Pressing out guide bushings
1 - mandrel А.60153/Я
Check the clearance between the valve guides and the valve stem by measuring the diameter of the valve stem and the bore of the valve guide. Estimated clearance for new bushings: 0.022–0.055 mm for intake valves and 0.029–0.062 mm for exhaust valves; maximum allowable clearance (when worn) 0.15 mm.
If the increased clearance between the guide sleeve and the valve cannot be eliminated by replacing the valve, replace the valve sleeves using drift A.60153/R.
To replace the two guide bushings for the intake and exhaust valves of cylinders N1 and N4, unscrew the two studs securing the camshaft bearing housing, as they interfere with the installation of the mandrel.
Press in the guide bushings with the retaining ring on until the ring stops against the plane of the cylinder head.
After pressing, expand the holes in the guide bushings with A.90310/1 reamers (for intake valve bushings) and A.90310/2 (for exhaust valve bushings). Then grind the valve seat and bring the width of the chamfer to the desired dimensions, as indicated above.