[GMCM76]

I am putting together a SD 455 I am using nos rods, nos pistons, nos balancer, nos flywheel, and an original standard crank. Any opinions on if I should the assembly balanced or not

[Bruce Meyer]

Originally Posted by GMCM76

I am putting together a SD 455 I am using nos rods, nos pistons, nos balancer, nos flywheel, and an original standard crank. Any opinions on if I should the assembly balanced or not

You should always balance the rotating assembly.

[Radman]

Balance it, the cost of the job is much less than the total of the parts that will be trashed if something is off.

[4zpeed]

I vote yes, the cost for me was between $600 and $700, money well spent.


Frank

[GMCM76]

Thanks for the input

[694.1]

It's clear that you are on a mission to create something extraordinary.
As Pontiac felt the need to balance that mess of parts, it seems like money well spent.

[todden8]

You will not regret doing it.

[dataway]

Curious ... did Pontiac individually balance rotating assemblies in production? Or did they weight sort parts in such a way to create a balanced assembly?

[SRR]

I would at least make sure the guy doing the balance job had intimate knowledge of Pontiac's. The thought of someone grinding on a set of NOS SD rod's would have me a little nervous.

[Dragncar]

Here is a pic of my balance sheet.
Notice the Initial Unbalance.
Then the Final Unbalance. That is what you are after.
Make sure the guy who does it knows what he is doing.
I brought the crank to him "balanced" from another shop. Glad I did it.

This guy told me to make sure the pins and pistons do not get mixed up because of the slight difference in weight of the Ferra pins. How much difference can there be ? Just told him yes sir and will do as I am told.
He only charged me 275$ for this after a initial quote of 350$ to fix someone else mess.

[i82much]

Originally Posted by 4zpeed

I vote yes, the cost for me was between $600 and $700, money well spent.


Frank

that sounds expensive to me, did that price include other work?

side note - I am very jealous of where you live. My grandfather lived in Cass, I have caught many a native brook trout out of the Shaver's Fork tributaries and done some deer hunting on Cheat and Back Allegheny mountains as well. Actually wearing my WV baseball hat today, looking forward to my kids getting older so we can head back east and take a trip to West By God!

[Tom Vaught]

I have balanced quite a few Engine assys, beginning in the early 1970s at one of the "Speed Shops" I worked at (PARKER AUTOMOTIVE).

If you have an accurate gram scale and a proper tool to measure the weight of the small end of the rod vs the big end of the rod (as well as the total weight of the rod) you can, with accurate tools get all of the pin to piston clearances the same and the weights with-in two grams which is fine for a typical "TRW Engine" using Pontiac 455 SD parts.

You will save the expense of paying someone else to do the job, have the equipment for future engine builds, and know exactly what the bob weight is for the Crank Balance by the crank grinder/balance shop. I would check the balance on the flywheel/flexplate and on the harmonic balancer too. With aftermarket pieces they would be zero balanced.
With production 455 SD parts I would have the crank assy checked to see how far the parts are from a zero balance. I have Joe at Moldex crankshaft spin my cranks assys.
He also does all of my custom crankshaft work as he is local.

Hope this helps.

Tom V.