http://www.ls1tech.com/forums/showthread.php?t=129712

Well after about 50 PM's in the last few days I will explain what we SUSPECT is a critcal problem under the LS1 valve cover of a modified engine.

Just a little back ground, I have supplied countess retainers, locks, and other cylinder head items to companies for years. My focus has always been valvetrain. I was approached by a current customer to produce parts for an LS1 project, keepers and retainers. So this project has been going on for around 3 months.

In the process of revising some tooling, one of our engineers noticed the stock lock in the LS1 is very loose in both aftermarket and OEM valves. Measuring this we found the lock can move in the valve radius as much as .075". Now by design with the valve and keeper being a male/female connection it does provide more clamping area, but with this much movement the locks mail radius bead will tend to "follow" the radius right out of the valves groove. This much movement we felt would alow the retainer and lock to loose clamping force at higher rpm or if a spring had harmonic set due to rpm and valve float, the lock retainer could be loose at moderate RPM and allow movement.

So a simple test was suggested of a timing light on the valve springs of a car. A customer performed this and he was frightened at what he saw. The lock seem to be jumping around under the rocker.

With this being the case, if a spring broke their is a good chance of dropping a valve and we all know what happens after that.

We had always based our new lock on the Super 7 design that the Cup guys have used for years due to its characteristic clamping force. This lock would give our customer re-assurance of a proven valve lock.

I have shipped 100's of thousands of 10 degree locks to companies for 5.0 HO engines. These valvetrain on the HO motors have steel locks, 1.450" inch steel retainers, dual springs, and lifters that are several grams heavier then the LS1, and heavier valves. The result is that these engines see similar hard lives and higher rpms and have minmal to non existant spring issues, but the valve lock is the old square tang and it does not have excessive movement.

We are currently doing some testing but due to the high traffic of mail I have recieved, I felt I would post our findings. I don't feel GM has made a bad part, it is just a part that when and engine is modified to go beyond the intended power range, it is a part not designed to do that and needs to be replaced with an aftermarket part.

We are about 2 weeks from shipping product to our cylinder head customers then the locks and retainers will be available to Stef's/B&B Wholesale Customers present and future. Individuals if you wish to PM me and ask for a dealer near you I will do so.

This is not to say run out and spend some more money, but in the future if you are going to mod your car you need to consider going to a better keeper and retainer system if extra HP is in you plan.

Chris Straub
Stef's Performance
423 854 0007

 

Good info, thanks :cheers:

 

Boy that will scare the crap out of you--thanks J

 

J- Rod - are these the locks for the New AFR Heads???
Thanks for the Link!

 

Insightful info J-Rod, thanks for the warning. :cheers:

 

Great info, thanks! Just in time also, I just ordered a heads/cam package from Patriot, and will wait for delivery so that I receive the new design retainers...thanks again.

 

Thanks for posting the info on this. It will certainly be useful to forum members.

 

So it looks like Patriot will be using the new locks? I just looked on their website and the Stage 2 heads state they use Patriot locks. Are these the locks you speak of, or are the Patriot locks something else. I'm very interested becauseI am shortly going to go h/c and was considering Patriot's. Now with this new info Patriot's are looking sweeter. :cheers:

 

New locks are from Steff's. Patriot has committed to using them.