MITSUBISHI 4M50 CRANKSHAFT AND CRANKCASE Installation: Mitsubishi 4M50 Lower crankcase
CAUTION • Before installing the main bearing cap bolts, check the number of punch marks on the head of each bolt. (A bolt with two or less marks is reusable.) • The number of punch marks corresponds with the number of times the main cap bolt has been tightened using the torque-turn tightening method. Any bolt that has three marks (i.e. that has been used three times) must be replaced. • Clean all sealant application surfaces. • Apply evenly thick beads of sealant to the upper crankcase without any breaks as shown in the illustration. • Install the lower crankcase within three minutes of applying the sealant, being careful not to dislodge the sealant.
• Apply engine oil to the Mitsubishi 4M50 main cap bolt threads and seating surfaces of the bolt heads, then tighten them to a torque of 49 N·m {36 lbf·ft, 5.0 kgf·m} in the order indicated in the illustration (1 to 10). • Tighten each main cap bolt further by 90° in the same order. • Finally, tighten each bolt to the specified torque in the order indicated in the illustration (11 to 26).
CAUTION • After installing the bolts, wait at least an hour before starting the engine. • Apply new beads of sealant whenever the main cap bolts have been loosened or removed. • After tightening the bolts using the above torque-turn tightening method, make a punch mark on the head of each bolt to indicate the number of times that it has been used.
CAUTION • The bolts that have been tightened using the torque-turn method must never be additionally tightened after the final angular tightening. • After installing the main bearing caps, rotate the crankshaft by hand. If it cannot be rotated smoothly, inspect the main bearing caps for correct installation.
Mitsubishi 4M50 Engine Parts contact email: EngineParts@HeavyEquipmentRestorationParts.com Phone: 269 673 1638
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