2017 Tahoe/ICT Valley Cover has no PCV port, how do I run the PCV now?

[snives]

I'm nearly done with my AFM/DOD delete on a 2017 Tahoe. I've elected to replace the VLOM with the ICT Billet valley cover (essentially a VLOM delete), and the optional oil pressure mount. I noticed the PCV line from the VLOM is absent on the ICT Billet valley cover. So where do I connect the PCV line from the intake manifold to now? How do I establish the correct crank case ventilation now?

Has anyone done this before? Please chime in.

Thanks

 

[Geotrash]

I'm nearly done with my AFM/DOD delete on a 2017 Tahoe. I've elected to replace the VLOM with the ICT Billet valley cover (essentially a VLOM delete), and the optional oil pressure mount. I noticed the PCV line from the VLOM is absent on the ICT Billet valley cover. So where do I connect the PCV line from the intake manifold to now? How do I establish the correct crank case ventilation now?

Has anyone done this before? Please chime in.

Thanks

Do you mean valve cover? There is no PCV port on the valley cover. Only an oil pressure sensor port.

 

[91RS]

There is a PCV port on the VLOM.

I would call and ask because I can’t imagine deleting the PCV system is good but I can’t see any way to keep it based on the picture of the plate on their web site.

 

[wjburken]

I'm nearly done with my AFM/DOD delete on a 2017 Tahoe. I've elected to replace the VLOM with the ICT Billet valley cover (essentially a VLOM delete), and the optional oil pressure mount. I noticed the PCV line from the VLOM is absent on the ICT Billet valley cover. So where do I connect the PCV line from the intake manifold to now? How do I establish the correct crank case ventilation now?

Has anyone done this before? Please chime in.

Thanks

You posted this in the 2007-2014 section. Let’s see if we can get this moved to the right section for your 2017.

@Miami-Dade @soulsea @Fless @07Burb, can one of you help?

 

[Miami-Dade]

I'm nearly done with my AFM/DOD delete on a 2017 Tahoe. I've elected to replace the VLOM with the ICT Billet valley cover (essentially a VLOM delete), and the optional oil pressure mount. I noticed the PCV line from the VLOM is absent on the ICT Billet valley cover. So where do I connect the PCV line from the intake manifold to now? How do I establish the correct crank case ventilation now?

Has anyone done this before? Please chime in.

Thanks

Moved you here.

Welcome from Miami!

 

[snives]

There is a PCV port on the VLOM.

I would call and ask because I can’t imagine deleting the PCV system is good but I can’t see any way to keep it based on the picture of the plate on their web site.

I emailed ICT Billet and had a few exchanges with their tech support. He said "We recommend two things, you can either splice it into another port or you can block it off it is not a required."

Can anyone understand what that means?

I interpret that as saying, you can route the intake manifold side of the PCV line to another port on the engine. Although I don't know where that would be as I don't have any other ports, other than ones on the valve covers. But those are the clean side of the PCV system which are supposed to draw IN fresh/metered air into the crankcase. So if I use one valve cover port for in, and the other for out that could work, although I am unsure of the health of that rocker area with moist dirty oil getting sucked into it all the time. I.e. would that cause a buildup of sludge in that rocker cover as the air/oil aerosol condenses on the cool rocker covers?

The alternative they suggest is that you don't need a PCV system, which sounds highly dubious.

Anyone been in this boat before? thanks

 

[wjburken]

I emailed ICT Billet and had a few exchanges with their tech support. He said "We recommend two things, you can either splice it into another port or you can block it off it is not a required."

Can anyone understand what that means?

I interpret that as saying, you can route the intake manifold side of the PCV line to another port on the engine. Although I don't know where that would be as I don't have any other ports, other than ones on the valve covers. But those are the clean side of the PCV system which are supposed to draw IN fresh/metered air into the crankcase. So if I use one valve cover port for in, and the other for out that could work, although I am unsure of the health of that rocker area with moist dirty oil getting sucked into it all the time. I.e. would that cause a buildup of sludge in that rocker cover as the air/oil aerosol condenses on the cool rocker covers?

The alternative they suggest is that you don't need a PCV system, which sounds highly dubious.

