Understanding Melling Camshafts and Their Role in Engine Performance

Selecting the right camshaft is one of the most consequential decisions you can make when building or rebuilding an engine. Melling camshafts have earned a trusted reputation in the automotive aftermarket for consistent quality, precise manufacturing, and reliable performance across a wide range of applications. Whether you are restoring a classic muscle car, upgrading a daily driver, or building a high-performance race engine, understanding how to choose and install a Melling camshaft correctly is essential.

A camshaft controls the opening and closing of the engine’s valves, directly influencing horsepower, torque, idle quality, and overall drivability. Melling offers a variety of camshaft profiles—from mild street grinds to aggressive race cams—each designed for specific engine characteristics. However, even the best camshaft can underperform or cause damage if installation issues arise. This guide will walk you through common installation problems, troubleshooting steps, and best practices to ensure your Melling camshaft delivers the performance you expect.

Melling Camshaft Types and Specifications

Before diving into installation and troubleshooting, it is critical to understand the different types of Melling camshafts and their intended uses. Melling produces camshafts for engines ranging from small-block Chevys to modern overhead-cam designs. Their product line includes:

  • OE Replacement Camshafts – Designed to match factory specifications for stock rebuilds. Ideal for vehicles that require emissions compliance and smooth idle characteristics.
  • Performance Camshafts – Engineered for increased lift and duration. Melling’s “Select” and “Pro” series offer varying degrees of aggressiveness for street/strip or competition use.
  • Hydraulic vs. Mechanical (Solid) Roller Camshafts – Hydraulic roller cams provide reduced friction and maintenance, while solid roller cams offer maximum performance for racing applications.

Key specifications to review before purchase include lift (intake and exhaust), duration at 0.050" valve lift, lobe separation angle (LSA), and intake centerline. These parameters determine where the engine makes power. For example, a cam with a tight LSA (110°) shifts power higher in the RPM range, while a wider LSA (114°) broadens the torque curve. Always cross-reference your cam selection with your engine’s displacement, cylinder head flow, induction system, and intended use. Melling’s catalog and online look-up tools provide detailed data for each part number.

Pro Tip: If you are unsure which Melling cam fits your build, consult their technical support or a trusted engine builder. Installing a cam that is too radical for your valvetrain or compression ratio can lead to poor performance and mechanical failures.

Pre-Installation Inspection: Avoid Problems Before They Start

Many common installation problems can be prevented by thorough pre-inspection. Before you even open the camshaft box, take these steps:

  1. Inspect the camshaft visually. Look for any signs of shipping damage, rust, or manufacturing defects. The lobes should be smooth and free of scratches or pitting. Minor cosmetic blemishes on non-lobe surfaces are usually acceptable, but any lobe abnormality is a reason to return the cam.
  2. Check the cam bearings. If your engine uses removable cam bearings, verify they are correctly sized and installed without burrs. For engines where the cam rides directly in the block (such as many older small-blocks), inspect the block’s cam bearing surface for wear or scoring.
  3. Measure the cam journal diameters. Use a micrometer to confirm that the cam journals are within factory specification. Out-of-spec journals can cause excess clearance, leading to low oil pressure and premature wear.
  4. Verify the camshaft end play. Most engines require a specific thrust clearance. If the cam moves excessively forward or backward during operation, timing chain tension and lifter alignment can be affected.
  5. Check the nose of the camshaft. Ensure the timing gear or sprocket mounting surface is clean and free from burrs. A damaged nose can cause the timing gear to sit crooked, leading to misalignment.

Taking these steps before installation can save hours of troubleshooting later. If you identify any anomalies, contact Melling’s customer support or your supplier for a replacement before proceeding.

Common Installation Problems and How to Solve Them

Even with careful preparation, installation challenges arise. Below are the most frequent issues mechanics encounter with Melling camshafts, along with step-by-step solutions.

1. Camshaft Misalignment or Binding During Installation

Symptoms: The camshaft does not slide into the bearings easily, or it binds when rotating by hand.

Causes:

  • Bearing misalignment or insufficient clearance.
  • Damaged or burred cam journals.
  • Block core shift (rare but possible in older engines).
  • Incorrect bearing size or improper installation.

Solutions:

  • Lubricate the cam journals and bearings generously with a high-quality assembly lube. Do not use engine oil alone during installation.
  • If the cam binds, remove it and re-check the bearings. Use a bearing install/removal tool to verify they are fully seated and aligned. A misaligned bearing can be gently tapped into position using a bearing driver and hammer.
  • Measure the clearance using a feeler gauge or Plastigage on the cam journals. Most camshafts require 0.001–0.002 inches of clearance per inch of journal diameter. Check Melling’s spec sheet for exact values.
  • If a burr is found on the journal, use a fine stone or crocus cloth to remove it. Be careful not to remove excessive material.
  • For persistent binding, check the block’s cam bore alignment. A misaligned block may require line boring, which should be done by a machine shop.

2. Incorrect Timing Marks or Timing Chain Installation

Symptoms: Engine runs poorly, backfires, or will not start. Timing marks on the crank and cam do not align as expected.

Causes:

  • Timing chain or belt installed with incorrect orientation.
  • Camshaft and crankshaft not in phase.
  • Misunderstanding of TDC (top dead center) reference.

