DIY Crankshaft Balancing

Crankshaft balancing is mandatory for a quality performance of your car or motorbike. Any wear and tear, damage, irregularity, or problem with weight in the rotating parts (for example rods, crankshafts or pistons) which is not catered to can possibly cause various issues. These issues range from putting too much stress on the engine and damaging it, failure of your vehicle’s bearings, or excess heat and uneconomic fuel consumption. A crankshaft is the part of any engine which keeps the machine running with the help of counterweights.

Crankshafts balancing must be achieved for your particular rod and piston combination and is only a moderately challenging project.

Tools and Materials Needed

  • Cardboard
  • Marker
  • Engine solvent
  • Clean cloth
  • Gram scale
  • Drilling machine

Step 1 - Work on the Devices

Before working on the balancing act, remove the various devices that keep your engine and cylinders functioning: namely the pistons, rod bearings, piston pins, piston rings, bearings and connecting rods. Once all these have been removed, place the piston sets on a plain sheet of cardboard and use a marker to mark as well as highlight the cylinder number against each set. Once done, clean these parts individually and thoroughly with the help of an engine solvent and a clean cloth in order to eradicate all possible dirt, grime, irregularity or soot. Proceed by placing the clean parts back onto the cardboard.

Step 2 - Work the Weights Out

As counterweights require a weight to be assigned to the countershaft, weigh all the removed pistons with the help of a gram scale and mark the one which weighs the least. The weight of the lightest one is the appropriate weight for the rest of the pistons and therefore, using a drilling machine, drill holes in the base on both the sides of the heavier pistons in order to regulate their weight by removing the bits of metal around them. See to it that you don’t rush through the process and use the gram scale accurately.

Step 3 - Work on the Connecting Rods

Proceed by removing weights from the connecting rods by shaving off their sides softly around the neck with a file not too large in size, covering all alternate sides equally. Try to attain as little a difference in the weights of the connecting rods as possible and repeat this activity of matching the weights on the smaller connecting rods too.

Also, shave off any excess from the top corner of the rod towards the area in the middle and vice versa as well as weigh out the rod bearing caps removing the weights that you desire or require for each.

Step 4 - Assemble and Weigh

Now, move towards assembling back the pieces that you removed: place the rings back onto the pistons, reinstate the piston pin, attach the top part of the rod to the pin and tie the rod bearing cap at the bottom collectively. By this point you should be able to weigh each specific piston set individually and match them up as per your weight criteria. Try to keep the difference in weight as little as possible.