Overhaul Periods; Cylinder Head; Valve Guides; Valves - Perkins 400 Series User Handbook Manual

MAINTENANCE SCHEDULE & CHECKLISTS

OVERHAUL PERIODS

The intervals at which routine overhauls are
required, to keep an engine in good
operating condition, will vary considerably
depending upon operating conditions, the
quality of lubricating oil and fuels used, and
the engine operating speed.
The frequency required for top overhaul will
depend upon the condition of valve seats,
and in the case of prolonged light load
operation, the
accumulated around the valves and on the
piston crowns.
A major influence on valve condition is
tappet clearance and the importance of
checking tappet clearances every 250 hours
cannot be overstressed.
After the FIRST 2500 HOURS operation of a
new engine it is good practice to remove the
unit injectors and check their condition, carry
out a compression test, and an endoscopic
(borescope) examination of liner and valve
condition. If there are any problems, then
remove TWO cylinder heads to assess the
condition of the valves, cylinder bores and
fuel injectors.
If all components are in good condition,
clean the parts and reassemble the engine
leaving the other cylinders alone.
This inspection will enable maintenance
engineers to decide upon the required
frequency of top overhaul to suit the
particular application.
EVERY 2500 HOURS (TOP OVERHAUL IF
NECESSARY)
A top overhaul may involve some or all of the
following operations depending upon the
hours run, the engine application and the
duty cycle.
WARNING
OTHER MEANS OF STARTING ENGINE.
59
amount of carbon
DISCONNECT THE
BATTERIES AND ALL

CYLINDER HEAD

NOTE: Service exchange cylinder heads
are available.
Remove the cylinder heads from the engine
and remove the inlet and exhaust valves.
Soak the cylinder head in a carbon removing
fluid or remove all deposits by use of a
scraper and wire brush.
Check for cracks especially between valve
ports and the injector hole. Check core plugs
and replace if leaking or corroded.
When handling, always protect the bottom
machined face from accidental damage.
Examine the injector tubes for leaks. Check
the nozzle seating face.
Prior o refitting the valves, wash the head
thoroughly and blow off with compressed air.
If new core plugs or injector tubes have been
fitted a hydraulic pressure test to 6.9 bar
(100 lb/in²) for leaks should be carried out
using hot water at 70-90°C (158-194°F) .
WARNING
ALWAYS WEAR EYE PROTECTION.

VALVE GUIDES

Inspect the bores of the guides for wear and
check the fit of a new valve. Check for pick-
up or scoring. Replace if necessary.

VALVES

Remove carbon and scale by soaking in a
water based solvent or by use of a scraper
and wire brush. Polish with fine emery cloth.
Examine the valve heads for cracks. Inspect
valve seats and true up by grinding to the
correct angle if required. Check the valve
stem tip for wear and reface by grinding if
necessary. (To a maximum limit of 0.4 mm
(0.015").
Check the valve stems for wear or scoring.
Check valve heads for distortion by rolling
the stems on a surface table. Scrap any bent
valves. Replace any worn collets and valve
spring retainers. Check valve protrusion
after refitting into head.
4012/16 Diesel, February 1997
WHEN USING
COMPRESSED AIR