How to balance pistons and rods

Discussion in '1994 - 1995 Specific Tech' started by grrrrrrr, Dec 6, 2003.

  1. I'm going to throw a new crank in my car this next weekend and I was thinking about balancing it at a machine shop. I heard that you balance pistons and rods by weighing them, selecting the lightest one and shaving metal off the insides of the pistons and the side of the rods close to the middle. Has anyone heard of this? I would much rather do this myself than leave them unbalanced or have a shop do it...
     
  2. I'm no engine builder but from what i've heard this isn't something that can be done at home.
    Mike
     
  3. That is what I have heard also. But you shave the metal off of the section of the piston & rod that is under the LEAST stress. Personally, I would leave it up to the machine shop to do it.
     
  4. Thanks for the info guys. I was trying to see if cutting a few corners was feasable... I don't think I have the proper tools to weigh them correctly so I'm going to scrap the idea...
     
  5. The pistons and the rods should be a matched set and within a few grams already. To balance it you have to take the crank, rods, pistons, flywheel and balancer to a shop that can balance it and they put it on a rotating machine and either remove or add metal to balance the entire assembly. I paid 170.00 to have mine balanced.
     
  6. wow. something i can actually give advice on. lol

    I balance rotating asemblies at my work alot. mostly the rods.

    2L8ULUZ2 is just about right. The pistons are already a matched set.

    the rods on the other hand come from the factory balanced but they do a pretty half ass job doing it. ford rods are probably one of my favorites to do because theres not that much material need to be remove. the worst are the dodge.

    to balance the rods, you have to weight the big end (where it surrounds the crank) and the small end (where the wrist pin go). if you add the big end to the small end it should be the total weight of the rod. to get the rods balanced you have to weight all the rods and find the lightest big end and lightest small end. then match all the lightest weighting big ends and small ends to all the others.

    everything is weighted in the rotating assembly. Crank, rods, pistons, wrist pins, bearings, balancer, and flywheel/flexplate are needed to be balanced. its all entered in the computer and tells you how much its off.

    hope that helps