Jump to content

Instead of catch can, why not delete PCV?


Recommended Posts

So as I was doing this mod, I checked some things out.

I noticed that the line from the catch can to the manifold, the hose that is under vacuum, was pretty much bone dry.  Now, I checked and there is no blockage, the system is drawing a pretty strong vacuum when the motor is idling.  I can remove the dip stick from the top of the catch can, and there is strong suction and a whooshing noise...

So why no real oil in the return line?  Because the catch can seems to be doing it's job.  After 1,500 miles I have collected several ounces of motor oil and a little bit of water.  Now, I know that you said that it only works when it is cold, via condensation.  One thing that I changed on my catch can, was inside, there is a smaller "canister" that screws into the lid.  It is connected to the line coming from the crankcase vent, and the hot air must pass through this cylinder and exit out the bottom via some holes...  That inner cylinder unscrews from the lid, and I filled it with moderately packed, very fine steel wool, and screwed it back in.  The hot oily air being sucked in via the vacuum line, is forced to pass through that steel wool "filter", if you will, with causes the mist to form droplets and separate out and drip into the bottom...  Those droplets are too large to get sucked up into the very top of the lid where the return line is...

It's working, it's collecting more oil than I expected it to so nothing is clogged or blocked, but clearly it's trapping 99% of the oil from going back into the motor.  I looked down that return line and couldn't see any oil in it, and it felt almost bone dry... hardly anything...

I then checked the valve cap lines and there was next to no oil in them,  minimal at best.  

So at this point I left my filtered catch can as it was, as it appears to be doing it's job of collecting oil and passing almost nothing back to the manifold.  I then did the Seafoam intake cleaner treatment... only got about 3/4 of the bottle in there because the staw wouldn't attach to the cap and I had to sit there trying to hold it in place...  But after that and letting it sit 15 minutes to heat soak, I went out and got on it and left a big cloud of white smoke in my neighbor's yard... sorry bout dat...  lol

I will redo a new can of the Seafoam this weekend and make sure to do the entire can this time, but everything seems fine.  I think that for whatever reason, my setup is in fact catching almost all of the oil and very little is passing to the motor and intake valves, and so another good cleaning and it should be fine and I won't worry much about it going forward...

Link to comment
Share on other sites

You will not be evacuating crankcase pressure. You’ve lost your vacuum source when you plugged off you intake manifold. 

Sure, all you are doing is venting out your rocker covers into the atmosphere. 

You don’t have a PCV anymore pal,

Let me know when your rear engine seal blows!!!!

Edited by Slvijoe
Link to comment
Share on other sites

Well, in my case I gave up on the idea of capping things off when I saw how little oil was going into the motor.  I left my catch can in place, so the PCV system is there, it just goes through the catch can to remove the oil before heading into the manifold... and the valve covers are still venting into my Airaid MIT... so everything is intact...  

I will do another valve cleaning process with a fresh can and call it a day.

Out of curiosity, is one product really better than another?  Should I do another round of Seafoam, or try the CRC brand this time?  The process was simple, but the straw refusing to attach to the nozzle was a real pain.  I was able to raise the revs by putting a 1x4 between the pedal and my front seat, and adjusting how much it pushed on the gas peddle by moving the power seat forward and back.  I was able to set the throttle to 1800-2000rpm while I sprayed the seafoam...

Link to comment
Share on other sites

8 hours ago, Doug_Scott said:

 The oil hard clumps of crap on the intake valve stem won't cause detonation simply because it is not in the combustion chamber. 

I meant the raw oil sucked into the manifold which would be sucked into the chamber and not the build up on the valve. You know what I meant. 

 

10 hours ago, SquireSCA said:

So you are saying that valve carbon buildup on modern gdi motors is a non issue?  It’s FUD and nothing more?

I don't know what FUD means but each new generation of GDI is much less problematic than it's predecessor. I have over a 100K miles on mine and I'm sill waiting for the other shoe to drop. I think it will be a long wait.

 

Look, the first GDI motors were German in the 1920's and problem ridden and people still believe they are as miserable today and they were in 1925. It's just hard to get the stink off that skunk. Vendors use that sort of crap all the time to sell fear. I'm pulling no punches here. 

 

4 hours ago, Slvijoe said:

 

Let me know when your rear engine seal blows!!!!

That will be a long wait if vented to anywhere. Never blew a seal in a motor with a road draft tube due to pressure build up. Come to think of it, never had one drive me out of the cabin with the smell either. 

 

Link to comment
Share on other sites

10 hours ago, Grumpy Bear said:

I meant the raw oil sucked into the manifold which would be sucked into the chamber and not the build up on the valve. You know what I meant. 

 

I don't know what FUD means but each new generation of GDI is much less problematic than it's predecessor. I have over a 100K miles on mine and I'm sill waiting for the other shoe to drop. I think it will be a long wait.

 

Look, the first GDI motors were German in the 1920's and problem ridden and people still believe they are as miserable today and they were in 1925. It's just hard to get the stink off that skunk. Vendors use that sort of crap all the time to sell fear. I'm pulling no punches here. 

