ls6 intake, coolant tubes or not??
Tech Contributor
Joined: Dec 1999
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I have an 02 Zo6 so I dont have the tube that runs from the rear to the front however, I up-graded to some ported heads and installed a front ZO6 tube in the rear where the two block off plugs are located.
You can either use your set up and trim the bottom (not a big deal) or use Two Late modle cross over tubes. Just apply some white paint on the tube and where it transfers, trim the ribs flat approx 1/4" on either side of the mark.
BC
You can either use your set up and trim the bottom (not a big deal) or use Two Late modle cross over tubes. Just apply some white paint on the tube and where it transfers, trim the ribs flat approx 1/4" on either side of the mark.
BC
Banned Scam/Spammer
Joined: May 2007
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From: Machineguns, because I don’t compromise
If you'll be selling the LS6 intake someday, it will be much better if there are no hacks in it.
I'd get the cheap '01+ tubes/blocks and forget about it.
I'd get the cheap '01+ tubes/blocks and forget about it.
Pro
Joined: Dec 2003
Posts: 654
Likes: 1
From: chandler az
I've heard some of the racers using the old style cross over tubes and saying it helped eliminate some detonation problems in #7 and #8. I'm glad I kept my old cross over tubes. One of these days I'll get around to reinstalling it and breaking out the fins on the LS6 manifold.
Burning Brakes
Joined: Apr 2009
Posts: 946
Likes: 2
I've heard some of the racers using the old style cross over tubes and saying it helped eliminate some detonation problems in #7 and #8. I'm glad I kept my old cross over tubes. One of these days I'll get around to reinstalling it and breaking out the fins on the LS6 manifold.
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Burning Brakes
Joined: Apr 2009
Posts: 946
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Here's the stuff I remembered from Kurt on Tech. I believe he made a similar post on performancetrucks.net, but I can't find it today. It's not quite the same as I remembered
This is from post 24 in this thread on another site.
Kurt does go on to say that they run the tubes on anything high powered, but that a street car may never boil the coolant anyway.
Although that thread definitely puts the "intake manifold is the cause of #7 failures to rest"
Originally Posted by Kurt Urban
We ran the tubes in the Motorola cup cars because if we put the back plug types in the #7 cylinder would have problems. It seemed to me with the testing we did that air pockets formed in the back of the head from the coolant boiling causing the engine to detonate on the back cylinders. Normally #7 would eat the piston or break the rod and #8 would show signs of trouble. These are just guesses on my part based on what the parts looked like broken!
One thing I did in the late 90's was put thermocouples on the 4 corners of the heads with the water still flowing. Then we put 10 02 sensors in, one in each port and one in the collector of each bank. I then parked the engine at 6500rpm/full load for 15 minutes at a time with the intake on normal and reversed to record coolant temp and afr. Nothing showed up that clued us in on why the 7 cylinder was fragile. The engine was a stock stroke forged piston Motorola cup legal LS.
Around 2000 or 2001 Unocal started sponsorship of the Nascar stuff and the Motorola cup could no longer use 94 Sunoco as the fuel on Union tracks, this forced them into 100 octane and the number 7 problems went away so we stopped looking for why....
Kurt
One thing I did in the late 90's was put thermocouples on the 4 corners of the heads with the water still flowing. Then we put 10 02 sensors in, one in each port and one in the collector of each bank. I then parked the engine at 6500rpm/full load for 15 minutes at a time with the intake on normal and reversed to record coolant temp and afr. Nothing showed up that clued us in on why the 7 cylinder was fragile. The engine was a stock stroke forged piston Motorola cup legal LS.
Around 2000 or 2001 Unocal started sponsorship of the Nascar stuff and the Motorola cup could no longer use 94 Sunoco as the fuel on Union tracks, this forced them into 100 octane and the number 7 problems went away so we stopped looking for why....
Kurt
Kurt does go on to say that they run the tubes on anything high powered, but that a street car may never boil the coolant anyway.
Although that thread definitely puts the "intake manifold is the cause of #7 failures to rest"
Tech Contributor
Joined: Jan 2007
Posts: 19,476
Likes: 1,171
From: Dyer, IN
Here's the stuff I remembered from Kurt on Tech. I believe he made a similar post on performancetrucks.net, but I can't find it today. It's not quite the same as I remembered
This is from post 24 in this thread on another site.
Kurt does go on to say that they run the tubes on anything high powered, but that a street car may never boil the coolant anyway.
Although that thread definitely puts the "intake manifold is the cause of #7 failures to rest"
This is from post 24 in this thread on another site.
Kurt does go on to say that they run the tubes on anything high powered, but that a street car may never boil the coolant anyway.
Although that thread definitely puts the "intake manifold is the cause of #7 failures to rest"
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
I decided to run the crossover tube and plum it into the front because I herd mixed opinions on if it helped or not. It if doesnt, I only wasted a few buck. If it does,,,I saved a few thousand!
BC
BC
Burning Brakes
Joined: Apr 2009
Posts: 946
Likes: 2
The above makes sense to me, and is the exact reason why I run a crossover (front and rear the same) with my 2001+ intake. What I was confused by was your statement "I've heard that the reason GM abandoned the rear tube was to eliminate problems with #7". It seems to me that for a high performance application, blocking the rear coolant bleeds caused a problem, not eliminated one.
Burning Brakes
Joined: Aug 2007
Posts: 756
Likes: 1
From: Oakton Virginia
I'm sure the conversation went something like- [GM engineer] "Hey, with this re-designed manifold we don't have clearance to run the steam tube. Hmm... ah, screw it- just block off the rears."
Or is that too cynical?
Melting Slicks
Joined: Nov 2008
Posts: 2,938
Likes: 65
From: Rochester Hills MI
i cut the fins on mine, and i even bought it brand new. i would have actually preferred to have bought it with the fins cut already. it is a little bit of work cutting those out without a dremel. Im sure anyone that will be replacing an ls1 manifold would prefer to pay less for the job by not needing to purchase new coolant tubes, and save the work of having to cut the fins. so i would not be so concerned about resale value.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Man,,,,,,,,,,,,,
,,,,,,,,,,,,You have it all WRONG. It was really like this:GM engineering Detroit:
George,,, we can save 50 cents per car if we eliminate this damn rear cross over tube and install these plugs. My brother Tom can make the plugs for 2 cents.
What do you think?? Bob,,,Go for it! No one will EVER know and we will save MILLIONS!
BC
