Hot Rods Experience running aluminum flywheels on the street?

After watching the GMC 6 banger flywheel explode at the HAMB drags a few years ago, I put my Pontiac steel flywheel on the shelf and bought a Schiefer aluminum flywheel to run behind my 370 Pontiac/muncie 4 speed [2.20 low] in my 34 ford. I'll be running my Winters quick change so I can tune my rear gearing to what the car likes.
The flywheel is drilled for a "long" style pressure plate setup with levers. The old Pontiac flywheel is drilled for a Borg and Beck style clutch which I have already...
Oh yeah....my cam is a Lunati 230/230 degree at 0.050 on 110 LSA. Has a nice lumpy idle to it.
Hoping to bring the finished car in at about 2700-2800 lbs.
What are your experiences running an aluminum flywheel on the street?

 

They are fine, I have run them a couple times and the fun factor is right up there! Gary

 

I ran one in a practically stock 302 Ford for a while in a 66 Fairlane. I didn't like it. It seemed to have less torque than the steel flywheel. I put the steel one back in. I would think if the car were a lighter one or the engine was built for hotter performance then it would have worked better.

 

Thanks, Gary and Don...anybody else have experience?

 

I have one on my Buick V6 powered TR3. When the engine was stock it had a very heavy stock flywheel and was impossible to stall. The engine now has a stage 3 Crower cam, 10:1 pistons, ported heads and weber carbs and weighs about 2100 lbs. It can be a little touchy until you get used to it but the throttle response is fantastic once the clutch is out and the car is moving.

 

the car will go faster with a heavier steel fly wheel. remember as fast as it revs up it also slows down a like amount. alum flywheels are for round round cars. the car will take more rpm to launch and will fall on its face before you reach the tree. i made this mistake. there are a few threads on this subject they all say don't do it. on the street it takes more rpm and more clutch slipping to get the car moving.

 

Don't know about the HAMB GMC explosion but what it wasn't was an unmodified steel wheel. No freakin way! However back on message...unless your car weighs <1800 # you don't want an aluminum wheel. A good old fashioned steel wheel something less than 30 lbs. should work great.

 

Light car with deep gearing Ok or a car that is traction limited.

 

I have run more then one with no problems.

Two that come to mind are one in my '41 Chevy pickup behind my 292 with a 3 speed. Mild cam, single 4 on offy and twice pipes on hookers. I am not sure what woke the inline up the most but I am sure that the light flywheel helped. No problems and always left well.

The other was behind a mildly warmed over 350 olds in a 3200 pound hatch back OT car. Another 3 gear. No problems there either.

Both were Schiefers and neither engine was professionally balanced if that makes an difference to you.

I also ran an aluminum of unknown pedigree behind the hot 312 in my '55 Vic. It had a license plate, but it got flat towed mostly the last year we had it. I did drive it for a year prior to that though. No problems either.

I never noticed that I had a torque problem with any of them but I seldom went idling around in them I either. Well I did run the gut once in a while in all of them but mostly I was driving them like they deserved to be driven.

 

Had a Weber aluminum flywheel in an OT '68 Camaro. The engine was an early 70's built solid lifter high compression 2.05 angle plug small block. An over the counter GM parts crate engine with an off road, 2nd gen. Z28 cam. Spooled up extremely well. Light car and/or extreme horsepower engine equaed a lot of fun. Third gear would bust the tires off at 55 mph with just a throttle stab. With the right ingredients ... you sir, will love that combination. Can't wait to see it. Good luck !!

 

Perhaps the aluminum wheel kept me from exploding the 312.
The Old Vic did Ok for what it was and I don't believe I could have made it any faster with a steel wheel. I guess the only way for me to tell would be to go back in time and switch wheels.

I am trying to wrap my head around your logic and I am not saying that you are wrong. So bear with me. OK?
We spend a lot of cash lightening lower ends or at least I have for the last 40 or so years to make them spin quicker. I have had good luck doing so. With that thought a lighter flywheel in my mind should net the same result. Am I making sense to you with my logic?

