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FORM-IN-PLACE GASKETS

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. Bead size, continuity, and location are of great importance. Too thin a bead can result in leakage while too much can result in spillover which can break off and obstruct fluid feed lines. A continuous bead of the proper width is essential to obtain a leak-free joint.

Two types of form-in-place gasket materials are used in the engine area. Mopar Silicone Rubber Adhesive Sealant and anaerobic gasket materials, each have different properties and cannot be used interchangeably.

MOPAR SILICONE RUBBER ADHESIVE SEALANT

Mopar Silicone Rubber Adhesive Sealant or equivalent, normally black in color, is available in three ounce tubes. Moisture in the air causes the Mopar Silicone Rubber Adhesive Sealant material to cure. This material is normally used on flexible metal flanges. It has a shelf life of one year and will not properly cure if over age. Always inspect the package for the expiration date before use.

MOPAR GASKET MAKER

MOPAR Gasket Maker is an anaerobic type gasket material normally red in color. The material cures in the absence of air when squeezed between two metallic surfaces. It will not cure if left in the uncovered

tube. It is normally red in color. The anaerobic material is for use between two machined surfaces. Do not use on flexible metal flanges.

GASKET DISASSEMBLY

Parts assembled with form-in-place gaskets may be disassembled without unusual effort. In some instances, it may be necessary to lightly tap the part with a mallet or other suitable tool to break the seal between the mating surfaces. A flat gasket scraper may also be lightly tapped into the joint but care must be taken not to damage the mating surfaces.

SURFACE PREPARATION

Scrape clean or wire brush all gasket surfaces removing all loose material. Inspect stamped parts to assure gasket rails are flat. Flatten rails with a hammer on a flat plate if required. Gasket surfaces must be free of oil and dirt. Make sure old gasket material is removed from blind attaching holes.

FORM-IN-PLACE GASKET APPLICATION

Assembling parts using a form-in-place gasket requires care but it's easier than using precut gaskets.

MOPAR Gasket Maker material should be applied sparingly 1mm(0.040 inch.) diameter or less of sealant to one gasket surface. Be certain the material surrounds each mounting hole. Excess material can easily be wiped off. Components should be torqued in place within 15 minutes. The use of a locating dowel is recommended during assembly to prevent smearing the material off location.

9 - 2 ENGINE

The MOPAR Silicone Rubber Adhesive Sealant gasket material or equivalent should be applied in a continuous bead approximately 3mm (0.120 inch) in diameter. All mounting holes must be circled. For corner sealing, a 3.17 or 6.35 mm (1/8 or 1/4 inch.) drop is placed in the center of the gasket contact area. Uncured sealant may be removed with a shop towel. Components should be torqued in place while the sealant is still wet to the touch (within 10 minutes). The usage of a locating dowel is recommended during assembly to prevent smearing of material off location.

CRANKSHAFT SPROCKET BOLT ACCESS PLUG

An Access plug is located in the right inner fender shield. Remove the plug and insert proper size socket, extension and rachet, when crankshaft rotation is necessary.

ENGINE PERFORMANCE

If a loss of performance is noticed, ignition timing should be checked. If ignition timing is retarded by 9, 18 or 27° indicating 1, 2 or 3 (timing belt) teeth may have skipped, then, camshaft and accessory shaft timing with the crankshaft should be checked. Refer to Engine Timing Sprockets and Oil Seals of the Engine Section.

To provide best vehicle performance and lowest vehicle emissions, it is most important that the tune-up be done accurately. Use the specifications listed on the Vehicle Emission Control Information label found in the engine compartment.

(1)Test cranking amperage draw. See Starting Motor Cranking Amperage Draw Electrical Section of this manual.

(2)Tighten the intake manifold bolts to specifica-

tions.

(3)Perform cylinder compression test.

(a)Check engine oil level and add oil if necessary.

(b)Drive the vehicle until engine reaches normal operating temperature.

(c)Select a route free from traffic and other forms of congestion, observe all traffic laws, and accelerate through the gears several times briskly.

CAUTION: Do not overspeed the engine. The higher engine speed may help clean out valve seat deposits which can prevent accurate compression readings.

(d)Remove all spark plugs from engine. As spark plugs are being removed, check electrodes for abnormal firing indicators fouled, hot, oily, etc. Record cylinder number of spark plug for future reference.

(e)Disconnect coil wire from distributor and secure to good ground to prevent a spark from starting a fire (Conventional Ignition System). For Di-

Ä

rect Ignition System DIS disconnect the coil connector.

(f)Be sure throttle blade is fully open during the compression check.

(g)Insert compression gage adaptor into the #1 spark plug hole in cylinder head. Crank engine until maximum pressure is reached on gage. Record this pressure as #1 cylinder pressure.

