[Formulas]

I have never bought a balanced total assy package.

My builds have been a mix of aftermarket and stock parts or a basket of single sourced aftermarket parts all of which need balancing by my efforts

I will say if I was to buy a single sourced balanced rotating assy I would expect to get a package that meets or exceeds OEM specs

Precise or to your numbers spec attention to details would take more effort time and money for a higher end build

[Verdoro 68]

I can tell you why I bought a balanced assembly - convenience and trust. I didn't have a good sense of my local shops at the time, felt what I would get from Butler would be good of the box to use and since they have a long history with Pontiacs I felt the risk was low.

My expectation in purchasing the assembly was that it was balanced with an industry standard spec (admittedly, I don't know what's acceptable) and would be equivalent to what any good local shop would do. When I showed the paperwork to the machinist that did my block he said the work was fine, but he said he would have taken it further in terms of balancing.

One thing that did have me curious with the Butler kit is that there weren't matched rods, pins and pistons. That tells me that they're doing what Paul said - weighing each part and balancing the crank rather than matching the parts and spinning up the crank to balance. In hindsight, I should have weighed each part and matched them to get things as equal as I could to see if further balancing was required, but I didn't know any better.

Anyway, that's my two cents from a hobbyist first time engine builder with just enough knowledge to be dangerous.

[Skip Fix]

Paul for me if I buy a "balanced assembly" I expect it to have matched weight piston/pins, matched rods and the crank balanced to what my local shop would do to performance industry standards. So I could drop it right in. If not why pay the extra for a balanced assembly vs the separate parts and not just get a good shop to do it correctly? They will have to start from scratch otherwise.

Of course to get really picky what weight for rings were used, bearings to get bob weights?

[PAUL K]

Originally Posted by Skip Fix

Paul for me if I buy a "balanced assembly" I expect it to have matched weight piston/pins, matched rods and the crank balanced to what my local shop would do to performance industry standards. So I could drop it right in. If not why pay the extra for a balanced assembly vs the separate parts and not just get a good shop to do it correctly? They will have to start from scratch otherwise.

Of course to get really picky what weight for rings were used, bearings to get bob weights?

I agree Skip. I never believed in the two tier system of its "kinda balanced" and "pretty close". With the thin ring technology they have to be taken into account. Bearing weights can vary quite a bit also depending on brand and material.

IMO everything should be at least set on a scale. I had a guy bring me a used set of Carrillo rods for a Pontiac blower motor. One rod had been replaced at some point and was about 60 grams heavier than the other seven.... What a PIA that turned out to be.

[Tom Vaught]

This is an acceptable connecting rod measurement tool set-up.

Tom V

Most of the reset of the stuff out there is Bathroom Scale level attempts

1) Precision (accurate) Gram Scale.
2) Proper fixture to measure the Rods.
3) Proper scale to measure all of the individual parts.

[mgarblik]

This is how we try to explain a couple of terms being used in this thread. Our interpretation of these terms and practice works for us and may not be the same as yours or other race shops. Blueprinted engine: This is an engine build in which all important dimensions are checked either against the factory specs. (not tolerance). Or the engine owners "blueprint", based on the use of the engine. (meeting their specs.). Of course when working with machinery, hitting that exact spec. is difficult. So within the class, the tolerance we use is the spec. +- .0001. Most factory tolerances on old domestic V8's are +-.0005". Of course it depends what part we are talking about but in my example, this would be true for crankshaft measurements, oil clearance, housing bores. End play, ring gap, deck height and such, factory tolerance is greater.

