Originally Posted by Katech_Jason (Post 1582784966)

Good news. I have received budget approval to run a valvetrain dynamics test for development purposes to prove out a few of the questions posed here on the forum. Before I write the test plan, I'm interested in hearing input from you guys to see if there are additional combinations that need testing. I'm not saying that every combination posted here will get tested, or any additional at all, but your suggestions will be considered.

We would like to run this test as soon as possible. The valvetrain test cell is currently down due to computer problems, but repairs are in progress that should get it back up and running within days. Because it was down there is a bit of a backup of programs that are waiting for testing so we will have to wait in line, but once it gets fixed that should go through smoothly. In other words, I can't guarantee exactly when, but it will get done soon.

Here is how I see the test plan:
1. Stock cam/springs, stock valves
2. Stock cam/springs, solid stainless exhaust valve
3. Stock cam/dual springs, solid stainless exhaust valve
4. Torquer cam/PSI springs, stock valves (already tested long ago, but we will baseline again)
5. Torquer cam/PSI springs, solid stainless exhaust valves
6. Torquer cam/dual springs, solid stainless exhaust valves
7. Torquer cam/PSI springs, Ti exhaust valve

The Torquer cam will be an example of your typical aftermarket cam lobe profile.

If there is any vendor out there who wishes to have their combination tested we would be happy to include it in the mix for just the cost of running the additional combinations.


Input is encouraged.

Originally Posted by jwmgr8 (Post 1583013809)

In the world of Engineering it would seem to me that you need to define the why, what and how of the tests. Your list looks like the what and I'm sure you'll define the how when you run the tests, but what is the why?
I know a lot of people would like to see the comparison of several setups but what is driving you to run the tests? plus before the tests are run what might the results tell us? is it possible to define poor, good and best?

Originally Posted by Katech_Jason (Post 1582922398)

It's not the parts cost (we only need one intake and one exhaust) it's time. The question is, which combination (see original post) would this be A-B tested on?

Originally Posted by Katech_Jason, in the OP (Post 1582784966)

[...] Here is how I see the test plan:
1. Stock cam/springs, stock valves
2. Stock cam/springs, solid stainless exhaust valve
3. Stock cam/dual springs, solid stainless exhaust valve
4. Torquer cam/PSI springs, stock valves (already tested long ago, but we will baseline again)
5. Torquer cam/PSI springs, solid stainless exhaust valves
6. Torquer cam/dual springs, solid stainless exhaust valves
7. Torquer cam/PSI springs, Ti exhaust valve

The Torquer cam will be an example of your typical aftermarket cam lobe profile. If there is any vendor out there who wishes to have their combination tested we would be happy to include it in the mix for just the cost of running the additional combinations. Input is encouraged.

Originally Posted by Mark200X (Post 1583058237)

Bumping this since several expressed interested (vertC6, myself, Mookster, Bad Ax, spinkick, RFE-57, atljar, and Michael D). To directly answer Jason's question (at least from my perspective):



1. Stock cam/springs, stock valves
1a. Above w/Yella Terra 1.8
2. Stock cam/springs, solid stainless exhaust valve
--- Since the above is expected to fail, no additional test.
3. Stock cam/dual springs, solid stainless exhaust valve
3a. Above w/Yella Terra 1.8
4. Torquer cam/PSI springs, stock valves (already tested long ago, but we will baseline again)
4a. Above w/Yella Terra 1.8 (assuming stock springs will not carry the weight in 1a above).
5. Torquer cam/PSI springs, solid stainless exhaust valves
--- Since the above is expected to fail, no additional test.
6. Torquer cam/dual springs, solid stainless exhaust valves.
6a. Above w/Yella Terra 1.8
7. Torquer cam/PSI springs, Ti exhaust valve
--- Test only if all YT combinations above w/OEM valve fail.

Depending on how things shake out, that looks like about 4 additional tests.

My main concern, while acknowledging that the aluminum rocker may not be the best choice in the long run (but it is the most cost-efficient in the short run), are scattered industry reports that a roller tipped rocker will reduce -- or at least equalize -- side load on the valve guide compared to the OEM style rocker, and do have a slight range of adjustment to center the wipe pattern on the valve stem tip (an unsolvable problem we are seeing with some OEM rockers). Given the problems the OEM LS7 heads have with valve guides, and given that we don't know exactly what is causing those problems, any help at all -- such as a reduction in side load or a centering of the wipe -- seems to be a worthwhile pursuit.
.

Originally Posted by Katech_Jason (Post 1583028974)

The why is explained in post #24: http://forums.corvetteforum.com/1582785923-post24.html

To understand what we are looking for, a good place to start is this article: http://www.gmhightechperformance.com...e/viewall.html

Originally Posted by Katech_Jason (Post 1583028974)

The why is explained in post #24: http://forums.corvetteforum.com/1582785923-post24.html

To understand what we are looking for, a good place to start is this article: http://www.gmhightechperformance.com...e/viewall.html

Originally Posted by Bad_AX (Post 1583079684)

[...] A good article comparing NASCAR Cup engines to F1. The Good Ol Boys are smarter than you might think. Includes some commentary on valve train components.
http://www.epi-eng.com/piston_engine..._cup_to_f1.htm

A very good article on valve spring technology, the Spintron, and the high costs of R&D.
http://www.popularmechanics.com/cars...nascar-6643778

Originally Posted by Bad_AX (Post 1583079684)

The only thing that could make this test better would be some video to post on Youtube at the conclusion. There is some very interesting stuff out there, but none specific to our LS7 engines.

T
A good article comparing NASCAR Cup engines to F1. The Good Ol Boys are smarter than you might think. Includes some commentary on valve train components.
http://www.epi-eng.com/piston_engine..._cup_to_f1.htm

A very good article on valve spring technology, the Spintron, and the high costs of R&D.
http://www.popularmechanics.com/cars...nascar-6643778

Originally Posted by jwmgr8 (Post 1583078372)

Obviously you should be thanked for your efforts and all the BS you sort through to help all of us better understand our engines.
I'm still curious do you test to failure? or are there specific numbers you'll record that helps define "safe"?
I'm just glad we have some one like you sorting through the fog of data. I'm sure you've seen 1000's of LS7's over the years and you have a much better understanding of the dynamics of this engine than 99.9% of the people on the forum
good luck

Originally Posted by mistermog (Post 1583091677)

any eta?

Originally Posted by hoefi (Post 1583094527)

Just like the guide wear report. No ETA either. :lol:

Originally Posted by Katech_Jason (Post 1583094653)

I posted about the guide wear report. Once GM made the announcement it kind of made it irrelevant. The report was just a collection of measurements that's been duplicated numerous times on this forum.