F
OR
M
ODELS
: JGI, JGM, JGN, JGP
AND
JGQ
S
ECTION
5 - M
AINTENANCE
PAGE 5-17
Crankshaft - Removal
1.
F
IGURE
5-12 C
RANKSHAFT
WITH
O
IL
S
LINGER
& S
PROCKET
Drive End
Oil Slinger
Main Bearing Journals
Crank Pins
Chain
Sprocket
Counterweights
Drain oil from crankcase.
2.
Remove the coupling. Remove the
coupling adapter.
3.
Remove the top cover and crank-
shaft seal housing (or connecting
rod, chain drive and crosshead
access covers for a JGI).
4.
Detach the connecting rods. (See
“Connecting Rod - Removal” on
page 5-6.) Move the rods to their
full outer position. For the JGI, crib-
bing at the crosshead guide
access hole is required to keep
connecting rod up at the full outer
position.
5.
Remove the cap screws on the chain adjustment cap. Turn the cap to loosen the
chain. Slip the chain off the crankshaft sprocket. Remove the force feed lubrica-
tor.
6.
Remove the cap screws from
the main bearing caps. Pull
the caps straight up to pre-
vent damage to the dowel fit.
If the cap is tight, use a Bear-
ing Cap Puller as illustrated
in the Figure. For the JGI
remove the cap screws in the
bearing carrier, remove car-
rier and slide crankshaft out
through carrier hole to
remove it.
F
IGURE
5-13 B
EARING
C
AP
P
ULLER
Crankshaft
13” (33 cm)
Long Steel Bar
1/2-13 UNC
Puller Hole
10” (250 mm) Long
1/2-13 UNC
Threaded Rod
Drill an 5/8”
(15 mm) Hole
1/2-13 UNC
Lock Nut
1/2-13 UNC Jack Nu
Turn Nut to Jack
Bearing Cap up.
7.
Before removing the crank-
shaft from the crankcase,
wooden saddles or a notched
wooden crate with sides high
enough to prevent the webs
or oil slinger from touching
bottom should be prepared in
order to store the crankshaft
during maintenance - even though it may be out for only a short time. In addition,
the crankshaft should be adequately protected from above so that dropped tools
or equipment cannot mar the surface of pins and journals.
8.
For horizontally opposed models, turn the crankshaft so that the drive end coun-
terweight is straight up. The two throw crankshaft weighs about 100 lb (45 kg)
and can be lifted out by two persons or by using a crane and a clean nylon lifting
sling at the second throw crank pin. The sling lifting point is to be above the cen-
ter of gravity of the shaft, so that it does not want to rotate when lifted. Lift the
crankshaft to tip up the chain drive end so that the crankshaft drive end will clear
the frame seal housing opening and allow removal. Great care must be taken