Balancing

[midnightrider1818]

How balanced were the pistons and rods from the factory, i see alot of people say they try to get there assembly within 2 grams of each other, i believe the new pistons out of the box would be pretty close to each other, if I am using the original rods how close were they, I plan on weighing the big end on all rods, the little end on all rods and the pistons and pins together and try to match them up to get the best balance, question is for a mostly stock rebuild what should I try to get my balance at

 

[Rebelrouser]

Balancing or making each rod and piston assembly is only the first step. After the assemblies are balanced then the crank must be balanced with those weights. Factory balance is done for the operating range of a stock engine, if you are running more rpm, better balance is a good thing. It is kind of like a tire that is smooth until 60 MPH if you drive it under that MPH then you never know it is out of balance a little. My only issue is balancing at a machine shop has gotten so expensive that most of the time I can buy a balanced rotating assembly cheaper than buying the individual components and then having them balanced. Mallory metal for adding weight to a crankshaft has gotten super expensive.

 

[rickseeman]

If you are going to check the balance of the pistons and the big and small ends of the rods you might as well use your die grinder and belt sander to balance these items to within a gram. Why not? It won't cost you anything. (They won't be within 2 grams.)

 

[midnightrider1818]

Yes that is what the plan is, question is though if I take the stock crank out of the engine and let's say all it needs is polished, i balance the pistons and rods at home with a gram scale. Would I be able to put those assemblies on the crank and run it that way or would I need to also get the crank balanced now

 

[PurpleBeeper]

Yes that is what the plan is, question is though if I take the stock crank out of the engine and let's say all it needs is polished, i balance the pistons and rods at home with a gram scale. Would I be able to put those assemblies on the crank and run it that way or would I need to also get the crank balanced now

You can run it that way.

 

[33 IMP]

Yes that is what the plan is, question is though if I take the stock crank out of the engine and let's say all it needs is polished, i balance the pistons and rods at home with a gram scale. Would I be able to put those assemblies on the crank and run it that way or would I need to also get the crank balanced now

IF the pistons and rods are near enough to stock weight, you should be fine.
If you take too much off the balance pads on the rods, or use significantly lighter rods or pistons, (or heavier, tho lighter is much more common) then yes, you should get the crank balanced.
IF you can give the balance shop VERIFIED weights of the rods, both ends, pistons, pins, rings, pin retainers, (so the balance shop doesn't have to weight match the other components) you should save some money on the balance job.