Solutions:

  • Verify that the engine is at TDC on the compression stroke for cylinder #1. Both the cam and crank timing marks should be aligned. If the marks are not close, rotate the crank again (it may be off by 360°).
  • Ensure the timing chain dampener (if equipped) is not interfering with the chain’s travel. Some aftermarket dampers require trimming.
  • Double-check that the cam sprocket and crank sprocket are correctly indexed. Some Melling camshafts have a keyway or multi-key bushing that must align with the manufacturer’s installation instructions. Refer to the engine service manual for proper positioning.
  • If using a degree wheel, verify the cam’s intake centerline matches the spec card. This is the most accurate method to confirm correct timing. A difference of more than 2° from the spec card may indicate a manufacturing error or installation issue.

External resource: For detailed instructions on degreeing a camshaft, refer to Engine Builder Magazine’s guide on degreeing a camshaft.

3. Insufficient Piston-to-Valve Clearance

Symptoms: Engine makes metallic clicking or knocking sounds at startup or during acceleration. In severe cases, valves hit pistons causing bent valves or damaged pistons.

Causes:

  • Camshaft has higher lift than the engine can accommodate without valve reliefs or flycutting.
  • Incorrect valve timing due to a stretched chain or misaligned gears.
  • Excessive valve float at high RPM (if combined with weak springs).

Solutions:

  • Always check piston-to-valve clearance during assembly. Use clay or a dial indicator to measure the minimum distance between the valve face and piston when the piston is at TDC. You need at least 0.080" for intake and 0.100" for exhaust (more for high RPM builds).
  • If clearance is insufficient, you have several options: flycut the pistons (requires removal), use a thicker head gasket, or select a camshaft with less lift or different lobe profile.
  • Verify that the valve springs can handle the cam’s lift. Melling provides recommended spring pressures for each cam; if your springs are weak, upgrade them. Coil bind is another risk—measure installed spring height and ensure there is at least 0.060" clearance before coil bind.

4. Lifter Noise or Failure After Start-Up

Symptoms: Ticking or clattering noise from the valvetrain immediately after the first startup, or after a short period of running.

Causes:

  • Hydraulic lifters not primed or bled down.
  • Incorrect preload on hydraulic lifters.
  • Excessive oil clearance in the lifter bores.
  • Lifter lobes not broken in properly.

Solutions:

  • Pre-soak hydraulic lifters in oil for at least 30 minutes before installation. Pump them while submerged to purge air.
  • Adjust lifter preload according to the cam maker’s specifications. For Melling hydraulic flat tappet cams, preload is typically 0.020–0.060". For hydraulic roller cams, follow the specific instructions (often zero lash plus a half turn).
  • After initial startup, vary the engine speed between 1500–2500 RPM for 20 minutes to properly break in the cam lobes. Do not let it idle for extended periods during break-in. If a lifter starts ticking, shut down immediately and check the valvetrain.
  • If the noise persists after break-in, re-check preload. Also inspect lifter bores for wear; if the lifters wobble excessively, the block may need to be bored and resized.

External resource: Melling’s official Camshaft Installation Guide provides specific break-in procedures for each cam type.

Post-Installation Troubleshooting: What to Check After First Run

Once the engine is running, monitor for these issues that indicate a lingering installation problem:

  • Low oil pressure at idle. Could indicate excessive cam bearing clearance or a plugged oil galley. Check the cam bearing clearance again and ensure the oil passage to the cam is not blocked by a misaligned bearing.
  • High engine temperature. A camshaft with too much duration can cause a lean condition or poor scavenging, leading to overheating. Re-check the timing and consider retuning the carburetor or ECU.
  • Rough idle or stalling. Either the cam is too aggressive for the engine’s compression or the idle circuit of the carburetor needs adjustment. For EFI engines, the idle air control and base timing may need recalibration.
  • Backfiring through intake or exhaust. Typically a timing issue—either the cam is not degreed correctly or the distributor timing is off. Re-degree the cam if necessary.

If the engine runs poorly but no mechanical noise is present, do not immediately assume the camshaft is defective. Often, the problem lies in the supporting systems: fuel delivery, ignition timing, or compression. Start with a thorough diagnostic check before pulling the cam.

When to Seek Professional Help

While many camshaft installations can be done in a well-equipped home garage, some situations warrant professional assistance:

  • If you encounter persistent binding or misalignment after multiple attempts, the engine block may require machining (line boring or cam tunnel repair).
  • If you do not have access to a degree wheel and dial indicator, getting the cam timing exactly right is nearly impossible. Many engine builders offer degreeing services.
  • If you suspect a defective camshaft (lobe wear, incorrect lift), contact Melling directly before installation. Their technical team can verify if the cam meets specifications and arrange a replacement if needed.
  • For high-performance builds with extensive modifications, a professional dyno tune after cam installation is recommended to optimize ignition timing and fuel mixtures.

Conclusion: Maximizing Your Melling Camshaft’s Potential

Installing a Melling camshaft is a rewarding way to unlock your engine’s potential, but it requires careful planning, precise execution, and troubleshooting readiness. By understanding the types of Melling cams available, performing thorough pre-installation checks, and knowing how to address common problems like misalignment, timing errors, and lifter noise, you can avoid costly mistakes and enjoy a powerful, reliable engine.

Remember that a camshaft is just one part of a balanced engine build. Pair your Melling cam with compatible valve springs, retainers, pushrods, and rocker arms for best results. When in doubt, consult Melling’s technical resources or an experienced engine builder. With the right approach, your Melling camshaft will deliver the performance gains you’re after—from a smoother idle to a hard-pulling top end.

For further reading and technical data, visit the Melling official website and explore their camshaft selection tools. Additionally, Summit Racing’s camshaft technical center offers complementary guides and product reviews that can aid in your build.