can offer assistance in how to do something, I like to share what I know to help you achieve your intended goals.

As for the quantity of oil captured/consumed, maybe someone will be able and willing to report their oil losses measured by the dipstick against odometer mileage, against catch can contents - if they were interested in that level of analysis to know where things flow to & from.

***
I also wanted to clarify that the PCV System is not meant to lubricate the valves.

Doh! I should have asked for this for christmas! Next year hahah.

JimSim20 wrote: ↑

Fri Dec 18, 2020 9:48 am

Thanks EdBwoy for the detailed explanation of how the air flows and the system in general, well done. I guess in my mind the main benefit of a catch can is too slow down the buildup of carbon on the back of the valves. I don't know if anyone will notice a performance improvement when driving with the catch cans. I got the cans and placed them at the back near the fire wall but haven't installed the hose yet. Installed them is probably more effort than it's worth in reality but maybe others that are using them can offer some benefits from having used them on their cars. Thanks again though.

I ran the cans I installed for a couple of years. Other than trapping some oil, there's really no performance improvement. As a matter of fact when I changed PCV valves, I was trapping a lot less oil. Turns out my PCV valves were leaking by, so I decided to pipe it back up to stock. I believe using full synthetic oil instead of dinosaur oil will help with carbon build up more than the catch cans. Just my two cents. I also believe oil consumption is a function of driving habit. If you do a lot of racing around and WOT's you're going to trap more oil in your cans and as such, may want to keep them installed. For normal driving I don't think they're necessary but it won't hurt a thing to have them.