Balancing 1963 L-84 Crankshaft

[Monte M.]

I am having my crankshaft done for my 63 fuel injected car. The machine shop asked me to bring in my balancer and flywheel with the cluth set-up, if I have it, to balance the crank in the best way possible. I trust the builder as he has machined quite a few engines over the years for me. I was wondering how many of you have had your set-up balanced this way.
He told me it is not needed, it is just the best way to go. There is no dollar factor as I did some work for him and it is just a favor in return so it is just time out of his pocket.
I just wanted to get your opinion.

And yes, I am having the crank drilled for the balancer.

Thanks.

[Dick W.]

Re: Balancing 1963 L-84 Crankshaft

You will get a better balanced engine if you add all those rotating parts.

[Michael G.]

Re: Balancing 1963 L-84 Crankshaft

If it spins......balance it. No need to second guess later down the road.

[Monte M.]

Re: Balancing 1963 L-84 Crankshaft

Thank You,
Gentelmen

Is this becoming the norm as the technolgy to do it progresses?

[Clem Z.]

Re: Balancing 1963 L-84 Crankshaft

if they balance the crank with the flywheel and damper attached and if you ever have to change either the flywheel or damper you will have to pull the crank to balance them. only when there there is not enough room for the counter weights in the engine do you balance the flywheel,damper and crank as a unit like a 400 cu in SBC. yes you balance the flywheel and damper but separately. you also balance the clutch separately for the same reason.

[Joe L.]

Re: Balancing 1963 L-84 Crankshaft

And yes, I am having the crank drilled for the balancer.

Thanks.

Monte-----


If the crankshaft is original to the engine it should already be drilled and tapped for a balancer retaining bolt.

[Timothy B.]

Re: Balancing 1963 L-84 Crankshaft

Monte,

I would be careful here because if the crankshaft is original to the engine and the engine internals are original it's balance should be good as is.

If the rods and pistons have been changed then the complete rotating assembly should be rebalanced.

[Duke W.]

Re: Balancing 1963 L-84 Crankshaft

Precision balancing also requires measuring/equalizing the mass of the rods and piston/pins assemblies, and he should also ask for one rod bearing and one ring set to include them in the balance calculations. Rod mass is actually measured on two scales simultaneously to get the top and bottom values.

The tops of the rods and pistons/pins/rings make up what is called reciprocating mass, and this determines the mass of the large crankshaft end weights in order to eliminate the first order rocking couple.

The flywheel and damper should be static balanced. Then the clutch pressure plate should be installed on the flywheel, any necessary balance mass welded to the clutch cover and the assembly matchmarked to insure assembly at the same clocking position.

Precision balancing will often eliminate the "shifter buzz", which is common on vintage Corvettes.

Duke

[Stuart F.]

Re: Balancing 1963 L-84 Crankshaft

That's interesting about the Shifter Buzz, Duke. I never have had that with my 63, but always did with every other 4-speed I've owned. I always figured it was because all the others were BW T-10's, and my 63 has the Muncie.

Been along time since I was concerned with "Blue Printing" and "Balancing" an engine. Darn! I miss the 50's and 60's!

Stu Fox

[Monte M.]

Re: Balancing 1963 L-84 Crankshaft

Thank guys,

Duke: that makes it very easy to understand. I will ask more about how the clutch and flywheel are being done. No "shifter buzz" is the goal, along with a good running engine.

This is what i was hoping for. Now I have enough information to ask the right questions.

His intent was not to balance it as a unit.

He was going to test the damper to make sure it was still good.

He did say he was balancing the flywheel and the pressure plate as a set.

The crank, rods, pistons, new bolts, bearing, and rings are all needed to balance the lower end according to him.

This sounds pretty good to me. Can anybody think of anything else to ask.

He also wants my gear box. He said he can do a spin test for vibration. I like the sound of that. I guess it can't hurt.

Like I mentioned before, this is being done as a return favor. I am sure he is doing the best he can.

Once again, I appreciate you taking the time to help out.

Monte

[Clem Z.]

Re: Balancing 1963 L-84 Crankshaft

[
He did say he was balancing the flywheel and the pressure plate as a set.
you do not want to do that because if you ever have to change the pressure plate you will need to pull the flywheel to balance them together. you balance the flywheel first and then balance the pressure plate bolted on the flywheel.

[Monte M.]

Re: Balancing 1963 L-84 Crankshaft

Thanks Clem. That makes a lot of sense.
Monte