• The main function of tie rods is to keep the entire engine structure in compression.
• This increases the fatigue strength of the engine structure.
• It ensures proper running gear alignment.
• The gas forces acting on the cylinder head are transmitted via the tie bolts down to the bottom structure.

• Excessive and heavy engine vibrations.
• Fretting and uneven wear of engine components.
• Breakdown of tie rods due to high vibration stresses.
• Loss of running gear alignment.
• Uneven loading and possible breakdown of running gear.

• During rounds, if a tie rod is broken/slack, its cover will be vibrating.
• The cylinder head jacket adjacent to the bolt lifts when piston nears TDC.

• Tie rods are made of high tensile steel.
• They are cold rolled to introduce compressive stresses and increase strength.

• Tightening must be carried out strictly as per maker’s specification.
• Normally, tightening starts from the center and proceeds outward in sequence.
• Procedure: tighten center → forward one → aft one → next forward → next aft, continuing this way to the ends.
• Tighten to exact maker-specified pressure only.

Usual tightening sequence is shown below