Frequently Asked Questions (FAQs)
1. What holds rocker arms in place?
Rocker arms are held in place by a trunnion pivot with a rounded bottom and a nut. This design provides support to the rocker arm while allowing it to move smoothly up and down.
2. What causes rocker arm failure?
Rocker arm failure can occur due to improper heat treatment and faulty manufacturing. This can lead to brittleness, cracks, and stresses in the rocker arm. When a rocker arm fails, it can cause the engine to stall or stop working until the damaged rocker arm is replaced.
3. What are the different designs of a rocker arm?
There are various designs of rocker arms used in engines, including stamped steel rocker arms, roller-tipped rocker arms, full roller rocker arms, shaft rocker arms, center pivot rocker arms, and end pivot or finger follower rocker arms.
4. Do rocker arms increase horsepower?
Roller rockers are believed to increase horsepower by reducing valvetrain friction. This benefit is particularly noticeable at high RPMs.
5. What does upgrading rocker arms do?
Upgrading rocker arms can effectively increase valve lift without changing the camshaft. By increasing the rocker arm ratio, you can achieve greater valve lift, resulting in improved performance.
6. What pushes the rocker arm?
In an overhead valve engine, the camshaft pushes the pushrod, which in turn presses on one side of the rocker arm. This causes the rocker arm to rotate and operate the intake and exhaust valves.
7. What happens if rocker arms are too loose?
When rocker arms are out of adjustment and too loose, the valves may not open as soon, as much, or for as long as required by the cam profile. This can lead to reduced engine performance, decreased power, and issues with exhaust gas scavenging.
8. What are signs of bad rocker arms?
Common signs of failing rocker arms include an illuminated check engine light, engine misfires, and clicking or ticking noises. If you experience these symptoms, it may be necessary to replace the rocker arms, which can cost between $100 and $500.
9. What do different rocker arm ratios do?
Increasing the rocker arm ratio can increase horsepower at higher RPMs. However, there can be drawbacks such as reduced power at lower RPMs and increased stress on the engine's valve train and rocker arm. It is important to ensure sufficient valve to piston clearance when changing rocker arm ratios.
