Rod balancing

[Cranky]

Or weight matching
Weighing the small end to see how much can be removed there. If you look close you can see where I already had ground in the seam on the beam. I gained 2 grams there. Not much. Certainly not as much as I was hoping.
LY rods. Working with what I have
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That scale looks like it's been to hell and back....how old is it?

 

[cbodybob]

That scale looks like it's been to hell and back....how old is it?

Don’t know. That’s the machine shop here in town. He’s been there 40 years. Does a lot of motors for the folks around here.

 

[1 Wild R/T]

FWIW my original pistons without the pins weighted in at a hefty 860 grams, the pins were another 221 grams.... I only weighed a single piston so I can't say how much variation they had...

My Icon 836 pistons weighted in at 709 grams & the pins added another 156 grams...
were all within a half a gram out of the box...

My stock LY rods came in at 900 grams again I only weighed a single rod so I can't say how much variation they had...
My Eagle rods came in at 880 grams and were within one gram out of the box... Big ends were all within half a gram...

Just to add a little info, that means each piston & rod assembly weighs 227 grams less than the stock parts.... thats 8.1 ounces.... Off each piston & rod...

Plus the reduced bob weight needed to balance the assembly...

eight times 8.1 ounces equals 64.8 ounces, The majority of the weight savings is reciprocating so the bob weight reduction is roughly 35 ounces...
Might as well call it a 100 ounce weight savings..

 

[1 Wild R/T]

That scale looks like it's been to hell and back....how old is it?

You think thats old? Check this out...... But then again this is a mechanical device, no electronics that can fail....

 

[Cranky]

You think thats old? Check this out...... But then again this is a mechanical device, no electronics that can fail....

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I have a digital scale that's about 30 or so years old but it doesn't sit out or was used on a daily basis.....and when it did sit out on the bench, I usually covered it when not in use. Guess it doesn't matter what they look like as long as the calibration checks out.

 

[toolmanmike]

My small block rods. They did a nice job.

 

[HawkRod]

Curiosity question.....should the rod be balanced with the bearings in place (as reciprocating weight)? Likewise, should the piston be balanced with the rings installed and if using full floating wrist pins, the pin and the pin retainers included? Just asking.....
BOB RENTON

No. you balance the rods by themselves (hardware to bolt them together included).

As @bm02tj stated, bearings are weighed, but they are actually quite precise so their weight is included in the calculation for the bobweight. No need to weigh them with the rod as you are balancing them. Same deal with pistons and pins.

 

[dvw]

Curiosity question.....should the rod be balanced with the bearings in place (as reciprocating weight)? Likewise, should the piston be balanced with the rings installed and if using full floating wrist pins, the pin and the pin retainers included? Just asking.....
BOB RENTON

Everything gets weighed separate. Heres a balance card.
Doug