Quick LS6 PCV Conversion Question
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Teching In
Joined: Mar 2013
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From: Maryland
Quick LS6 PCV Conversion Question What's up guys. I am currently upgrading the PCV / Valley Cover on my 1999 LS1 to the LS6 system.
On a few installation threads the LS1 PCV valve was re-used and put inline on the new intake to Valley cover hose. Like below:
On other setups, people have been purchasing the LS6 intake to valley hose and leaving the stock, LS1 PCV valve out. Like below:
I've read the below regarding 03 vs 04 LS6 Valley covers:
My valley cover is stamped with 12577927 (which would mean it is a 04). Does this mean the PCV valve is included in the valley cover and I do not need the LS1 PCV valve?
Thank you for the help. I will also be running a catch can system, but I need to figure the PCV stuff out regardless.
On a few installation threads the LS1 PCV valve was re-used and put inline on the new intake to Valley cover hose. Like below:
On other setups, people have been purchasing the LS6 intake to valley hose and leaving the stock, LS1 PCV valve out. Like below:
I've read the below regarding 03 vs 04 LS6 Valley covers:
12577927 This is the part number for the 2004 ls6 valley cover
12594779 This is the part number for the valve-less hose for the 2004 valley cover
12568011 This is the part number for the cap to plug the hole in the back of the driver side valve cover
12568002 Pre 03 LS6 Valley Cover
12594779 This is the part number for the valve-less hose for the 2004 valley cover
12568011 This is the part number for the cap to plug the hole in the back of the driver side valve cover
12568002 Pre 03 LS6 Valley Cover
Thank you for the help. I will also be running a catch can system, but I need to figure the PCV stuff out regardless.
Last edited by duballstar; Jun 7, 2014 at 11:18 PM.
Thread Starter
Teching In
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From: Maryland
So after further research I think I answered my own question, but would love confirmation from someone.
Conclusion:
If you are running the pre 03' LS6 Valley cover (GM 12568002) it does NOT include a valve in line and you are required to re-use the LS1 valve inline on the intake hose.
If you are running a +04' Valley Cover (GM 12577927) w/ valve included, you need a straight through hose (GM 12594779).
Both systems required blocking off rear breather ports, drivers side rear with (GM 12568011) and passenger rear with universal nipple plug.
Make sense?
Conclusion:
If you are running the pre 03' LS6 Valley cover (GM 12568002) it does NOT include a valve in line and you are required to re-use the LS1 valve inline on the intake hose.
If you are running a +04' Valley Cover (GM 12577927) w/ valve included, you need a straight through hose (GM 12594779).
Both systems required blocking off rear breather ports, drivers side rear with (GM 12568011) and passenger rear with universal nipple plug.
Make sense?
Thread Starter
Teching In
Joined: Mar 2013
Posts: 8
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From: Maryland
Thread Starter
Teching In
Joined: Mar 2013
Posts: 8
Likes: 0
From: Maryland
1. Bend the LS1 coolant lines to fit around the dimples on the LS6 cover. (modify intake too)
2. Run LS6 steam ports and block off rear and connect front to radiator.
3. Run LS6 steam ports and a T-fitting to connect the rear to the front, then all to the radiator.
4. Block off all four ports.
How much benefit would I gain from incorporating the rear steam ports into the system VS. blocking them off and only connecting the front steam ports to the rad? Is it worth all the extra hoses to achieve a "balanced" system?
Thread Starter
Teching In
Joined: Mar 2013
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From: Maryland
I just found this:
I would love to run the rear blocked off for a simpler, cleaner looking setup, but don't want to harm the engine. I don't have a swirl pot or "open" radiator cap, but would I still be safe with just an aluminum radiator and blocked off rear ports? Any input?
Long story short ~ Pratt & Miller (http://prattmiller.com/) and Dr. Jamie Meyer (head of GM Performance) both say that the rear two should stay blocked off.
I used to advocate having fittings that went to -4an on all 4 steam vents feeding into a coolant swirl pot, which then drained back into the lower hose or return heater line... this is a setup that was used successfully by a few race teams, but it looks like this was a band-aid once I got 'real' information from REAL race teams.
The issue is not flow - the coolant passages flow plenty - it's pressure. When driven hard, engines need coolant pressure to "scrape" the steam bubbles that form on hot spots in the head off the wall of the passage. With all 4 ports open, there's not enough pressure locally (in the head) to promote proper heat transfer unless you run your overall coolant pressure extremely high (30psi or so). Indy and F1 cars run MUCH higher than that, due to higher hp/liter (heat concentration).
