Shade Tree Flywheel Balance Test

[Diogenes]

I am approaching assembly time on my C-6 to toploader conversion and a potential issue occurred to me. The parts were sourced from a 66 7Litre car, with the steel flywheel being marked "360-390 FE 184T T10", no other markings or stampings are apparent.

I have no way of knowing if the trans and flywheel were actually on the 428, or if the engine had been removed and a 390 put in it's place.

I need to ascertain whether this is an internal or external balanced flywheel. I am unable to get it spin balanced anytime soon due to the time of year, so I've thought I could use my friend's old wheel/tire bubble balancer to figure out if it is neutral balance or not. There are two fairly shallow drills on one side (sort of looks original to the part), but this may be to zero balance the part.

Any thoughts on my plan, positive or negative? Anyone have any other quick ways to establish the facts (or reasonably approximate the facts)?

[gdaddy01]

is it steel or oem cast iron ? if cast it will have a small counter weight made into it like a 289-302 .

[machoneman]

http://www.mustangtek.com/flywheel/Flywheel.html

[Diogenes]

the steel flywheel being marked "360-390 FE 184T T10", no other markings or stampings are apparent.

[Gregwill16]

If it doesn't have an added weight or lots of drilled spots it is most likely zero balanced.

[427John]

If it doesn't have a counterweight,casting number,or Ford part number stamped in it,the only way to find out for sure that it is for a 428 is to have the amount of imbalance checked.The fact that it is marked 360-390 FE wouldn't give me much confidence that it was anything other than that.

[gt350hr]

   "428" flywheels ( and 427 only) have recesses for the flywheel bolts. The 428 (early) has C6AE cast into the back side in the counterweight area. Later 428 flywheels have the raised counterweight area and  a hand stamped C8ZE on them. As mentioned you could also have one where the outer has allot of drilled holes done at the time of balancing ( not factory). I have a 427 flywheel that has been converted that way.
   Randy

[Gregwill16]

Good point Randy, that is an easy identifier for a "factory" HP fe flywheel is the recessed bolt holes.
I have never seen a 428 flywheel with a C8ZE hand stamp though.? All the "late" ones I have and have seen have C8OE-A hand stamped out by the ring. The SCJ has a C9ZE stamping.

[gt350hr]

  You're right Greg!!! My error . C8OE for CJ and C9ZE for SCJ.

[Diogenes]

Despite the shade of the tree, and an utter absence of part numbers and casting numbers (since it is a steel flywheel, as originally stated), the old-school bubble  balancer revealed a .25oz off balance. This essentially told me what I wanted to know--this flywheel is not an external balance piece. My post regarded the efficacy of using a bubble balancer to determine the facts regarding the potential balance/imbalance of the flywheel, something most (though not all) conveniently overlooked.

Thank you to all those who critically read my post and provided constructive feedback.

[427John]

I guess most of us read your post as a way of confirming if it was balanced for a 428 instead of confirming that it wasn't for a 428.That is 2 completely different scenarios.

[gdaddy01]

what ?  lots of folks call a cast flywheel , steel . I was just trying to make sure what you had before moving forward . sorry for trying to help .

[427John]

The 410 and 428  weren't the only FE design engines that did not use a detroit or neutral balance flywheel.