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Old 07-28-2011, 03:01 PM   #21
bearcatt
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You do not agree with what? The rev limiter on my 01 was factory set to 6500 RPM, I've had it as high as 6700 RPM when I was autocrossing without valve float, I brought it back down because it did not gain me anything.
I believe most everyone knows that the 02-04 cam has .025" higher lift than the 01 cam, ergo the smaller base circle and longer valve stems. You should have read my comments in post NR 10 before assuming that I don't know what is required to control valve motioin.
We all read and hear alot of things...

http://www.gmhightechperformance.com...ine/index.html

The '01 base circle reduction did not require a change in dimensions of any other valve train part; however, the 405-horse cam was a different story. "I wasn't comfortable reducing base circle that much," Hicks told us, "without compensating for it somehow, because the position of the plunger within the hydraulic lifter is not optimal any more-you're too high in the lifter.

"There's different ways to correct the geometry. The one we selected to minimize the impact on our manufacturing operations was to increase the length of the valve. The valves in the '02 LS6 are 0.6mm longer than the valves in all other Gen III engines."

With .025 inch more intake lift, the same intake duration at "fifty-up" but a little less duration at lash and the same rev limit; something had to be done to the rest of the valve train to keep it in control at high rpm. While the '02 exhaust lobe doesn't have quite the aggressive profile as the intake, it's still got more lift, so something had to be done there, too. The choices GM made were to decrease valve weight and increase valve spring pressure.

2002 LS6 Engine Valves
Not only are '02 LS6 valves...


"With the higher lift, we needed to reduce the mass of the valvetrain or start getting into a float condition," John Juriga commented. "We went to hollow stem intake and exhaust valves, very similar to what we used in the '96 LT4. We pushed the edge with a state-of-the-art 0.8mm wall thickness-very thin stuff. The exhaust stems are sodium-potassium filled." The '01 intake weighed 99 grams but the '02 weighs only 76. The '01 exhaust weighed 86 grams but the '02 exhaust weighs 63 grams. The exhaust stems are filled with a 78 percent potassium/22 percent sodium mix to help cool the valve. "NaK" is unstable and may spontaneously combust when exposed to air with 50 percent or higher humidity. Do not cut open or shorten '02 Z06 exhaust valve stems.

As a result of the more aggressive cam, the valve springs were also changed. "Even with the lighter valves," Juriga said, "we still needed better control because we open and close them very fast. The closed loads are the same-400 Newtons (90 lbs.) on the seat-but the open loads increase from 1150N (259 lbs.) to 1310N (294 lbs.) for both springs."

A bigger cam, lighter valves, stiffer springs-so goes the ruthless pursuit of power. And what's this new camshaft and valve train stuff worth by itself? Jim Hicks: "You can do a direct A/B comparison and there's an easy 8-10 hp there, whether you change the back pressure or not. There are other changes in the '02 package-exhaust system and induction system-which increase the power more. The overall power increased about 20 hp and the cam was half of it. Again, that's because it's a short-duration design with low overlap so it's not really affected that much by back pressure.



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Old 07-28-2011, 03:18 PM   #22
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I decided to just go with a custom grind from AI with the PSI valve springs. It will be a baby cam for sure, as I want stock idle. Can't wait to install it.
Good choice.


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Old 07-28-2011, 03:23 PM   #23
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Good choice.


.
Thanks .

I used to be obsessed with max HP and would choose my parts accordingly.

But theres nothing wrong at all with 400 rwhp and stock idle/mpg/drivability/longevity! The beauty of having a very light car.
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Old 07-28-2011, 03:43 PM   #24
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Thanks .

I used to be obsessed with max HP and would choose my parts accordingly.

But theres nothing wrong at all with 400 rwhp and stock idle/mpg/drivability/longevity! The beauty of having a very light car.
I hear you, I've been there.

I'm very happy with my pretty much stock 2004 Z06. I like how light weight it is too.

The only thing I've done is install hardened pushrods, new LS6 yellow springs-retainer-keepers, Harlen-Sharp trunion upgrades and maintaince.

The only other thing I plan on doing possibly is a bigger radiator, oil cooler and maybe high output fans to bring the temps down a bit. I know I could program the fans to kick on at a lower temp but I don't want my fans running all the time.



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Old 07-28-2011, 04:12 PM   #25
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I hear you, I've been there.

I'm very happy with my pretty much stock 2004 Z06. I like how light weight it is too.

The only thing I've done is install hardened pushrods, new LS6 yellow springs-retainer-keepers, Harlen-Sharp trunion upgrades and maintaince.

The only other thing I plan on doing possibly is a bigger radiator, oil cooler and maybe high output fans to bring the temps down a bit. I know I could program the fans to kick on at a lower temp but I don't want my fans running all the time.



