Jump to content

6.6 - Catch Can - Final Answer

6.6HD

By 6.6HD
in 6.6L Gas V8 (L8T)

 Share

Recommended Posts

Grumpy Bear Senior Enthusiast

Grumpy Bear

Posted
Posted (edited)
9 hours ago, CRApex said:

So problem solved, Easy GDI service and modern engine full synthetic!

 

More like problem better "understood". :) 

 

Anyone who has ever torn down a high mile carburetor motor with poor valve seals/stems has seen the backs of intake valves that are quite caked with carbon. 

 

Valve seals don't eliminate oil past the stem. They control it in concert with fit. Just like oil "CONTROL" rings don't eliminate oil into the chamber. But done well both look like no oil is being used "over a reasonable oil service period". Catch can won't help either of those causes. IN fact, nothing but a mechanical service will fix the valve stem issue. 

 

If the rings are bad enough that blowby gasses are entraining an unusual amount of oil into the PCV system, then a catch can will limit but not eliminate oil migration via that route. 

 

In a healthy motor, most of what a can catches is water vapor, fuel vapor and a nominal amount of oil mist. What oil that is entrained can be partially mitigated by choice of base oils and chemistry. Ester or ester/AN bearing oils leave less carbon on valve backs than straight up Group III/IV. 

 

I know little to nothing about these new Valvoline products. 

 

 

Edited by Grumpy Bear
  • Like 1
  • Thanks 1
  • Replies 50
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

mrjulian416
mrjulian416

The passenger side tube is the "fresh air" line allowing clean, metered air a path into/out of the engine.  It is not a "foul air" line letting blowby out of the engine.  There is much higher vacuum a

It's Tim
It's Tim

Peeps are worried to death about a little engine oil in the intake manifold but seemly could less that their arteries are almost plugged solid from fat food. ?

It's Tim
It's Tim

So... this dudes an "expert" in "catch cans" but failed to notice the engine was only running on 7 cylinders multiple times? Probably time to find a different mechanic and not waste money on a snake o

Posted Images

CRApex Enthusiast

CRApex

Posted
Posted (edited)
26 minutes ago, Grumpy Bear said:

 

More like problem better "understood". :) 

 

Anyone who has ever torn down a high mile carburetor motor with poor valve seals/stems has seen the backs of intake valves that are quite caked with carbon. 

 

Valve seals don't eliminate oil past the stem. They control it in concert with fit. Just like oil "CONTROL" rings don't eliminate oil into the chamber. But done well both look like no oil is being used "over a reasonable oil service period". Catch can won't help either of those causes. IN fact, nothing but a mechanical service will fix the valve stem issue. 

 

If the rings are bad enough that blowby gasses are entraining an unusual amount of oil into the PCV system, then a catch can will limit but in eliminate oil migration via that route. 

 

In a healthy motor most of what a can catches is water vapor, fuel vapor and a nominal amount of oil mist. What oil that is entrained can be partially mitigated by choice of base oils and chemistry. Ester or ester/AN bearing oils leave less carbon on valve backs than straight up Group III/IV. 

 

I know little to nothing about these new Valvoline products. 

 

 

I thought the Valvoline article was informative, was just poking fun of how they sum it up with the Instant oil change GDI service and full modern synthetic oil as the solution.  That said, I too know little to nothing about the new Valvoline products so maybe the laughs on me??

Edited by CRApex
  • Like 1
  • Haha 1
lineman1234 Enthusiast

lineman1234

Posted
Posted

OK, so as mentioned, this is ( just ) and experiment for me. This added, will be all i have till it fully warms up hear and or when i try non ethanol fuel at 87 octane. A full tank full when i stumble across it hear in the northern midwest. 

...

For the heck of it, yesterday i went to install a added catch can on the passengers side. In all ( there ) wisdom, the connectors and plastic hose isnt the same as the drivers side. So no can installation. 

... Today, i took a couple Q-tips and went for a look into iffff, anything did or does go between the passengers side front valve cover and the intake. 

... As of about 5,700 miles on my 2024 L8T,,, nothing. 

... 

Every one likes pics. the first pic is the plastic pipe that goes between the intake and passengers side valve cover. Next pic is the 2 ports or spots it plugs into. Next pic is it and 2 Q-tips i swabbed the intake and valve cover as well as the pipe, as far as i could with the said Q-tips. Nothing. 

... The same 44 mile trip today with an empty can, on the drivers side,,,  resulted in about a teaspoon of oily water vs the other times about 1.5 tablespoons. It was 50-55 today vs the other times 20-30, so seems temp plays a part in the can. 

20240401_110936.jpg

20240401_110847.jpg

20240401_110836.jpg

Pryme Senior Enthusiast

Pryme

Posted
Posted
15 hours ago, lineman1234 said:

OK, so as mentioned, this is ( just ) and experiment for me. This added, will be all i have till it fully warms up hear and or when i try non ethanol fuel at 87 octane. A full tank full when i stumble across it hear in the northern midwest. 

