Converting to LS6 PCV worth it?
That's almost exactly how I did mine. A bit more attention on your part, but it worked under the BBK intake. The FAST won't clear, so FYI, if you go FAST, you'll have to get the LS6 crossover
I saw on ls1howto jmx uses the stock external pcv valve on the line from the valley cover to the intake manifold. Is this necessary? I though the internal pcv valve eliminated the need for the external one?
Thread Starter
TECH Resident
Joined: Feb 2007
Posts: 831
Likes: 0
From: Boston, MA
I installed mine with just the new PCV valley and the $3 GM PCV hose
I see on the 01-03 LS6 valley cover they use an exterior PCV valve. then on the 04 they modified the system and only utilized the valley cover without the exterior PCV valve.
TECH Addict
Joined: Jul 2013
Posts: 2,189
Likes: 123
From: Portland, Oregon
You couldn't pay me to plug the rear steam vents. Fast intake, or not, I would do whatever it takes to retain the four corner venting system.
You can use hard brake line and go around the intake, versus under it. There are plenty of options, and all of them are better than plugging the back steam vents.
You can use hard brake line and go around the intake, versus under it. There are plenty of options, and all of them are better than plugging the back steam vents.
You couldn't pay me to plug the rear steam vents. Fast intake, or not, I would do whatever it takes to retain the four corner venting system.
You can use hard brake line and go around the intake, versus under it. There are plenty of options, and all of them are better than plugging the back steam vents.
You can use hard brake line and go around the intake, versus under it. There are plenty of options, and all of them are better than plugging the back steam vents.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
01-up ls1 motors and every ls engine since then hasnt had rear steam vents and they all run just fine
TECH Addict
Joined: Jul 2013
Posts: 2,189
Likes: 123
From: Portland, Oregon
And GM hasn't boosted any other LSx motors besides the lsa and ls9, but it doesn't stop everyone from wanting to boost their LSx.
The decision to drop the rear steam vents was purely motivated by saving money. Simple risk analysis said the likelihood of engine failure was less than the cost of continuing to use that part... So that part is no longer used, and it's pennies in the pocket for the general. Nevermind that cylinders 7 & 8 are always the first to go bad. There's no way that's connected, right?
The decision to drop the rear steam vents was purely motivated by saving money. Simple risk analysis said the likelihood of engine failure was less than the cost of continuing to use that part... So that part is no longer used, and it's pennies in the pocket for the general. Nevermind that cylinders 7 & 8 are always the first to go bad. There's no way that's connected, right?
And GM hasn't boosted any other LSx motors besides the lsa and ls9, but it doesn't stop everyone from wanting to boost their LSx.
The decision to drop the rear steam vents was purely motivated by saving money. Simple risk analysis said the likelihood of engine failure was less than the cost of continuing to use that part... So that part is no longer used, and it's pennies in the pocket for the general. Nevermind that cylinders 7 & 8 are always the first to go bad. There's no way that's connected, right?
The decision to drop the rear steam vents was purely motivated by saving money. Simple risk analysis said the likelihood of engine failure was less than the cost of continuing to use that part... So that part is no longer used, and it's pennies in the pocket for the general. Nevermind that cylinders 7 & 8 are always the first to go bad. There's no way that's connected, right?
Coolant block off plates are equal to going from NA to FI?
Cost for the coolant cross over tubes vs warranty claims on blown engines due to design failure is why they run block off plates on every LS except the LS1?
Joined: May 2004
Posts: 1,593
Likes: 267
From: Halfway back on the Highway to Hell...again!
There is no need for a cross over in the back. At first GM thought is was needed. It's not. Later Gen IIIs used a block off piece then Gen IV now just have a plug in the head. Since I see many GM cars/trucks roll in every day for years now, have I seen where this "update" has caused a problem. Besides, if you purge the system correctly and not get in a rush, you will never have an issue.
