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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. |
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Developement target |
●Reliability in high RPM, and improvement in an initial response ●High durability against metal fatigue
●High durability against the shocks from jump and bounce ●High durability against surging ●High sag resistance |
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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. |
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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. |
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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. |
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| Terminology |
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Surging |
The Phenomenon which material of the valve spring resonance and causes the spring itself to vibrate violently. |
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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. |
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Bounce |
The Phenomenon that the valve is bouncing repeatedly from valve seat other than sticking to it when it is closing. |
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Fatigue |
Breakage that occurs during the repeat operation of the spring. (The larger lift, the more possibilities to get fatigued) |
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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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Application |
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Diam. |
Set
length
（mm） |
Lift
height
（mm） |
lift |
set load
(kgf) |
lift load
(kgf) |
RPM
(ex.) |
Material |
coating |
Color |
| RB26 |
A type |
|
ø3.9 |
37.7 |
27.2 |
10.85 |
24.0±7% |
77.2±7% |
8500 |
SWOSC-VX |
Nitriding |
White |
| B type |
|
ø4.2 |
40.2 |
29.0 |
11.50 |
24.0±7% |
97.8±7% |
9500 |
SWOSC-VX |
Nitriding |
Yellow |
| C type |
IN |
ø2.0 |
34.6 |
18.9 |
11.50 |
3.6±8% |
14.0±7% |
10000 |
SWOSC-VX |
Nitriding |
Green |
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OUT |
ø4.2 |
40.2 |
29.0 |
24.0±7% |
97.8±7% |
Yellow |
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I+O |
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IN 30.3±8%
EX 27.6±8% |
IN 111.8±8%
EX 108.1±8% |
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R33
RB25DET
(with IN retainer) |
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ø3.9 |
35.0 |
25.0 |
10.25 |
24.2±7% |
80.6±7% |
8500 |
SWOSC-VX |
Nitriding |
Blue |
| RB20,VG,CA |
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ø3.9 |
35.0 |
25.0 |
10.35 |
24.2±7% |
80.6±7% |
8500 |
SWOSC-VX |
Nitriding |
Blue |
| SR20 |
A type |
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ø4.0 |
40.0 |
27.5 |
12.50 |
25.6±7% |
81.6±7% |
7500 |
SWOSC-VX |
Nitriding |
Red |
| B type |
IN |
ø2.5 |
32.2 |
19.7 |
12.50 |
3.4±8% |
23.4±8% |
8000 |
SWOSC-VX |
Nitriding |
Red |
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OUT |
ø4.0 |
40.0 |
27.5 |
25.6±7% |
81.6±7% |
SWOSC-VX |
Nitriding |
Red |
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I+O |
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29.0±8% |
105.0±8% |
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| 4G63 |
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3.6(H)
x
4.5(W) |
39.6 |
27.1 |
11.50 |
33.6±6% |
82.0±6% |
8000 |
SWOSC-VT |
Nitriding |
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TOYOTA
3S-G |
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ø3.9 |
35.0 |
25.0 |
10.00 |
24.2±7% |
80.6±7% |
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SWOSC-VX |
Nitriding |
Blue |
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