Hello Everyone,
Following a near loss of my engine due to unexpected and recently worsening 4qt/5k mile oil use, I decided to try my hand at designing a budget price baffled non-vacuum connected catch can setup. I did this non-vacuum setup because the plenum vacuum was pulling way too much oil out of the valve cover and into the plenum. Healthier engines may not need an ambient setup like this but mine sure does!

This is the final result and I will follow up with some prototype pictures and a diagram of the setup.

The materials needed were as follows:
3 ft 3/8" fuel hose
2 Dorman Help GM pcv elbows (Part No. 47052)
1 3/8" brass tee
1 http://www.ebay.com/itm/182086883351?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT2 3/8" rubber vacuum caps
Total price: $80

The final product:


Here is the routing diagram:


Since the oil loss was pretty severe and I did not have a real catch can initially, I made this prototype, which worked as a catch can but was a failure due to oil fumes coming in through the AC:


After that, I ran a line to the Z tube PCV inlet and this worked, though a glass jar was still a pretty chintzy solution:


When I finally got the catch can in the mail, this was my initial setup:



While this setup worked, it still vented oil smell out the tiny filter, just not as badly as the glass jar prototype. I ended up capping off the catch can filter port, as you can see in the first picture at the top.

I should take time to mention that those Dorman pcv elbows worked so perfectly because I was able to press fit the fuel hose in the skinny end and push the larger end over the rear valve cover port and the Z tube port. The fuel hose does not go in easily but you can get in in with some soft soap if needed and it stays put. I plan on adding some spring clamps to the other hose joints but so far, everything is snug and the elbows prevent hose kinking.
As for the original pcv, I just drilled out the bottom enough to get the valve pushed out and used the empty body as the hose connector into the valve cover.

One of my design goals was to put this whole under the plastic engine cover and I was able to do that by running the hoses to the tee junction under the intake plenum. There are also some nice brackets here and there that allow for clean hose routing.

Finally, I highly recommend a baffled catch can so your z tube/intake pipe and throttle body gets minimal oil misting inside.

Hopefully this can help someone else too!

 

I forgot to mention, I had to flatten out and twist the mounting bracket that came with the catch can, drilled out one of the mounting holes, and dremel out some clearance for one of the screws in the catch can.

 

Couple questions:

1) How many miles on the engine?
2) have you had it on long enough to report on the degree this reduced consumption? I always thought the major cause was rings.

If it's too soon to answer #2, please circle back sometime to update the thread with you outcome.

 

The cause of OC is cheap Chinese oil rings and nothing short of possibly re-ringing the pistons or engine replacement is going to correct the issue! Catch cans will have zero effect on the OC issue, that's just wishful thinking. Catch cans will keep oil out of your plenum which I did with less than 3K miles on SLICK!
Gary

 

The engine is rocking 93k miles and runs beautifully otherwise, right up to when it nearly ran out of oil! I have held off on posting this for 3 weeks to gauge oil loss for 500 miles and so far, the dipstick level has remained steady.

I have no doubt that cheap chinese oil control rings (really Nissan?? Come on!) are the culprit for my problems that result in blowby. My working theory is that blowby creates lots of oil mist which gets vacuumed out of the crankcase through the plenum vacuum connection. If it is always getting removed by vacuum, it can never condense and drain back down internally.

I have no doubt that I am still losing oil in the combustion chamber but I definitely have lower consumption in the past 500 miles. I will report back in another 500 though.

 

This is a good solution for FI as well. Well done. I suspect you had a stuck/clogged PCV valve originally. Oil consumption will improve but may not go away if the ring clearances are a little large. Just need to keep the oil level monitored and you'll be fine. No big deal.

 

Thank you!
I did think stuck pcv initially but the valve was functional and clean (albeit a bit oily). I wouldn't doubt that my rings are worn though.

 

I missed my 500 mile checkin so here is my 1k mile checkin: the catch can is doing its job in terms of catching oil but my hope of reduced oil loss was too optimistic: At ~1000 miles, I am 1 qt down
My oil loss has maxed out at 1.5qt/1k miles before the catch can so I suppose this is a marginal improvement but not great nonetheless.
It seems like a rebuild is my best hope and I don't think I am willing to go that far.

 

Catch cans do their job by collection oil vapor from the upper plenum. I drive on average 5K mile a year, changing my Mobil 1 synthetic twice a year. Once a year I drain my catch can, the maximum collected is about half a cup give or take what's inside my turkey baster. It's doing what I want but it doesn't suck oil enough to show up on my dip stick between changes,
Gary

 

Would capping the INTAKE PCV inlet cause any issues if I am planing to run the driver side valve cover went to the catch can and then to manifold inlet?

 

I have the baffled catch can as well, with both passenger and driver side valve cover routed to the catch can. I mainly did it to keep my mrev2 clean from oil sludges. And yes, I could smell the fumes from the cabin but I just mainly press the air circulation button from ac and it is not as bad. Yes I have the rev-up engine, yes I still monitor my oil regularly. It is not a fixed to OC like others said.

 

Did you plug your intake pcv port or you plenum one? or did you route to both still be functional?

 

Yes intake port and plenum both plugged