Step-by-Step Valve Adjustment
Introduction
Valve adjustment is a key maintenance task to keep your VW engine running smoothly, efficiently, and to prevent valve/noise damage. In 1978, many U.S. VW Buses shipped with hydraulic lifters (GE-coded engines), but over time engines get swapped, rebuilt, or converted — so you might also encounter solid (mechanical) lifters. This guide walks you through both methods, with clear photos and diagrams to help you follow along.
In this post you’ll find:
- A visual overview of the Type 4 engine layout
- Tools, specs, and preparatory steps
- Detailed steps (with photos) for solid lifters
- Detailed steps (with photos) for hydraulic lifters
- Tips, mistakes to avoid, and a printable checklist
Engine Layout & Valve Train Overview
Here’s a view of the rocker arms and valve area on a VW Type 4 engine (note: this is for illustration purposes).
In each head, each cylinder has two valves (intake + exhaust). The general arrangement is:
- Rocker arms pivot on a shaft or stud and push down on valve stems via a tappet or pushrod
- Adjustment is done at the rocker / adjuster foot contacting the valve stem
- In a hydraulic lifter design, the lifter automatically takes up slack (no fixed clearance)
- In a solid lifter design, a fixed clearance (lash) must be set via a feeler gauge
Below is a photo showing the rocker / adjuster area in more detail.
Tools, Specs & Prep Steps
Tools & Supplies You’ll Need
- Feeler gauge set (especially 0.006 in / 0.15 mm blade)
- 13 mm wrench (for locknuts on adjusters)
- Flat-blade screwdriver (for turning adjuster screws)
- Ratchet & socket to turn crankshaft / fan nut
- Clean rags, light, drip tray
- Valve cover gaskets (if current ones are worn)
- If desired: grease to dab onto valve cover lips (for sealing)
Spec & Engine Notes
| Lifter Type | Adjustment Spec |
|---|
| Solid / mechanical | 0.006 in (0.15 mm) intake & exhaust, engine cold |
| Hydraulic | Zero lash + ~1 – 2 turns preload (commonly ~1.5 turns) |
Firing order / adjustment rotation: 1 → 4 → 3 → 2. You will rotate the crank 180° between adjustments when going cylinder to cylinder.
Typical procedure: set #1 on compression TDC, adjust both valves, then rotate half a turn for #4, then #3, then #2.
Before you start, verify which lifter type your engine actually has (stock or swapped). Don’t assume — perform a visual check (pushrod differences) or consult engine rebuild documentation.
Getting #1 Cylinder to TDC (Compression Stroke)
- Remove valve covers and set aside (also remove any obstructions).
- (Optional but helpful) Remove spark plugs to ease cranking.
- Rotate the engine (via the crank pulley or fan nut) until the timing mark lines up with “0” on the Type 4 timing scale and the distributor rotor points to the #1 spark plug wire.
- If the rotor points 180° away from #1, you’re on overlap — rotate another full turn to get to compression TDC.
Once #1 is correctly positioned, both #1 valves are closed and ready for adjustment.
Method A: Adjusting Solid (Mechanical) Lifters
This is the method when your engine uses fixed lash (no automatic compensation).
Step-by-step (for each cylinder at its TDC)
- Identify Intake and Exhaust Valves
On the head, the front valve (closest to the front of engine) is usually intake, rear is exhaust (verify on your setup). - Back off the locknut
Use the 13 mm wrench to slightly loosen (but not remove) the locknut on the adjuster. - Insert feeler gauge (0.006 in / 0.15 mm)
Slide the gauge between the valve stem tip and the adjuster foot. You should feel a slight drag. - Adjust the screw
Use a flat-blade screwdriver to turn the adjuster screw while gently sliding the feeler gauge back and forth until you achieve the correct drag (slight resistance). - Hold screw & tighten locknut
Hold the screw in place and tighten the locknut. Re-check the feeler gauge after tightening to ensure you didn’t distort the setting. - Rotate crank 180°
Turn the engine half a revolution and proceed to the next cylinder in the sequence (1 → 4 → 3 → 2), repeating the same process. - Repeat for all cylinders
Always be precise — too tight a valve can burn or warp, too loose leads to tapping, power loss, and noise.
Example photo of adjuster area
Method B: Adjusting Hydraulic Lifters
Hydraulic lifters use a spring & plunger to take up slack, so you don’t set a fixed gap — instead you set preload.
Step-by-step (for each cylinder at TDC)
- Loosen the adjuster
Turn out the adjuster screw until there’s free play (the rocker or pushrod can move slightly up/down). - Bring back to zero lash
Turn the adjuster inward until the free play just disappears (zero lash). The pushrod or rocker will just settle without up/down slack. - Add preload
From zero lash, turn the adjuster 1 to 2 full turns (commonly ~1.5 turns) inward to apply preload. - Tighten the locknut
Hold the adjuster screw and tighten the 13 mm locknut carefully. - Rotate crank 180°
Turn to the next cylinder in the firing sequence and repeat until all eight valves are set. - Run engine & re-check
After adjustment, start engine. It may clatter briefly as lifters bleed up, then quiet down. After a short run, re-listen/observe for noises.
Tip: After a fresh engine build or when lifters have bled down, allow a few minutes of idling or driving at varied RPM so lifters fully pump up.
Common Pitfalls & Tips
- Always adjust when the engine is cold (for solid lifters).
- After tightening locknuts, always recheck the clearance. The act of tightening often shifts the adjuster.
- Don’t overtighten valves — if you hear a “popping” sound while adjusting, you’ve gone too far.
- For hydraulic lifters, don’t overtighten beyond preload range — the lifter must still move freely.
- Replace valve cover gaskets if hard or glazed.
- Double-check that your cylinder is on compression (both valves closed) when adjusted.
- Always rotate crank in the correct direction (usually clockwise when viewed from the pulley side) — avoid forcing backwards.