Anyone been in this boat before? thanks

I don't know about the newer generation motors, but on every other motor I have worked on, the PCV is to draw air/vapors/gases out of the crankcase by means of vacuum generated in the intake manifold, not put air into the crank case. This is typically done by means of a PCV valve/port on the valve cover connected to the intake manifold. That being said, I am not seeing how having a PCV on the VLOM does anything anyways, but again, I am not familiar with the 2017 generation of units.

 

[snives]

I don't know about the newer generation motors, but on every other motor I have worked on, the PCV is to draw air/vapors/gases out of the crankcase by means of vacuum generated in the intake manifold, not put air into the crank case. This is typically done by means of a PCV valve/port on the valve cover connected to the intake manifold. That being said, I am not seeing how having a PCV on the VLOM does anything anyways, but again, I am not familiar with the 2017 generation of units.

My understanding is that on the Gen V LT motors there is fresh metered air from the air box connected to the valve/rocker covers. This is atmospheric pressure at idle. The heads have a passageway into the crank case where oil returns down to the pan, thus it's connected to the crank case. The PCV is located on the valley cover, which houses a check valve, to ensure the flow of air is always outwards (from crank case out). This PCV is connected to the intake manifold, which is under vacuum at idle. This means the flow of air at idle ultimately draws fresh metered air from the airbox, through both rocker covers, into the crank case, and past the PCV check valve and into the intake manifold. The reason why this does not affect the idle is because that air was already metered from the MAF, it's accounted for.

At WOT the airbox and intake manifold are roughly the same pressure (atmospheric) and blow by gasses are free to flow out of all three ports, which is how oil sometimes gets into the stock air box, but when you return to idle the oily residue in the air box and lines then gets drawn back down into the rocker covers and back into the pan because the PCV in the valley cover is drawing air using manifold vacuum. Please feel free to correct me if I am missing something.

So I am beginning to lean more towards reversing the flow of the drivers side rocker cover and use that as a PVC, though I will probably need to restrict that hose down to the size of the stock PCV line.

 

[donjetman]

If you say so, but I'm not buying it.
Every pvc system I know of uses intake vacuum to pull gasses "from" the crankcase only.
Metered leak(s) "into" the crankcase? What would be the point of that?

 

[snives]

To dry the oil because it's a flex fuel vehicle. And the ECM uses torque tables which are very sensitive to unmetered air.

 

[wjburken]

 

[Just Fishing]

C6 vette has a PCV that fits down in the valley.
can't have AFM with that though.

I don't know if later vettes have the same config or not, but it sounds like you might have vette valve covers.

 

[Just Fishing]

Stock system also has an intake side, pulls fresh filtered air from the airbox.
then from the other side it's connected to the intake, that's on the other side of the valve cover.

The vette setup has the crankcase suction from the valley cover, I'm not sure where they pull the fresh air from.
Does the ICT have an pcv connection on one of the valve covers?

Also, I only know this because I have a Vette PCV that I'm planning to run once I'm in the mood to tear into the tahoe again.

 

[donjetman]

I just had the intake, valve covers, etc off my 2002 C5 vette last week to install a catch can and to clean things up. There isn't a air line from the airbox going to the valve covers, intake, pvc system.

 

[snives]

What I am going with for now is to run an inline PCV from the drivers valve/rocker cover to the stock intake manifold port. I threw a catch can in the mix for good measure but its essentially that. The passenger valve/rocker cover will continue to source clean air from the airbox, as it was intended from GM. So the system should function like stock, except the direction of flow of the drivers side rocker cover will be an OUT instead of an IN. Other GM engines have used this arrangement in the past so, in theory it may be just fine.

Some consideration was given to the orientation of the PCV valve as older designs which used an inline PCV in the horizontal alignment tend to get gummed up and don't "self clean", so I selected a vertical arrangement with a 90 end on it for this reason. I used a random hose clamp for now to hold the PCV while I order a suitable spring clamp. All the GM vacuum hose fittings were repurposed from their original parts. I think it came out okay.

 

[Geotrash]

There is a PCV port on the VLOM.

Ah. It was originally posted in the 2007-2014 section and on that generation we have no PCV on the VLOM.

 

[steve45]

I don't know much about this system, but I would ask why you can't simply drill and tap a hole in the intake manifold and put your PCV valve there?

I can't imagine running an engine without a PCV system, even lawnmower engines have them. The purpose of the valve is to prevent a backfire from getting into the crankcase, which could blow out the crankshaft seals and the dipstick.