DPR Racing - Custom Valve train Components
- DPR's Custom "Conical" Valve Springs, Light, Low Harmonics
- Valves, Custom, Coated, Hollow, Filled
- Rocker Arms, and rocker Assemblies
- Roller Rocker Arms, The ultimate in high RPM Strength
- Shimless Buckets, For High RPM and Longevity!
- Lightened, Polished Rockers, These are the lightest, Strongest, High RPM Rockers!
DPR Racing - Custom Conical Valve Springs
DPR and family have successfully developed advanced import car valve trains for more than 55 years! Never ending development has lead to increased performance, and reliability. Other than computer controlled variable cam timing/lifts and /pneumatic /electric valve control I believe nothing has had such a positive overall effect on the entire engine than upgrading to this new design of valve springs. But are they really new? Read on…
The DPR Conical progressive valve spring is the cutting edge in cylinder head and valve train design. These springs are no stranger to the performance world. Conicals have been used for years in the Formula 1 and high end production cars including Mercedes, BMW, and Ferrari. We have been using and abusing them for many years, nationally and internationally in a variety of performance engines. Surpassing all expectations, and zero failures, we are now making these springs available to the public!
A conventional linier wound performance spring has a natural harmonic frequency, that in operation will find several coils grouped tightly together up next to coils extremely stretched out. This pattern will travel up and down similar to what you might see with a slinky toy. This spring surge action causes costly negative effects and disastrous engine failures. In an attempt to try and control the harmonics, there must be dual springs with the idea being “tune out” each other’s negative frequencies.
DPR Conical “beehive” springs, Skeptically meek in appearance, their advanced design and reduction in moving mass apply the laws of physics to control harmonics, and greatly reduce the amount spring pressures normally required to control your valve train. If a dual conventional spring doesn’t do the job, they often press them tightly together and run a dampener and third coil. With the idea being rubbing together they will surely dampen the harmonics. . Unfortunately this path demands even more pressures to compensate for huge amount of friction. Pressures that the valve train doesn’t want to see, along with major abrasives that contaminates your oil. This in turn tears at your rings, bores, bearings, and literally....wears down your entire engine!!
This is why NASCAR now has stepped up to conical Long awaited and following F1 technology. Also 80% of all auto manufactures world wide now utilize them. Higher RPM, better throttle response, less maintance, less operating cost huge cost savings. Performance, reliability, and longevity. Just as fuel injection, carbon fiber, and steel belted radials…..We are developing more applications so if you don’t see your application , just ask us. available See If DPR has a conical progressive application for you....
Oh I failed to mention, our steel retainers are usually lighter than most titanium. Take a look at any retainer that has been run on conventional springs. Scary. And if you do want to use Titanium , we have them also. Usually about the weight of a 1981 and older penny.
Advantages of Conical Valve Springs:
1) Ability to use smaller retainers greatly reducing moving mass of the valve train
2) Improved harmonics means less wear, heat, friction, stress, and longer seat, spring, and valve life
3) More clearance before coil bind allowing higher lift cams to be run
There are three main advantages the conical springs have to offer. First, due to the tapered design, the retainer can be made drastically smaller which will greatly reduce valve train weight and moving mass. This reduction in weight means you can run 25% less spring pressure and rev higher without floating. The second advantage of using conical springs is the improved harmonic characteristics that its design offers. The shape of the wire allows the conical spring to handle the extreme stress that today’s valve springs are put through. This design makings them more efficient, better performing and more reliable by creating less stress, less heat, less and less wear, as well as longer valve and seat life. This design more effectively distributes the stress over the entire wire area allowing for more complexity within the spring. The third advantage is the increased clearance before coil bind. This allows you to run a cam with more lift.
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“I need dual springs because one cant give enough pressure” WRONG
“I run dual springs because if my main spring breaks then the inner one will save the day”. WRONG some of them are only 5-15lbs and you need 60, 80,and 90?? Single valve heads move up proportionally. Upwards of 1000lbs
It's true… Starting with a small diameter top coil you need about ½ the retainer. Lightning the springs moving mass ratio will typicially find about ½ the moving mass weight.
Massive and heavy conventional springs/retainers with their huge friction, mandates the rest of the valve train to be equally massive to support it . If you are utilizing stock valve train considers the squared effects of strain and the wear from your higher RPMs and the pressure created from double and triple springs. Just think about cam journal and cam cap wear.
DPR has run ½ the required “race” pressures and reduced the moving mass weight to ¼ (75% lighter) higher RPM
Unfortunately this is a bit of an anti stimulus package. Not millions , but billions will be lost by manufactures, repair shops, speed shops, performance warehouses, and cylinder head shops.
(Do you wonder if they were suppressed in the market??)
