LS3 Crate Motor PCV - The 1947 - Present Chevrolet & GMC Truck Message Board Network

MIKESAD50 · 07-26-2017, 10:28 AM

I'm trying to find a factory routing for the LS3 crate motor. has the plastic pipe from valley cover to Intake manifold. Came with a plug on the fitting on rear of left side valve cover and a fitting that was open on the front of the right valve cover.

My thinking from reading is that all is need to hook up hose from fitting on the right valve cover to the air intake pipe after the AMM. Is this correct?
Would just a filter to filter the fresh air into the motor be ok and not effect the fuel system as in cause fuel trim issues?

I find a million different routing diagrams by googling.

Thanks for any information and diagrams

**mongocanfly** · 07-26-2017, 10:54 AM

may not be much help but here's how my factory ls3 is run...Im not using the factory air tube so I'm in the same boat as you..I don't see why a filter wouldn't work

MIKESAD50 · 07-26-2017, 12:12 PM

mongocanfly,
Thanks for the information. I haven't found a fitting that will not look terrible connecting to the air intake pipe.
Is the rear fitting n left side just plugged on your engine?
And I'm assuming that unlike Euro cars a crankcase vacuum leak will not cause fuel trim
issues?

**mongocanfly** · 07-26-2017, 12:44 PM

there's no provision on drivers side cover for a pcv..as you know the v-covers are different what with the fill tube and whatnot..

**mongocanfly** · 07-26-2017, 12:46 PM

I was just thinking ...what if you welded a bung onto the intake tube and used a small stainless braid line to connect it?

BR3W CITY · 07-26-2017, 03:43 PM

This is a topic that gets confusing depending on exactly what config you start with. IIRC
Drivers side and valley cover are "dirty", Passenger side front is clean.

IMO
Valley and DS cover tie to the manifold (or inlet of catch can, which i always support), outlet to manifold
PS front port straight to the TB.

MIKESAD50 · 07-26-2017, 06:02 PM

this is the valve cover fitting on the left rear, came with cap on it.

Appreciate all the help and advise.

BR3W CITY · 07-26-2017, 06:29 PM

Unless that image is flipped, your showing the right valvecover. Engine left and right are from the front. It might be easier just to use DS and PS to note location.

MIKESAD50 · 07-26-2017, 07:11 PM

I think this is why I'm confused alittle. that is left valve cover at back and this picture is on the right front cover right by oil filler

sprint_9 · 07-26-2017, 07:26 PM

Port by oil filler to your air intake after MAF, before throttle body

Port on valley to intake as it is already plumbed.

I would leave the cap on the rear port as you have shown in the pictures and forget about it.

BR3W CITY · 07-26-2017, 07:26 PM

... but thats gotta be the LEFT valvecover....no LS motor has a drivers side oil filler.

MIKESAD50 · 07-26-2017, 08:19 PM

Oil filler is on the right cover. Last picture is of the valve cover vent fitting near the filler. First pics are of left cover with fitting in rear, no oil filler on that side. The left rear fitting came with cap on it as shown in picture straight from GMPP.
Sprint, that was what I figured I was doing, just trying to verify it's correct.
Also wanted to make sure it wasn't going to effect fuel trims if mot hooked up, or hooked up incorrectly.
Do you see a reason why you couldn't just add a small filter there? Seems to me it has to be post AMM otherwise it would be lean all the time.

Im just over thinking it based on Euro cars I deal with Daily

**mongocanfly** · 07-26-2017, 09:45 PM

ok...now I see what your talking bout..my left side valve cover has that same cap on that same hose barb..there was nothing hooked to it in the camaro...I was looking for the same style pcv tube that is on the right side valve cover on the left one...
i agree ..I'd just leave it capped off...that's what I'm gonna do on mine..

sprint_9 · 07-27-2017, 10:14 AM

Quote:

Originally Posted by BR3W CITY

... but thats gotta be the LEFT valvecover....no LS motor has a drivers side oil filler.

Looking from the front of the motor it is, but in relation to the vehicle I guess it is the right/passenger side. Too many ways to describe it from ones own perspective.