.
Yup, the c5z is a stout car already. My dad has one and its just as fast as my FRC. Those gear ratios help out a lot. We did the same thing on his car and got rid of the silver springs for the yellows as well. Good preventative step IMO.

I was in the market for a c5z before I got my FRC, but with my cam/head install experience, I opted for the much cheaper FRC since I knew I would be modding it anyway. Goal from day one was efficiency/reliability over power, so I am sticking to my guns. I was initially going to do just heads only and stay that way, but my year ls1 cam just effing sucks, so I have to swap it now to hit my power goal.

One thing I realized...you always get used to the power, no matter how much. But you NEVER get used to your car NOT leaving you on the side of the road . That feeling knowing you will get 30 mpg and can drive across the country with no issues never gets old.
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Old 07-28-2011, 05:21 PM   #26
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Originally Posted by mchicia1 View Post
Yup, the c5z is a stout car already. My dad has one and its just as fast as my FRC. Those gear ratios help out a lot. We did the same thing on his car and got rid of the silver springs for the yellows as well. Good preventative step IMO.

I was in the market for a c5z before I got my FRC, but with my cam/head install experience, I opted for the much cheaper FRC since I knew I would be modding it anyway. Goal from day one was efficiency/reliability over power, so I am sticking to my guns. I was initially going to do just heads only and stay that way, but my year ls1 cam just effing sucks, so I have to swap it now to hit my power goal.

One thing I realized...you always get used to the power, no matter how much. But you NEVER get used to your car NOT leaving you on the side of the road . That feeling knowing you will get 30 mpg and can drive across the country with no issues never gets old.

That's weird that your Dad's Z06 had silver springs, so did mine with three orange strips.

The modification path you're taking seems to be one that will give you the best of both worlds in terms of power and reliablilty.

Once in a while I like to take road trips, so reliablilty is important.
LOL, getting stuck on the roadside is not something I want to get use to.
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Old 07-28-2011, 05:38 PM   #27
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Originally Posted by bearcatt View Post
To throw a little wrench in the works... GM's latest LS6 replacement spring. They are all blue now, no more yellow.

http://forums.corvetteforum.com/c5-z...s-from-gm.html

Click the image to open in full size.


.
The spring in the picture above would be the LS6 (2001) spring only. Single spring part number is 12565117.

As stated in my Original Post, the current NEW springs are full yellow and a much better replacement spring compared to the ones it replaces.

Quote:
Full Yellow spring is the new color and part number, 12586484 It is used on:
2002 2004 LS6
All LS3
All LS9
2005 2007 LS2
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Old 07-28-2011, 06:08 PM   #28
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Originally Posted by bearcatt View Post
That's weird that your Dad's Z06 had silver springs, so did mine with three orange strips.

The modification path you're taking seems to be one that will give you the best of both worlds in terms of power and reliablilty.

Once in a while I like to take road trips, so reliablilty is important.
LOL, getting stuck on the roadside is not something I want to get use to.




Unfortunately, with my last GTO, which made 460, I got both used to the power and sitting stuck on the roadside.

This was all last summer....


1) First the oil pump went (stuck relief valve)
2) Then the clutch went
3) Then the rearend exploded at the track (ok not the cars fault)
4) Then the lifters went and put debris through the motor and took out the cam bearings and the cam.

NOT FUN. I ended up just cutting my losses and sold it to a friend as is then bought my frc. So, that car jaded me a little bit in terms of modding cars to the extreme levels. The lifters going was the worst obviously...which is one of the reasons the first thing I did on the FRC was swap to ls7's and the good ls2 trays.

That gto was perfectly fine (just slow) with boltons only. Going with big *** cams just takes it toll on the valvetrain overtime (not just your springs).
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Old 07-28-2011, 06:21 PM   #29
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To get factory-engineering answers to all the questions about the various LS1-LS6 valvetrains, just Google "The Ruthless Pursuit of Power - the Sequel" by Hib Halverson. Really informative reading about the development of the '02 LS6.
If I remember correctly, there was advice that using the '02 cam and springs with the heaver valves would lead to stress if the rev limit was not reduced to below 6300 or so.

DG
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Old 07-28-2011, 06:22 PM   #30
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Originally Posted by Eric D View Post
The spring in the picture above would be the LS6 (2001) spring only. Single spring part number is 12565117.

As stated in my Original Post, the current NEW springs are full yellow and a much better replacement spring compared to the ones it replaces.

(sigh)

12499224 is the new replacement part number.

I can promise you that they no longer make the yellow springs.
The new yellow springs are now painted blue with the newer part number.

I searched every vendor that sells GM parts on and off of the forum. Many of the pictures on various websites show yellow springs. Even vendors on this website will send you the blue springs to replace your old yellow springs.

I ended up buying a new set of yellow springs from a member on LS1tech otherwise I would have used an aftermarket spring.

If you find a brand new set of yellow springs they will be left over stock.



.

