Volkswagen Valve Adjustment
Volkswagen Valve Adjustment
Valves allow fresh air and fuel to enter the combustion chamber allow exhaust gasses to leave. For everything to work as engineered by the Germans, the valves must be allowed to fully seat when not open so that heat can be dumped to the head's heat sinks. This requires periodic adjustment of your VW's valves so that there is just enough play to allow for thermal expansion and wear of valve parts.
VW recommends that you adjust your valves every 3,000 miles. Some VWers adjust them every 1,000 miles, while others adjust them once a year.
13mm Box Wrench
19mm Box Wrench
Flat Tip Screwdriver
0.006in Feeler Gauge
Valve Cover Gaskets (2)
Proper valve adjustment requires that your VW engine is cold. Ideally, you should park your auto overnight and adjust your valves the following day. If your VW is really dirty, you may wish to give your work area a quick rinse.
Set your park brake and put your engine in neutral. Now familiarize yourself with you engine. The #1 cylinder is on the front right hand (passenger side of US autos) side of the engine. The #2 cylinder is behind the number one cylinder. The #3 cylinder is on the front left hand (driver side) of the engine. And the #4 cylinder is behind the #3 cylinder.
You need to get your #1 cylinder to Top Dead Center (TDC). This is done by using your distributor to as a cylinder position compass. Use your flat tip screwdriver to undo the 2 clips on the distributor. Under where the distributor cap was seated should be a slot in the lower right had side of the distributor as you face it from the rear of your VW. This slot indicates the position of the #1 cylinder.
Use your 19mm wrench to turn your generator/alternator pulley until the rotor in your distributor is facing the slot. If turning your fan pulley doesn't turn your engine pulley, you need to adjust or replace your fan belt. You can also use your 19mm wrench to turn the crank pulley directly.
If you have a crank pulley with laser engraved degree markings, life couldn't be easier. Just fine tune rotate your pulley so that TDC lines up with the seam between the engine halves. If you have a stock crank pulley, what you do exactly depends on which pulley you have. Review Finding Top Dead Center/Crankshaft Pulley to determine exactly where TDC is in you VW and mark your pulley at TDC and BDC (180 degrees opposite). The key in the crank pulley is at 9 o'clock if everything is lined up.
Thread a clean (slightly stained is OK) rag through the right (passenger side) valve cover bail, then pull on the rag to unlatch the bail. A rag won't scratch or dent the valve cover like a screwdriver.
Now you are set to adjust the valves on the #1 cylinder. Press bottom of the front two rocker arms to "open" things up. Use a 0.006" feeler gauge on both the #1 exhaust (rear most - adjacent to the rear exhaust pipe). The feeler gauge should just drag between the rocker arm and valve. If too tight (must force gauge) or too loose (slight too easy or rattles), use your 13mm box wrench to unlock the jam nut. Use your flat tip screwdriver to adjust the valve clearance. Then tighten the jam nut and recheck. Repeat until the clearance is just right on both of these valves. Then tighten your jam nuts all the way and do one final check.
Time to switch to cylinder #2. Turn your generator/alternator pulley Counterclockwise (to the left) so that the crank pulley rotates 180 degrees to Bottom Dead Center (BDC). Check and adjust your valves as needed, just like you did with the valves for Cylinder number one. The exhaust valve for the #2 cylinder is the rearmost valve (adjacent to the rear right header port) and the intake valve is the one just in front of the #2 exhaust valve.
Now we will check the #3 cylinder valves. Turn your generator/alternator pulley Counterclockwise (to the left) so that the crank pulley rotates 180 degrees to TDC. Remove your left (driver side) valve cover like you did with your right side. Check and adjust your valves as needed, just like you did with the valves for Cylinder number one. The exhaust valve for the #3 cylinder is the most forward valve (adjacent to the front left exhaust port) and the intake valve is the one just to the rear of the #2 exhaust valve.
Time to switch to cylinder #4. Turn your generator/alternator pulley Counterclockwise (to the left) so that the crank pulley rotates 180 degrees to BDC. Check and adjust your valves as needed, just like you did with the valves for Cylinder number one. The exhaust valve for the #3 cylinder is the rearmost valve (adjacent to the rear left header port) and the intake valve is the one just in front of the #3 exhaust valve.
If this is the first time you have ever adjusted your valves, you can recheck each valve again by rotating the crank pulley counter clockwise to TDC and start back at the #1 cylinder valves.
Now it's time to replace your valve covers. Check your valve cover gaskets (See the Valve Cover Gasket section below) and replace as necessary. Carefully reinstall your valve covers and pop the bails back on. Reinstall your distributor cap.
You are done. Start up your engine and listen for sounds. If you hear some clanking, something is too loose. Tapping is ok, and good.
Valve Adjustment 101
Valve Cover Gasket
Like just about everything with the VW, there are options to include poor quality options.
The original German cork gaskets work great. If you have time to get these, order them from Bus Depot.
Repo rubberized cork gaskets - some work fine, while others don't
Neoprene - these look like black rubber and seem like a good idea. The tend to leak.
Silicone - meant to be 100% reusable. They too seem like a good idea, but tend to leak.
RTV - this is messy and a bitch to remove later. It can also break off and jam up your oil passages in your VW engine. Aircraft sealant and glue seems to be a popular choice for those considering an RTV solution
One of the causes of valve cover leaks is that the gasket moves when you reinstall your valve covers. And if your gasket isn't lined up just right between your heads and valve cover, it's going to leak. Luckily there are several ways to keep your gaskets lined up.
Methods for Gasket Alignment
Wheel bearing grease - this will temporarily hold the gaskets in place while you are installing your valve covers. Some just grease the valve cover side, while others grease both sides. Go easy on the grease.
RTV - use a very thin bead of RTV on the valve cover to hold the gasket down. You should not have any RTV squeeze out into the inside of the valve cover. Do not put RTV on the head side of the gasket as this will make valve cover removal difficult and the silicone can squeeze into the head area, brake off and jam up your oil passageways.
Weld in tabs - a few VWers have welded in a few small tabs to hold their gaskets in place. This is nice solution for those wanting to avoid silicone and leaks.
The original German steel covers are durable (important for offroaders), seal well, can be banged back out when dented and actually cool your VW engine better than fancy aluminum covers.
These can get old, stretched or otherwise damaged. They can be rebent for more valve cover retention pressure or replaced with new ones. Bolt on valve covers are also available and seem like a good idea. Unfortunately, bolt on valve covers are notorious for leaking.
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