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Instead of catch can, why not delete PCV?


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5 minutes ago, davester said:

Are you sure about this?

 

I know for my truck, 6.0l LQ4, the intake design would just store a bunch of liquid in it (as in, when I took it off, I poured a bunch of oil out of it as I turned it over).  Pouring a liquid into the intake would just sit in it, until either enough was poured in so it would run into the intake ports in the heads (or back out the front of the intake manifold) [note: pouring enough in to get liquid into the heads intake ports would be a bad thing, as starting the engine, the liquid flows into the cylinder and you can hydraulically lock the engine], or short of that, it would evaporate or movement of the truck would result in some getting splashed into the intake ports.

 

The vacuum in the intake won't atomize anything, as the air will just flow over the surface of the liquid, and perhaps some of the liquid will evaporate over time, but that's it.

 

And just evaporation isn't a great thing, as it takes quite some time (so it's very slow), and the different compounds in the product will evaporate at different rates or not at all.

 

If you want it to be effective, you want to use a spray can to atomize it, and get it into the intake as the truck is running.  IIRC, a spray can of seafoam I bought had a long, U-shaped nozzle extension, so I could insert the extension into the intake and put the intake hose from the MAF back on, over it so very little extra air could get in.

 

I think what he is trying to say is that water in a vacuum will boil at room temperature.  Oil won't boil at room temperature in a vacuum though.  

I don't know how they figure that direct injection is part of the problem though.  Crap building up on back of intake valve has been an issue since they started overhead valves.  If you go back to the 80s and older, small block chev engines used on o ring on valve stems that was not that effective at controlling oil.  They were better than nothing, 

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I capped my PCV line to the manifold, not a problem.

 

You can Cap the intake breather tubes and run the Valve cover breathers to the atmosphere, or to an atmospheric catch can or like I did: to the Exhaust with a Crankcase Evacuation System.

 

Its been years and I haven't had any issues whatsoever.

 

You can get a glimpse of my set up in the video explaining how to delete the Vacuum Pump:

 

 

What is the purpose of deleting the vacuum pump? Why not use the vacuum pump to pull a vacuum on the crankcase to help all around power and torque? The higher the rpm the more pressure builds in the cc and with the vacuum pump pulling that pressure out, the piston can move more freely down the cylinder. Racing engines utilize this setup. I would imagine this helping power and torque throughout the rpm range very well. Just use a t fitting to connect the breather hoses from the valve covers, block off the pcv in the valley under the tb, then join the new line into the vacuum line from the vacuum pump. I would use a catch can with this setup though because you would be pulling more vapor out and accumulating more oil in the can.

 

 

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On 11/6/2019 at 3:03 PM, wmgeorge64 said:

Sorry Doug those PVC valves had a hose directly to that air cleaner as I described, how else could they pull a vac on the CC?  That valve had a hose that went to the air cleaner so the carb could pull the vacuum.  The air entering the CC was through the oil fill cap which had a mesh screen filter open to the atmosphere on the opposite bank of the V8. I worked on many of those setups. The air cleaner is always in a vacuum when the car is running with a carburetor.  My first car I purchased in 1958 and it was a 49 Ford flat head six. 

http://econofix.com/pcv.html     for reference. 

There is never a vacuum ABOVE the throttle plates.  Just not possible to pull a vacuum in the air filter housing, provided you are not holding you hand over the air filter housing snorkel.

 

Chryslers had their PCV into a grommet on one valve cover, with the line going to either the vacuum tree behind the carb, or the base of the carb, below the throttle plates.  The other valve cover had a large vent cap that had a hose running to the air filter.  Fords were very similar, GMs were the same concept as well.


You are not reading the lines "Most PCV inlets are now via a hose to the valve cover from the air cleaner. Sometimes the air cleaner has a separate filter for the PCV inlet hose" on your reference site incorrectly.  The PCV inlet that site talks about is the cap with hose to the base of the air cleaner assy.  That is where the air enters the crankcase.

 

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8 hours ago, Doug_Scott said:

I think what he is trying to say is that water in a vacuum will boil at room temperature.  Oil won't boil at room temperature in a vacuum though.  

I don't know how they figure that direct injection is part of the problem though.  Crap building up on back of intake valve has been an issue since they started overhead valves.  If you go back to the 80s and older, small block chev engines used on o ring on valve stems that was not that effective at controlling oil.  They were better than nothing, 

The vacuum in an intake manifold isn't nearly enough to make water boil at room temp.  And while these products appear clear, they shouldn't have that much water in them.  Also, given a high enough vacuum, even oil will boil at room temp (or rather, various components of oil will boil off at different levels of vacuum).

 

And I think you'll find those products (seafoam, etc) are much less effective, if not completely ineffective, if they go through your engine from evaporation rather than atomization.  The concentration will be much lower via evaporation, as well as different components of the product will evaporate at different rates.

 

Simply put, pouring the products in their liquid form into your intake isn't a particularly good thing to do.