 

That will be a long wait if vented to anywhere. Never blew a seal in a motor with a road draft tube due to pressure build up. Come to think of it, never had one drive me out of the cabin with the smell either. 

 

FUD = Fear, Uncertainty and Doubt.

  • Thanks 1
Link to comment
Share on other sites

So because I did a half ass job with the Seafoam I went and got another can, and went with the CRC brand as it had a much better nozzle and seems to get good reviews...  This time, instead of spraying it into the throttle body, I figured I would plug it in to the vacuum line going to the manifold... you know, so it would suck it in and follow the exact same path that the engine oil travels when the stock PCV line is connected...

Followed the instructions, put the motor at 2000rpm and sprayed the contents of the can into the motor via the manifold vacuum line, let it idle for another minute and then shut the motor off.  Says for it to sit and heat soak for 1 hour and then go drive it at highway speeds for 10 minutes, which I will did...  At first the truck ran a little rough and I got a check engine light a few times, but after riding it around a bit and stomping on the gas a few times to run the motor through the entire rev range, it cleared up and is running just fine.  Plugged in my SuperChips Flashpaq F5 to scan and make sure there was no DTC to clear and it didn't find any...

At this time, I have done two intake valve cleanings, and now knowing that my catch can with steel wool inner filter appears to be trapping 99% of the oil, I think I will stop worrying about this whole thing.  ?

Edited by SquireSCA
Link to comment
Share on other sites

3 hours ago, SquireSCA said:

So because I did a half ass job with the Seafoam I went and got another can, and went with the CRC brand as it had a much better nozzle and seems to get good reviews...  This time, instead of spraying it into the throttle body, I figured I would plug it in to the vacuum line going to the manifold... you know, so it would suck it in and follow the exact same path that the engine oil travels when the stock PCV line is connected...

Followed the instructions, put the motor at 2000rpm and sprayed the contents of the can into the motor via the manifold vacuum line, let it idle for another minute and then shut the motor off.  Says for it to sit and heat soak for 1 hour and then go drive it at highway speeds for 10 minutes, which I will did...  At first the truck ran a little rough and I got a check engine light a few times, but after riding it around a bit and stomping on the gas a few times to run the motor through the entire rev range, it cleared up and is running just fine.  Plugged in my SuperChips Flashpaq F5 to scan and make sure there was no DTC to clear and it didn't find any...

At this time, I have done two intake valve cleanings, and now knowing that my catch can with steel wool inner filter appears to be trapping 99% of the oil, I think I will stop worrying about this whole thing.  ?

FYI I stopped using CRC intake cleaner because it contains Diesel Fuel and makes the engine knock a lot when applying throttle in the minutes after using it.

 

SeaFoam is a fine cleaner, but if you want more cleaning power for the money, get the fuel injector cleaner that contains the most PEA detergents. That would be Techron Marine or Techron Concentrate and pour them like they were seafoam. Much less smoke and mess.

 

 

Edited by VdellaV
Link to comment
Share on other sites

35 minutes ago, VdellaV said:

FYI I stopped using CRC intake cleaner because it contains Diesel Fuel and makes the engine knock a lot when applying throttle in the minutes after using it.

 

SeaFoam is a fine cleaner, but if you want more cleaning power for the money, get the fuel injector cleaner that contains the most PEA detergents. That would be Techron Marine or Techron Concentrate and pour them like they were seafoam. Much less smoke and mess.

 

 

So disconnect the air intake tube and literally pour it in?  Why not out it into a spray bottle and spray it in?  haha

Link to comment
Share on other sites

2 hours ago, SquireSCA said:

So disconnect the air intake tube and literally pour it in?  Why not out it into a spray bottle and spray it in?  haha

Yes, you could do that either way.

 

Once liquid gets into the vacuum of the intake manifold, it all atomizes anyway tho

Link to comment
Share on other sites

1 hour ago, VdellaV said:

Yes, you could do that either way.

 

Once liquid gets into the vacuum of the intake manifold, it all atomizes anyway tho

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.

 

Link to comment
Share on other sites

1 minute 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.

 

This is why I used the vacuum line, and sprayed the stuff into that, with the engine running at 2000rpm...  Figured that would suck it in properly that way...

Link to comment
Share on other sites

3 minutes ago, davester said:

Spraying it in, should be fine, as the spray should largely be atomized, and it doesn't put in the raw volume of liquid that pouring it in would.  But, depending on the location of the vacuum line, you may not get coverage of all the cylinders...

True, but I would imagine that using the vacuum line, would put the cleaner going down the same path to the same cylinders that the oil was going down before the catch can was installed.  So while it may not hit all the intake valves equally, in theory it should hit the ones the oil used to hit, the most...

Edited by SquireSCA
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Forum Statistics

    245.8k
    Total Topics
    2.6m
    Total Posts
  • Member Statistics

    333,234
    Total Members
    8,960
    Most Online
    Donald Dolan
    Newest Member
    Donald Dolan
    Joined
  • Who's Online   3 Members, 0 Anonymous, 718 Guests (See full list)




×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.