when converting over to an LS6 intake, most people do the block off plugs in the rear oand there are some use an LS6 front tube in the rear. What are the advantages or disadvantages to each? Thanks

 

Either should be fine. The back ports on mine were blocked off when I bought the car. Also had them blocked off on my procharged SSS as well. Never had a problem that way.

 

Using a 4 point system should do the best job getting rid of any possible air pockets that could form in the heads. I ended up using one from a truck on the rear ports that will tie into the front ls6 crossover. I got this cheap from a junk yard. If you do a search some attribute the rear block off to running hot on cylinder #7. A truck rear crossover is cheap for some piece of mind. I couldn't justify spending $250 on the nitrous outlet system even though it looks sweet.

 

I was also curious about the efficiency of using 2 of the LS6 tubes as far as coolant flow. I also have a 12605716 pipe from GM to use in the rear and run a line down the drivers side to a "T" in the front.

 

Someone must have already tried this,, but you know how it is when you get to thinking.. What if you added a fitting to the radiator tank right by the upper hose, and ran the 4 ports to it? Wouldn't that make the thing self bleed any steam or air to as near the cap as possible?
You could probably run like a small reducer pill in the return line to keep it from flowing too much water.

I just wonder because on most sprint engines, you run 4 AN10 or AN12 return lines 2 for each head instead of the valley fitting where a stock thermostat would usually go..

 

I vented all 4 corners on my heads last time I had the engine out of the car. Some agree with venting all 4, some think it's not needed... To each their own. Here is what did and some other guys set up...

https://ls1tech.com/forums/generatio...ant-tubes.html

https://ls1tech.com/forums/generatio...e-routing.html

 

use the LS1 steam pipe and just clip the checkerboard off of the bottom of the LS6 intake. Have NEVER heard of any problems with doing that. Plus its free. Plus you get a true 4 corner steam system. Plus its free.

 

I was thinking about that, but, I am doing the PCV upgrade which includes the LS6 valley cover, unfortunately the LS1 steam pipes wont fit. LS1 on the left, LS6 on the right

 

Why won't the ls1 steam pipes fit? Of course they will

 

I was also thinking about since I have a pipe bender, maybe try to bend the LS1 tubes in a way that they will fit under the intake, I believe why they wont fit is the "bumps" in the LS6 valley cover(see my previous post), comes from where GM attached the new PCV underneath the valley cover. Also notice at the front of LS6 valley cover, the pipe attached.

 

they won't fit because of the shape of the bottom of the ls6 intake. you break off the checkerboard on the bottom and everything fits. People have been doing this for over 10 years.

 

yes, I was thinking about removing the checkerboard underneath where the pipes would run.

 

I decided to run 4 steam vent ports. Another member on here gave me the idea when his buddy's boosted car kept overheating. He was able to fix the issue permanently by venting all 4 steam vents to an overflow tank I installed on the head. I made my own kit but this looks real similar to what I bought.

steam vent kit

Here's a couple pics of my setup just to get an idea







There's also a Kurt Urban steam vent kit if you don't want to have to add a tank.

http://kurturbanperformance.net/home...r-vent-system/

 

The system needs to be properly burped several times to eliminate ALL air pockets in the engine. If the system is not 100% air free when you put the cap on, the highest point in the motor, or highest point in the cooling system, becomes the weakest link.

The air bubble just allows the coolant to splash into it, and it doesn't actually move the hot coolant out of the line

Just to verify it wasn't a "steam tube" and that my system was 100% bled I went and got some clear spa hose to run to the cross over pipe

If.you haven't used a cap adapter or a really long funnel to burp the system I guarantee your car is using the cross over as a "steam pipe". That top point in the cross over becomes the spot where all of the hottest coolant rises up to, and just collects heat from the heads. If you have air in those lines you overheat from the air bubble down. Back into the engine. I assure you the radiator cools the engine better than a metal tube, and that it is a coolant cross tube and absolutely not a steam pipe

It was difficult to bleed the system, but it is more important to be air free than to have 50 cross overs.

That is the exact reason gm deleted the rear cross overs. In the end the extra tubing just made no difference in coolant temperatures and added additional points where air could collect

 

Do you have a procedure for properly burping the system?

 

I'll do a write up in a few days for everything including the reinforced clear tubing you get from the home improvement store. It's typically called spa hose for use on a hot tub. I need to get the reinforced clear hoses from home depot to get rid of the blue hose on the adapter.

The spa hose is commonly used in the turbo import community for breather and catch can setups, I've seen full radiator hoses done in them as well though I think that's a little drastic






Basically
Raise the vehicle so that the engine is angled up. This forces air to naturally come out of the highest point at the front cross over pipe.

With the cap off use a large funnel, or radiator cap adapter, and fill the funnel to a high level so that it is clearly the highest point in the cooling system.





Turn the heater on and start the car. The engine needs to get to operating temperature and the thermostat needs to open. Once the thermostat opens you will get a burp of air out of the radiator cap into your funnel, and the level of the coolant will fall once that air bubble is burped out of the cap.

After the large burp of coolant you will still want to squeeze the upper and lower hoses, and let the fans cycle on and off 3 times to indicate the thermostat has opened and closed 3 times to remove the coolant

With the clear hose I was immediately able to tell when the system was completely removed of air. I had to finesse that cross over hose to move the air bubbles to the radiator to come out of the cap.

Once the largest bubbles and pockets were gone I saw a steady stream of very small bubbles for about 3-4 minutes going from the cross over hose into the radiator. After that 3-4 minutes the hose was filled with solid coolant.

Properly burped the system uses the cross over as an outlet for hose coolant to go into the radiator.

Air in the line and it's a steam tube that collects the hottest coolant from the engine.

Example of air bubbles causing a "steam pipe"





On a stock fbody with the hose connected to the throttle body the throttle body itself should get really freaking hot if the car has been properly burped. The brass fitting on the size adapter on the clear hose was scalding hot to the touch

I've never been burned by a stock fbody throttle body, so I would bet from the factory these cars came with a huge air bubble at the throttle body, because there's no way you could purge air out of the throttle body being higher than the radiator cap. So stock the fbody used the throttle body as the steam pipe. Not very effecient

So my first statement wasn't correct, it's a steam pipe. I'm guessing the emissions guys at gm said the tb needs to be heated and the routing was turned up to the throttle body and it became an afterthought after engine design during production .

 

I have stock ls1 tubes and still have the fins on my ls6 intake. If you slightly flatten the tubes(not much, I tested with water off the car and they still flow through) they'll clear with ease. Didn't have to snap fins and I'm sure it'll clear damn near any intake manifold I could put on there.

 

98 and some 99 models were the only cars that received the full back to front coolant cross overs

I don't remember if they would clear a fast intake, though the fast intake bottom was completely flat and should allow it to fit.

Nifty little mod is to put some hear resistant or blocking tape on the underside of the stock ls1 plastic intake. Can slightly lower air intake temps

 

I like the idea of four corner cooling on these engines and all mine will always have it.

I was able to easily fit the original four corner LS1 coolant manifold on my engine with the LS6 PCV mod and a LS6 intake manifold. Of course, the ribs needed a good shaving. A sharp wood chisel did the job nicely.

I don't believe these plastic intake manifolds have any issues with heat soak affecting the intake charge.

 

Using a variety of easily available hose fittings, a four corner setup can even look nice. The rears have ninety degree fittings, the fronts are tees and the two sides come together in a Y-block.