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TOMEI

Tomei VALVE SPRING EJ205/207/255/257

Tomei VALVE SPRING EJ205/207/255/257

SKU: 163057
Regular price £186.57
Regular price Sale price £186.57
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High quality designed springs is required to transfer the exact movement of the camshaft to the valves at high engine speeds on high performance engines. The TOMEI products are always engineered with precision in mind to suit the user’s needs. So with this in mind careful choices in material selection is made with surface coating and other technologies. Then the pre-production products are put through an extensive testing program for checking durability, quality and performance. We spend time and money to help you save your valuable time and money.

PRODUCT INFO

APPLICATION COMPATIBLE LIFT(mm) P/N NOTES
EJ205/207/255/257 ~11.0 163057 For high cam lift

FEATURE / SPEC

DIA METER FREE LENGTH(mm) SET LENGTH(mm) LIFT LENGTH(mm) COMPRESSED LENGTH(mm) SET LOAD(kgf) LIFT LOAD(kgf) MATERIAL PROCESS COLOR ID
Φ3.80 45.1 36.2 25.5 23.9 32.0±6% 85.0±6% NHK620 Nitride Blue

■ Multi Coil Unequal Pitch Springs
By combining several steps of spring rates into the one spring and vibration frequency becomes amazingly high. This greatly minimizes resonance and the chances of surging. 

■ Advanced Oil Tempered Chromium-silicone Alloy Steel Core
Oil tempered chromium-silicone alloy steel wire is used which is considered to be the best material for springs for performance applications and evolved it even further. Combined with a new optimized design, not only did we make it tougher, we also succeeded in suppressing valve jumps or bounce even when raising the engines speeds RPM limit.

■ Shot Peening
A process that strikes many small steel balls onto the surface of the spring at high speeds is made to enhance the surface of the spring to raise its fatigue limit. Although it has been carried out earlier during the manufacturing process.

■ Warm Setting
The process that is adding higher loads beyond the actual limits to the highly heated spring. This will modify its shape and keep it permanently fixed. We succeeded in securing the highest performance over a long period of time while preventing sagging.

■ Nitriding
The surface treatment method for making nitrogen permeates the spring and gives it large surface compression repulsion. This method was chosen to raise the fatigue limit to suit the demands or running high lift camshafts. The dangers of spring failure is greatly reduced with the 1.5 times increase in the springs fatigue limit with the combined use of Oil tempered chromium-silicone alloy steel wire and Nitriding. This is how our valve springs are suitable for use on extreme engine speed conditions of super-high revs exceeding 10,000 RPM which had not been previously possible with high lift camshafts. 
Terminology
【Surging】
The Phenomenon which material of the valve spring resonance and causes the spring itself to vibrate violently.

【Jump】
The Phenomenon that the valve rallies to the cam surface instead of settled back. It happens when the valve cannot follow the camshaft rotation and lifted irregally.

【Bounce】
The Phenomenon that the valve is bouncing repeatedly from valve seat other than sticking to it when it is closing.

【Fatigue】
Breakage that occurs during the repeat operation of the spring. (The larger lift, the more possibilities to get fatigued)

【Sag】
The Phenomenon in which the load (free play) of a spring decreases while inuse. It is related to the maximum stress under operation and use time.
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