Rod Balancing DIY?, end-to end Options

[malcolm2]

Rod Balancing, End-to-end. I also wondered how in the hell do you balance END-TO-END.

I found this 20 minute video (balance at 6 minutes) where he hangs one end on a nail and puts the other end on the scale.... weighs each rod and compares, removes material, repeats....

is that the way to do it? Good way, Bad Way???

This link and the embedded vid starts at 6 minutes.

https://youtu.be/U3IXSywgTnM?t=386


https://www.youtube.com/watch?v=U3IXSywgTnM?t=389

[gereed75]

When rebuilding my motor I tried very hard to do this including building a DIY balance rig. I could never get consistent weights that I trusted. I ended just balancing overall weight.

Not saying it can’t be done. If you look at the geometry a small amount of variation in how the rod sits in the rig will effect the weights, especially in the gram range.

Maybe someone can chime in with better results. Good luck.

[Chi-town]

If you are not experienced, do NOT go removing material from your rods.
Please consult a real machinist, it could save you a lot of money in the long run.

[rhodyguy]

Get a digital scale. Achieving or close to balanced by removing casting flashing won't hurt the integrity of the parts. Don't forget the caps and fasteners when weighing.

[BK911]

I have not built a flat 4 yet, but have built quite a few flat 6s.

For a street car;
-Weigh all the pistons and put them in order from lightest to heaviest.
-Weigh all the piston pins and put the heaviest pin with the lightest piston, and heaviest pin with the lightest piston.
-Weigh the set and put them in order from lightest to heaviest.
-Weigh the rods and put the heaviest rod with the lightest set, and lightest rod with the heaviest set.

This usually got me within a gram from heaviest combo to lightest combo, and always good enough for a street engine.

[malcolm2]

I have not built a flat 4 yet, but have built quite a few flat 6s.

For a street car;
-Weigh all the pistons and put them in order from lightest to heaviest.
-Weigh all the piston pins and put the heaviest pin with the lightest piston, and heaviest pin with the lightest piston.
-Weigh the set and put them in order from lightest to heaviest.
-Weigh the rods and put the heaviest rod with the lightest set, and lightest rod with the heaviest set.

This usually got me within a gram from heaviest combo to lightest combo, and always good enough for a street engine.

I forgot to say this WILL be a street engine. But funnier thing is it will be in a VW bus (IMG:style_emoticons/default/driving-girl.gif)

Thanks for the input. Your way sounds good. I can easily give it a try.

[barefoot]

When rebuilding my motor I tried very hard to do this including building a DIY balance rig. I could never get consistent weights that I trusted. I ended just balancing overall weight.

Not saying it can’t be done. If you look at the geometry a small amount of variation in how the rod sits in the rig will effect the weights, especially in the gram range.

Maybe someone can chime in with better results. Good luck.

I tried the end to end also and could not get consistent readings, so just balanced overall weight. I matched pistons & wrist pins also and had access to a lathe so put small chamfers in a couple pin end ID's to get needed weights.

[Mark Henry]

Balancing rods end for end is an exercise of a dog chasing it's tail, you take a little off of here and you fuch up everything over there. One of the reasons even in race balance it's +/- 1 gram.
The shop I use for balancing doesn't give me a break if I do the rods or pistons myself, they still want them. Balancing is all my shop does and they don't trust you to do their job.

Sure on stock jobs I balance the pistons by swapping pins,etc., but the stock spec is +/- 6 grams, within factory spec you'll never feel that unbalance on a stock mill.

[IronHillRestorations]

Around 35 years ago I did a full rebuild (my first) on my 1.8 with NPR big bore p/c's. I balanced all the rods and pistons to 1/10th of a gram, and to my knowledge that motor hasn't been apart since. I just used a dual balance type scale. I don't know how much it truly helped, but I didn't have any experience, just a little help from a friend with a VW and another friend that was a GM small block guy