Steam vent tube alternative for an LS motor
11-18-2012, 12:21 PM
#22
All LS engines from ~2004?, have has the rear holes blocked off.
BTW, its the head, not he block.
I don't even see where the steam would come from...The water would have to evaporate to cause steam. Under pressure, it shouldn't.
11-18-2012, 05:00 PM
#23
So is there anybody out there that has blocked off thier steam ports and not had/or had trouble?? it would be soooooo much easier to not have to worry about the silly steam vent tubes and what to do with them....
does anyone have any sound info on what damage it causes other than urban legend??
does anyone have any sound info on what damage it causes other than urban legend??
11-18-2012, 08:54 PM
#25
I'm sure the engineers had something in mind in the beginning. But when the LS1 first came out in 1997 it had tubes in the back too...Those were blocked off for the LS6 and now ALL current LS engines have them blocked off now...
That tube in the front is pretty small...I'm sure its meant to be there for a reason, I'm just not too confident it's critical. That tube is too small to pass enough coolant to be the determinate of an over heating condition. The thing is...nobody is brave enough to try and find out
I wish I had a cooling system schematic to see where the water goes throughout the engine.
That tube in the front is pretty small...I'm sure its meant to be there for a reason, I'm just not too confident it's critical. That tube is too small to pass enough coolant to be the determinate of an over heating condition. The thing is...nobody is brave enough to try and find out
I wish I had a cooling system schematic to see where the water goes throughout the engine.
11-18-2012, 11:33 PM
#26
Doesn't the front coolant crossover tube "T" off and pass coolant through the Throttle Body.
Wasn't it GM's reasoning that this would help heat the air charge passing through the TB on cold winter days or something. And don't most people do the TB coolant by-pass so this never actually happens, as most of us only really drive these cars in the summer.
On my 02 block the rear steam vents were capped off (OEM) and only the front cross over was functional. When I did my heads I just replaced the gaskets and kept everything the same. So the rear steam vents are capped off with only the front crossover being functional.
Wasn't it GM's reasoning that this would help heat the air charge passing through the TB on cold winter days or something. And don't most people do the TB coolant by-pass so this never actually happens, as most of us only really drive these cars in the summer.
On my 02 block the rear steam vents were capped off (OEM) and only the front cross over was functional. When I did my heads I just replaced the gaskets and kept everything the same. So the rear steam vents are capped off with only the front crossover being functional.
Last edited by KrazyKamaro; 11-18-2012 at 11:42 PM.
11-19-2012, 12:02 AM
#27
Doesn't the front coolant crossover tube "T" off and pass coolant through the Throttle Body.
Wasn't it GM's reasoning that this would help heat the air charge passing through the TB on cold winter days or something. And don't most people do the TB coolant by-pass so this never actually happens, as most of us only really drive these cars in the summer.
On my 02 block the rear steam vents were capped off (OEM) and only the front cross over was functional. When I did my heads I just replaced the gaskets and kept everything the same. So the rear steam vents are capped off with only the front crossover being functional.
Wasn't it GM's reasoning that this would help heat the air charge passing through the TB on cold winter days or something. And don't most people do the TB coolant by-pass so this never actually happens, as most of us only really drive these cars in the summer.
On my 02 block the rear steam vents were capped off (OEM) and only the front cross over was functional. When I did my heads I just replaced the gaskets and kept everything the same. So the rear steam vents are capped off with only the front crossover being functional.
11-19-2012, 12:40 AM
#29
TECH Senior Member
Even under pressure, steam pockets can form (depending on local hot spots in the head).
The engine tilts down a little at the rear, so in concept any steam/air pockets should migrate to the front of the heads where they can exit via the front crossover tubes... in concept.
edit: corrected typo: s/can't/can/
The engine tilts down a little at the rear, so in concept any steam/air pockets should migrate to the front of the heads where they can exit via the front crossover tubes... in concept.
edit: corrected typo: s/can't/can/
Last edited by joecar; 11-19-2012 at 09:41 AM.
11-19-2012, 12:56 AM
#30
I have spent many slow moments at work considering the consequence of an air pocket in the coolant journals in my heads. I have modified an LS1 steam tube to fit under my LS6 intake for my B4C for the peace of mind, but my FAST 102 equipped stroker is what I'm most concerned about. I have plans to pull the intake some time this winter and install either a spare LS6 front line that I have lying around or the Kurt Urban tapped plugs I picked up. However, this topic being discussed again has me thinking...
Indeed, GM did start blocking off the rear ports when the LS6 intake came around. Indeed, the #7 cylinder is a problem child in LS motors and from what I've read, it's not 100% decided that it's not due to coolant issues. So, what if GM engineers decided to start blocking the rear plugs because the front tubes are the highest point for coolant in a stock suspension LS1 equipped vehicle due to the slight downward angle of the rear of the engine? What if modifying your suspension and/or wheel/tire combo shifts the high point in the block cooling to the back?
