Just How Important Is Flywheel Balancing?

[Shadetree]

I have my flywheel back from the machine shop where they drilled and tapped it for the smaller pressure plate. They couldn’t balance the flywheel so I will have to look elsewhere. So just how important is the balancing of the flywheel? It not likely I will be cranking 6 grand but I don’t want it to rattle my windows at low RPM either.

Also, I can’t find part# 6677 advertised, anyone know where I can find one?
Thanks in advance guys.

[kelly.ga]

I would think flywheel balancing is critical. Even a drive shaft out will make your car viberate. JMO

[scrapiron]

You should find a proper engine shop that can "zero" balance the bare flywheel and then check the balance with the pressure plate attatched.

[oldford2]

Your diagram looks like an 8BA block with the truck cast bell housing and steel starter plate. That setup will bolt right into a 46/48 transmission. The part you are looking for is a steel "cup" and is swaged into the bell housing to protect the bendix from the elements. Probably not reproduced?? Those bell housing are fairly common at swap meets.
John

[Ol' Ron]

What would concern me nmore than flywheel balance is the consintrisity of the new clutch installation. Spin that mother with the pressure plate on it.

[ford1]

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Ole Ron. i have to agree with you, balance every thing at one tome, if you change clutch and pressure plate some time in the future, nothing will be balanced any way, it would be nice to have a balanced fly wheel, but it wont be with new parts installed unless they are balanced with the fly wheel, if you change any parts your still going to have to rebalance the wheel, you can balance the other parts but will the be syncronized with the fly wheel balance, to be pefectly balanced all parts need to be balanced together

[no6]

Originally Posted by Ol' Ron

What would concern me nmore than flywheel balance is the consintrisity of the new clutch installation. Spin that mother with the pressure plate on it.

X2, I am having my assembly balanced now and my machinist wants everything except the clutch disc.

[Walt Dupont--Me.]

I have many flywheels and P plates balanced. I've never seen a stock flywheel out by very much. Most P plates are out quite aways. My balancer spins up the wheel and might dill 1-2 little holes, then bolt on the P plate and spins it up and usually has to drill a few holes in the plate to balance the assemably. Then marks the P plate and wheel so it gets bolted on in the right place. I had one P plate out 100 grams, to much to balance, had to get another P plate. Walt

[coupe5w36]

re part #6677, I made one quite easily using steel tube that was a "tap in" fit (I also applied a tiny bit of Loctite). I welded a flat cap to the open end, linished it so it all looked like one piece, painted it & away we went. As everyone else is saying, balance must include the p/plate then mark the location as Walt says.

[Shadetree]

I measured from the edge of the flywheel to the pressure plate and it looks good. Not a precise way I know. The machine shop said they would do it by computer. They drilled six holes and tapped them and I will fill those holes with six bolts, it looks like if all was perfect it would still be balanced. But I can't take that chance, I sure don't want to take it apart again.

Thanks to everyone for your help. I'll sure be glad when this project is done, yet I have kind of enjoyed it...

[Pete]

You always balance the flywheel first, by itself, then put the clutch cover on and balance the assembly by drilling the spring stand bosses.
You can balance the clutch disc by putting it on an arbor by itself but they are very seldom off far enough to matter.

[FL&WVMIKE]

Originally Posted by Shadetree

I have my flywheel back from the machine shop where they drilled and tapped it for the smaller pressure plate. They couldn’t balance the flywheel so I will have to look elsewhere. So just how important is the balancing of the flywheel? It not likely I will be cranking 6 grand but I don’t want it to rattle my windows at low RPM either.

Also, I can’t find part# 6677 advertised, anyone know where I can find one?
Thanks in advance guys.

SHADETREE .....................
Did you ever check in at John Ellison's machine shop in Reedy ? That guy can do about anything !
MIKE

[Ol' Ron]

RE-drilled flywheels, can be WAY OFF.

[Ian NZ]

I would have the flywheel balanced with the pressure plate and when you bolt the pressure plate onto the flywheel make sure you use the correct bolts as a portion of them near the head has no thread on them so they can protrude through the flywheel a certain amount.

[makemc]

always balance flywheel and pres, plate as a unit and have them mark the bolt position so you will install it the same way it was balanced..lesson learned the hard way

[Shadetree]

Well, today I took the flywheel and pressure plate to a well known machine shop in Marietta, Ohio. I used some of my Fordbarn knowledge and asked them to balance the flywheel first and then bolt the pressure plate on and balance it. The machinist reply was, "Thats the only way we do it." I knew I was at the right place.

I then drove up the scenic Ohio River to a friend's garage. He had part number 6677 still on a bell housing, sand blasted and painted. Once I looked it over I saw why they aren't so plentiful. It looks like they are crimped on both sides of the casting at the factory and would be almost impossible to remove without destroying it.

Thanks to all for your help.

It was a good day...