Just bought a cheap boroscope today.

[Grumpy Bear]

1 hour ago, Randal Scott said:

Ok, back to the right cover to catch can. When I was looking at stuff about catch cans. They were saying that the one going to the air intake was the clean side and the pcv side is the dirty side. I took it as air going in one side and sucked out the other side. Is this wrong thinking. 

 

You got it right. Pulls in clean and metered air through the system. PVC is the dirty side. 

[Jettech1]

8 minutes ago, Grumpy Bear said:

 

You got it right. Pulls in clean and metered air through the system. PVC is the dirty side. 

I'm confused.  Can you expand on that more please?  I was under the impression that both valve covers acted as a passive PCV system.  

[Ausslo]

.

Edited April 22, 2023 by Ausslo

[Ausslo]

15 hours ago, Grumpy Bear said:

 

You got it right. Pulls in clean and metered air through the system. PVC is the dirty side. 

Except at WOT and heavy acceleration/engine loads then pressure overcomes vacuum.

Edited April 22, 2023 by Ausslo

[Grumpy Bear]

55 minutes ago, Ausslo said:

Except at WOT and heavy acceleration/engine loads then pressure overcomes vacuum.

 

Too simple an explanation sir. If the pressure in the air box could ever get higher than the pressure in the manifold, then a carbureted car would simply shut off when you bring it full throttle as it relies on this differential to pull gas from the bowl and losing that differential the gas would shut off. 

 

The PVC system uses the same pressure reference point but takes a different path. That is, through the crankcase. This area is subject to blow-by gasses past the rings and in a healthy normally aspirated motor with a PCV valve that blow-by is never high enough to create a pressure high enough in the crankcase to be higher than that of the inlet box. The PCV is a "variable flow" check valve. (Effectively a pressure balanced against a spring 'mini-me' throttle body. Something like a CV motorcycle carburetor effect) It's also the reason it is on the 'dirty side'. 

 

Could crankcase pressure get so high that the PCV valve path could not handle the volume? Yes! If you hole a piston, break a ring or the motor is so worn the rings are at 50%+ leak down or stuck in their lands to the same effect. Plug the baffles with sludge. Then sure, it could happen. But not in a healthy motor no matter how much throttle you're feeding it. 

 

Okay, but how about if the system does not use a PCV valve but rather a CCV 'Orifice"?  In this case it takes much less blow-by to overwhelm this 'fixed aperture' metered orifice flow AND there is no check valve feature. These systems can and will backflow. In fact, in the 2.4 I-4 there is a design feature in the airbox to accommodate this; a mini clean side catch can you have to clean out several times a winter is colder areas. You have to know which type you are working with. 

 

15 hours ago, Jettech1 said:

I'm confused.  Can you expand on that more please?  I was under the impression that both valve covers acted as a passive PCV system.  

 

In my case, Ecotec3 4.3 there has only been one type ever. PCV valve. GM however has used both types with the 5.3 and perhaps the 6.2 motors and I am not expert enough to know which models and years used which systems. It's why I didn't answer your request last night when I saw it. I would have to physically look at yours OR......

 

We have actual GM Tech's on this site who chime in from time to time. 

Edited April 22, 2023 by Grumpy Bear

[Randal Scott]

Ok, looking at the 5.3L and 6.2L at there air resonator boxes. They have both sides connected to the air resonator. The 6.6L only have the right side connected to the air resonator. That must be the 2 different systems? And that would be why the cold air intake kits have a place to connect the right side to. I wish someone would make just a tube replacement for the resonator. They have it for other makes and motors. 

[Grumpy Bear]

1 hour ago, Randal Scott said:

Ok, looking at the 5.3L and 6.2L at there air resonator boxes. They have both sides connected to the air resonator. The 6.6L only have the right side connected to the air resonator. That must be the 2 different systems? And that would be why the cold air intake kits have a place to connect the right side to. I wish someone would make just a tube replacement for the resonator. They have it for other makes and motors. 

 

Two different plumbing systems for the same system. Depending on where they decide to place the PCV valve or orifice. 

 

They do the same thing and work the same way. If it is attached to the airbox that is the clean side. PCV vapors are never drawn through the the throttle body by design. 

[Ausslo]

 

11 hours ago, Grumpy Bear said:

 

Too simple an explanation sir. If the pressure in the air box could ever get higher than the pressure in the manifold, then a carbureted car would simply shut off when you bring it full throttle as it relies on this differential to pull gas from the bowl and losing that differential the gas would shut off. 

