Dnepr MT9 - Checking the Valve Seat for Play

apply a thin layer of abrasive paste to the valve head chamfer
and, after first insert i ng the valve with the pressing - out spring into
the gu.ide bushing, fit an appliance TIP-1366 on the end of valve
stern for rotation of the valve;
rotate the valve by means of the appliance in both directions so
that the valve turn s progressively in one direction or the other . While
rotating the valve, periodically press it down to the seat.
f'ig. 16. Checking the valve seat for
play
Lap the head int o the seat careful ly so as not to remove too much
met al from the working chamfers as this will reduce the number of
permissible repairs. Toward s the end of lapping, reduce the amount
of paste and, at the final stage, perform the l apping using only a
pure oil.
Continue the lapping until a un iform l ust r eless colour appears on
the working surfaces of the valve head and seat, which is an indica-
tion of
sa ti sfacto ry lapping.
After lapping, thoroughly wash the valves, valve seats, gu.ide
bushir;gs, throat and cylinder head compression chamber to comple-
tely
remov e all the abrasive paste, then wipe them dry with a clean
cloth.
52