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Discussion Starter · #1 ·
I am having a hard time finding resources for this.

The 6.6 is a DI engine. I suspect a can is needed.

Does anyone know or have install instructions?
 

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Yes a catch can is a must on any direct injected motor.

Really doesnt have anything to do with AFM. The issue is that oil and oil vapors come through the PCV system and enter the intake. Now on a port injection system like the older motors, this isnt a huge issue since there is fuel flowing over the intake valves to help keep them clean.

But with direct injection, there is just the air and oil. So you get a lot of carbon build up on the intake valves, which creates issues for power loss, running rough, valve seal wear, etc. So its critical to keep the oil out of the intake.
 

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There's many multiples of threads of catch cans on the site if you do a search, with everything from DIY cans to $300 cans. Pick one you like!!!
 

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My understanding was that the oil injection system for when the AFM kicks in to coat the cylinders down with oil to keep them cool causes much more oil vapors in the PVC system mucking up the system and rings making those cylinders prone to ring damage and even more oil consumption which in my opinion was the most important reason for a catch can. I am not saying any engine wouldn't benefit from a catch can I just thought a direct injected with AFM had more of a need for it than a non AFM motor. Now I am being told AFM has nothing to do with it? sounds like I may need to learn more, but I am suspicious of the statement that AFM has nothing to do with the need for a catch can when what I thought was common sense says it has everything to do with it.
 

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Yes, AFM is a 100% independent system from the PCV system.

Not so much on the ecotec motors, but the vortec motors were pretty bad on some of them for straight up just burning oil. Sometimes shutting off AFM helped on those, but again, the two systems are not related to each others function in any way.

And it isnt just GM that has an issue with the DI motors. Its every brand. In fact, some manufacturers are going to a multi injection system that uses direct injection, but also has fuel injected into the intake. That is a good idea in my opinion.
 

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So your saying when in 4 cylinder mode and the AFM system injects-sprays oil directly on the piston skirts at 2000 rpm or so that none of the oil vapors that get generated in the oil pan and crank case is somehow separated from the PCV Valve ( positive crankcase ventilation ) that is a new one to me.
So how is it that the oil vapors stirred up from AFM activation gets separated from the crankcase? Not trying to be argumentative just trying to learn because this just does not make sense to me. ( Keep in mind I have never had one of these engines apart personally but I have watched many get rebuilt online and on too many TV shows to count).
 

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Well of course the oil vapors in the crank case get through the pcv system and into the intake.

But that is happening regardless of if AFM is there or not. Sure maybe if AFM is active you'll get a little more in the catch can, but one system is not dependent, or really caring about the other. They perform two completely separate functions.

Like I mentioned, whether the motor has AFM, no AFM, AFM disabled/deleted, has no bearing on needing a catch can.

If it is a DI motor, and has a closed PCV system, it needs a catch can. Doesnt matter the brand or type of engine. Some of the fords with the turbos are really bad at this.

An open breather is the best, but a catch can is the next best thing.
 

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I get all that but it was claimed "Really doesnt have anything to do with AFM" which is what got my panties in a wad.
It is my opinion that a AFM engine with an active AFM system will have much more oil vapors in the air fuel mixture introduced by the pcv system thus needing a catch can much worse than a brand new 2020 6.6 engine with tight tolerances and very little if any blow by.
My main point is that no one with a brand new truck with a non AFM engine that is still under warranty needs to rush out and modify their truck with a catch can possibly risking warranty issues.
In my opinion the only thing that will happen if the OP does nothing is eventually the intake valves and exhaust valves will have a build up on them which can eventually after many miles reduce the air flow into and out of the engine. which happens no matter what to the exhaust valve catch can or no catch can.
Personally I think the catch cans are blown way out of proportion and have no real benefit on a new non AFM engine. This is just my opinion.
 

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Well I can tell you my personal experience with two trucks.

My 17 had AFM disabled since around 2k miles or so, and a catch can basically simce day 1.

I caught just as much oil as my fathers truck does and he still runs AFM (his range module has issues). So AFM on or off makes no difference in oil that is collected. Or at least not a measurable difference

And like I said before, motors that dont, nor ever had, AFM, like the ford ecoturd motors, have the same issues with valve coking as the GM motors do.

So a catch can is very much a needed item in my book on any motor with direct injection only. If someone doesnt want to run one, it doesnt matter, they should make their decision based off knowledge and facts of how the direct injected motors function, and the countless accounts of the valve coking that are all over the web.
 

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Two facts about catch cans in the PCV line:
1. It will help your engine.
2. it will not harm your engine.

Get one.
 

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Discussion Starter · #13 ·
I understand all the benefits and why and whatnots... I ran a can for my '17 for over a year. I have two full jars of shit I pulled out over the year or two I ran it.

My real question is about this new 6.6. It is a DI engine... But, wasnt/not sure if there is something new with it that negates needing a can. Further, if it does need a can, is there any reason I cant use the E2 on it? The engine is much bigger than my 5.3... does it matter?
 

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Discussion Starter · #15 ·
Ok. That is what I suspected.

Next question - anyone know hot to mount it in this new 6.6. I have not been able to find any videos or instructions.
 

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If you can find the PCV line, where it comes out of the crankcase and then where it goes into the intake, that's all you'll need. The rest will be the same.

In GM fashion I'm sure its setup very similar to their other motors. They usually dont change a whole lot as far as that stuff goes. And they are generally laid out nicely.
 

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Discussion Starter · #18 ·
So far, I have not been able to find where it comes out of the crank case. I followed the pcv line from the intake back... and it goes to a spot at the top of the engine on the right...

I did follow another line that goes to the back of the engine out of site... my fear is that is the one...

Any mechanic out there know where it is??
 

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Discussion Starter · #19 ·
Ok, I am going to do a vid of the engine bay and see if anyone out there can help me identify the pcv system. stand by
 

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Delrio said:
Ok, I am going to do a vid of the engine bay and see if anyone out there can help me identify the pcv system. stand by
How many miles do you have on your engine? Have you pulled the air box off to inspect the throttle body for signs of oil?
I just installed a Catch Can for my 2015 5.3 and changed the oil using VALVOLINE MODERN ENGINE FULL SYNTHETIC MOTOR OIL which is supposed to also help with carbon build up ( but not cure it ) I figured anything helps. Yet I tried to look up to see if they recommended it for your engine and they do not even list the 6.6 Gas engine perhaps an oversight but if you can find out if this oil is OK to run in your engine plus not effect the warranty it may be something to consider while your working on coming up with a catch can install for your engine.

https://www.valvoline.com/our-products/ ... -motor-oil
 
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