Food for thought... Joecar and BWW, y'all seem pretty knowledgeable about this subject, please feel free to chime in.
Indeed, GM did start blocking off the rear ports when the LS6 intake came around. Indeed, the #7 cylinder is a problem child in LS motors and from what I've read, it's not 100% decided that it's not due to coolant issues. So, what if GM engineers decided to start blocking the rear plugs because the front tubes are the highest point for coolant in a stock suspension LS1 equipped vehicle due to the slight downward angle of the rear of the engine? What if modifying your suspension and/or wheel/tire combo shifts the high point in the block cooling to the back?
Food for thought... Joecar and BWW, y'all seem pretty knowledgeable about this subject, please feel free to chime in.
11-19-2012, 02:17 AM
#31
It very well could if you modify the suspension etc. But here's another perspective...
GM did not build these cars with the notion that people modify their cars. The elimination of the rear ports was simply a way around the ls6 intake. It was proven that in a bone stock vehicle, it could survive the 3/36 warranty therefore it stuck.
Same with the 10 bolt. It's up to the owner to figure these things out.
After major internal engine mods are made, the cylinder temps go up exploiting the #7 cylinder hot spots, which brings the need for a 4 corner steam tube setup.
The reason for the steam tubes is simple. When the gen 1 small blocks were being produced, they had a nearly identical cooling system, but...the coolant exited from the water neck in the intake, which exited in damn near the same spot the ls1 front steam ports are located. This was the highest point in the cooling system.
The ls engines return coolant back thru the block downward of the head, which happens to be lower than the radiator, but higher than the rest of the system, making it a prime spot for air pockets to form.
GM did not build these cars with the notion that people modify their cars. The elimination of the rear ports was simply a way around the ls6 intake. It was proven that in a bone stock vehicle, it could survive the 3/36 warranty therefore it stuck.
Same with the 10 bolt. It's up to the owner to figure these things out.
After major internal engine mods are made, the cylinder temps go up exploiting the #7 cylinder hot spots, which brings the need for a 4 corner steam tube setup.
The reason for the steam tubes is simple. When the gen 1 small blocks were being produced, they had a nearly identical cooling system, but...the coolant exited from the water neck in the intake, which exited in damn near the same spot the ls1 front steam ports are located. This was the highest point in the cooling system.
The ls engines return coolant back thru the block downward of the head, which happens to be lower than the radiator, but higher than the rest of the system, making it a prime spot for air pockets to form.
11-19-2012, 03:47 PM
#32
TECH Senior Member
By using the phrase "in concept" I was implying that in practice it does not always work (i.e. steam/air pocket may get trapped at rear of heads) as bww3588 noted.
11-19-2012, 10:36 PM
#33
It very well could if you modify the suspension etc. But here's another perspective...
GM did not build these cars with the notion that people modify their cars. The elimination of the rear ports was simply a way around the ls6 intake. It was proven that in a bone stock vehicle, it could survive the 3/36 warranty therefore it stuck.
Same with the 10 bolt. It's up to the owner to figure these things out.
After major internal engine mods are made, the cylinder temps go up exploiting the #7 cylinder hot spots, which brings the need for a 4 corner steam tube setup.
The reason for the steam tubes is simple. When the gen 1 small blocks were being produced, they had a nearly identical cooling system, but...the coolant exited from the water neck in the intake, which exited in damn near the same spot the ls1 front steam ports are located. This was the highest point in the cooling system.
The ls engines return coolant back thru the block downward of the head, which happens to be lower than the radiator, but higher than the rest of the system, making it a prime spot for air pockets to form.
GM did not build these cars with the notion that people modify their cars. The elimination of the rear ports was simply a way around the ls6 intake. It was proven that in a bone stock vehicle, it could survive the 3/36 warranty therefore it stuck.
Same with the 10 bolt. It's up to the owner to figure these things out.
After major internal engine mods are made, the cylinder temps go up exploiting the #7 cylinder hot spots, which brings the need for a 4 corner steam tube setup.
The reason for the steam tubes is simple. When the gen 1 small blocks were being produced, they had a nearly identical cooling system, but...the coolant exited from the water neck in the intake, which exited in damn near the same spot the ls1 front steam ports are located. This was the highest point in the cooling system.
The ls engines return coolant back thru the block downward of the head, which happens to be lower than the radiator, but higher than the rest of the system, making it a prime spot for air pockets to form.
Why #7 and not #8??
There are way too many LS powered F-bodies out there with 100-200K miles with no issues.
Its a mystery, because its random and rare. Are you saying none of the 1998-99 4th gens suffered #7 issue? Because it did have rear vents?
