750 dollars to balance a crank. Is this crazy or is it just me.

[gryphon]

I called a shop here in Oregon yesterday to get a price on balancing a crank. This crank had already been torn down, balanced to my pistons, and re-assembled by T&O for $175 once. I was thinking of changing pistons though and wondered what a rebalance would cost. So I called the shop and told them I would be bringing in the crank and pistons so there is no engine removal or engine tear down involved and he quoted me 10 hours at $75 per hour. That's $750. I thought he mis-understood me so I ran it by him again. He said they've been doing it for years and that 10 hours is what they always charged. Am I missing something here. When I told him I could buy a NEW complete crank assembly with rods already balanced from Ultima for $550 he just got pissed. Why so much. What do you guys pay. Truett and Osborn (a major reputation shop) only charged $175. What's going on?

[Norton Commando]

I think there is some mis-communication here. I too, believe the $750 rate quoted by your Oregon shop is absurd.
$175 for balancing is reasonable and is about what I paid recently.

[CraigArizona85248]

When I had my panhead crank/rod/pistons balanced, it cost me around $200.  So yeah... $750 seems way high.  By the way... I don't think a rebalance is necessary for just changing pistons, unless there is a dramatic weight difference from the old to new pistons.

-Craig

[gryphon]

After the first time I was told $750 I was very careful to explain what I wanted done as I also assumed they had mis-understood my request but they insisted it was 10 hours. The new pistons are about .125" taller than the ones I had my crank balanced to. I don't want to take any chances putting my new motor together. I currently have S&S pistons and cylinders but was thinking about going to the Ultima pistons and cylinders. The Ultima cylinders are .125" taller and so are the pistons. Since I don't yet have my heads, going to the new cylinders would allow me to use the Ultima or the S&S heads.

[moose]

maybe he thought you wanted to buy some crank   

[mc9395]

Hey try balancemasters.com. I have used them several times and always pleased. They cut a grove in the pinion side of the flywheels and install a mercury filled blatter and seal it off. This will balance the motor the entire rpm range and I think it can be done with the flywheel already assembled. I have always sent them just the pinion side.

[Garry in AZ]

Pardon me for sort of getting off topic a bit here, but I don't understand something. Well, actually I don't understand many things, but that's another problem. 

If we assume the new pistons are equal in weight, why does the crank need to be looked at? I always thought if you balanced a reciprocating mass, and then changed the overall mass equally, the balance would be retained. I'm sure no expert on any of this stuff, but I'm confused on this issue. I have changed a lot of pistons, rings, and piston pins over the years and I never thought to get a crank re-balanced. I just tried to make sure the parts I replaced weighed the same amount.
Can someone a lot smarter than me, please explain what am I missing? 

Garry

[gryphon]

Well ya know, that's exactly what I always thought too. Then I asked that very question here on HTT and got so many "I don't  know for sure" and "maybe" that then I didn't know anymore either. Just don't want to chance it. It does seem though that as long as the piston weights were the same (probably some sort of + or - here) it shouldn't matter.

[BikerJim44]

Gryphon, I am of the same belief that if the crank is already balanced and the weight of the pistons haven't changed then there should be no reason to rebalance a perfectly good balance job. I mean unless you just wanted to break the cases apart to see how everything looks down below I wouldn't mess with it.
However if you want the crank trued, balanced, welded and plugged then I would contact Andrew Daulenbeck at Revolution Performance or Steve from GMR. I am not sure if Steve does his own truing or sends it out but ihe does I believe he uses Rev Perf too. The number for them is:866-892-2109 i don't have GMR's number but I bet someone does and he's more local to you if you are on the West Coast side of the world. Spidey.

[gryphon]

It's an EVO motor so welding and plugging aren't necessary. The crank assembly is still in the box that Truett and osborn shipped it in.

[hotroadking]

either way it's a ton of money...

If it's already balanced I'd make sure the new pistons with rings are balanced then you should be golden...

[FSG]

Why not just call Truett and Osborn and ask them if a rebalance is needed if you change pistons?

[hotroadking]

Why not just call Truett and Osborn and ask them if a rebalance is needed if you change pistons?

hey you get people to start doing that all the time, whatta we gonna do here?


