Jeep Wrangler TJ. Manual - part 424
• High speed power tool with an abrasive pad or a
wire brush.
NOTE: Multi-Layer Steel (MLS) head gaskets require
a scratch free sealing surface.
Only use the following for cleaning gasket surfaces:
(Fig. 3)
• Solvent or a commercially available gasket
remover
• Plastic or wood scraper.
• Drill motor with 3M Roloc™ Bristle Disc (white
or yellow).
CAUTION: Excessive pressure or high RPM (beyond
the recommended speed), can damage the sealing
surfaces. The mild (white, 120 grit) bristle disc is
recommended. If necessary, the medium (yellow, 80
grit) bristle disc may be used on cast iron surfaces
with care.
MEASURING BEARING CLEARANCE USING
PLASTIGAGE
Engine crankshaft bearing clearances can be deter-
mined by use of Plastigage or equivalent. The follow-
ing is the recommended procedure for the use of
Plastigage:
(1)
Remove oil film from surface to be checked.
Plastigage is soluble in oil.
(2) Place a piece of Plastigage across the entire
width of the bearing shell in the cap approximately
6.35 mm (1/4 in.) off center and away from the oil
holes (Fig. 4). (In addition, suspected areas can be
checked by placing the Plastigage in the suspected
area). Torque the bearing cap bolts of the bearing
being checked to the proper specifications.
(3)
Remove the bearing cap and compare the
width of the flattened Plastigage with the metric
scale provided on the package. Locate the band clos-
est to the same width. This band shows the amount
of clearance in thousandths of a millimeter. Differ-
ences in readings between the ends indicate the
amount of taper present. Record all readings taken.
Compare clearance measurements to specs found in
engine specifications (Refer to 9 - ENGINE - SPECI-
FICATIONS). Plastigage generally is accompa-
nied by two scales. One scale is in inches, the
other is a metric scale.
NOTE: Plastigage is available in a variety of clear-
ance ranges. Use the most appropriate range for
the specifications you are checking.
(4) Install
the
proper
crankshaft
bearings
to
achieve the specified bearing clearances. (Refer to 9 -
ENGINE/ENGINE
BLOCK/CRANKSHAFT
MAIN
BEARINGS - STANDARD PROCEDURE) (Refer to 9
- ENGINE/ENGINE BLOCK/CONNECTING ROD
BEARINGS - STANDARD PROCEDURE)
FORM-IN-PLACE GASKETS AND SEALERS
There are numerous places where form-in-place
gaskets are used on the engine. Care must be taken
when
applying
form-in-place
gaskets
to
assure
obtaining the desired results. Do not use form-in-
place gasket material unless specified. Bead size,
continuity, and location are of great importance. Too
thin a bead can result in leakage while too much can
result in spill-over which can break off and obstruct
fluid feed lines. A continuous bead of the proper
width is essential to obtain a leak-free gasket.
There are numerous types of form-in-place gasket
materials that are used in the engine area. Mopar
t
Engine RTV GEN II, Mopar
t ATF-RTV, and Mopart
Gasket Maker gasket materials, each have different
properties and can not be used in place of the other.
MOPAR
t ENGINE RTV GEN II is used to seal
components exposed to engine oil. This material is a
specially designed black silicone rubber RTV that
retains adhesion and sealing properties when exposed to
engine oil. Moisture in the air causes the material to
cure. This material is available in three ounce tubes
and has a shelf life of one year. After one year this
material will not properly cure. Always inspect the
package for the expiration date before use.
MOPAR
t ATF RTV is a specifically designed
black silicone rubber RTV that retains adhesion and
sealing properties to seal components exposed to
automatic transmission fluid, engine coolants, and
moisture. This material is available in three ounce
tubes and has a shelf life of one year. After one year
this material will not properly cure. Always inspect
the package for the expiration date before use.
Fig. 4 Plastigage Placed in Lower Shell - Typical
1 - PLASTIGAGE
TJ
ENGINE 2.4L
9 - 11
ENGINE 2.4L (Continued)