(h)Repeat Step G for all remaining cylinders.

(i)Compression should not be less than (689kPa) 100 psi and not vary more than 25 percent from cylinder to cylinder.

(j)If one or more cylinders have abnormally low compression pressures, repeat steps 4b through 4h.

(k)If the same cylinder or cylinders repeat an abnormally low reading on the second compression

test, it could indicate the existence of a problem in the cylinder in question.

The recommended compression pressures are to be used only as a guide to diagnosing engine problems. An engine should not be disassembled to determine the cause of low compression unless some malfunction is present.

(4)Clean or replace spark plugs as necessary and adjust gap as specified in Electrical Group 8. Tighten to specifications.

(5)Test resistance of spark plug cables. Refer to Ignition System Secondary Circuit Inspection Electrical Section Group 8.

(6)Inspect the primary wire. Test coil output voltage, primary and secondary resistance. Replace parts as necessary. Refer to Ignition System and make necessary adjustment.

(7)Ignition timing should be set to specifications. (See Specification Label in engine compartment).

(8)Test fuel pump for pressure and vacuum. Refer to Fuel System Group 14, Specifications.

(9)The air filter elements should be replaced as specified in Lubrication and Maintenance, Group 0.

(10)Inspect crankcase ventilation system as outlined Lubrication and Maintenance, Group 0. For emission controls see Emission Controls Group 25 for service procedures.

(11)Inspect and adjust accessory belt drives refering to Accessory Belt Drive in Cooling System, Group 7 for the proper adjustments.

(12)Road test vehicle as a final test.

HONING CYLINDER BORES

Before honing, stuff plenty of clean shop towels under the bores, over the crankshaft to keep abrasive materials from entering the crankshaft area.

(1) Used carefully, the cylinder bore resizing hone C-823 equipped with 220 grit stones, is the best tool for this job. In addition to deglazing, it will reduce taper and out-of-round as well as removing light

scuffing, scoring or scratches. Usually a few strokes will clean up a bore and maintain the required limits.

(2)Deglazing of the cylinder walls may be done using a cylinder surfacing hone, Tool C-3501, equipped with 280 grit stones (C-3501-3810) if the cylinder bore is straight and round. 20-60 strokes depending on the bore condition will be sufficient to provide a satisfactory surface. Inspect cylinder walls after each 20 strokes. Use a light honing oil available from major oil distributors. Do not use engine or transmission oil, mineral spirits or kerosene.

(3)Honing should be done by moving the hone up and down fast enough to get a cross-hatch pattern. When hone marks intersect at 50-60 degrees, the cross hatch angle is most satisfactory for proper seating of rings (Fig. 1).

Fig. 1 Cylinder Bore Cross-Hatch Pattern

(4)A controlled hone motor speed between 200-300 RPM is necessary to obtain the proper cross-hatch angle. The number of up and down strokes per minute can be regulated to get the desired 50-60 degree angle. Faster up and down strokes increase the cross-hatch angle.

(5)After honing, it is necessary that the block be cleaned again to remove all traces of abrasive.

CAUTION: Be sure all abrasive are removed from engine parts after honing. It is recommended that a solution of soap and hot water be used with a brush and the parts then thoroughly dried. The bore can be considered clean when it can be wiped clean with a white cloth and cloth remains clean. Oil the bores after cleaning to prevent rusting.

Fig. 2 Plastigage Placed in Lower Shell

Fig. 3 Clearance Measurement

MEASURING MAIN BEARING CLEARANCE AND CONNECTING ROD BEARING CLEARANCE

PLASTIGAGE METHOD

Engine crankshaft bearing clearances can be determined by use of Plastigage or equivalent. The following is the recommended procedure for the use of Plastigage:

(1)Remove oil film from surface to be checked. Plastigage is soluble in oil.

(2)The total clearance of the main bearings can only be determined by removing the weight of the crankshaft. This can be accomplished by either of two methods:

PREFERRED METHOD Ð Shimming the bearings adjacent to the bearing to be checked in order to remove the clearance between upper bearing shell and the crankshaft. This can be accomplished by placing a minimum of 0.254mm (.010 inch) shim (e.g. cardboard, matchbook cover, etc.) between the bearing shell and the bearing cap on the adjacent bearings and snuggling bolts to 14-20 Nzm (10-15 ft. lb.)

²When checking #1 main brg shim #2 main brg

²When checking #2 main brg shim #1 & 3 main brg

²When checking #3 main brg shim #2 & 4 main brg

²When checking #4 ming brg shim #3 & 5 main brg

²When checking #5 main brg shim #4 main brg