Valve “lash” is the technical name for the gap between the valve and tappet. The lash is critical to a healthy running engine. Too little lash and you’ll see starting problems and reliability issues. Too much lash will reduce power and potentially ruin the valve.
Adjust the valve tappets to a clearance of:
- Intake 0.002″ – 0.004″
- Exhaust 0.003″ -0.006″
How-to: Adjust your Valves
If you’ve just replaced the camshaft, make sure it’s properly timed. You’ll need a set of 0.004″ and 0.005″ feeler gauges, and a 9mm wrench.
Start by getting familiar with your valve and rocker assemblies.
- Loosen the tappet locking nut on the top of the tappet and turn the tappet out several turns.
- Sandwich the 0.004″ feeler gauge between the bottom of the tappet and the top of the valve.
- Tighten the tappet while moving the feeler gauge back and forth until you can feel a slight drag on the feeler. Then carefully re-tighten the locking nut. You may need a set of pliers to keep the head of the tappet from turning.
- Repeat for the remaining valve.
Check your work!
It’s important now to recheck the lash of each valve. Rotate the crankshaft a couple times and run the 0.004″ feeler gauge through again. Then try to insert 0.005″ feeler. If it doesn’t fit, you’re set properly.