As far as engine balance, that gets much more complicated. Crankshaft balance is often thought of as a "black art". Everyone agrees that a perfectly balanced rotating assembly will be very smooth and the bearings will last longer. The intended RPM, true weight of the components, the balance of the parts hanging on each end, internal vs external and imbalance on each end of the crank all have an effect on vibration. Type of transmission, engine mounts and other external components also effect vibration. I try to explain the situation relating it to a tire, something we are all familiar with. A crankshaft balancer is very much like a computer tire balancer. Same technology, greater sensitivity. An out of balance tire causes a vibration that can be annoying. If severe, it can wear suspension components at a faster rate than normal. Springs, shocks, joints can all wear faster. A computer tire balancer splits the wheel/tire assembly in half and you add weight to the inside and outside to reach a zero balance. (Typical tolerance is +-.25 oz. )
With a V8 crankshaft, you are trying to balance 100% of the rotating weight of the assembly and 50% of the reciprocating weight. This is because 1/2 of the reciprocating weight balances itself out naturally from opposing forces. Much like a tire, the crankshaft balancer splits the readings into left and right readings. Some of the imbalance cancels itself out if the right and left is on opposite sides. This plays into the counterweight placement on the shaft.
The software and age of the machine determines the dead accuracy you can get. Our 30 year old basic Sunnen balancer will balance to +-3 grams on a mid-weight, (Pontiac) crankshaft. It looks like the Hines machine shown in this thread will balance to closer than 1 gram per end. That is fantastic.
Factory balance on cranks we have spun, not necessarily Pontiac fall into the total imbalance range of 20-40 grams total. Very few are better than 20 grams. That's where I said it's unlikely you will feel an imbalance less than 20 grams on a typical passenger car.
Sorry for the long post. Not intending to insult anyone's intelligence.

[Jay S]

When I have had engines balanced the work often varies in price because some engines took more work to balance, more lightening on the rotating assembly, more expensive Mallory metal added to balance it. I balance the assemblies to save money and time to get it done quicker at the shop.

I looked it up out of curiosity, and Butler’s charge $200 to balance a rotating assembly. Which isn’t high, and not really low. When I see a “fixed” cheaper price in a rotating assembly with balancing, I automatically assume:

1. They assumed the rods came in a matched batch, and are close, but not exact.

2. The crank was balanced to the lightest Bob weight, measured from the lightest rod and piston assembly.

3. Nothing was done on ANY of the rod or pistons to get the weights to match. If something was done, it was very minimal.

4. Depending engine platform it is, the total crank out of balance should be close to a factory balance job. Kind of sounds to me like it will be with in that 20 to 40 range the Mike just mentioned in the last post.

One of my friends favorite movie quotes when something seems cheap is from the 1980 movie USED CARS. When taxi’s are painted blue with water base paint to be sold as used cars….water base paint? “Sure, we don’t get much rain around here, what do you expect for $200, metal flake? Lol

[Tom Vaught]

I have personally checked all of my engine internal parts on a very accurate gram scale
when I worked at Ford. I will probably only build 3 more engines in my lifetime.
9.5" "Short Deck" engine, 10.230" aluminum Butler engine, and a 11.0 cast iron "Tall Deck" engine from All Pontiac.

Moldex always did the Balance Jobs (after I did the initial weighing of the parts).
(They weighed them too and did the crank balancing as well as the Nitriding.)

Last count they have done 32 cranks for me over the years. (Ford stuff, Hot Rod stuff for friends, and my own stuff. I always had a good relationship with "Whitey" and Mr Gillian.
Same deal with Joe (Whiteys son).

If you find a good crank shop treat them VERY NICE. And BE PATIENT.

Tom V.

[kingbuzzo]

If the block was balanced previously, and then disassembled for inspection, then put back together again does it need to be re-balanced?

[PAUL K]

Originally Posted by kingbuzzo

If the block was balanced previously, and then disassembled for inspection, then put back together again does it need to be re-balanced?

No Sir

[PAUL K]

Originally Posted by Tom Vaught

I have personally checked all of my engine internal parts on a very accurate gram scale
when I worked at Ford. I will probably only build 3 more engines in my lifetime.
9.5" "Short Deck" engine, 10.230" aluminum Butler engine, and a 11.0 cast iron "Tall Deck" engine from All Pontiac.

Moldex always did the Balance Jobs (after I did the initial weighing of the parts).
(They weighed them too and did the crank balancing as well as the Nitriding.)

Last count they have done 32 cranks for me over the years. (Ford stuff, Hot Rod stuff for friends, and my own stuff. I always had a good relationship with "Whitey" and Mr Gillian.
Same deal with Joe (Whiteys son).

