Introduction
Valve lash is a critical aspect of maintaining and optimizing engine performance, especially in high-revving Honda B-Series and K-Series engines. Proper valve lash ensures correct valve timing, prevents valve damage, and optimizes power output. Unlike hydraulic lifter setups found in other engines, these Honda powerplants require periodic manual adjustment due to their mechanical rocker arm design.
Incorrect valve lash can lead to a variety of issues, including excessive ticking noise, power loss, and even engine damage. In this guide, we’ll walk you through the step-by-step process of setting valve lash correctly.
Tools & Parts Needed
Before getting started, gather the necessary tools:
- Feeler gauge set
- 10mm wrench (for adjustment nuts)
- Flathead screwdriver
- Torque wrench
- Honda gasket sealant (if replacing valve cover gasket)
- Replacement valve cover gasket (if needed)
- Shop rags
- Engine oil
Step 1: Engine Preparation
- Ensure the engine is completely cold. Valve lash adjustments should always be done when the engine is at ambient temperature.
- Remove the valve cover. If working on a K-Series engine, disconnect the ignition coil packs. On a B-Series engine, remove the spark plug wires and distributor cap if necessary.
- Rotate the crankshaft to Top Dead Center (TDC) for cylinder #1. Do this by aligning the crank pulley and cam gear marks. Ensure both cam lobes for cylinder #1 are pointing upward.
Step 2: Understanding Valve Lash Specs
Different Honda engines have specific factory clearance values. Here are the common specifications:
Engine |
Intake Clearance (Cold) |
Exhaust Clearance (Cold) |
B16A / B18C |
0.006-0.007" |
0.007-0.008" |
K20A / K20A2 |
0.008-0.010" |
0.010-0.011" |
K24A2 |
0.008-0.010" |
0.010-0.011" |
Race applications may require custom settings depending on camshaft profiles and desired powerband.
Step 3: Adjusting the Valves
- Begin with cylinder #1 at TDC. Ensure both cam lobes are pointing upward.
- Insert the correct feeler gauge between the cam lobe and rocker arm.
- If the gauge slides in too easily or has excessive resistance, adjust using the flathead screwdriver and 10mm lock nut.
- While holding the adjustment screw in place, tighten the lock nut carefully.
- Recheck the clearance after tightening, as tightening the lock nut may slightly change the setting.
Step 4: Repeat for Remaining Cylinders
Follow the correct firing order:
- B-Series: 1-3-4-2
- K-Series: 1-3-4-2
Rotate the crankshaft to TDC for each respective cylinder and repeat the adjustment process.
Step 5: Reassembly & Final Checks
- Reinstall the valve cover, using a fresh gasket if needed.
- Torque the valve cover nuts to Honda spec (~7 ft-lbs).
- Start the engine and listen for any unusual noises.
- If excessive ticking or hesitation occurs, double-check valve lash settings.
- Recheck valve lash after a few heat cycles if needed.
Final Thoughts & Troubleshooting
- What happens if lash is too tight? Valves may not fully seat, leading to power loss, excessive wear, and potential engine damage.
- What happens if lash is too loose? Increased tapping noise, inefficient valve timing, and possible performance loss.
- How often should valve lash be checked? Every 30,000 miles for street cars; more frequently for track or high-performance applications.
- Does high-lift camshafts require different settings? Yes, depending on the cam profile, consult manufacturer specifications for best results.
Closing
Regular valve lash adjustments ensure your Honda engine performs optimally, providing reliability and peak power. If you need valve cover gaskets, Hondabond, or upgraded valvetrain components, check out IPGparts.com for the best performance parts available!
Happy wrenching!