V-304, V-345, V-392,
V-401, V-461, and V-549 Engines
PISTON BURNING, CYLINDER WALL SCUFFING AND SCORING
Piston
burning and cylinder wall scoring and scuffing can result in
the International V-8 engine for a number of reasons. Most or
all of these problems can be eliminated by following the suggested
service tips:
1. Allow .0035
to .0045 clearance between the piston and the cylinder wall,
top and bottom.
2. If possible, use a C-grind piston
that has an interrupted surface or thread finish in place
of the tin-coated or regular piston. If a C-grind piston is
not available, lightly micro-knurl the piston on both thrust
surfaces. CAUTION: Be sure that the piston-to-cylinder wall
clearance is rechecked after the pistons are knurled. The
light knurling pattern will expand the pistons slightly and
it is important that the piston-to-cylinder wall clearance
be checked carefully in accordance with the recommended clearance.
NOTE: C-grind piston refers to skirt
finish not to a C cam.
3. Chamfer the bottom edge of the piston
45 degrees around the entire outside diameter of the piston.
Chamfering the bottom edge of the piston provides better lubrication
and piston cooling.
4. Use a 160° thermostat in the radiator. The 160° thermostat will open faster and will allow the heat transfer
from the cylinder to the coolant more rapidly.
5. Be sure that the radiator and all
coolant hose and connections are in good condition. The radiator
should be cleaned and rodded to insure maximum cooling capacity.
6. Installation
of valve seals to improve engine performance should be considered.
Valve seals eliminate excessive oil from passing through the
valve guides, and reduce oil consumption.
This
also eliminates contamination of the air fuel mixture and
insures better engine performance. Oil and air leaking through
the guides can also increase fuel octane requirements for
the engine by dilution of the fuel-air mixture in the combustion
chambers and often resulting in piston burning and cylinder
wall scuffing and scoring.
7. Be sure that the vacuum line is
disconnected when setting timing. It is important that the
timing be rechecked after the vacuum line is reconnected.
This will insure that the timing has not been advanced beyond
the manufacturer's recommendations.
8. Ignition timing: Disconnect the
vacuum line to the distributor. Use a timing light and set
the ignition timing to the following specifications:
V-304
V-345
V-392
TDC
TDC
5° 0BTC
V-401
V-461
V-549
5° 0BTC
7° 0BTC
7° 0BTC
All Propane engines: 14° BTC
NOTE: Connect the vacuum after setting
the ignition timing.