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19 hours ago, emaxxer86 said:

What is the purpose of deleting the vacuum pump? Why not use the vacuum pump to pull a vacuum on the crankcase to help all around power and torque? The higher the rpm the more pressure builds in the cc and with the vacuum pump pulling that pressure out, the piston can move more freely down the cylinder. Racing engines utilize this setup. I would imagine this helping power and torque throughout the rpm range very well. Just use a t fitting to connect the breather hoses from the valve covers, block off the pcv in the valley under the tb, then join the new line into the vacuum line from the vacuum pump. I would use a catch can with this setup though because you would be pulling more vapor out and accumulating more oil in the can.

GM issued a recall on Vacuum Pumps because they are prone to breaking.

 

Since I dont live anywhere near a GM dealer, The easiest fix I could find was just to delete it and run the booster on intake Manifold Vacuum, like most other cars.

 

You could do that using the vacuum pump, but I didn't find any solid reason to do so. I have all my PCV to the exhaust, that makes a vacuum too using an PCV Scavenger System.

 

 

 

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GM issued a recall on Vacuum Pumps because they are prone to breaking.
 
Since I dont live anywhere near a GM dealer, The easiest fix I could find was just to delete it and run the booster on intake Manifold Vacuum, like most other cars.
 
You could do that using the vacuum pump, but I didn't find any solid reason to do so. I have all my PCV to the exhaust, that makes a vacuum too using an PCV Scavenger System.
 
 
 


And don't forget the extra 1/4 hp you gained from not driving the pump.

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  • 2 weeks later...
On 12/5/2019 at 5:21 PM, Doug_Scott said:

I think what he is trying to say is that water in a vacuum will boil at room temperature.  Oil won't boil at room temperature in a vacuum though.  

I don't know how they figure that direct injection is part of the problem though.  Crap building up on back of intake valve has been an issue since they started overhead valves.  If you go back to the 80s and older, small block chev engines used on o ring on valve stems that was not that effective at controlling oil.  They were better than nothing, 

Did a carb and throttle body injection constantly flush the intake valve with gas?

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2 hours ago, Hoginedgewood said:

Did a carb and throttle body injection constantly flush the intake valve with gas?

To the naked eye it does.  All cylinders will go through the required 4 strokes every 2 revolutions.  800 rpm would mean there are 400 full cycles per minute, which is about 6.667 full cycles per second. 

 

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On 11/5/2019 at 2:29 PM, wmgeorge64 said:

Anyone remember the first PVC valves?  It was a check valve stuck in as I remember on the Ford drivers side valve cover top rubber grommet  and the hose was routed directly into the air cleaner housing, before the filter element.

 

    So all that stuff was filtered before getting sucked into the Carb intake.  When the bottom of the air filter housing got covered with oil or the air filter element got oily you know you had problems. I had overhauled a couple of engines from that era and never noticed  a lot of carbon on the intake valves.  

 

   Maybe the air filter housing and filter element were acting as a catch can?

 

 

Maybe the carb dumping gas onto the valves while the oil was wet flushed them clean.

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  • 1 year later...
On 12/2/2019 at 12:21 PM, VdellaV said:

I capped my PCV line to the manifold, not a problem.

 

You can Cap the intake breather tubes and run the Valve cover breathers to the atmosphere, or to an atmospheric catch can or like I did: to the Exhaust with a Crankcase Evacuation System.

 

Its been years and I haven't had any issues whatsoever.

 

You can get a glimpse of my set up in the video explaining how to delete the Vacuum Pump:

 

Did you get codes that you had to tune out?¿

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This was a great topic to read!!! Just found it and read everything from beginning to end as this is exactly something I am currently looking at doing to my 2015 Sierra 6.2. Yesterday I pulled the TB and was surprised/disappointed at the amount of oil in my manifold.

 

So I have a thought and I don't believe I saw this previously suggested but if it was then my apologies. Specifically about where to send the "filtered" air after the catch can. It seems there are basically two options. Venting to open, return to intake manifold or sending unfiltered air to the exhaust. So as long as the catch can is effective and filters the crankcase air why not have the "filtered air" dispense into your exhaust( after your last O2 sensor) using the nipples from the Moroso Crankcase Evac System #25900 that VdellaV introduced awhile back (thank you Vdella). Using those nipples and tapping into the exhaust pipe at an angle could create a "Venturi" like effect creating a vacuum on the catch can system assisting the removal of crankcase vapors and pressure. Now if the can does not catch nearly all of the oil than its not for me. I would not want this going to my mufflers or creating smoke. I'm sure there are potential issues this could create? 

 

Just a thought

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20 hours ago, VdellaV said:

Nothing at all

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

 

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Once upon a time in a land far far away the word IF had some meaning. But somewhere along the line IF became an absolute. Truth is that since the 50's ring seal has improved.  We use to actually measure the volume of vent gas with something like this below. Disconnecting the PCV from the manifold and plugging and closing the fresh air vents. 

 

Series VFB Visi-Float® Flowmeter (shown with no valve)

 

 

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