The proper setup all my LSx racers are using is, assuming the top of your radiator is below the steam vent port:
*The rear vents blocked off, the front tee'd (LS6-style).
*Radiator cap replaced with "open" cap (free flow through radiator overflow port)
*Steam vent tee and radiator "overflow"/free flow feeding into coolant swirl pot (aka expansion tank)
*Swirl pot has pressurized radiator cap, bottom drains to non-thermostat-controlled water pump return
I used to advocate having fittings that went to -4an on all 4 steam vents feeding into a coolant swirl pot, which then drained back into the lower hose or return heater line... this is a setup that was used successfully by a few race teams, but it looks like this was a band-aid once I got 'real' information from REAL race teams.
The issue is not flow - the coolant passages flow plenty - it's pressure. When driven hard, engines need coolant pressure to "scrape" the steam bubbles that form on hot spots in the head off the wall of the passage. With all 4 ports open, there's not enough pressure locally (in the head) to promote proper heat transfer unless you run your overall coolant pressure extremely high (30psi or so). Indy and F1 cars run MUCH higher than that, due to higher hp/liter (heat concentration).
The proper setup all my LSx racers are using is, assuming the top of your radiator is below the steam vent port:
*The rear vents blocked off, the front tee'd (LS6-style).
*Radiator cap replaced with "open" cap (free flow through radiator overflow port)
*Steam vent tee and radiator "overflow"/free flow feeding into coolant swirl pot (aka expansion tank)
*Swirl pot has pressurized radiator cap, bottom drains to non-thermostat-controlled water pump return
I would love to run the rear blocked off for a simpler, cleaner looking setup, but don't want to harm the engine. I don't have a swirl pot or "open" radiator cap, but would I still be safe with just an aluminum radiator and blocked off rear ports? Any input?
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Teching In
Joined: Mar 2013
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From: Maryland
Thanks again for all your help. Have a good night brother.
Steam Tubes Hey pal check these threads out if you havent already. If it were me I would run the rear myself ( which is what I did ).
https://ls1tech.com/forums/generatio...ast-102-a.html
https://ls1tech.com/forums/generatio...ant-tubes.html
https://ls1tech.com/forums/generatio...ast-102-a.html
https://ls1tech.com/forums/generatio...ant-tubes.html
Thread Starter
Teching In
Joined: Mar 2013
Posts: 8
Likes: 0
From: Maryland
Hey pal check these threads out if you havent already. If it were me I would run the rear myself ( which is what I did ).
https://ls1tech.com/forums/generatio...ast-102-a.html
https://ls1tech.com/forums/generatio...ant-tubes.html
https://ls1tech.com/forums/generatio...ast-102-a.html
https://ls1tech.com/forums/generatio...ant-tubes.html
Front LS6 Tube, GM Part # 12602544
Rear Cadillac Tube, GM Part #12605716
I will probably run the connecting rubber line with the Y-fitting along the side of the intake manifold (along the injectors). I really hate to add more "piping" to the engine bay, but for the extra few bucks I will sleep better at night.
It seems like the rear steam port discussion is a never ending debate on the various forums. The way I see it, the LS1 came stock with all four connected to the radiator, so why not keep it that way… it can't hurt anything.
Additional question…. Does anyone know of a GM part that incorporates a passenger side outlet for the front steam vents?
Last edited by duballstar; Jun 8, 2014 at 05:20 PM.
Sorry to thread jack here but do you know if you have to do this with the iron block engines too? I have a 5.3 that is getting an LS6 intake and I was going to upgrade the PCV to the LS6 style while I was at it but cutting the iron would be harder than aluminum and is making me worried to do it.
I am not sure on the LQ blocks.. I know for the aluminum it took me about 5 minutes with a fresh cut off disc in my dremel..
may just have to stock up on a few discs and have at it if the embossement is there.
may just have to stock up on a few discs and have at it if the embossement is there.
Getting back to the orginal PCV question...I've got a crate '04 LS6 in my '98 Z28. I STILL got oil in my intake from the LS6 PCV set-up, so I installed an oil catch can when I recently switched over to my FAST 92mm... I would recommend a catch can even with the LS6 PCV set-up.