Quote:

Originally Posted by MIKESAD50

Sprint, that was what I figured I was doing, just trying to verify it's correct.
Also wanted to make sure it wasn't going to effect fuel trims if mot hooked up, or hooked up incorrectly.
Do you see a reason why you couldn't just add a small filter there? Seems to me it has to be post AMM otherwise it would be lean all the time.

It is my understanding that you want this air source to be metered by the mass air flow sensor. If it isnt the engine could act like it has a vacuum leak. With that I wouldnt run just a small filter on it as it wouldnt be metered.

knomadd · 07-27-2017, 12:54 PM

Quote:

Originally Posted by BR3W CITY

Unless that image is flipped, your showing the right valvecover. Engine left and right are from the front. It might be easier just to use DS and PS to note location.

Quote:

Originally Posted by BR3W CITY

... but thats gotta be the LEFT valvecover....no LS motor has a drivers side oil filler.

Typical "right vs left" representation is noted as sitting in the drivers seat, facing the front of the vehicle, not looking from front to back, so he is correct in his statements of right (PS) and left (DS).

Quote:

Originally Posted by sprint_9

Looking from the front of the motor it is, but in relation to the vehicle I guess it is the right/passenger side. Too many ways to describe it from ones own perspective.

THIS^^^

Also, I'll mention that my DS valve cover is not plugged, but rather it goes to the top of the intake on my Van/Truck 6.0 to something that looks like a PCV valve that's set inside the intake. I don't have a valley cover port though. The PS valve cover was intended to plug into the intake tube, after the MAF, before the throttle body.

sprint_9 · 07-27-2017, 09:19 PM

Quote:

Originally Posted by knomadd

Also, I'll mention that my DS valve cover is not plugged, but rather it goes to the top of the intake on my Van/Truck 6.0 to something that looks like a PCV valve that's set inside the intake. I don't have a valley cover port though. The PS valve cover was intended to plug into the intake tube, after the MAF, before the throttle body.

Truck engines vent out the valve cover. It is a fixed orifice in the valve cover, the port on the intake is just a pipe nipple, there is no PCV valve.

knomadd · 07-28-2017, 10:46 AM

Quote:

Originally Posted by sprint_9

Truck engines vent out the valve cover. It is a fixed orifice in the valve cover, the port on the intake is just a pipe nipple, there is no PCV valve.

Good to know. Can the valve cover port be vented through a filter, or does it need to go to the intake?

sprint_9 · 07-28-2017, 11:54 AM

I would leave it connected to the intake as you want a vacuum on that end.

The pcv system works in principal by pulling clean air in from the fresh air side and exhausting moisture and combustion by products out of the dirty side into the intake to be burned off. Crank case pressure is not enough alone so it uses engine vacuum to help in this process.

07-26-2017, 10:28 AM	#1
MIKESAD50 Registered User Join Date: Feb 2014 Location: Sunnyvale, CA Posts: 605	LS3 Crate Motor PCV I'm trying to find a factory routing for the LS3 crate motor. has the plastic pipe from valley cover to Intake manifold. Came with a plug on the fitting on rear of left side valve cover and a fitting that was open on the front of the right valve cover. My thinking from reading is that all is need to hook up hose from fitting on the right valve cover to the air intake pipe after the AMM. Is this correct? Would just a filter to filter the fresh air into the motor be ok and not effect the fuel system as in cause fuel trim issues? I find a million different routing diagrams by googling. Thanks for any information and diagrams __________________ 1950 3100 5 window

07-26-2017, 10:54 AM	#2
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,670	Re: LS3 Crate Motor PCV may not be much help but here's how my factory ls3 is run...Im not using the factory air tube so I'm in the same boat as you..I don't see why a filter wouldn't work Attached Images

07-26-2017, 12:12 PM	#3
MIKESAD50 Registered User Join Date: Feb 2014 Location: Sunnyvale, CA Posts: 605	Re: LS3 Crate Motor PCV mongocanfly, Thanks for the information. I haven't found a fitting that will not look terrible connecting to the air intake pipe. Is the rear fitting n left side just plugged on your engine? And I'm assuming that unlike Euro cars a crankcase vacuum leak will not cause fuel trim issues? __________________ 1950 3100 5 window

07-26-2017, 12:44 PM	#4
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,670	Re: LS3 Crate Motor PCV there's no provision on drivers side cover for a pcv..as you know the v-covers are different what with the fill tube and whatnot..