So… you do your leak down, and compression test. You read the oil analyses test results from Blackstone Laboratories, and find out you can again safely run another season without a rebuild. Your valve springs are still ok Maybe you can afford a new paint job and upgrade to that new DPR cylinder head mod!(LOL)
Private race teams can spend thousands each year on just replacement springs and retainers.Pro teams do spend sometimes tens of thousands.
Upwards of one hundred friction points created by springs pressed together per valve use add more resistance that must be compensated with even more spring, more weight, more friction heat and you don’t even want to know how much steel they shave off into your engine.
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DPR Racing - Custom Valves
DPR Custom Lightened Valves, Stainless Valves, Hollow Stem and Sodium Filled Valves, & Keepers available for all applications!
DPR Racing - Custom Valves, Competition 6000, Tuner Plus, Sodium Filled and Hollow Stem Valves
The leading manufacturer of racing valves,introduces the already race-proven 6000 Series Competition Valves.
This Valves Series is designed to provide excellent reliability in an environment of high RPM and high spring pressures, at a budget price. These valves have higher fatigue resistance and tensile strengths than our competitor’s best offering. The 6000 Series Competition Valves are specially designed for street, drag and rally racing applications.To manufacture the valves we use our exclusive two-step slowforging process applied to the special alloys selected to suit intake and exhaust applications. We provide a unique heat-treatment and stress-relieving process, along with hard chrome stems and friction-welded hard tips. We finish the valves with a swirl-polished head. Our Valves feature flow improvements to deliver the power needed for today’s sophisticated
Sport Compact racing engines.
Lightweight Hollow Stem Valve for Sport Compact applications.
Our manufacturing process emphasizes the interior finish of the hollow stem using gun drill and
micro polish techniques. The valves also feature seat hardness for longer life in this critical area,
avionics chrome plated stem, radial groove, friction welded tips and Super Flo stem to improve
the flow design. This lightweight valve achieves higher rpm’s to improve the combustion cycle and
obtain more HP. Sodium Filled valves are used where additional cooling of the valve is required such as super- charged or turbo-charged applications.
Our NEW Import-Tuner Plus Valve Program
features specially designed valves for use in racing
engines that are subjected to extreme exhaust
temperatures with Turbo, Nitrous, or Supercharger.
We use a Special Alloy designed specifically for this
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DPR Racing - Custom Retainers, Custom Rocker Arms and Roller Rockers
DPR Custom retainers, lightened polished rockers, and Special roller rockers available for most applications.
DPR Racing - Roller Rocker Arms
The Special “Aluminum-Magnesium Roller Rocker System” was designed and developed to replace the factory “Steel Rocker Arm System” and eliminate the V-TEC Function. Factors such as weight, mass moment or inertia, deflection, and cycle durability are taken into account throughout the design and testing process. Several DPR Racing Development’s race engines campaigned our rocker arms very successfully.
Premium Material: We use special high quality 70 Series Aerospace Aluminum-Magnesium Alloy, heat-treated to provide superior strength at elevated temperatures.
Manufacturing: Fully CNC machined, profiled for weight reduction, (OEM unit weighs 108% more) which improves inertia, and increases the RPM range of Valvetrain.
Roller Wheel: The Roller Needle Bearings prevents roller from skidding across the camshaft surface, unlike the (OEM) stock rocker pad, thus reducing friction dramatically.
Tool Steel Pin: The Tool Steel Roller Pin is compressed between the rocker to stabilize the rocker motion throughout the entire RPM range.
Installation: Our Roller Rocker System comes with all hardware and requires no head modifications for installation.
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DPR Racing - Shimless Bucket Conversion
- Lignter than Stock OEM
- Coated with Microlon to reduce valvetrain friction
- Less mass which allows for higher and safer RPM
- Direct Replacement(Lashing is Necessary)
- The Buckets are individually inspected providing the best quality product
Don't Risk the chance of throwing a shim, Shimless buckets are definitely the way to go whether your engine is stock or highly modified.
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DPR Racing - Lightened, Polished Rocker Arms
- Reduced critical valvetrain weight for higher and safer rpm’s
Rocker arm shaft micropolishing and blueprinting.
- Allows greater clearance to accommodate larger camshafts
- Detailed Wear Inspection
- Removes stress risers for increased durability and reliability
- Flat spots are removed from adjuster screw and polished for less friction and easier more presise adjustments and more precise valve adjustments
- Honda/Acura VTEC elimination modifications also available (for serious performance and weight reduction)
- Includes B16A B17A B18C H22A VTEC
- also available:
Microlon metal treatment to reduce friction and wear.(Click here for "Microlon" Treatment)
DPR retainers and spring kits
High Performance Conical valve springs
Cryogenic treatment (click here)
WCP treatment for added strength, improved lubrication and life.
(Click to visit "WCP" site)
Custom High Performance modifications for superior oil flow.
Competition balance and blueprint
High luster rocker arm polishing
Contact us regarding modifications available for your rocker arm assembly.
Please contact us via E-mail at
for pricing and availability!