All valves and valve seats should be checked for wear and damage and repaired or replaced if necessary. Valve springs should be checked for their unloaded and loaded lengths and any springs that do not meet the target numbers should be replaced. To accurately control the valve springs, use a special test device.
The valve guides are checked for wear with a special control rod. If the outer side slides into the hole, the valve guides must be replaced. Valve guide bushings are knocked out with a special rod. If valve guides with normal size 1 can still be fitted, the bushings are driven in with a pin until they reach the thrust spring. If oversized valve guides are to be fitted, the main hole must be machined with a hand reamer. Valve guides should be selected so that the required overlap is maintained. Heat the cylinder head in a water bath to 80'-90'C and, if possible, cool the guide bushings with dry ice. Lubricate the guide bushings with grease and drive them in with a pin until they reach the thrust ring in the cylinder head.
Check the inner diameter of the guides with a control rod. The control side of the control rod should fall,"while the oversized side should not pass. If necessary, reamer the inside side.
The valve seat rings are pressed into the cylinder head. The old ring is best removed by drilling or turning it out with a valve seat rotator until it can come off. In doing so, care must be taken not to damage the cylinder head. Measure the main hole D1.
Engine 280S and 280SE: Left - intake, Right - exhaust.
V8 engine: Left - intake, Right - exhaust.
If necessary, move on to the next oversize. A new valve seat ring may be used without machining the main bore if the required overlap is present.