Flywheel balance required?

[Funracer]

Will put my new Sachs clutch on next week. Had my flywheel turned locally. Now reading I need to have them balanced together? Is the new Sachs set already balanced out of the box?

Also I did not mark my flywheel when I took it off. Does it have to be bolted onto the crank the same way it came off? Is there a mark somewhere that would help me orient it?

Thanks

[smadsen]

Look for little "pips" from a punch near the bolt circle on the flywheel. Look for similar marks on the back of the crankshaft.

I don't know how they did it at the factory. Maybe they balance each piece individually and then just assemble it. Typically a performance motor would have a final balance of the entire rotating assembly and then the clocking of the flywheel and the pressure plate should be marked. If you have the flywheel off, but the case has not been split, I'd have the PP/flywheel assy balanced & call it good.

[john walker's workshop]

The flywheel only fits one way. The sachs kit should be factory balanced. Never had issues with it. The flywheel should be ok if it was not warped and was machined evenly all around, rather than warped and more ground off one side than the other.

[stownsen914]

Always smart to check balance. Much easier to do now while car is disassembled.

[KTL]

It's good practice to have them balanced as an assembly but it's not always a must. The parts are pretty well balanced when manufactured. You can see on the back of a flywheel there's drilled holes there to balance it. The clutch has similar weight reduction to balance it.

To reinforce what John Walker said, take a look at this video I shot years ago (wow, it's been SEVEN years now....... ) to show how the 9 bolt flywheel only fits in one position.

https://youtu.be/n-KVrrR8Oyg

The video worked out pretty good to show how even if you removed the locating pin/dowel, it still only fits in one position. Sounds crazy, I know, because one tends to think the bolt spacing is symmetric. It's not. I go nine rotation increments back to the start and the bolt holes line up in only ONE clocking position- at the start and at the finish.

The video begins with all of the bolt holes lined up. Follow the tiny dowel hole at the bottom as I rotate the flywheel around the crank flange. The bolt hole to the left of the dowel hole at the start of the video is the one that I used for a point of reference in stopping the rotation each time. Each time I stop rotating, take note of that same hole. It's the only hole that properly aligns with a crank flange hole each time I stop. Admittedly, I was a little sloppy at aligning my hole for stop #4. At stop #5 we are REALLY close to having all the holes line up but still not close enough. Not until I go a full 360 degrees back to the starting point do all the holes line up. Sorry I also got a little sloppy at the very end, as I had to back it up a little bit to show I was back on the mark.

Note that the crank I was using is a 3.0L SC crank and it doesn't have a dowel pin in it. There's no dowel pin because it was drilled through to create an additional cleaning hole in the end of the crank. A set screw was installed to plug the hole after tapping the hole for threads. So my point of sharing that missing dowel is simply to say it was convenient that I didn't have the dowel and that allowed me to easily do the rotation test. I'm not sharing this to suggest you should remove the dowel to make a cleaning hole!

[Funracer]

Originally Posted by john walker's workshop

The flywheel only fits one way.

Just checked it. You are correct of course. Not obvious to the eye but it only fits one way.

Thanks

[Funracer]

Thanks Kevin. I did the same thing this morning. One position is pretty close but it only goes one way.

Regards

[Walt Fricke]

I always like zero balancing - each part individually balanced. That way you can replace a worn component with a new one without having to take both to the balancer. As in replacing the pressure plate without having to pull a flywheel which is in good shape. So even if you take both to the balancer (though a new PP ought to be balanced out of the box), I'd have them balanced separately.

[Funracer]

Originally Posted by Walt Fricke

I always like zero balancing - each part individually balanced. That way you can replace a worn component with a new one without having to take both to the balancer. As in replacing the pressure plate without having to pull a flywheel which is in good shape. So even if you take both to the balancer (though a new PP ought to be balanced out of the box), I'd have them balanced separately.

Too late. All installed and torqued up today. Not taking it out for a street car.

Thanks guys