Engine Balancing Fixtures

[CompetitionWedgeRacing]

I am in the market for an engine balancing fixture and new scale. I have a small digital and a triple beam, but its time for something better/faster.

What brand scales do you use, where did you purchase it and approx price.

Same question for the balancing fixture. I DONT want a cheapy version either. Not sure I like the looks of the Goodson fixture. Looks kinda like a ProForm type of deal. Thats not what I want.

Looking for suggestions.

Thank you.

[SchmidtMotorWorks]

I used to balance cranks all day and looking back I would do a few things differently. I don't know if anyone makes them, but if you could have bob-weights that had different thickness washers with certian weights so you could just stack the right combination of washers I think it might be faster than using the lead shot that I used to use.

Another thing is the fixture that the crank spins in. I think it would be good if it spun the crank on centers in the front and back instead of rolling on the journals. I sometime had problems with light scuff marks on the journals no matter how clean I kept it. That type of fixture would also be better for in balancer machining.

The last idea I have is if I were balancing lots of the same crank I would make a balancer and flywheel with offset weights in them to duplicate the affect of the bob-weights that would save lots of time.

[SupStk]

For balancing fixture, are you refering to the method of weighing the rods? If so I fabricated my own. It is fast, repetable and it's very easy to dupicate. PM me I can send pics.

[CompetitionWedgeRacing]

SUPSTK,

Please check your PM's. I sent you a email address to send pics to.

thanks.

[SupStk]

I did receive your email along with a couple others. The photos have been taken and processed, since I don't have a scanner I need to get that done. Will get them on the way ASAP.

[headman]

I used to balance cranks all day and looking back I would do a few things differently. I don't know if anyone makes them, but if you could have bob-weights that had different thickness washers with certian weights so you could just stack the right combination of washers I think it might be faster than using the lead shot that I used to use.

Another thing is the fixture that the crank spins in. I think it would be good if it spun the crank on centers in the front and back instead of rolling on the journals. I sometime had problems with light scuff marks on the journals no matter how clean I kept it. That type of fixture would also be better for in balancer machining.

The last idea I have is if I were balancing lots of the same crank I would make a balancer and flywheel with offset weights in them to duplicate the affect of the bob-weights that would save lots of time.

"stacking" weights are much faster than shot containers. Only way to go.

The idea of using centers would require exact rotational centers respective to the main journal. Wonder if you would lose some resolution associated with the effort to clamp and retain the weight of the workpiece???

Lastly, the stroke and phasing varies between journals. But you could get close, Everyone needs to note: this would only work if you standardize your bobweight value.

Anyway, some of the bobweights today go on and off very quickly.
(dowel and quick nuts)

good ideas, the modified flywheel/ balancer weight is a good way to quickly prove/sort 305 from 350 crankshafts.

[Dave Koehler]

I don't see the center thing as workable. Some of the cranks are way off center wise. Stock Chryslers come to mind. Too much hassle for no gain.
Even .001 off center will have an effect. Since the crank flops around more than that in a running engine that is a whole 'nother dicussion.

Preset flywheel and balancer: Sounds logical on the face of it but the mass and position of the bobweight that simulates the real rod and piston assembly has an effect on the outcome.
Mass production folks will use the same bobweight for a series of cranks and kind of "get away with it". Praise rubber motor mounts for this. This process assumes as Headman said that the rods and pistons used throughout are all identical weights and the rod journals and index are perfect. Seen any 2 like that lately? Custom aftermarket work dictates that we adjust as needed to make the final balance the best it can be.

Crank marking: Assuming a hard bearing balancer the V block affair solves that problem. I converted mine from nylon to delrin material. This created less drag on start up with heavy assemblies. I also narrowed the material so I have less than 1/4" of contact.
I use rollers on driveshafts, industrial stuff and really heavy cranks like diesels.

Shot vs stacking: Having used both over the years, stacking using Equipoise tooling gets my vote every time.

Have a safe race
Dave Koehler
www.koehlerinjection.com