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Instead of catch can, why not delete PCV?

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On 3/25/2021 at 6:06 PM, CANUCK88 said:

First of all, thank you for the R&D with the vacuum pump delete and for going through with your plan and documenting it for the rest of us. Greatly appreciated!


I just pulled the intake manifold on my 2014 with almost 200k/124,000 miles. Job went well, I'll be posting it on the forum in the future. Build up wasn't as bad as I was expecting but it is largely highway kms. Daily driver in canada. Mainly parked outside in the cold... to be continued....after cleaning I installed a catch can as I couldn't find much info on crankcase evac... starting to regret getting a cc, especially since I mounted it at brake booster bolt and can feel it vibrate through the pedal. Anyways, some questions about crank evac system:

1) Does your tail pipe get black and smokey after a while? Better than that fouled air being fed back into the engine though I suppose


2) Did you drill and weld into exhaust at two points,  for each vent,  or did you "T" them both into one 5/8" line?


3) Are check valves necessary to prevent backdraft??


4) My biggest concern, Could frigid canadian winters have negative effects on evac system? Such as, condensation freezing in line/check valve and pluging it shut, thus causing a pressure build up...

Although my CC has a safe gaurd built in. If the can/line freezes, air will vent through a check valve to airbox. Set up much like the clean side seperator. Hose goes from oil fill port to intake port where valve cover woukd normally be attached. 


Which brings me to question #5)

Now that I've already paid for and installed a CC system, would it make sense to vent the CC to exhaust like an evac system? Seems like kind of foolish overkill but would clean some of the crud before getting baked on my exhaust and make some tree hugers happy i guess?¿ lol.


I suppose you could call me a fool for buying a pricier CC in the first place. It's the 

UPR 14-18 GM Chevrolet GMC Trucks 5.3L Pro Series Dual Valve Oil Catch Can CSS Plug N Play ™ 


What can I say, figured I'd spoil myself on some top notch CC since I save big time doing all my own maintenance and repairs. After looking into things further, a moroso crankcase evav system which is basically maintenance free, cheaper,  and 100% effective seems to be the better choice.  So long as it doesn't screw with motor functionality in any way.


Anyways, begining to bang head on the wall with catch can vs evac debate. Might just stick with what I have seeing as my carbon build up wasn't all that horrible after 200k, all stock. And I'm confident I can take apart and blast in a day when I feel the time is right...


Ps...anybody interested in a really good catch can? Lol


Happy to be of help!


The reason Catch Cans dont work is that they're technically destilleries. Hot vapor comes in, condenses inside (when the catch can is cold). But when the vessel gets hot, vapors just pass through. I have been saying that for years and nobody seemed to listen, i blame the wonders of marketing.


Thank you for taking your manifold off and telling it like it is! 


1.- Tail pipe doesnt get any dirtier


2.- I just drilled and welded 1 port on the exhaust, and just run 1 valve cover line, the other side is capped. I put a vacuum meter on the other port and 1 exhaust line is plenty enough to pull all pcv vapors. (Stock engine, stock ring gaps). I would like to have the 2 sides to a Y, just for symmetry tho.


3.-No, no exhaust gases return. The kit comes with a check valve but i removed it because i checked that i didnt need it.


4.- I dont know if extreme cold could cause any issues like that, i dont think so because the lines dont carry that much water, but you would detect them right away. Any excess of Crankcase pressure will pop off the oil dipstick.


5.- YES it makes sense, thats how i used to run the system before, worked fine!


We all fall for marketing schemes, i had a catch can, we all have had catch cans thinking they worked.


As George Carlin used to say: "Teach children to Question what they read,  teach them to question everything"

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Most of the vapor traffic in a crankcase is generated by manifold vacuum drawing on the atmosphere. Ring blow by gasses are exceeding small in a healthy motor. 



Edited by Grumpy Bear
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