EDIT: and where 7 & 8 go bad, never heard of that. We do many re-ring jobs on 5.3s all the time and many, many AFM lifter jobs. I have never seen where it was only 7 & 8 needing rings.
EDIT: and where 7 & 8 go bad, never heard of that. We do many re-ring jobs on 5.3s all the time and many, many AFM lifter jobs. I have never seen where it was only 7 & 8 needing rings.
Last edited by SAPPER; Nov 12, 2015 at 12:56 PM.
TECH Addict
Joined: Jul 2013
Posts: 2,189
Likes: 123
From: Portland, Oregon
The four corner steam vent system is a nice and easy insurance for when you aren't in a rush at all, and you thought you did everything correctly to purge the system, but you still missed that last little air bubble. I have noticed that on most of the big builds, where people go the extra mile to do everything right, that they drill and tap the rears to add four corner venting. You think someone with a solid roller cam and Frankenstein heads doesn't know how to properly purge the system? Then why would they add it when GM decided it's not necessary? GM doesn't think the port work is necessary that everyone else does, otherwise we wouldn't have to port the factory castings. GM doesn't think that a lot of good stuff is necessary for the LSx, like solid roller cams or turbos.
The fact is, it's really, REALLY easy to set up. So unless you just have NO room for it, I don't see any legitimate reason to eliminate it. It's just like a catch can or a driveshaft loop. Better to have it and not need it, than to need it and not have it.
As for the 7 & 8 cylinders being the first to go... It's just a startlingly consistent trend I have noticed in threads pertaining to bent rods, broken pistons, or catastrophic detonation. And I'm not the only one to notice this, because I have literally seen someone else make the exact same observation that 7 & 8 are the first to go. And I have seen it blamed on the LACK OF four corner venting, as well as the design of the intake making the air fuel ratio different from the front cylinders to the rear cylinders. Either way, I'm not making this stuff up.
The fact is, it's really, REALLY easy to set up. So unless you just have NO room for it, I don't see any legitimate reason to eliminate it. It's just like a catch can or a driveshaft loop. Better to have it and not need it, than to need it and not have it.
As for the 7 & 8 cylinders being the first to go... It's just a startlingly consistent trend I have noticed in threads pertaining to bent rods, broken pistons, or catastrophic detonation. And I'm not the only one to notice this, because I have literally seen someone else make the exact same observation that 7 & 8 are the first to go. And I have seen it blamed on the LACK OF four corner venting, as well as the design of the intake making the air fuel ratio different from the front cylinders to the rear cylinders. Either way, I'm not making this stuff up.
99.9% of the time number 7-8 goes from a bad tune, running lean or something along those lines. If you notice too that's a problem a lot with ls1's. Newer ls motors dont seem to suffer from that condition. BUT even if they did can anyone prove thats what its from? That tiny amount of circulation going on back there isnt going to make a dramatic cooling effect on a 1k degree's combustion chamber. 7-8 blowing up existed on early and later ls1's so the tubes made little to no difference.
You're comparing things like turbo's, head porting, etc to coolant block offs, seriously? One key point you missed there is that all of those things increase hp which increases engine strain. Which means they'd have to build the motor stronger in order to offer warranty. If the coolant blockoffs really served a significant purpose to keep the motor safe would you think they'd want to do that? Ya know, to make the motor run longer so they dont need to fix it when it breaks...
You're comparing things like turbo's, head porting, etc to coolant block offs, seriously? One key point you missed there is that all of those things increase hp which increases engine strain. Which means they'd have to build the motor stronger in order to offer warranty. If the coolant blockoffs really served a significant purpose to keep the motor safe would you think they'd want to do that? Ya know, to make the motor run longer so they dont need to fix it when it breaks...
TECH Addict
Joined: Jul 2013
Posts: 2,189
Likes: 123
From: Portland, Oregon
I also compared it to a catch can. And catch cans are one of those things you add to increase service life, you know, so you don't have to fix it as often? And GM doesn't think that a catch can is at all necessary, either, but lots of smart people install catch cans even though GM didn't.
