Question to the braintrust for motor building Options

[Mikey914]

Looking to make a larger motor (4) planning on a 2665, as I don;t really want to go over 103mm to make cooling easier.

The 80 crank is available for stock rods not the Chevy rods. It is my understanding that the Chevy option offers a significant upgrade to the strength. I'm tempted to do the stock.

My question is : should I wait an indeterminate time for the crank with the Chevy rod option? What am I really loosing here? or is this just a must for the larger motors?

My 1st engine build.

[Superhawk996]

Other big bore considerations beyond thermal effects:

T4 Crank only has 3 bearing journals to carry loads. Not ideal for lots of power reliably over long durations of time.

Rotating inertia of the crank increases as a function of mass and stroke^2 (exponential). Rotating mass and/or inertias may increase substantially due to bigger pistons and wrist pins, stronger rods, the added mass from the stroker crank depending on the components you use.

In addition to those inertial loads you now have more combustion based torque load applied to the crank with each combustion event.

Horizonallly opposed 4 cylinder engines - although they have perfect primary and secondary balance, the non overlapping combustion events contribute to torsional oscillation of the crank. Normally a harmonic damper would be used to damp these out. Not aware of a harmonic damper for T4's. The more power the engine puts out, the more quickly the crank will be fatigued by the increased torsional vibrations.