Table 3.05-1. Connecting Rod Specifications

CRANKCASE SERVICING

CONNECTING ROD, BUSHING AND BEARING

ROD MATERIAL - Heat treated steel forging

ALLOWABLE WEIGHT VARIATION - 90 grams (3 oz.)

Measurement Wear Limit mm (in.) New Minimum mm (in.) New Maximum mm (in.)

(A) Rod Length, Center To Center 259.96 (10.234) 259.96 (10.234) 260.04 (10.237)

(B) Rod Small End Finish Size - 53.848 (2.120) 53.800 (2.118) 53.830 (2.119)w/o bushing

(C) Bushing Bore Diameter 1 50.076 (1.9715) 50.030 (1.969) 50.043 (1.970)

(D) Rod Large End Finish Size - 88.519 (3.485) 88.483 (3.483) 88.505 (3.484)w/o bushing

(E) Rod - w/bearing-Inside Diameter - New 84.302 (3.319) 84.233 (3.316) 84.255 (3.317)

Bushing Press Fit In Rod 0.043 (0.0017) 0.069 (0.0027) 0.150 (0.0059)(Interference Fit Between Rod And Bushing)

Rod Large End Width - 58.75 (2.312) 58.80 (2.314)

Rod Side Clearance - 0.20 (0.008) 0.35 (0.013)

Bearing Running Clearance 0.213 (0.0084) 0.05 (0.0019) 0.112 (0.0044)

Connecting Rod Maximum Twist 0.02 (0.0007) - -Small End Maximum Taper 0.018 (0.0007) - -Big End Maximum Taper 0.014 (0.0005) - -NOTE: 1 Connecting rod surface quality must be 0.6 micrometers (23.6 microinches) roughness average.

CONNECTING ROD, INSPECTINGr:A WARNING

Use only non-flammable cleaning solvent. Do notuse gasoline, paint thinners or other volatile fluidsfor cleaning. Comply with the solvent manufactur-er's recommendations for proper use and handlingof solvents. Improper handling or misuse couldresult in severe personal injury or death.

1. Clean the connecting rod threads and the matingsurface between the rod and the cap with an approvedcleaning solvent.

2. Clean the oil hole at the top of the rod.

3. Clean all bolts thoroughly and inspect for nicks orthread damage.

4. Lubricate the bolts with SAE 30 oil and screw into therod face by hand.

NOTE: If bolts cannot be installed by hand, clean thethreads of the rod again and try a new bolt. If a new boltdoes not screw in freely, discard the rod and install anew one (PIN 351043).

I A CAUTION I ~onotretaPtheconnect-.....;••==- .mg rod or bolt threads asthey are a special rolled thread.

5. Lubricate the bolt threads and washer faces withclean engine oil.

6. Torque connecting rod bolts in two steps to a torqueof 110 N·m (81 ft-Ib).

I A CAUTION I Connecting rod bolts•• can be tightened three

times before they must be replaced.

7. Check the inside diameter of the connecting rodbore, without the bearing insert, using a dial bore gauge(see Figure 3.05-8).

Figure 3.05-8. Measuring Connecting Rod Bore

FORM 6259 First Edition 3.05 - 3

CRANKCASE SERVICING

8. With rod cap torqued to specification, measure andrecord the three inside diameters of each connectingrod at points A, B, and C (see Figure 3.05-9).

DIAMETERB

DIAMETERA

Figure 3.05-9. Measuring Connecting Rod

9. If the difference between points A and C is over0.05 mm (0.002 in.), the rod should be discarded.

10. If the difference between point B and the average ofA and C (A and C divided by 2) exceeds 0.05mm (0.002in.), the rod should be discarded.

11. Check the inside diameter of the connecting rodpiston pin bore. Replace the bushing if worn beyonddimensional limits. Refer to Section 1.05 GeneralInformation for dimensions.

I A CAUTION I Spe~ial attention should'-== ....1 be given to all aspects ofthe connecting rods and bolts. Lack of attentionduring an overhaul could result in rod bearingfailure.

NOTE: Always check the connecting rod if thecylinder has been water filled, a piston has seized ora valve is broken.

I A CAUTION I Never s~raighten a bent'-.==- ---'.connectmg rod. It mustbe replaced.

CHECKING CONNECTING RODSTRAIGHTNESS

CONNECTING ROD TWIST

NOTE: This procedure should be performed afterpiston pin bushings have been checked, rod capsinstalled with markings aligned and bolts have beentorqued to 110 N·m (81.ft-lb).

1. Attach the connecting rod to an alignment fixture andinstall the piston pin into the piston pin bushing (seeFigure 3.05-1 0).

{

r

INDICATOR VSG159

Figure 3.05-10. Connecting Rod Twist Gap

2. Place the indicator on the piston pin.

3. With the indicator studs horizontal, use a feelergauge to measure the gap between the studs and thefixture.

NOTE: Connecting rod allowable maximum twist is0.02 mm (0.0007 in.).

4. If the connecting rod does not meet specifications itmust be replaced.

3.05 - 4 FORM 6259 First Edition

CONNECTING ROD BENDING

CRANKCASE SERVICING

1. With the connecting rod still mounted in the align-ment fixture proceed as follows:

• With indicator studs vertical, use a feeler gauge tomeasure gap between the studs and the fixture (seeFigure 3.05-11).

INDICATOR VSG158

Figure 3.05-11. Connecting Rod Bend Gap

• The maximum gap between either indicator stud andthe fixture is 0.1 mm (0.004 in.).

2. If connecting rod does not meet specifications it mustbe replaced.

PISTON, INSPECTING

1. Visually check pistons for scuffed or scored skirtsand cracked or worn piston ring lands. Replace thepiston if this type of damage is found.

2. Check the piston tops for evidence of burning,etching or melting caused by detonation or preignition.

3. Check for imprints caused by contact with valves. Ifimprints can be seen the engine has been assembledout of time. Retime the engine.

4. Inspect the piston pins for wear or damage. Replaceif necessary.

PISTON, CLEANING

A WARNINGUse only a non-flammable cleaning solvent. Do notuse gasoline paint thinners or other highly volatilefluids for cleaning. Comply with the solventmanufacturer's recommendations for proper useand handling of solvents. Improper handling ormisuse could result in severe personal injury ordeath.

NEW PISTONS

1. Make sure that the piston is clean.

2. Coat the pistons with clean engine oil and assembleinto the engine.

USED PISTONS

1. Use an approved cleaning solvent and a soft bristlebrush to degrease the pistons.

2. To remove carbon deposits, immerse the pistons in aconcentrated solution of liquid cleaner heated to 50° C(122° F) for a minimum of twenty four hours.

3. If stubborn deposits remain, brush the pistons usinga hard brass brush.

4. Dry with moisture-free compressed air.

NOTE: After piston cleaning has been performed,reinspect to determine usability of pistons. Refer toTable 3.05-2.

5. Coat with clean engine oil and assemble into theengine immediately. See Section 4.00 CrankcaseAssembly, for piston installation.

FORM 6259 First Edition 3.05 - 5