Balancing Rotating Assembly Question??
 

What happens if you spin a coupler? When my engine was balanced the coupler was marked to go onto the flywheel in a specific location.

The reason I am asking this is, I am thinking of assembling a spare engine. What would happen if I have that engine balanced without a coupler then add one later?

Re: Balancing Rotating Assembly Question??
 

Couplers are neutral or "zero" balanced from the factory so you could mount it any way you want without affecting your motors balanvce,if you want to really be precise take a new coupler in and have it balanced perfect as a spare for your spare motor,Smitty

Re: Balancing Rotating Assembly Question??
 

I replaced my coupler and just bolted it on. Never even thought about balancing it. I figured it was like bolting up a clutch or torque converter in a car.

Re: Balancing Rotating Assembly Question??
 

My current engine was balanced, and they even drilled holes in the coupler.
Would they do that to get it neutral?

Re: Balancing Rotating Assembly Question??
 

The coupler came at neutral but could be off a gram or 2 and what they most likely did was balance it perfect to a tenth of a gram. You'll see this sometimes on harmonic balancers too,other than the real new stuff,the 454 and 400, most other chevy balancers are "neutral balnced" but when you get everything balanced they'll spin it up and drill some real slight holes in it to make it perfect. It's remotely possible, but no engine builder would normally do this, that they used your coupler to help achieve corrective balance for the "off balance" your motor needed on the flywheel if it was externally balnced but it would be the dumbest thing I ever seen and there would be serious holes drilled in it or weight welded to it,Smitty

Re: Balancing Rotating Assembly Question??
 

My harmonic balancer also has small holes drilled into it.

So let me get this right, they are making these components neutral?
I never pay attention to the flywheel. I don't remember seeing any drilling there.
I never have really understood the steps in balancing an engine, just paid for it :D

Re: Balancing Rotating Assembly Question??
 

Exactly,they were "neutral" to start with by mass production standards but brought to "perfectly neutral" by a tighter standard,Smitty

Re: Balancing Rotating Assembly Question??
 

Ok Last question.
My coupler was marked with a big YELLOW stripe along with the flywheel.
Does this mean they where balanced as one component??

Re: Balancing Rotating Assembly Question??
 

I'm not sure of the answer on that. They might have been balanced together,did you get a balance sheet,Smitty

Re: Balancing Rotating Assembly Question??
 

coupler is neutral. balancer and flywheel (on a 454 and 502) are not neutral.

quickie version:
When you balance, you equalize pistons to the lightest one, then you equalize the little ends of the rods to the lightest one, the big ends of the rods to the lightest one, then the neutral components are balanced alone. Then all the parts are put together and the entire rotating assembly is balanced.

That's sort of a real quick explanation.

Re: Balancing Rotating Assembly Question??
 

If the balancer doesn't have a mandrel to hold the coupler, it must be balanced with the flywheel. Most high performance balancing companies will balance each individual component. Then if needed they will assemble the pieces and re-check their work to make sure it's still perfect. I'll bet he didn't have the mandrel for the coupler so he attached it to the flywheel and balanced them as a pair.

Re: Balancing Rotating Assembly Question??
 

The real deal is that the motor and even the coupler are made to certain production tolerances to be in a ballpark acceptable tolerance limit. This is just how it was done.
Of course a really good machinist will be able to correct a balancer or flywheel and make it close to perfect.
When bulding a H/P marine engine, this is definitely an area that pays off. When trying to make more power out of anything , the margin of error closes up, and things have to be more perfect and less forgiving... BBB

Re: Balancing Rotating Assembly Question??
 

better stick the drive on too ....get it all done ..... :D

I'm building 496's out of MIV blocks and the rotaing assemblies are internal balanced and we just took the MIV "externally" balanced flywheels and made them neutral ...and used neutral HB's .....

Re: Balancing Rotating Assembly Question??
 

My understanding is, ONLY the harmonic balancer is "externally balanced" on a MkIV and the flyweel is neutral. Correct me if I'm wrong.

Re: Balancing Rotating Assembly Question??
 

On the face of the flywheels there weights ( actually thicker areas) in stratigec area's around the flywheel ....The machine shop removed those and actually removed more material where needed. I know you can get them either way ....It was a lot cheaper just to get them Neutralized ...