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From time to time, the valves need to be adjusted. It is necessary for the engine to function properly that the valves are properly adjusted. 

On both sides of the engine block is a cylinder head with a total of four valves. Two exhaust valves and two intake valves. In particular, the exhaust valves have to deal with it. The red-hot gas mixture that has just been burned blows past it again and again at an enormous speed. The temperature of this combusted gas can rise to about 1000ºC. The valves are therefore constantly cooled with oil.Despite this, both the valves, the valve stems and the rocker arms get quite warm. However, warm materials expand and to prevent the valves from closing completely due to expansion, a small amount of space must be left between the rocker arm and the valve stem. Not too much, because then the valves won't open far enough, but certainly not too little, because then they won't be able to close properly.It seems so simple, a little space or play in between and then you're fine. But over the years, various engine types have been developed. The valves of all these types have to be adjusted periodically (every 10000km), but unfortunately not all in the same way. We will try to indicate as briefly as possible what differences there are and then only describe the adjustment of the valves of the .

Koud of warm?2CVs from before March 1954 are set with a cold engine, then until about 1973, with a warm engine. This meant that the car had to be driven for a while before adjusting the valves. The first mentioned adjustment when the engine is cold is 0.15 mm for the intake valves. and 0.20 mm. for the exhaust valves. If the adjustment has to be done for a warm engine (see the Citroën manual for this) then the clearance for both types of valves is 0.20 mm.

With the 2CV6 engines, the valves are adjusted at 20ºC outside temperature, with a cold engine. Both the inlet and exhaust valves are adjusted to 0.20 mm.This applies to modern 602cc engines.

Adjusting valves for a 2CV6 and similar engines with cooled engine:Place a small container (e.g. from the Chinese or an empty butter dish) under the valve cover, to collect the oil that is in the valve cover. It's just a little bit of oil, but if there's no container underneath, it makes a lot of mess.

After loosening the nut of this cover with wrench 12, it is sometimes necessary to give the cover a small tap with a plastic hammer to loosen it. We do the same on the other side.

There are three methods that can be used to adjust the valves. All three work equally well and it's up to you what you find easiest to work with.

Method 1: (Opposite Valves) The engine should be turned until one valve is fully opened on one side. Now adjust the same valve on the other cylinder. This procedure must be performed for each valve.

Method 2: (Same Side) One valve is fully open; The other valve on the same side needs to be adjusted. This procedure should also be performed for each valve.

Method 3: (balanced) On one side, both valves must be in the same position. The exhaust valve closes and the intake valve is just starting to open. When both valves are at the same height, adjust both valves on the other cylinder.

What I'm describing here is method 1.

We can make the engine run slowly by hand with the crank, or by lifting one front wheel just off the ground with a jack. When the gearbox is put in second gear, the wheel can be turned with little force and the engine rotates with it. Some people disassemble the spark plugs so that the engine runs more easily without resistance. Personally, I am not in favour of this, because something could always fall into it.

We then turn the engine around until we see one of the bottlenose dolphins go inside.

We stop turning and can now check the rocker arm of the opposite cylinder and adjust it if necessary.

If a 0.20 mm feeler gauge can pass smoothly between the valve stem and the rocker arm, the valve is in the right position. If you hear a (soft) tap when you run a feeler gauge of 0.20mm through it, it is just not in the right position. What should definitely go smoothly through it is 0.15 mm. If 0.25 mm fits smoothly, the clearance must be adjusted to 0.20 mm.The easiest way to adjust this is with a special valve adjustment wrench. However, I can also do it with (ring) wrench 10 and a well-fitting screwdriver.

We check the other valves in exactly the same way by opening the same valve from the opposite cylinder.

Personally, I always err on the side of caution, and turn the engine around a few times and then measure again. After all four valves have been properly adjusted, the cover is reassembled. First, check the valve cover gasket. This one should still be flexible, you should be able to make an impression in it with your nail. Replace the gasket if it is too hard.

The valve cover gasket should be glued to the valve cover with Bostik 1400 Neoprene adhesive. If present, the widest part of the gasket should be at the bottom. The lid should only be tightened very lightly, 5-7 Nm if you have a torque wrench. In practice without a torque wrench, you can tighten the nut of the valve cover by hand and then half a turn extra with the wrench12 tighten until there is some tension on the lid. The lid must no longer be able to be moved back and forth by hand, otherwise the nut will have to be turned at most once. If you make more strokes, you run the risk of pulling out the stud when the engine warms up. After lightly tightening the covers, check if there is any oil leakage by running the engine. After this, check the oil level and top it up.