Compression Pressure Inspection - Hyundai Seasall S250S Workshop Manual

Engine Mechanical System

Compression Pressure Inspection

✍ NOTICE
• If the there is lack of power, excessive oil
consumption or poor fuel economy, measure the
compression pressure.
• Whenever removing injectors for compression
pressure inspection replace the gaskets with new ones
and tighten them with the specified torque.
1. Warm up engine until the normal operating
temperature (80~95°C (176-203℉)).
2. Remove the injectors. (Refer to Injector in FL Group)
3. Check the cylinder compression pressure.
1) Insert a compression gauge SST(00200-0T004，
00200-0T005) into the injector hole.
2) Fully open the throttle.
3) While cranking the engine, measure the
compression pressure.
✍ NOTICE
Always use a fully charged battery to obtain engine
speed of 220rpm or more
. 4) Repeat step 1) though 3) for each cylinder
✍ NOTICE
This measurement must be done in as short a time as
possible.
Compression pressure :
2,745.85kPa (28.0kg/cm², 398.25psi) (220 rpm)
Minimum pressure :
2,255.52kPa (23.0kg/cm², 327.14psi)
8
5) If the cylinder compression in 1 or more cylinders is
low, pour a small amount of engine oil into the cylinder
through the spark plug hole and repeat step1)
through ３) for cylinders with low compression．
• If adding oil helps the compression, it is likely that the
piston rings and / or cylinder bore are worn or damaged.
• If pressure stays low, a valve may be sticking or
seating is improper, or there may be leakage past the
gasket.
• If pressure doesn't rise despite dropping oil on the
pistons because of low pressure in the neighboring
cylinders, it can be caused by a poor cylinder head
gasket or stained oil or coolant in the cylinder head.
4. Reinstall the injectors. (Refer to Injector in FL Group)
General Information