All categories
Featured selections
Trade Assurance
Buyer Central
Help Center
Get the app
Become a supplier
(1509 products available)
Valve tappet adjustments are used to ensure that the correct clearance is maintained between the camshaft lobes and the valve stems. This is done to avoid valve tappet noise and prevent engine damage that may be caused by improper valve timing. There are several types of valve tappet adjustments, including:
Hydraulic Valve Lifters
These are commonly used on modern internal combustion engines. Their primary function is to automatically maintain the correct valve clearance. Hydraulic lifters use engine oil pressure to keep the lifter body expanded. This expansion eliminates any clearance between the lifter and the valve stem. Consequently, the hydraulic lifter absorbs the camshaft's rotation, opening and closing the valves at the right time.
Adjustable Rocker Arms
These are used in high-performance engines as well as some older engines. The adjustable rocker arms allow the mechanic or engine builder to set the correct valve clearance with a valve tappet tool. Typically, the adjustable rocker arms have a screw or a threaded shaft that lets users turn the nut and move the rocker arm closer to or farther away from the valve stem. This makes it possible to achieve the desired valve clearance.
Non-Adjustable Rocker Arms
These are most commonly used in modern engines that have overhead camshafts and solid valve lifters. Typically, the non-adjustable rocker arms are pre-set at the factory to provide a specific valve clearance. Mechanics can correct any changes in the valve clearance that may occur as a result of wear and tear by replacing worn-out components. This includes the rocker arms, the valve lifters, and the shims under the valve. The mechanic may also grind the camshaft or the cylinder head to obtain the right valve clearance.
Fixed Valve Lifters
The fixed valve lifters are designed to maintain a constant valve clearance. This means that the clearance will remain the same throughout the lifespan of the engine component. The fixed lifters eliminate the need for regular adjustments. However, they can result in engine performance issues if the clearance increases or decreases due to wear and tear.
Pedestal-Mounted Rocker Arms
The pedestal-mounted rocker arms are usually found on engines with a V-configuration. Instead of being mounted on the cylinder head, these rocker arms are mounted on a pedestal. This design improves the precision of the valve clearance settings.
Here is some important information about the specifications and maintenance of valve tappet adjustments.
Specification
The specifications for valve tappet adjustments can vary depending on the make, model, and engine type. However, here are some common specifications to consider:
1. Tappet clearance: This is the distance between the valve and the tappet. It is usually measured in millimeters or thousandths of an inch. The specified tappet clearance should be precise, as too much or too little clearance can cause engine problems.
2. Adjustment method: Different engines use different methods for adjusting valve tappets. Some may require shims, while others use screw-and-locknut arrangements. The specification should include the adjustment method used in the engine.
3. Torque specifications: When reassembling the engine after a tappet adjustment, it is important to follow the specified torque for bolts and nuts. This ensures proper engine function and prevents damage to engine components.
4. Adjustment sequence: The specification should include the recommended sequence for adjusting the tappets. This may involve adjusting the valves in a particular order or adjusting the intake and exhaust valves separately.
5. Inspection intervals: The specification should indicate how often to inspect and adjust the valve tappets. Regular maintenance is important for optimal engine performance.
Maintenance
Here are some maintenance tips for valve tappet adjustments:
1. Regularly check the valve tappets for signs of wear or damage. Worn or damaged tappets can cause valve timing problems and affect engine performance.
2. Follow the manufacturer's recommended maintenance schedule for valve tappet adjustments. This ensures that the engine valves are correctly timed and maintain optimal engine performance.
3. Use the correct adjustment method and tools as specified by the manufacturer. This ensures that the valve tappet adjustment is done accurately and prevents engine damage.
4. Follow the specified torque for reassembling engine components after a valve tappet adjustment. This ensures proper engine function and prevents damage to engine parts.
5. Maintain the specified tappet clearance during adjustments. Too much or too little clearance can cause engine problems. If unsure about the correct tappet adjustment, consult a professional mechanic.
There are several factors that buyers should consider when choosing valve tappet adjustment.
Engine Type
Buyers should consider their engine type when selecting a valve tappet. This is because not all engines use the same valve system. For instance, some engines have overhead valves that use a different tappet adjustment compared to overhead valve engines. Buyers should ensure that they are using the right tappet adjustment for their engine type. This will ensure that the engine runs smoothly and the valves open and close at the right time.
Manufacturer Recommendations
Buyers should also consider the manufacturer's recommendation when choosing a valve tappet adjustment. Most manufacturers provide a specific valve tappet setting that is ideal for their engine. Buyers should go through their owner's manual or contact the manufacturer to get the recommended valve settings. Adhering to the manufacturer's recommendation ensures optimal engine performance and longevity.
Engine Sound
Buyers should pay attention to their engine sounds before and after they make the valve tappet adjustment. A properly adjusted valve usually results in a smooth and quiet engine operation. If the engine is noisy or sounds different, it could be a sign that the valve tappet adjustment is not correct. Buyers should revert to the previous settings if they notice any changes in the engine sound after making the adjustment.
Trial and Error
Choosing the right valve tappet adjustment can be difficult because different engines require different settings. Buyers can start with the factory recommended settings and make slight adjustments as needed. They should be patient and persistent when finding the right valve tappet adjustment for their engine.
Before making any adjustments to tappets, it's essential to have the right tools for the job. The tools needed for valve tappet adjustment include:
Follow these steps to adjust valve tappet:
Ensure the engine is cool and wear safety gear.
Read the manual for specific instructions.
Remove covers to access the tappets.
Use a feeler gauge to check specifications.
loosen nuts and use screws or shims.
Recheck and tighten nuts securely.
Replace covers and secure fasteners.
Start the engine and ensure smooth operation.
Q: How often should tappet adjustments be made?
A: There is no specific number of miles or time limit before a tappet adjustment is made. However, users should check their vehicle's manual for guidance on when to make adjustments. Generally, users are advised to check their tappets at least once a year or after 12,000 miles.
Q: What are the symptoms of misaligned valve tappets?
A: Misaligned valve tappets can cause several problems that users might notice. These include a noisy engine (tappet noise), poor engine performance, and starting problems. If the engine performance is affected, it might lead to increased fuel consumption.
Q: Can a non-mechanical person perform valve tappet adjustment?
A: With the right tools, a detailed user manual, and perhaps some online videos, anyone can attempt a valve tappet adjustment. However, it is highly recommended that users have a professional mechanic perform the adjustment. This is to ensure that the adjustment is done correctly to avoid further engine problems.
