Attention: On models 316i, 318i, the exhaust valves are filled with sodium to improve heat dissipation. They cannot be smelted and used as a tool (like punches). Explosive! Also, these valves should not just be thrown away. To dispose of them, cut the valve with a hacksaw in the middle of the valve stem into 2 parts. Do not allow the valve to come into contact with water. After that, throw the sawn parts of the valve into a bucket of water and step aside.
Caution: When sodium comes into contact with water, a rapid chemical reaction occurs, during which the sodium burns out.
Withdrawal
Attention: When reinstalling the parts of the valve actuator, they must be installed in their original places. To do this, when removing the parts, they must be folded in the order of installation.
Remove rocker arms (see section «Removal and installation of rocker arms»)
Compress the valve springs with BMW tool 111040 and remove the valve cotters -C-.
Attention: A conventional valve presser can also be used to compress the springs. Depending on the tool used, it may be necessary to remove the intake or exhaust manifold.
Unload the springs and remove the upper spring cup, valve spring, and lower spring cup.
Remove the oil seals with a special tool. The 791-5 flinger pliers or the 791-2 inertial puller from HAZET are best suited for this.
Pull the valve out of the cylinder head towards the combustion chamber.
Remove the next valve.
Installation
Before installing the valves, check the valve guides and possibly lap the valve seats.
Attention: When installing a new valve, lapping of the valve seat is mandatory.
Remove burrs from the contact surface of the valve stem with crackers.
Lightly coat the valve stem and guide with engine oil, and insert the valve.
Lightly lubricate with engine oil and push on flinger -A- with appropriate tool -D- until it stops.
Caution: To prevent damage to the oil slinger, put a mounting sleeve -H- on the valve stem before installing it. If there is no mounting sleeve, cover the contact surfaces of the valve cotters with smooth adhesive tape. After installing the flinger ring, remove the adhesive tape.
Insert the lower valve spring cup.
Insert spring and upper valve spring cup. Install springs only with the same length, manufacturer's markings and wire thickness.
Attention: From September 1982, springs with a length of 38±1 mm are installed (previously installed springs with a length of 37±1 mm). When installing a new cylinder head on an exhaust engine before September 1982 and at the same time changing the old valve springs, a 1 mm thick washer must be placed under the valve head. Later cylinder heads are marked with the letter «5» on the intake side and on the exhaust side.
Compress the valve spring and insert crackers. Slowly unload the valve spring, while ensuring the correct seating of the cotters.
Install the next valve. Do not confuse intake and exhaust valves.
Install rocker arms (see section «Removal and installation of rocker arms»).