604 Valve Springs **Exciting News**

[brad hibbard]

NEW Valve Spring Design for 604 Engines

We all asked and they listened

Its no secret that the valve spring quality in the 604 engines has been less than desirable and without a doubt very inconsistent.

That’s about to change as the new design spring has been installed on the newest engines leaving GM and conversion kits for all other 604 engines will be available soon.

This announcement is to inform the racer of the exciting news but also to make all tech officials aware that some engines have already left the warehouse and could possibly show up in competition this weekend.

Any questions regarding a tech situation can be sent to Brad Hibbard by phone or text 330-540-7223 or e mail at brad@race-1.com

Race-1; Sweeney Chevrolet and Pace Performance do not currently have any of the new inventory but expect delivery from GM as early as next week.


Brad Hibbard
www.race-1.com

below is a statement sent to us from GM officials


ladies and Gentlemen:

I have spoken to many of you in the recent past regarding some upgrades we were testing for the #88958604 ( aka CT400 or 8604, or 604) in response to field tech input and racer input regarding the valve train components we have used for the past 10 years. In short, we have experienced valve spring pressure variations, both high and low, that were not meeting customer expectations. We have permanently corrected that issue. We are switching to a "beehive" style spring, currently used by all of our production LS-style performance engines, specifically the LS3 used in the Corvette and Camaro SS models, incorporating stringent quality controls, along with enhanced durability and stability for extended high RPM operation. The details of the cylinder head changes and the resulting new engine part number are explained in the attached memos. (see below)

It has been a real challenge to manage and execute these changes, attempting a transparent transition as we move from one valve spring design to another. We attempted to synchronize the installation of the new head content while balancing existing engine inventory going into the peak of the season. We came pretty close, as the first batch of the new engine (#19318604) was shipped Monday, May 20. The new engine is readily identified externally by the Chevrolet Bowtie emblem engraved on the end of the cylinder head, where GM Performance Parts formerly was. Engines with this head have the"blue beehive" valve springs and components already installed.

This component change was made for valve train stability, durability and consistency, not for an increase in horsepower. Dyno tests have validated our contention that there is no horsepower gain, but there is an improvement in valvetrain stability. Operating and maintenance costs should actually be reduced, as spring life should improve in most cases.


For those racers that want to upgrade their existing heads to incorporate the new beehive valve springs, we have developed a conversion kit, which contains all of the components required to convert an existing engine. The component breakdown is in the attached memo. This is a no-modification, bolt-on conversion. Existing components will continue to be serviced for those that choose to stay with the original valve train.

Since "new" engines will be in the field later this week, they could show up in competition this weekend. We apologize if that seems to be short notice (it is), but again, we were trying to balance inventories, not creating a wildfire demand. It is important to emphasize what the upgrade is designed for, and not that there is a big increase in power. The cylinder head is exactly the same, only the spring components have changed.

From the inception of the sealed racing engine program, we have attempted to maintain a level playing field, building affordable Chevy racing engines on a low-volume production line. We hope you find that this change will continue to insure that level playing field for years to come.

We appreciate your support and partnership in providing affordable racing engines. Chevy Performance intends to continue on this path as long as the sport exists!

Important Note: This message is being sent in advance of a formal product bulletin announcing these changes to our dealers. A formal product bulletin will be distributed next week. We did not want to risk the possibility of a "new 8604" running this weekend and getting DQ for "illegal components". Please make sure that your tech organization is informed and aware of these changes before your next scheduled event.

Good Racing!

[swingarm4life]

Brad, are they already legal in Fastrak and Nesmith, How much will the conversion kit cost, When and where will we be able to purchase them?
Thanks

[brad hibbard]

with the release of the new engines it has to be legal in all sanctions if they are going to use the 604 engine
FASTRAK has accepted this and talking with Tim Simms at NeSmith he has just been waiting on the release from GM

let me perfectly clear about the conversion process>>>>>>
as with all the other parts within the engine these are specific parts for the conversion
it includes a different locating shim, keeper and retainer as well as the spring all parts must be installed and maintain specification for installed height and pressure

the kits should be available at your local dealership next week and retail pricing is in the $300 range

Brad
www.race-1.com

[sidebite7]

brad , I am understanding that these new springs will be much more consistent in rate compared to the previous ones. will they also be a lot more durable and last longer?

[brad hibbard]

the springs are from the CT525 engine and my 525 customers rarely if ever change valve springs (how nice is that ?)

BUT----my concern for awhile will be the keepers and retainers----I'm noy saying that we will have a problem just saying that I will recommend keeping an eye on this area

Brad

[brad hibbard]

here is an update on the spring


as of 8:30 am on 5/28/13 GM has not sent out any conversion kits to it's dealers

we are able to refresh this information 3 times daily and will make everyone aware when they check their local dealership for the kits.

we have been flooded with calls about the springs

please send questions to our e mail and we will keep you up on progress that way

thanks
Brad
brad@race-1.com

[rubbinsracin]

will these kits be providing ay type of a competive advantage, other than the fact they are more consistent and last longer?

[brad hibbard]

below is the statement from GM officials

This component change was made for valve train stability, durability and consistency, not for an increase in horsepower. Dyno tests have validated our contention that there is no horsepower gain, but there is an improvement in valvetrain stability. Operating and maintenance costs should actually be reduced, as spring life should improve in most cases.

[balljoint]

How does they compare weightwise? more rpms now?

[brad hibbard]

with a more stable valvetrain and yes the top of the spring will be lighter---many folks are thinking more RPM

BUT keep in mind the components in the bottom end------they "seem" to withstand 6800 OK with good valvetrain maintenance but we still recommend a bit lower-----we have found no combination of parts that makes power past 6150 to 6200------I know you run them higher to keep the low numbers up but don't think your doing anything but making noise at 7000

anything over 6800 will increase your tire bill as you will be running over connecting rods before long

Brad

[MM90]

If it's brand new it should already have the new springs in it. I suppose it depends when that engine was assembled though.

[brad hibbard]

sorry folks for not responding but my log in info was messed up for awhile (very frustrating)

anyway

stockcar---you will not notice a difference in the seat by a spring upgrade while on the 6400 chip rule but it still will be better on the valvetrain as far as durability

mm90-----stockcar is correct in what he has--it is "old style"----there have only been 30 "new style" engines released so far across the country-----PLEASE keep in mind "new style" only is refering to valve springs-----to the best of our knowledge and research the new engines are EXACTLY the same as as previous engines except with the spring upgrade that is available to everyone thru the GM conversion kit

glad to be back

Brad
www.race-1.com
330-540-RACE

[Casper60]

Are there any whispers of plans for doing this for the 602's?