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

 

That is good info,but I've never heard of anyone loosing retainers/keepers before?

 

Sorry, thats not the problem. the loose retainer and lock then allows the spring to bonce more. This then amplfies the problem of valve float. The spring is now under "attack" by 2 harmonics. Harmonics will destroy spring pressure and eventually lead to spring breakage.

Springs have been blamed by being faulty. It is our opinion that the spring on a LS1 is undergoing extreme harmonic load.

Chris

 

If in fact this is the case,Will my REV duels be able to be upgraded to this type of lock Chris?
I've never had a problem YET but its nice to know I could add some safety by adding this lock....

The only thing that perplexes me is GM Has the Z06 motors revving to 6500 for countless HRS with the stock lock but u dont hear about keepers comming loose in these motors?

I guess spring psi,ramp speed plays a factor in this stuff?
Anyway,Let us know when they'll be avalable....

Thanks for the R&D.....

 

Thats interesting. Keep us up to date on your findings and solutions.

 

The keepers will fit any retainer designed to use a super 7 lock. As long as the retainer is designed to fit the spring, it is an easy fix.
There wont be problems in an untouch performance engine from GM.. The parts are designed to perform under those criteria. These occurances are happening on modified engines with cams, rockers, and heads turning higher rpm.
I have been in close contact with Terry at Patriot because they had expressed interest in the new locks. Terry has helped us with some of our findings and I feel that is why Patriot is switching to our super 7 lock.

Chris

 

When or under what conditions should we consider switching out our locks and retainers?

Does the condition (harmonics) occur above 6500 rpm or is it a specific valvetrain geometry or after we change to some specific lobe profile?

I would certainly appreciate a recommended benchmark for when we should start considering your locks and retainers.

Thanks for the info. Very intersting.

 

Patriot will use the new locks 100% of the time.Good bye to the stock locks.

 

will the heads your sending to me as we speak include the new locks? It seems like everytime an issue gets solved with these motors another one is created lol...thank terry

lata
Bill

 

When will these new locks start being incorporated into ur heads, and will it be at an extra cost? I'm just curious cuz i'm finally getting around to purchasing a set within the next month (broke a manley valvespring in my stock heads, so instead of buying new springs, i'm gonna buy ur LS6 style heads) and wanna know if i'll have 'em or not. I also have a friend that just bought ur LS6 style heads and might be sellin his car, so he might sell me the heads, how much would it be to send 'em back to you for the upgraded locks if I ended up getting them off of him instead of brand new?

 

There seems to be a little dancing around the question of at what rpms does the problem appear?

Also what is meant by a simple fix to make them work with our retainers.

 

Camshaft lobe profiles very quite a bit. Depending on ramp rates and flank velocities the problem can occur at different rpm levels. Was the cam ground on a CNC machine or on a traditional master style machine. Traditional lobes are designed in 1/2" increments and are very smooth profiles. CNC generated cams are generated in much higher increments, as much as .020". This makes for an eractic profile for the lifter to follow and can create harmonics at moderate rpm. Also the springs on the car, have they lost pressure due to harmonic set.. If they have the problem will show up at lower rpm.
To many variables to nail down an exact.

Chris

 

As soon as,I recieve the first order of them. Hopefully in the next few weeks.The new locks and retainers will not raise the price of the heads.All pricing will stay the same. I want to use the best quality components that are available.

 

Will these locks come with your new gold spring/retainer/seat/seal kits for stock diameter pockets that you recently told me about? How much more will the kit be?

Thanks!

 

It will be included in the kit.The kit price will be the same price $295.00.This will include Patriot GOLD dual springs,seat bases,titanium retainers and seals.

 

The keepers will fit any retainer designed to use a super 7 lock. As long as the retainer is designed to fit the spring, it is an easy fix.[/QUOTE]

Can someone explain what this means?

 

Terry, will the super 7 locks fit the retainers you have on heads already? For instance, can I just swap out my locks and solve this or does the lock have to be incorporated into the design of the retainer?

 

No,you will need a new retainer.I can work something out with you.

 

So let me ask this....

If your cam/valvetrain combo is of such, that you are experiancing the condition you describe above, would the issue of spring breakage (due to this condition only, assuming there was no 'fault' in your particular set of springs) be most likely to occur at an early mileage? If you have say 5K miles, or 15K miles, or even 30K miles on your combo and haven't had one break yet, then is it safe to say this condition is probably not occuring with your setup? Or could a result (such as spring breakage) of this condition be just as likely to manifest itself after, say 20K miles, as it would after 500 miles?

Basically, is this a type of issue that, if you have it, will either result in broken springs right away or not at all????

 

Sent you a PM.