Last edited by bearcatt; 07-28-2011 at 06:30 PM.
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Old 07-28-2011, 06:29 PM   #31
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Originally Posted by mchicia1 View Post
[/B]

Unfortunately, with my last GTO, which made 460, I got both used to the power and sitting stuck on the roadside.

This was all last summer....


1) First the oil pump went (stuck relief valve)
2) Then the clutch went
3) Then the rearend exploded at the track (ok not the cars fault)
4) Then the lifters went and put debris through the motor and took out the cam bearings and the cam.


NOT FUN. I ended up just cutting my losses and sold it to a friend as is then bought my frc. So, that car jaded me a little bit in terms of modding cars to the extreme levels. The lifters going was the worst obviously...which is one of the reasons the first thing I did on the FRC was swap to ls7's and the good ls2 trays.

That gto was perfectly fine (just slow) with boltons only. Going with big *** cams just takes it toll on the valvetrain overtime (not just your springs).
Man, I'm sorry to hear about all that. What a bummer last summer.

Click the image to open in full size.





.

Last edited by bearcatt; 07-28-2011 at 06:37 PM.
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Old 07-28-2011, 06:36 PM   #32
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Originally Posted by The Wrench View Post
To get factory-engineering answers to all the questions about the various LS1-LS6 valvetrains, just Google "The Ruthless Pursuit of Power - the Sequel" by Hib Halverson. Really informative reading about the development of the '02 LS6.
If I remember correctly, there was advice that using the '02 cam and springs with the heaver valves would lead to stress if the rev limit was not reduced to below 6300 or so.

DG
Like the link I posted earlier ?
http://www.gmhightechperformance.com...ine/index.html


By the way vettenutts is a mechanical engineer by trade and he knows his stuff.

Here's an example...
http://forums.corvetteforum.com/c5-t...e-pattern.html



.
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Old 07-28-2011, 06:41 PM   #33
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Yeah that's the link - sorry for redundancy.

dG
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Old 07-28-2011, 06:52 PM   #34
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Yeah that's the link - sorry for redundancy.

dG


It's all good, it a great article.
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Old 07-28-2011, 09:38 PM   #35
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Originally Posted by The Wrench View Post
To get factory-engineering answers to all the questions about the various LS1-LS6 valvetrains, just Google "The Ruthless Pursuit of Power - the Sequel" by Hib Halverson. Really informative reading about the development of the '02 LS6.
If I remember correctly, there was advice that using the '02 cam and springs with the heaver valves would lead to stress if the rev limit was not reduced to below 6300 or so.

DG
I never run that high anyway so a set of .025 longer pushrods should allow my 01 Z06 heads, 02 Z06 cam, and yellow springs to work.
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Old 07-29-2011, 09:41 AM   #36
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Originally Posted by bearcatt View Post
(sigh)

12499224 is the new replacement part number.

I can promise you that they no longer make the yellow springs.
The new yellow springs are now painted blue with the newer part number.

I searched every vendor that sells GM parts on and off of the forum. Many of the pictures on various websites show yellow springs. Even vendors on this website will send you the blue springs to replace your old yellow springs.

I ended up buying a new set of yellow springs from a member on LS1tech otherwise I would have used an aftermarket spring.

If you find a brand new set of yellow springs they will be left over stock.
For what it's worth, I stand corrected on the color. I spoke with the engineer in charge of small block valve springs this morning. He confirmed the current replacement springs as you pointed out are blue. I was using the GM EPC which I believe needs to be updated. Later today I will have a list of most current part numbers and colors of the springs that I will post.
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Old 07-29-2011, 09:53 AM   #37
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Originally Posted by Eric D View Post
For what it's worth, I stand corrected on the color. I spoke with the engineer in charge of small block valve springs this morning. He confirmed the current replacement springs as you pointed out are blue. I was using the GM EPC which I believe needs to be updated. Later today I will have a list of most current part numbers and colors of the springs that I will post.
That will be very helpful........and find out about that balancer
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Old 07-29-2011, 11:40 AM   #38
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The 12499224 number is a 'set' of 16 springs from GM Performance Parts.

12565117 is 2001 LS6 spring - discontinued.

12586484 is the 'individual' 2002-2004 LS6 replacement spring from GM Parts. It has been replaced by number 12625033. Can't comment on the color.

Last edited by voda1; 07-29-2011 at 11:44 AM.
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Old 08-08-2011, 03:21 PM   #39
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Originally Posted by voda1 View Post
The 12499224 number is a 'set' of 16 springs from GM Performance Parts.

12565117 is 2001 LS6 spring - discontinued.

12586484 is the 'individual' 2002-2004 LS6 replacement spring from GM Parts. It has been replaced by number 12625033. Can't comment on the color.
I can comment on the color for 12625033, it is Blue.
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Old 08-08-2011, 03:21 PM
 
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