Balance the crankshaft

[menfou]

Hello, it's the french

I changed my rods,pistons on my K20A2 engine, and I bought JE Piston as you recommand me.

If I change the piston and the rods(crower), I must to balance my crankshaft or not ?
I don't know the crower rods weight and stock pistons weight.
But toda says 589grams for the stock rods, and for the JE Piston 9:1 it's 309 grams.
The crower rods are +/- 0.5gram and JE Piston +/- 1gram

[K I L R O Y]

Any rotating assemblies i have balanced have happened like this.

1. Spin the crank on a balancing rig and balance it (nothing attached)

2. Pivot the rods on the crank end, let the piston end sit on the scale, find the lightest one, and make them all match.

3. Pivot the rods on the piston (wrist pin) end, let the rod end sit on the scale, find the lightest one and make them all match.

4. Weigh the total rod, find the lightest one, and remove material from the beam to make them all match.

5. Weigh the pistons, find the lightest one, and make them match.

So, to answer your question, your crank balance should have nothing to do with the rods and pistons. I would however check the crank for balance while it's out. It's probably close, but i'll bet it could be better.

Sorry for the long-winded reply.

[LSVtec_Tuner_Driver]

I would suggest if going to have the crank balance. Is take some weight off of it is to do a knife edge and then have it spun and re-balance with the flywheel, rods, and pistons you plan on using.