...

For the heck of it, yesterday i went to install a added catch can on the passengers side. In all ( there ) wisdom, the connectors and plastic hose isnt the same as the drivers side. So no can installation. 

... Today, i took a couple Q-tips and went for a look into iffff, anything did or does go between the passengers side front valve cover and the intake. 

... As of about 5,700 miles on my 2024 L8T,,, nothing. 

... 

Every one likes pics. the first pic is the plastic pipe that goes between the intake and passengers side valve cover. Next pic is the 2 ports or spots it plugs into. Next pic is it and 2 Q-tips i swabbed the intake and valve cover as well as the pipe, as far as i could with the said Q-tips. Nothing. 

... The same 44 mile trip today with an empty can, on the drivers side,,,  resulted in about a teaspoon of oily water vs the other times about 1.5 tablespoons. It was 50-55 today vs the other times 20-30, so seems temp plays a part in the can. 

20240401_110936.jpg

20240401_110847.jpg

20240401_110836.jpg

Seems your truck is running as intended. 
 

if you start swabbing inside your exhaust you will probably get some soot residue in there. Doesn’t mean anything. 
 

internal combustion engines are messy. 
 

  • Like 2
lineman1234 Enthusiast

lineman1234

Posted
Posted

No, no, this summer im going to take flat black paint and do this.... So i can hang with the non cool people. 

20201222_161008.jpg

  • Haha 1

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Grumpy Bear
      Sugar Bears 2015 GMC Terrain SLE-2 2.4 AWD

      By Grumpy Bear · Posted

      287,500 Mile Service   8/13/2026   Reset Fuel Trims   Since the work done in the previous post there was a good improvement in response in all areas except right after a fill up where the LTFT would go -20%+ for about four miles while the STFT was near neutral. Before the work they both went very negative for a few miles after a fill up but act normal thereafter.    We did a systems check of the vapor recovery system for functionality and ability to hold a vacuum. That checked out fine. But this doesn't mean the charcoal canister is dead in the water. Testing that is next up. For now the reset of the fuel trims.    I intentionally shorted the fill exactly two gallons to eliminate any chance of filling the canister. On start up the trims were behaving normally until I got up and rolling where the LTFT went -10 / -11%% but the short was + 2 to 0%. Within a mile the the STFT offset the LTFT and by 2 miles they were neutral. HUGE improvement but still not hunky-dory.    I'll watch them for a few days. Perhaps another tank where I will fill completely to 'first click' and compare. Meanwhile on the hunt for a new canister and I'll toss another purge value at it for good measure. Pending the outcome of the canister test that is. Progress of any kind is welcome.    Fuel economy improvement with bringing hole #3 back to the living was a noticeable bump to the positive. Even on the few miles I drove after the refill I already see another bump up by the trims reset.     She's purring like a kitten with a warm bowl of milk.    BTW, adding 50 rpm to the idle took the majority of the negative timing out on cold start up and leaned the cold idle. No longer burbles in the cat. What a dumb way to heat a cat.      
    • OnTheReel
      Post your UOA, (used oil analysis) here

      By OnTheReel · Posted

      Yeah, shame I can’t really get that filter easily anymore. Running a PureOne. Your fave!    TAN would be neat to see. Confirmation I ran it too long probably. 🤣
    • superdave160
      Roll up bed cover experiences

      By superdave160 · Posted

      My son and I both bought new trucks in 2017. Both of us immediately put Truck Covers USA American Roll Covers on our trucks. My son still has his truck and it never sees the inside of a garage. We live in Alabama, so not much snow. My truck was my daily driver and was in the garage when I wasn't driving it or at work. No issues with either cover even after almost 9 years. About a year ago I sold my truck to my brother and bought a 2025 Silverado 2500. The second thing that I put on that truck was a new Truck Covers USA cover. They are very well made and have a very positive locking system. I looked at a Retrax and my concern was the way that the cover locked to the rail. BTW, the first thing I put on the new truck was step bars. Those new trucks are high!
    • superdave160
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By superdave160 · Posted

      The Allison 10 speed torque converter doesn't "lock up" like the previous transmissions. It has 4 operational modes; open, slip, transition from open to slip; transition from slip to open. I have an Edge CTS3 monitor and I monitor transmission torque converter slip. Step on the gas and you get a little slip. Take your foot off the gas and you get a little negative slip. I have not found a way to display the torque converter mode beyond that. My Edge CTS3 also displays something that our trucks should already display, the current gear. I also monitor throttle body position and engine load. If I see the engine load getting too high, I'll manually drop a gear.
    • Grumpy Bear
      Post your UOA, (used oil analysis) here

      By Grumpy Bear · Posted

      Nice result. Your filter is working well  I'd have like to have seen the acid number for this sample. Curious type that I am. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...