Technical How would you tell if rods/pistons are balanced-rods reconditioned?

I've got a number of SBC and Ford FE rods and rotating ***emblies and noticed that some rods are ground off on the flat on the bottom cap. Some are rounded and some thinner. I think these are balanced ***emblies. Please enlighten me.

Also I've got a bare set of rods and was told they were reconditioned rods.
Any way to visually tell? I've been told to measure CL crank to CL piston pin and compare to a stock rod.

Thanks >>> Movin/on

 

A reconditioned rod that has not been used, will have a fresh crosshatch hone marks in the big end, with no evidence of a bearing having been installed in it.

Balanced rods usually have rounded ends, or at least the machining marks will be fresh, compared to the rest of the rod.

If you post some pictures, nice clear in focus, we might could help you figure it out.

 

These days you can get a digital kitchen scale that is very accurate, accurate enough to check a set of rods and see if all are the same weight, and all small ends and big ends weigh the same.

 

I used to balance sbc rods, took a while, got weight balance close on a digital scale, fixture for small end to weigh the big end, back and forth a bunch of times, getting big ends to weigh the same and overall rod weight the same. Pistons, just weight balance and take material off the backside close to center.
it's far from a balanced ***y, but I felt it was worth the effort.

 

It's only a balanced ***embly if it is an ***embly. All eight rods, pistons and the crankshaft they were balanced to. Having eight rods of the same weight is just a start.

 

If you lay a strait edge across the cap of a recon rod the surface will not be flat. You will see light at the out side edges.

 

Yes the crank needs to match. and the block needs to be square and all the deck heights the same. then the heads all need to be c CC ed so every combustion chamber is the exact same. However That wasnts the OP,s question. The OP wanted to know how to tell if the rods had been reconditioned or balanced.

 

Well if the rod was reconed with the old trick of grinding the cap at a slight angle you will see its not flat but some shops cut the caps straight.. then you might see a shadow near the parting line were the hone stone barely touched

 

Here is a picture of one of the FE rods. The pin bushing has been honed and the journal end has hone marks under the bearing. New bearings are there.
The base of the rod is slightly rounded where stock are flat. They weigh within 2 grams of one another (not a digital scale as mentioned) so I think they are reconditioned and a balanced set. They have new ARP bolts as well.

 

I was told by my local shop that they balance to within one gram. The digital kitchen scales referenced earlier can measure to a tenth of a gram.

My question has always been what happens to the balance when the rods & stuff get coated with the oil that is flying around inside a running engine. I'm thinking that it would throw the balance off by at least a gram.

Just one of those things that came up while trying to get all eight to the same weight.