My research shows me, its mainly caused by a lean condition from improper tunes and Boosted applications.
Last edited by badazz81z28; 11-19-2012 at 10:50 PM.
11-20-2012, 12:06 AM
#34
Why #7 and not #8??
There are way too many LS powered F-bodies out there with 100-200K miles with no issues.
Its a mystery, because its random and rare. Are you saying none of the 1998-99 4th gens suffered #7 issue? Because it did have rear vents?
My research shows me, its mainly caused by a lean condition from improper tunes and Boosted applications.
There are way too many LS powered F-bodies out there with 100-200K miles with no issues.
Its a mystery, because its random and rare. Are you saying none of the 1998-99 4th gens suffered #7 issue? Because it did have rear vents?
My research shows me, its mainly caused by a lean condition from improper tunes and Boosted applications.
Why 7 and not 8? I've seen problems on 8 as well. As well as 5 and 6.
The point is, engineers don't just put stuff on a vehicle if it's not needed. The revision in 01 was simply to clear the ls6 intake and it was determined to not cause problems on a stock vehicle. I'm sure steam pockets form back there on stock vehicles, but in stock form, it's not enough to blow a hole in the piston from getting too hot.
11-20-2012, 12:03 PM
#35
It's more prevelent in 01+ cars. And how many 150k+ mile cars are all modified miles? I didn't say this was as issue with stock vehicles. How many cars have 150k miles on a built engine? Not many.
Why 7 and not 8? I've seen problems on 8 as well. As well as 5 and 6.
The point is, engineers don't just put stuff on a vehicle if it's not needed. The revision in 01 was simply to clear the ls6 intake and it was determined to not cause problems on a stock vehicle. I'm sure steam pockets form back there on stock vehicles, but in stock form, it's not enough to blow a hole in the piston from getting too hot.
Why 7 and not 8? I've seen problems on 8 as well. As well as 5 and 6.
The point is, engineers don't just put stuff on a vehicle if it's not needed. The revision in 01 was simply to clear the ls6 intake and it was determined to not cause problems on a stock vehicle. I'm sure steam pockets form back there on stock vehicles, but in stock form, it's not enough to blow a hole in the piston from getting too hot.
I do know that there a lot of LS engines out there making killer power with the rear ports blocked off w/no known issues.
It just doesn't make sense to me....either its an issue or its not. I would think if it was a big concern, someone would have made an aftermarket tube or some sort of solution to the problem by now here 11+ years later. Yet, even the 600+ hp ZL1, ZR1, and Z06 still continue to have the rear ports blocked off.
11-20-2012, 02:25 PM
#36
Didn't the #7 failures usually occur with motors under a lot of boost?
Nevermind, the question's been answered.
Damn.
I'm not real certain myself if there's any benefits in connecting the front and rear steam ports, but I'm going to connect them anyway while I have my own motor apart just for peace of mind.
Nevermind, the question's been answered.
Damn.
I'm not real certain myself if there's any benefits in connecting the front and rear steam ports, but I'm going to connect them anyway while I have my own motor apart just for peace of mind.
11-20-2012, 04:22 PM
#38
TECH Senior Member
Well, if its more prevalent in 01+ cars, are saying the 98-00 cars have suffered? That tells me IF it is the steam issue, than even the tubes don't help. Its random, possibly another issue...I guess the back banks of the engine are covered in the F-body bay.
I do know that there a lot of LS engines out there making killer power with the rear ports blocked off w/no known issues.
It just doesn't make sense to me....either its an issue or its not. I would think if it was a big concern, someone would have made an aftermarket tube or some sort of solution to the problem by now here 11+ years later. Yet, even the 600+ hp ZL1, ZR1, and Z06 still continue to have the rear ports blocked off.
I do know that there a lot of LS engines out there making killer power with the rear ports blocked off w/no known issues.
It just doesn't make sense to me....either its an issue or its not. I would think if it was a big concern, someone would have made an aftermarket tube or some sort of solution to the problem by now here 11+ years later. Yet, even the 600+ hp ZL1, ZR1, and Z06 still continue to have the rear ports blocked off.
the problem is not when your engine makes killer power... the problem arises when operating in the boundary conditions... and this is compounded by various things like PE fueling being not sufficiently rich and cooling system being in other than good condition
(you will not know about these conditions unless you constantly monitor lambda/egt sensors and view thermal spectrographs).
[ do you ever remember seeing the external steam hose mods on SBC/BBC...? ]
As you can see from other posts above there are aftermarket solutions.
11-20-2012, 04:23 PM
#39
TECH Senior Member
$0.02
11-20-2012, 04:27 PM
#40
So... if a motor was BONE STOCK as in no parts swaps, straight out of the donor vehicle, i'm assuming it would be ok to run the block off on all 4 corners??