Perkins New 1000 Series, Руководство по ремонту, Страница: 56 / 290

12
56 Workshop Manual, TPD 1350, issue 3
New 1000 Series
To fit valve seat inserts 12-14
1 Remove the valve guide and clean the bore into
which the guide is to be fitted.
2 Fit new partially finished valve guides , see
operation 12-11 .
3 With the bore of the new partially finished valve
guide used as a pilot, machine the recess in the
cylinder head to the dimensions shown in data and
dimensions at the end of this section, or machine out
the old insert. Remove all debris and clean the insert
recess.
4 If the bottom face of the cylinder head has been
machined, the insert will have to be surface ground on
the back face to ensure that there is no protrusion of
the insert above the bottom face of the cylinder head.
After the back of the insert has been ground, ensure
that the outer edge of the back face has a 0,9/1,3 mm
(0.035/0.051 in) chamfer at 30° to the vertical.
5 With the bore of the new, partially finished, valve
guide used as a pilot, and with the rear face of the
insert towards the cylinder head, press in the insert
with the valve seat insert tool, see data and
dimensions. Do not use a hammer on the insert and
do not use lubrication. Use a hydraulic press or a
hand press in one continuous movement. Ensure that
the bottom of the insert is in contact with the bottom of
the recess.
6 Ream the valve guide and cut the valve seat at an
included angle of 88° for 46° valve seats or 118° for
31° valve seats
, see operation 12-13 . Ensure that the
depth of the valve head below the face of the cylinder
head is within the production limits, see data and
dimensions. Work as near as possible to the minimum
figure to allow for future wear on the valve seat.
Purchased from www.WorkshopManuals.co.uk