If you find a good crank shop treat them VERY NICE. And BE PATIENT.

Tom V.

I agree Tom. My crank guy has thirty eight years (and counting) experience operating a crank grinding machine full time. He prides himself in keeping all the specs "perfect" instead of "in spec"..... Great guy to have on our team.

[mgarblik]

Moldex sure makes a beautiful billet crankshaft. Strong piece with exact dimensions. But as Tom mentioned, PATIENCE with a capital P. Like at least a YEAR lead time for a billet crankshaft, probably longer. So plan ahead. Not sure how long to have a crank ground and balanced. But don't expect 1-2 week service.

[grivera]

Originally Posted by PAUL K

Thanks for your answer. Last I looked most rotating assemblies cost about $150 extra. Most shops seem to charge about $250 to balance a rotating assembly. I was curious why folks were buying the "balanced" assemblies. Most the balanced assemblies we see have one of each part weighed and the crank balanced. Most shops weigh every part and match each part to the lightest unit, then spin the crank. The spinning the crank is the biggest deal and there is no way to "check" that without going through the process of (balancing) spinning the crank on a balance machine.

If one is particular about the quality of their build, one would be better off letting the shop of their choice balance things rather than paying to have the assembly balanced and then asking their favorite shop to check it.

Paul - of the methods you described above do you know which Butler uses in their “balanced assemblies “?

[AG]

I've bought a balanced rotating assembly from Butler for a customer and it came with a bobweight sheet with all the weights. I'll try to post a pic of it.

[kyle_blake]

From their website on the subject:

The Butler Process
All rotating assemblies sold by Butler Performance, regardless of brand, are balanced in our shop by our experienced machinists.

Most other shops offer assemblies unbalanced or charge additional balancing fees.

We don't take anyone else's word when it comes to the parts we stand behind. We put all rotating assemblies through the Butler Process for quality and performance. Our internal balancing process ensures each part of the kit is put through a multi-step inspection process. We then weigh and pin fit the rods and pistons as needed. We computer balance the crankshaft to the rest of the assembly. This process ensures that all the parts of the assembly are matched to form a "Butler Performance" worthy assembly. We then document all weights and information on a balance card that ships with the assembly.

[PAUL K]

Originally Posted by kyle_blake

From their website on the subject:

The Butler Process
All rotating assemblies sold by Butler Performance, regardless of brand, are balanced in our shop by our experienced machinists.

Most other shops offer assemblies unbalanced or charge additional balancing fees.

We don't take anyone else's word when it comes to the parts we stand behind. We put all rotating assemblies through the Butler Process for quality and performance. Our internal balancing process ensures each part of the kit is put through a multi-step inspection process. We then weigh and pin fit the rods and pistons as needed. We computer balance the crankshaft to the rest of the assembly. This process ensures that all the parts of the assembly are matched to form a "Butler Performance" worthy assembly. We then document all weights and information on a balance card that ships with the assembly.

That's good stuff.... Things were different over there before the "Butler process" ..... Good to see they are learning.

[PAUL K]

Originally Posted by grivera

Paul - of the methods you described above do you know which Butler uses in their “balanced assemblies “?

I haven't seen much Butler stuff recently.

[grivera]

Based on Kyle’s post seems it is a thorough balance job. Would be nice to see a third party review.

[Verdoro 68]

FWIW, I did not get a balance card with my Butler kit in late 2022. I was expecting to get a sheet with the weights and matched pairs of pistons, rods, ring packs as well as the location to install them. The rods had clearly been opened and inspected but they weren't labeled or numbered in the box. I'm not sure the pistons were opened and inspected, but they did come with a sheet from Ross that had the weight of each piston. The crank had been worked on as well and had my name written on it (rod bearing clearances were spot on).

I suppose the parts could have been individually balanced close enough to each other to where it didn't matter where they go (seems unlikely given what I've learned about balancing since), but I would have at least liked to have seen the proof. In hindsight, I should have given them a call, but it seems to be running fine.

[vicgto]

Here is my balance card from Eagle, what do you guys think, pretty typical balance job?