LOL

[FSG]

Sleep .... zzzzZZZZZ   

[gryphon]

Call T&O and ask them. Duh, don't know why I didn't do that first. SG, your not getting paid enough.

[Garry in AZ]

I was a physics major but talk about use it or lose it... but I think I recall that for an object to be in balance or equilibrium you have to have the resultant of all force vectors equal zero. It would follow then that a body in rotational equilibrium would have no resultant torque acting on it, which would not be the case if the mass was different where connected to the moment arm. But if the masses are equal, the force vectors that could cause torque should have a sum of zero, and the body would be balanced.

This leads me to believe that if the new pistons are pretty close in mass, you should not have to re-balance the crankshaft.

Garry

[gryphon]

Well I got a pretty good answer from T&O. Gotta get to work right now but it was good info and I'll share it later in a seperate thread on balancing. My ex always told me I needed "professional help". This is probably what she meant.

[One4Tone]

..I bet he thought he had to take the crank out of the motor..failing that i would tell them to get off the coke and try pepsi...much cheaper...

[stroker800]

 i could see a balance job if you are running the torque monster wheels,,,Like I said before is most engines are set up for 60% balance,,,this is a general set up..Unless the pistons are outta a 454 chevy it should be fine,,,and 10 hrs labour cost  WTF are they retarded?,,My last evo was $200.00,,,,balance & true rods&wheels,,install oil pump,cam,breather gear,...good luck..
Dave

[Clintster]

S&S will rebuild your S&S crankshaft for $505 retail, just sayin'

[Admiral Akbar]

I was a physics major but talk about use it or lose it... but I think I recall that for an object to be in balance or equilibrium you have to have the resultant of all force vectors equal zero. It would follow then that a body in rotational equilibrium would have no resultant torque acting on it, which would not be the case if the mass was different where connected to the moment arm. But if the masses are equal, the force vectors that could cause torque should have a sum of zero, and the body would be balanced.

This leads me to believe that if the new pistons are pretty close in mass, you should not have to re-balance the crankshaft.

Garry

If the new pistons. rings and pins weight the same as the originals, no reason to rebalance... One thing fer sure you cannot perfectly balance a 45 degree v twin.. If you balance in one plane it will be out in the other.

i could see a balance job if you are running the torque monster wheels,,,Like I said before is most engines are set up for 60% balance,,,this is a general set up..Unless the pistons are outta a 454 chevy it should be fine,,,and 10 hrs labour cost  WTF are they retarded?,,My last evo was $200.00,,,,balance & true rods&wheels,,install oil pump,cam,breather gear,...good luck..
Dave

I think that SnS balance to 51% IIRC

If a set of heavier flywheels are balance and the pistons changed the to a different weight. The resultant vibration will be less with heavy  than with a light set of flywheels. This is one of the reason the new SnS motor has heavier flywheels. The imbalance characteristics of a 45-55 degree twin is less.

Max

[harleyjt]

I was a physics major but talk about use it or lose it... but I think I recall that for an object to be in balance or equilibrium you have to have the resultant of all force vectors equal zero. It would follow then that a body in rotational equilibrium would have no resultant torque acting on it, which would not be the case if the mass was different where connected to the moment arm. But if the masses are equal, the force vectors that could cause torque should have a sum of zero, and the body would be balanced.

This leads me to believe that if the new pistons are pretty close in mass, you should not have to re-balance the crankshaft.

Garry

I was thinking the same thing,  Why bother with balancing as long as the piston assemblies are the same weight as each other?  But I had a minor in physics...lol!!  

Then as I thought about it, it does make sense that you would want to balance the assembly since its a 45 deg V twin, if there is any measurable difference in mass compared to the originals.  (If the weights of the new piston assys are the same as the original, then I wouldn't think any rebalance would be necessary). You will have more or less mass working in one resultant vector and the crank counterweights would need to be adjusted to compensate for that difference.  If it were horizontally opposed, then it wouldn't make any difference (assuming piston assy wts are equal) and crank assy itself is balanced.  But then again, I didn't major in physics. 
jt

[gryphon]

Back on the original subject, it kinda bums me out that they would give such a rediculous quote. I was gonna have them assemble my motor.