 

The PVC system uses the same pressure reference point but takes a different path. That is, through the crankcase. This area is subject to blow-by gasses past the rings and in a healthy normally aspirated motor with a PCV valve that blow-by is never high enough to create a pressure high enough in the crankcase to be higher than that of the inlet box. The PCV is a "variable flow" check valve. (Effectively a pressure balanced against a spring 'mini-me' throttle body. Something like a CV motorcycle carburetor effect) It's also the reason it is on the 'dirty side'. 

 

Could crankcase pressure get so high that the PCV valve path could not handle the volume? Yes! If you hole a piston, break a ring or the motor is so worn the rings are at 50%+ leak down or stuck in their lands to the same effect. Plug the baffles with sludge. Then sure, it could happen. But not in a healthy motor no matter how much throttle you're feeding it. 

 

Okay, but how about if the system does not use a PCV valve but rather a CCV 'Orifice"?  In this case it takes much less blow-by to overwhelm this 'fixed aperture' metered orifice flow AND there is no check valve feature. These systems can and will backflow. In fact, in the 2.4 I-4 there is a design feature in the airbox to accommodate this; a mini clean side catch can you have to clean out several times a winter is colder areas. You have to know which type you are working with. 

 

 

In my case, Ecotec3 4.3 there has only been one type ever. PCV valve. GM however has used both types with the 5.3 and perhaps the 6.2 motors and I am not expert enough to know which models and years used which systems. It's why I didn't answer your request last night when I saw it. I would have to physically look at yours OR......

 

We have actual GM Tech's on this site who chime in from time to time. 

I think you miss-read that a little, It really is a simple system.

Normally asperated engine-Fixed orifice or PCV Valve (open crankcase ventilation) 

Under high vacuum conditions (idle/less throttle opening) air flows from airbox through the tube into motor and back out through PCV into the intake behind throttle plate. Under low or near zero vacuum conditions the crankcase pressure created by normal blow by (combined with lack of vacuum to the crankcase from the intake) is actually pushed to the air cleaner/box or anywhere in front of the throttle plate through said tube. This is why carbon builds on the throttle plate.

Under wide open throttle vacuum goes to zero and near about zero under heavy load, at that point crankcase pressure is slightly higher than crankcase vacuum and it doesn't take massive amounts of blow by to push vapor into the airbox side of this equation, even though there is a slight vacuum in the airbox created by the incoming air, if you disconnect the crankcase to airbox tube sometimes you can actually see the vapor come out of the tube under said conditions, yes even on a healthy motor.


Actual 35 yr Master Technician/Advanced Level Specialist chiming in, cheers

Edited April 23, 2023 by Ausslo

[Pryme]

1 hour ago, Ausslo said:

 

I think you miss-read that a little, It really is a simple system.

Normally asperated engine-Fixed orifice or PCV Valve (open crankcase ventilation) 

Under high vacuum conditions (idle/less throttle opening) air flows from airbox through the tube into motor and back out through PCV into the intake behind throttle plate. Under low or near zero vacuum conditions the crankcase pressure created by normal blow by (combined with lack of vacuum to the crankcase from the intake) is actually pushed to the air cleaner/box or anywhere in front of the throttle plate through said tube. This is why carbon builds on the throttle plate.

Under wide open throttle vacuum goes to zero and near about zero under heavy load, at that point crankcase pressure is slightly higher than crankcase vacuum and it doesn't take massive amounts of blow by to push vapor into the airbox side of this equation, even though there is a slight vacuum in the airbox created by the incoming air, if you disconnect the crankcase to airbox tube sometimes you can actually see the vapor come out of the tube under said conditions, yes even on a healthy motor.


Actual 35 yr Master Technician/Advanced Level Specialist chiming in, cheers

Impressive credentials. All with GM or other brands too?

 

what do you think about the DI on the 6.6 and what system they put in place to mitigate the oil coating valves?

[Ausslo]

8 minutes ago, Pryme said:

Impressive credentials. All with GM or other brands too?

 

what do you think about the DI on the 6.6 and what system they put in place to mitigate the oil coating valves?

Foreign (Asian European) and Domestic to many to list, I only put qualifications there in response to the GM Tech comment lol, hope nobody took that wrong, although I earned those qualifications they don't really mean anything except I have some experience. I certainly don't know everything or about every vehicle. 

