Crate Engine: Legal Valvespring Upgrade From Chevrolet Performance

Chevy Crate Legal Valvesprings

 

We know a lot of OneDirt nation races crate engines, and while there is usually very little that can be done to the engines legally, we are always on the lookout to help you race better and have more fun at the track.

And the new valvesprings Chevrolet Performance has available for it’s popular CT400–also known as the  “604”–crate race engine may be exactly what you are looking for. These new valvesprings won’t magically give you an extra 50 horsepower (Chevrolet says they make no change to the horsepower and torque ratings) but they are a real improvement over the original springs in several areas. So we wanted to take a closer look to help you decide if they are worth investing in for your next rebuild.

We wanted to see how the new crate-legal beehive springs stacked up to the original pieces, so KT Engine's cylinder head specialist Kevin Troutman ran everything over the scales for us. The new beehives weigh in at 82 grams with a 12 gram retainer. The original springs weigh 91 grams with a 15 gram retainer. That's a reduction in 12 grams off the mass of the valvetrain at each valve which will help maintain better valve control at higher rpm levels and create less stress on the valvetrain overall.

We wanted to see how the new crate-legal beehive springs stacked up to the original pieces, so KT Engine’s cylinder head specialist Kevin Troutman ran everything over the scales for us. The new beehives weigh in at 82 grams with a 12 gram retainer. The original springs weigh 91 grams with a 15 gram retainer. That’s a reduction in 12 grams off the mass of the valvetrain at each valve which will help maintain better valve control at higher rpm levels and create less stress on the valvetrain overall.

The new valvesprings are a beehive design, so they will also require new, smaller retainers. Chevrolet Performance sells them in a kit (part number 19300952) with sixteen each of springs, retainers, locks and seats. Street price is 360 bucks.

Granted, that is quite a bit more than a set of the original springs for the 604, which normally go for around 50 bucks, but those springs varied so greatly that teams normally buy a dozen sets or more and rate each spring individually trying to find two or three well matched sets of 16. Plus, those original springs are also notorious for losing pressure very quickly.

These new springs should be able to maintain proper spring pressure longer because Chevrolet even says for themselves that they are a higher quality. By making the top of the spring smaller, the beehive shape moves the greater stresses lower on the spring where the coils don’t see as much vertical movement. Another clue is the fact that these beehives utilize an oval-shaped wire to maximize valve travel before the spring goes into coil bind. This is important because in the manufacturing process, properly coiling an oval wire into a spring requires both greater control and a higher quality raw material for the wire. Chevrolet also says that, “The oval/multi-arc wire shape places the maximum area of the wire at the point of highest stress to handle valve train stress more efficiently and allow better heat dissipation for longer life.”

To find out more details we stopped by the shops of KT Engine Development in Concord, NC, while they were rebuilding a 604 crate. KT Engines is an approved rebuilder of these sealed crate engines for a handful of racing series, and as part of this particular rebuild they were installing the new spring kit. Engine builder Ken Troutman says, like Chevrolet, he hasn’t seen much of a difference in the power levels of engines with the new springs on the dyno, but he does believe the higher quality spring results in fewer broken springs–and ruined nights–at the race track.

Here's a comparison shot of the original valvespring (left) versus the new beehive spring (right). Not only is the top of the spring smaller to cut weight, you may also be able to see that the wire used in the new spring is oval and not round like the original. This not only helps increase available valve lift before the spring goes into coil bind, but for our purposes it is also an indicator that higher quality materials are used in the construction of the wire.

Here’s a comparison shot of the original valvespring (left) versus the new beehive spring (right). Not only is the top of the spring smaller to cut weight, you may also be able to see that the wire used in the new spring is oval and not round like the original. This not only helps increase available valve lift before the spring goes into coil bind, but for our purposes it is also an indicator that higher quality materials are used in the construction of the wire.

The new valvespring requires a different retainer and seat/locator, so Chevrolet sells all the components (along with new locks) in a single kit.

The new valvespring requires a different retainer and seat/locator, so Chevrolet sells all the components (along with new locks) in a single kit.

Troutman checked the spring pressures and found they were right in line with the specs Chevrolet provides. The new springs have a very light seat pressure at just 85 lbs while the open pressure of 260 pounds is right in line with the original spring. Troutman did say, however, that he's noticed the new springs are much more consistent from spring to spring than the old units.

Troutman checked the spring pressures and found they were right in line with the specs Chevrolet provides. The new springs have a very light seat pressure at just 85 lbs while the open pressure of 260 pounds is right in line with the original spring. Troutman did say, however, that he’s noticed the new springs are much more consistent from spring to spring than the old units.

When swapping to the newer spring design, you must be very careful to get all your installed heights set correctly. Do not assume that they will be the same from the old springs--some shimming may be necessary.

When swapping to the newer spring design, you must be very careful to get all your installed heights set correctly. Do not assume that they will be the same from the old springs–some shimming may be necessary.

Chevrolet says the new springs won't make any real torque or horsepower changes in the racing rpm range of the 604 crate engine, and engine builder Ken Troutman confirms this. But the improved design and quality should mean these new springs will maintain proper spring pressure longer and will be less likely to break.

Chevrolet says the new springs won’t make any real torque or horsepower changes in the racing rpm range of the 604 crate engine, and engine builder Ken Troutman confirms this. But the improved design and quality should mean these new springs will maintain proper spring pressure longer and will be less likely to break.

 

 

 

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About the author

Jeff Huneycutt

Jeff Huneycutt has been in the automotive industry long enough to collect more project cars than he can afford to keep running. When not chasing electrical gremlins in his '78 Camaro, he can usually be found planning unrealistic engine builds.
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