What is the purpose of two stroke engine tie rods? During the firing period in a cylinder, there are downward forces acting on the piston. However, equal forces act upwards on the cylinder cover and they transmit through the cylinder block. Engine frame and bedplate transverse girder, resulting in these components.
These tie rods extend from the lower face of the bedplate to the upper face of the cylinder block. And the compressive force they exert on these parts of the structure ensures that any tensile stress which does occur during the peak cylinder pressure period will be well below that. This could cause fatigue cracking. it would be possible to keep tensile stress low by increasing the section thickness of all parts of the structure.
But that would result in a very heavy and expensive engine. The rods provide strengthening just where it needs and so allow for a light engine but one which is able to develop high power. The rods pass through tubes welded into the frames and bracing provides at certain locations in these tubes to prevent transverse oscillations which could cause fatigue failure. Where engine headroom limits, tie rods make in sections with suitably located joints to make removal and refitting easier.