When compared to other auto makers what GM and Ford are doing to mitigate the issue seems to be working better than others. As far as the D.I. on the 6.6 -time will tell, my advice is to change your oil frequently -personally 3,000 miles full synthetic Mobil 1. Call it overkill if you want but food for thought, every vehicle I have had come to me with a VVT problem (which is quite a few) has gone 5,000 or more on there oil changes using conventional to full synthetic. I have never had replace a VVT component on my personal or family's vehicles that have followed the 3,000 rule, could be luck I guess, I know what the manufacturers recommended interval is in the manual but I disagree with them on that one. Keeping the engine clean as possible goes a long way to reducing those deposits as well. Good old GM/AC Delco top engine cleaner, Carburetor tune-up,  X66 or whatever they are calling it now works well to remove carbon as well just don't get carried away inducing it into the intake. 

[KARNUT]

19 minutes ago, Ausslo said:

Foreign (Asian European) and Domestic to many to list, I only put qualifications there in response to the GM Tech comment lol, hope nobody took that wrong, although I earned those qualifications they don't really mean anything except I have some experience. I certainly don't know everything or about every vehicle. 

When compared to other auto makers what GM and Ford are doing to mitigate the issue seems to be working better than others. As far as the D.I. on the 6.6 -time will tell, my advice is to change your oil frequently -personally 3,000 miles full synthetic Mobil 1. Call it overkill if you want but food for thought, every vehicle I have had come to me with a VVT problem (which is quite a few) has gone 5,000 or more on there oil changes using conventional to full synthetic. I have never had replace a VVT component on my personal or family's vehicles that have followed the 3,000 rule, could be luck I guess, I know what the manufacturers recommended interval is in the manual but I disagree with them on that one. Keeping the engine clean as possible goes a long way to reducing those deposits as well. Good old GM/AC Delco top engine cleaner, Carburetor tune-up,  X66 or whatever they are calling it now works well to remove carbon as well just don't get carried away inducing it into the intake. 

So for the little if any fuel mileage benefit from cylinder deactivation. You add a few more components to the engine and go back to oil change intervals from 50 years ago and back. Eliminating any, if any gains in fuel mileage. That’s just brilliant. 

[Ausslo]

1 minute ago, KARNUT said:

So for the little if any fuel mileage benefit from cylinder deactivation. You add a few more components to the engine and go back to oil change intervals from 50 years ago and back. Eliminating any, if any gains in fuel mileage. That’s just brilliant. 

Well KARNT other than the a/c condenser defect , 1 Thermostat, 1 front and 1 rear brake job I have had 0 repairs to my AFM-VVT vehicle -0 in 115,000 no lifter ticks nothing.
If that is brilliant to you, great,  I am just happy that I spent less on those oil changes than others did in repairs. What's your experience working on cars or owning an AFM-VVT engine? 
Also Exactly what components did I add to the engine? you lost me there. 

[Grumpy Bear]

2 hours ago, Ausslo said:

 

I think you miss-read that a little, It really is a simple system.

Normally asperated engine-Fixed orifice or PCV Valve (open crankcase ventilation) 

Under high vacuum conditions (idle/less throttle opening) air flows from airbox through the tube into motor and back out through PCV into the intake behind throttle plate. Under low or near zero vacuum conditions the crankcase pressure created by normal blow by (combined with lack of vacuum to the crankcase from the intake) is actually pushed to the air cleaner/box or anywhere in front of the throttle plate through said tube. This is why carbon builds on the throttle plate.

Under wide open throttle vacuum goes to zero and near about zero under heavy load, at that point crankcase pressure is slightly higher than crankcase vacuum and it doesn't take massive amounts of blow by to push vapor into the airbox side of this equation, even though there is a slight vacuum in the airbox created by the incoming air, if you disconnect the crankcase to airbox tube sometimes you can actually see the vapor come out of the tube under said conditions, yes even on a healthy motor.


Actual 35 yr Master Technician/Advanced Level Specialist chiming in, cheers

 

See that is where we disagree. If it's got enough crankcase pressure to accomplish this, then I say that the amount of blow-by isn't normal. Rings are not sealing as they should. I did concede that earlier. 

 

Sad as it is to say this, sealing, although not a difficult goal, it isn't the goal of OEM's as your experience as a 35-year Master Tech bear out. Nor are sensible vent systems designed by the OEM as the orifice systems bear out. 

 

GM Master Technicians are not doing anything but a piston/ring swap on warranty motors with up to 150K miles on them. It's in the TSB.  Does it have the Zebra stripe? No? Straight up parts swap. Don't even measure the bore for the warranty work. No hone, just wipe and swap. GM Ecotec 2.4 I-4.

