When disassembling your engine, one thing you are doing (or should be doing, anyway) is inspecting the components for abnormal wear patterns. Not only can you spot something that has worn more than is acceptable, but the pattern of wear can tell you a lot about what is happening in your engine. Ferrea Racing Components’ Director of Marketing, Zeke Urrutia goes over the correct and incorrect wear patterns you’ll find on the tip of your valve stem, where the rocker arm makes contact with the valve. “We specifically want to look at two different wear patterns on the tip of the valve — the star pattern and the sweep pattern,” says Urrutia. “These two patterns are a clear indication of whether things are working properly or you’re starting to have and issue on your valves.”
The Star Pattern
The star pattern is not what you want to see on your valve tip. “That is an incorrect pattern to have on the tip area of the valve, where the roller is coming off of the valve, or the [rocker arm] geometry isn’t set up correctly. Urrutia explains. “The two main factors that can cause the star pattern. The first is the loss of spring pressure, which allows rotational movement of the valve. That rotational movement can be what causes the star-shaped wear pattern on the valve tip.”
Urrutia mentions that the second potential cause of the star pattern is poor valvetrain geometry. “The star pattern can be a clear indication that you’re having a geometry issue and you need to address it. Here at Ferrea, we’ll look at all the different variables within a combination — valve spring pressure, engine RPM, camshaft profile, and any power-adders in the combination. We look at all those factors when diagnosing the star pattern,” explains Urrutia.
The Sweep Pattern
The pattern you want to see on your valve tips when you’re tearing down your engine is the sweep pattern. “When you see the sweep pattern, that means that everything throughout the valvetrain is happy. The valve spring pressure is correct, the camshaft lift is correct, the geometry is correct, and everything is where it needs to be in the top end,” Urrutia says.
Paying attention to the small things when tearing down an engine can provide a lot of important information on the general health of your combination. So make sure to slow down and take a look during your next teardown. If you have any questions about what you find,…
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