Onan DJA Series User Manual

seating on the cylinder wall. Fit each ring to the cylinder
wall at the bottom of its' travel, using the piston to square
the ring in the bore. Check the gap with a feeler gage. It
should be .010" to .020". If the gap is too small, file the
butt ends of the rings. Do not use rings that need a lot of
filing, they will not seat right on the cylinder wall. If an
oversize piston is used, use the correct oversize rings.
CONNECTING RODS
Clean the connecting rod and check for defects. Check the
connecting rod bushings for proper clearance with the piston
pin. Clearance should be .0002" to .0007".
If the bushings are excessively worn, press them out and
install one new bushing from each side of the bushing bore.
Press the new bushings only until flush with the sides of
the rod to leave 1/16" to 7/64" oil groove in the center
(Fig. 12-2).
CONNECTING ROD BEARINGS
Inspect the connecting rod bearings for burrs, breaks, pits
and wear. Measure the clearance between bearings and the
crankshaft journal. The clearance should be .001" to .003".
If necessary, replace with new standard or oversize pre-
cision bearings.
For information about the crankpin journals, see Engine
Disassembly Section.
ASSEMBLY AND INSTALLATION
1. Install the connecting rod on the piston with the pin
and retaining rings. If new bushings were installed,
check to see that the ends are flush with the connect-
ing rod to provide for the oil recess in the center.
. 2. Install the rings on the piston.- Tapered rings will be
marked top or identified in some pther manner. Place
this mark toward the closed end of the piston. Space
the ring gaps 1/4 gap of the way around the piston from
one another. No gap should be in line with the piston
pin. Oil the rings and piston.
3. Position a bearing half in the connecting rod. Be sure
there is no dirt under the bearing. This could cause
high spots and early bearing failure.
4. Oil the cylinder wall. Install the piston in the cylinder
using a suitable installer. The assembly should be in-
BE SURE THAT CONNECTING
O ROD WITNESS MARKS ARE
ALIGNED
nmillU'ltlllllHimillil
y-
o
CRANKSHAFT
FIG. 12-3
stalled with the stamp on the piston in the same direc-
tion as when removed.
5. Position the connecting rod on the crankshaft, oil the
joumal and install its' rod cap with bearing half. When
installing the rod cap, position so the raised witness
mark on the forging matches the mark on the connecting
rod (Fig. 12-3).
6. Tighten the cap screws to the specified torque.
7. Crank the engine over by hand to see that the bearings
are free.
8. Install the oil base with a new gasket.
9. Install the cylinder head using an even bolt tightening
sequence and specified torque.
10. Replace oil.
BREAK-IN PERIOD
Whenever new rings or pistons are installed or the cylinder
refinished, the engine must be run-in before regular operation
can be resumed. Run the engine for 15 - 20-minutes at no
load, about 1/2-hour at 1/3-load and 2 - 3-hours at 2/3-load.
Then regular operation can be resumed. Avoid light load
operation during the following several hours for best ring
seating to control oil.
34

Onan DJA Series Specifications

General

Brand	Onan
Model	DJA Series
Category	Engine
Language	English