 

I know this as I have TWO of these pigs. GM did zip to help. Called it 'normal'. Oh, it is for GM. Your experience is telling you the state of the business, not the state of the pressure balance. Even my Ecotec3 4.3 has a ring TSB on it. Bulletin No.: 19-NA-036. (Ever seen an oil eater with a sub 25% leak down?) 

 

I have monitored the crankcase pressures of my wife's personal self-destructive Ecotec 2.4 with proper Dwyer instrumentation, after engineering a proper baffled PCV system and plugging the always plugged manifold 1/16" orifice I can tell you the crankcase pressure never goes positive in that motor. -3" H20 is as close at it ever gets.  Never gets liquid of any kind in the metered and factory intact clean air side and never freezes in the winter. Zero carbon on the throttle blade.  Been doing this sort of thing for myself and hire for about five decades.

 

All I have for this topic. Night-night termites.  

 

 

 

 

 

 

 

 

 

 

 

 

 

[Ausslo]

8 hours ago, Grumpy Bear said:

 

See that is where we disagree. If it's got enough crankcase pressure to accomplish this, then I say that the amount of blow-by isn't normal. Rings are not sealing as they should. I did concede that earlier. 

 

Sad as it is to say this, sealing, although not a difficult goal, it isn't the goal of OEM's as your experience as a 35-year Master Tech bear out. Nor are sensible vent systems designed by the OEM as the orifice systems bear out. 

 

GM Master Technicians are not doing anything but a piston/ring swap on warranty motors with up to 150K miles on them. It's in the TSB.  Does it have the Zebra stripe? No? Straight up parts swap. Don't even measure the bore for the warranty work. No hone, just wipe and swap. GM Ecotec 2.4 I-4.

 

I know this as I have TWO of these pigs. GM did zip to help. Called it 'normal'. Oh, it is for GM. Your experience is telling you the state of the business, not the state of the pressure balance. Even my Ecotec3 4.3 has a ring TSB on it. Bulletin No.: 19-NA-036. (Ever seen an oil eater with a sub 25% leak down?) 

 

I have monitored the crankcase pressures of my wife's personal self-destructive Ecotec 2.4 with proper Dwyer instrumentation, after engineering a proper baffled PCV system and plugging the always plugged manifold 1/16" orifice I can tell you the crankcase pressure never goes positive in that motor. -3" H20 is as close at it ever gets.  Never gets liquid of any kind in the metered and factory intact clean air side and never freezes in the winter. Zero carbon on the throttle blade.  Been doing this sort of thing for myself and hire for about five decades.

 

All I have for this topic. Night-night termites.  

 

 

 

 

 

 

 

 

 

 

 

 

 

-"I have monitored the crankcase pressures of my wife's personal self-destructive Ecotec 2.4 with proper Dwyer instrumentation"-
Get a scope, Pico, Snap on or the like and do a throttle snap test while watching vac/pressure readings, much more accurate and viewable on a graph than a digital gauge.
I also disagree that you have the only engine on the planet that does not form carbon on the throttle plate with this type of PCV system. Crankcase vapors do in-fact travel from the engine crankcase to the intake via the airbox through the throttle body under certain operating conditions on a normal operating engine. 

Edited April 23, 2023 by Ausslo

[KARNUT]

8 hours ago, Ausslo said:

Well KARNT other than the a/c condenser defect , 1 Thermostat, 1 front and 1 rear brake job I have had 0 repairs to my AFM-VVT vehicle -0 in 115,000 no lifter ticks nothing.
If that is brilliant to you, great,  I am just happy that I spent less on those oil changes than others did in repairs. What's your experience working on cars or owning an AFM-VVT engine? 
Also Exactly what components did I add to the engine? you lost me there. 

It’s what GM adds to enable the cylinder deactivation process. Some people had good luck with GMs 5.7 diesel’s too. We had three all bad. I didn’t keep my experimental GM with the Frankenstein engine to find out. I did have it long enough to determine that the gas mileage wasn’t improved much with it on. When during the chip shortage GM sold some trucks that didn’t activate the cylinder deactivation. You got a 50$ rebate. Claiming the fuel mileage doesn’t differ much. As far as problem free GMs I’ve had many. I can say that with most of the different brands I’ve owned. I own four different brands currently. A Honda, Genesis, Acura, Avalanche. All but one have around 130k miles. My Avalanche close to 200K. All problem free. The Honda has cylinder deactivation. There’re track record with cylinder deactivation is almost flawless. GM not so much.