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Rod balancing limit

Practical Engine Building

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Is there a limit to removing material from a connecting rod? I'm already seeing 2 sets of Manley that come from the factory with 2 to 3 grams of difference in the big end

Hi Cristian,

When it comes to balancing weights it all depends on how far your going with the build etc, high revving high boost applications will try and balance so that the whole assembly is no more than a few grams apart.

When I was building wtcc engines we would swap around pistons and rods to match them the best we could but it was not practice to remove any material due to the punishment these engines saw and it being unnecessary. I would be happy when weighing the assembly (piston/pin/ring set/rod/bolts) to be within a few grams across the cylinders but again this comes down to what your going to be using the engine for.

Once you have all the assemblies "matched" or close that information can be given to a balancer to make up bob weights to balance the crank and rotating assembly.

When it comes to how much to remove if you worried then stop, find a machine shop local to you or post some pictures here; again being bang on is only really needed for high high stress engines the likes of drag and top fuel etc

Hope this helps.