What, you think adding a little extra crankcase ventilation is going to make any difference? Well, umm, it does. And maybe, just maybe, adding a little extra steam venting does, too.
What, you think adding a little extra crankcase ventilation is going to make any difference? Well, umm, it does. And maybe, just maybe, adding a little extra steam venting does, too.
I also compared it to a catch can. And catch cans are one of those things you add to increase service life, you know, so you don't have to fix it as often? And GM doesn't think that a catch can is at all necessary, either, but lots of smart people install catch cans even though GM didn't.
What, you think adding a little extra crankcase ventilation is going to make any difference? Well, umm, it does. And maybe, just maybe, adding a little extra steam venting does, too.
What, you think adding a little extra crankcase ventilation is going to make any difference? Well, umm, it does. And maybe, just maybe, adding a little extra steam venting does, too.
People dont even like new diesels that need urea added in every once in a while, they sure as hell wouldnt want to empty oil from a can either. That's not hard to understand
A catch can doesnt add any ventilation smh...Stop please lol. Gm doesnt add a catch can because how would any car company like to tell their customers, "you have to empty this can every oil change because the engine sucks oil through the pcv"
People dont even like new diesels that need urea added in every once in a while, they sure as hell wouldnt want to empty oil from a can either. That's not hard to understand
People dont even like new diesels that need urea added in every once in a while, they sure as hell wouldnt want to empty oil from a can either. That's not hard to understand
TECH Addict
Joined: Jul 2013
Posts: 2,189
Likes: 123
From: Portland, Oregon
If I'm the horse, then what water have I been led to? GM doesn't use the rear steam vents anymore... No ****. That does nothing to say why or why not anyone else should use them. Catch cans, turbos, and steam vents all have their merits, and GM probably has seven different reasons for not using each of them. The tiny amount of additional "maintenance" involved in emptying a catch can during an oil change cannot be a legitimate reason to not use it, right? You were, indeed, joking about that, correct? And you can make a catch can just as closed loop as the original pcv system, so the EPA wouldn't give a ****. They do care if you modify your pcv system after the fact, but if GM installed it from the factory, then it would be perfectly fine.
TECH Senior Member
Joined: Jan 2004
Posts: 5,798
Likes: 16
From: St.Charles MO
The back two cylinder issues some of these engines have is due to intake design making them run lean, combine that with oil ingestion coating the top of the pistons and its a bad recipe.
The argument then is if adding the steam vents will prevent the back cylinders from running hotter, making a significant difference at all. Id like to see real test numbers either way.
Catch cans, turbos, and steam vents all have their merits, and GM probably has seven different reasons for not using each of them. The tiny amount of additional "maintenance" involved in emptying a catch can during an oil change cannot be a legitimate reason to not use it, right? You were, indeed, joking about that, correct? And you can make a catch can just as closed loop as the original pcv system, so the EPA wouldn't give a ****. They do care if you modify your pcv system after the fact, but if GM installed it from the factory, then it would be perfectly fine.
And you do NOT want to run a "closed loop" system (if you are talking about putting what the can catches back into the engine) with a catch can seeing that the can is catching water condensation too, you do NOT want that back into the crankcase.
On The Tree
Joined: Jun 2015
Posts: 182
Likes: 3
From: Portland OR
Aren't the front vents the only ones needed due to the angle of the motor placing the front ones higher?
An LS is not like the old SBC that needed water circulation at the rear of the head.
The steam line is there just to purge air bubbles that will collect at the highest point. It seems that the only time a rear port would collect any air would be if the car was pointing downhill!
An LS is not like the old SBC that needed water circulation at the rear of the head.
The steam line is there just to purge air bubbles that will collect at the highest point. It seems that the only time a rear port would collect any air would be if the car was pointing downhill!