I have a buddy that does metal lathe work. Was wondering if I gave him my stock flywheel, and he made a copy of it out of aluminum would it hold up?

 

Oh, boy!

 

You need to know a lot about the inherent strength of the aluminum, for safety's sake at least use aeronautical grade, which is stronger than 6061.

Big risks involved in this project but it has been done, maybe contact a flywheel manufacturer and ask what grade they use.

 

And if you do use a homemade flywheel, get a professionally made shield for between the transmission and the floor in case it decides it's going to shatter while going 7,000rpm

Jon

 

physics tells you it would not come through the floor, you do risk damaging your bellhousing, hood, and maybe youre winshield deending where it lands,, good on you for thinking of projects like this.. you will need an automatic counterwieght, hes gonnna need more than a lathe... a milling machine with gear cutting attatchement will work, or try using a steel ring gear, definately try and find out what sort of aluminum manufacturers use if not use chromoly and make it thinner..

Paul

 

This is a risky project, for several reasons. Strength and durabilty as already noted along with balance and wear issues. Many of the lightweight flywheels have a repaceable steel insert for the clutch disc wear area. The other concern I have is balance in relation to the rest of the rotating mass of the engine. Duplicating the configuration of the stock flywheel, then trying to add an auto counter weight most likely will not work due to space restrictions. A better option would be to duplicate an exisiting light weight flywheel, then add the auto counter weight and balance the entire rotating assembly.

In the long run it would be cheaper to buy the lightweight flywheel and counter weight. Toasting a single engine due to imbalance puts the entire project in the red.

 

A stock flywheel has a counterbalance in it's shape. So by copying that shape you end up with the same sized balance, yet a lot lighter, since you'll use aluminium. In other words: the engine WILL run out of balance. The only way of making your own flywheel would be using a solid disc (= no counterbalance shaped in), and having it balanced. Then use a automatic transmission counterwheight, as said above. You will still need a steel pinion ring: I don't think the aluminium would hold if you'd cut the theeth in it.
And as said in an earlier post: you'd need steel (or other hard wearing) surface area's for the clutch. Else the flywheel will be eaten away.
Unless you need a custom flywheel (for engine transplants or using a gearbox from a non-rotary) I guess it's way safer, easier and maybe even cheaper to get a lightwheight flywheel from a brand name (RB...)

 

What duraluminum? It's nearly the strength of stainless steel, and is only slightly heavier then regualr aluminum. I know this stuff is used alot in aircraft construciton, and was invented in the first world war, for use on the first armored all metal aircraft. I belive it was also used on a german monoplane fighter as well.

Its cool stuff.

 

hammer your ring gear off the factory flywheel and slide it on to your new one, aluminum teeth won't hold up to the starter!

 

I had a mate machine this flywheel from normal billet aluminium about 3 years ago. Its been on a 13b turbo that puts out 250hp at the wheels no vibrations, it hasn't cracked and is still in perfect condition. If your buddy knows what he's doing it will be fine.

 

if your dead set on doing this get some 7075-O then after all the machining is done have it heat treated to T6 it'll re-refine the grain structure of the aluminum. as for the ring gear, if your buddies good and knows how to make form cutters he could mill out the teeth whith an indexing head and a fly-cutter with the appropriately shaped form cutter. me personally i'd just buy one from RB or Fidanza, less trouble and may wind up costing you less.

 

Whats the lining on the contact surface made of?

 

figures it would be done in australia first...

 

i must agrea with the people above me here 1. if it was cnc i would be alot more likely to accept, 2, thier is a but load of stuff that you are not taking into consideration 3, if you do get it i would deffinitally get a shield!!! and btw thier is alot of enginiering that goes into them to withstand the brutal beating they often take from people "trying" to race them ect.... i would personally never attempt this on my own without at least using a cnc, to me your idea sounds sorda like in welding shop one time where this idiot kid insiting on putting on the tail pipe (he had money + parts but couldnt weld worth shi354) and put it right next to the drivers ear (on a go cart) without a pre silencer cata or a muffler, we all tried to tell him but he wouldnt listen to us. he is know quite deaf... hmm i wonder why?? personally i prefere my engine not to be a home made metal shard bomb.

 

I was going to suggest just buying the replaceable surface for an aluminum flywheel from RB or something, and machine to fit it, then you could have readily available lining replacements easy. Also, as Jimmy said, just use the stock toothed ring from the original flywheel. Good luck

~T.J.

PS - If its balanced on the lathe, it shouldnt be too hard to get it "close enough" so that after you have the whole thing done and ready, you can take it to a machine shop that regularly does them, and have them actually balance it by removing metal in the right areas and such.

 

The lining is made from an old brake disc machined to the same size as the clutch disc. This is the fourth flywheel my mate has made two of which are on dedicated race cars. total weight is 4kg including counterweight and only cost $420AUD.