Step by step instructions on how to perform valve adjustments in an air cooled VW engine.
Maintaining proper valve adjustment will help your air cooled engine to run smoother and more efficient. Improper valve clearances are one of the primary core causes of mechanical and efficiency problems in air cooled engines. Due to the nature of the air cooled engine frequent valve adjustments will have a major impact on your classic Volkswagen engine’s life and performance.
If the valve clearances are too small the valves will remain open too long which will cause them to over heat. If clearances are too large the opposite will happen, the valves will stay closed too long and will interfere with the intake of fuel and exhaust of burned fuel. Either way, if your valves aren’t adjusted correctly your air cooled Volkswagen will not run smoothly. Read on to learn how to adjust your own valves.
On many later model Volkswagens the cylinder order is printed on the engine cover. Whether or not your VW has the cylinder order printed on the sticker you can easily determine the ordering. Stand, or imagine standing, behind your VW. The cylinders are numbered from front to back on all air cooled VW engines. The cylinder nearest the passenger side back seat is Number 1. Cylinder Number 2 is directly behind it and nearest the passenger side rear. Cylinder 3 is in the front on the left (drivers side) and 4 is behind it.
The engine must be completely cool when checking and adjusting valves.
1. Disconnect the positive battery cable to help avoid accidents; Engage emergency break or chock the wheels if necessary; Put the transaxle in neutral – Be safe!
2. Take off the distributor cap and set it aside so that you can see the rotor button and the distributor rim.
3. The engine needs to be turned so that the appropriate piston is at top dead center (TDC). Using a wrench or socket turn the crankshaft pulley clockwise until the rotor button is pointing at the mark in the distributor rim. Now look down at the timing mark on the pulley, it should be aligned with the seem of the crank case. With your engine in this position the number 1 cylinder is at TDC and both intake and exhaust valves are closed.
4. Remove the cylinder valve cover by inserting a large screwdriver or similar tool into the wire bail and prying upwards. Be careful not to bend the cover or make any dings in the cylinder head rim. Try wiggling the pair of rocker arms toward the front of the engine, on your right as you are facing the cylinder head. The rocker arms should have some clearance. Believe it or not experienced air cooled engine mechanics can tell right here whether or not the valve clearances are correct.
5. Insert the appropriate feeler gauge in between each valve stem and it’s adjusting screw. If the blade slides in and out smoothly or with just a slight tug your valves are adjusted properly. If a valve needs to be adjusted first loosen the locknut then turn the adjusting screw while rechecking the clearance. The trick is to get the locknut tightened back down without altering the valve clearance. Be sure to verify the clearance once a locknut is tightened and readjust if needed.
Now you are ready to go on to cylinder number 2. Rotate the crankshaft so that the rotor button rotates counterclockwise until the button is pointed 90 degrees from the mark in the distributor rim. Cylinder 2 is now at TDC. For cylinders 3 and 4 just repeat the steps, each time rotating the rotor button counterclockwise an additional 90 degrees.
6. Before replacing the valve covers inspect the rocker arms and the oil as well as the rim of the cylinder head. If there are any pieces of gasket material stuck to the head it will need to be cleaned off. Also inspect the inside of your valve covers. Once everything is clean reinstall the valve covers, preferably with new gaskets.
Proceed to Step 3 of tune up procedure How To Change & Adjust Air Cooled VW Points
Written by David Slone, Copyright 2008 all rights reserved.
Here is a video that will give you some good details about adjusting valves on an air cooled Volkswagen engine. This air cooled Volkswagen valve adjustment How to video is presented for its valuable information, I did not produce this video nor do I endorse those who did:
This is a vintage VW training film recorded directly from the original filmstrip and record. It describes how to adjust the valves: