Avoid Engine Wear: Check Your Pushrod Length
Maintaining your engine's health is crucial for its longevity and performance. One often-overlooked aspect of this maintenance is checking and adjusting your pushrod length. Incorrect pushrod length can lead to significant engine wear, reduced power, and ultimately, costly repairs. This article will guide you through understanding the importance of proper pushrod length, how to measure it, and the consequences of neglecting this vital check.
What are Pushrods and Why is Their Length Important?
Pushrods are slender rods connecting the rocker arms to the camshaft in overhead valve (OHV) engines. They transfer the up-and-down motion of the camshaft lobes to the rocker arms, which in turn open and close the valves. The precise length of these pushrods is critical for proper valve operation. If the pushrods are too short or too long, it can lead to several problems:
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Improper Valve Adjustment: Incorrect pushrod length affects valve lash (clearance). Too little clearance can cause the valves to remain slightly open, leading to valve float, burnt valves, and damaged valve seats. Too much clearance reduces valve lift, decreasing engine power and potentially causing uneven engine running.
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Premature Wear: Incorrect valve lash due to faulty pushrod length increases friction and stress on the valve train components, including the camshaft lobes, rocker arms, valves, and even the pushrods themselves. This accelerated wear can lead to premature failure of these parts.
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Reduced Engine Performance: Inefficient valve operation, as a result of incorrect pushrod length, directly impacts engine performance. You might notice reduced power, poor fuel economy, and rough idling.
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Engine Noise: Abnormal valve train noise, such as ticking or clattering, often indicates a problem with pushrod length or valve adjustment.
How to Measure Pushrod Length: A Step-by-Step Guide
Measuring pushrod length requires precision and care. Here’s a general guide; always consult your engine's specific service manual for detailed instructions:
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Gather Your Tools: You'll need a set of pushrod length measuring tools (typically including a pushrod measuring tool and a feeler gauge), a socket set, and possibly a torque wrench.
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Remove the Rocker Arms: Carefully remove the rocker arms from the valves. This allows for accurate measurement of the pushrod length without interference.
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Insert the Pushrod Measuring Tool: Carefully insert the pushrod measuring tool into the pushrod hole in the cylinder head. This tool ensures accurate measurement.
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Measure the Pushrod Length: Using the pushrod measuring tool, carefully measure the length of your pushrods. Note the length of each pushrod individually as they may vary slightly.
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Compare to Specifications: Compare your measurements to the manufacturer's specifications found in your engine's service manual. Any deviation indicates the need for adjustment or replacement.
What Happens If Pushrod Length is Incorrect?
Consequences of Too Short Pushrods:
- Premature Valve Seat Wear: The valves may not fully close, leading to excessive wear on valve seats.
- Burnt Valves: The valves may remain slightly open during combustion, causing the valve face to overheat and burn.
- Valve Float: At high RPMs, the valves may not close properly due to insufficient closing force.
Consequences of Too Long Pushrods:
- Reduced Valve Lift: The valves won't open as far as they should, limiting engine performance.
- Valve Spring Damage: The increased valve train stress could damage valve springs.
- Bent Pushrods: Long pushrods may bend due to the increased stress.
Frequently Asked Questions (FAQ)
How often should I check my pushrod length?
The frequency depends on your engine, usage, and maintenance schedule. Consult your engine's service manual for recommendations. However, checking them during a major engine service or if you notice unusual engine noise is always a good idea.
Can I adjust pushrod length myself?
While some adjustments might be possible using shims or adjusters (depending on the engine design), improper adjustments can cause significant damage. It's best to consult a qualified mechanic if you're unsure.
What are the signs of incorrect pushrod length?
Signs include unusual engine noise (ticking, clattering), decreased engine performance, poor fuel economy, and rough idling.
By understanding the importance of proper pushrod length and following the steps for measurement, you can significantly contribute to the health and longevity of your engine. Regular checks and maintenance are key to preventing costly repairs and ensuring optimal performance. Always consult your engine's service manual for specific instructions and recommendations.