07-26-2017, 12:46 PM	#5
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,670	Re: LS3 Crate Motor PCV I was just thinking ...what if you welded a bung onto the intake tube and used a small stainless braid line to connect it?

07-26-2017, 03:43 PM	#6
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: LS3 Crate Motor PCV This is a topic that gets confusing depending on exactly what config you start with. IIRC Drivers side and valley cover are "dirty", Passenger side front is clean. IMO Valley and DS cover tie to the manifold (or inlet of catch can, which i always support), outlet to manifold PS front port straight to the TB. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

07-26-2017, 06:02 PM	#7
MIKESAD50 Registered User Join Date: Feb 2014 Location: Sunnyvale, CA Posts: 605	Re: LS3 Crate Motor PCV this is the valve cover fitting on the left rear, came with cap on it. Appreciate all the help and advise. Attached Images __________________ 1950 3100 5 window

07-26-2017, 06:29 PM	#8
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: LS3 Crate Motor PCV Unless that image is flipped, your showing the right valvecover. Engine left and right are from the front. It might be easier just to use DS and PS to note location. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

07-26-2017, 07:11 PM	#9
MIKESAD50 Registered User Join Date: Feb 2014 Location: Sunnyvale, CA Posts: 605	Re: LS3 Crate Motor PCV I think this is why I'm confused alittle. that is left valve cover at back and this picture is on the right front cover right by oil filler Attached Images __________________ 1950 3100 5 window

07-26-2017, 07:26 PM	#10
sprint_9 Registered User Join Date: Nov 2012 Location: 9 Posts: 862	Re: LS3 Crate Motor PCV Port by oil filler to your air intake after MAF, before throttle body Port on valley to intake as it is already plumbed. I would leave the cap on the rear port as you have shown in the pictures and forget about it.

07-26-2017, 07:26 PM	#11
BR3W CITY meowMEOWmeowMEOW Join Date: Sep 2009 Location: MKE WI Posts: 7,128	Re: LS3 Crate Motor PCV ... but thats gotta be the LEFT valvecover....no LS motor has a drivers side oil filler. __________________ *'66 Short Step / SD Tuned / Big Cam LQ4 / Backhalfed /Built 4l80e / #REBUILDEVERYTHING* MY BUILD THE H8RDCPTR //\\ MY YOUTUBE CHANNEL REV J HD

07-26-2017, 08:19 PM	#12
MIKESAD50 Registered User Join Date: Feb 2014 Location: Sunnyvale, CA Posts: 605	Re: LS3 Crate Motor PCV Oil filler is on the right cover. Last picture is of the valve cover vent fitting near the filler. First pics are of left cover with fitting in rear, no oil filler on that side. The left rear fitting came with cap on it as shown in picture straight from GMPP. Sprint, that was what I figured I was doing, just trying to verify it's correct. Also wanted to make sure it wasn't going to effect fuel trims if mot hooked up, or hooked up incorrectly. Do you see a reason why you couldn't just add a small filter there? Seems to me it has to be post AMM otherwise it would be lean all the time. Im just over thinking it based on Euro cars I deal with Daily __________________ 1950 3100 5 window

07-26-2017, 09:45 PM	#13
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,670	Re: LS3 Crate Motor PCV ok...now I see what your talking bout..my left side valve cover has that same cap on that same hose barb..there was nothing hooked to it in the camaro...I was looking for the same style pcv tube that is on the right side valve cover on the left one... i agree ..I'd just leave it capped off...that's what I'm gonna do on mine.. Attached Images Last edited by mongocanfly; 07-26-2017 at 09:56 PM.

07-28-2017, 11:54 AM	#18
sprint_9 Registered User Join Date: Nov 2012 Location: 9 Posts: 862	Re: LS3 Crate Motor PCV I would leave it connected to the intake as you want a vacuum on that end. The pcv system works in principal by pulling clean air in from the fresh air side and exhausting moisture and combustion by products out of the dirty side into the intake to be burned off. Crank case pressure is not enough alone so it uses engine vacuum to help in this process.



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.