Help me out here I am not too old to learn I promise.

Gene
The busted steel wheel at the HAMB Drags was on a machine that was doing the Smokey Yunic thing with the rules. I don't doubt that that old wheel was lightened to the max and obviously they had taken it a little too far. Falls under live and learn.

 

ok let me try to explain. the heavier wheel has inertia. a wheel in motion wants to stay in motion. at a stop light or on the line when the car is reved up there is stored energy in the flywheel. as the clutch comes in it wants to pull the engine down. its the stored energy that keeps the engine running so it wont stall. with less inertia the car wont pull away as well. the engine will have to be reved higher to overcome the drop in the stored inertia that the alum has. the alum flywheel engines sound great. they rev up real fast and are very throttle snappy. they sound like you just threw in a bunch of hp. now just as fast as it revs up it also slows down a like amount. so you have not only the launch were the engine wants to stop spinning but every gear change as well. once the flywheel is spinning it takes very little hp to keep it spinning. alum flywheels do have a purpose and application. my feeling is the average street car or drag car will see lower performance and be harder to drive. they are popalar in circle track because the engine gets pulled down going into a corner. then rev upfast coming out. as street cars and drag cars we dont want the engines rpms going down. only very light or supercharged engines like the alum. when i switched from my steel wheel the first time i drove it i knew i made the wrong choice. being stubborn i drove it any way for a few months. i just couldnt take it and switched back. now this is just my experience and certainly not the rule for everyone. thats what makes this all so fun. the experimenting to maximise you own combination. as far as light weight lower ends they are not designed to act as fly wheels. the flywheel does the job it was designed for. there is benefit to a light rotating assemble. the fly wheel does not change dirrection where the rods and pistons do.

 

Porknbeaner and Racer-X are both right- you can easily blow the tires off at the starting line with too heavy a fly wheel-so it's not all cut and dry. there's give an take- a light car that doesn't need the inertia at the starting line will rev up quicker in each gear as stated. it's all about the combination and how you want to use it.-rick.

 

Thanks now I am better understanding what you are saying and yes I have learned something today.
Hopefully someone else did as well, and maybe this helps Rocky in his decision.

 

I've run an aluminum flywheel in my Nomad for the last 15 years. I have a lot of fun with it. Mild 350, M-20 Muncie, 3.70 rear gears.

 

Years ago mopar offered its racers a wide selection of flywheels that had different weights. look in the old dc catalogs. Some were over 50 lbs. Think how that ss car came out of the hole at 6000 rpm.Experimenting is the only way to know whats best.

 

I think it works different with driving style and perhaps the big end makes a lot of difference too.

The Vic for instance was only a 12 second car, which was respectable enough for what it was and with 7" slicks it was peddle to the floor and side step the clutch on the second light.

I don't recall there being and clutch slipping on either of my street cars but I was pretty intoxicated a lot back then and both engines made a lot of torque off the bottom.

I think I still have an old DC catalog either here or at my buddy's house I will give it a look for grins. Thanks for the heads up.

@Rocky

NOTE: Scatter shield with the aluminum if you can't find one we'll make you one. I still have both feet and all my toes but as my mom always said, "God loves drunks and idiots" so I have always had double protection.

 

In the 1980s Car Craft had an interview with a big-name drag racer and he said the flywheels on Pro Stock cars were so heavy the car would launch even if the engine stalled. (I do not know why that quote, of all things, is still stuck in my head after all these years? I can't remember what I had for lunch yesterday.)
He then went on to say it only made sense because they made so much horsepower and ran such high rpm.
So...with no personal experience at all I guess I am saying it all depends on the car, engine, and intended use

 

Watching and reading all the responses..thanks, guys. Remember, this is a street car but I may bust it through the lights at the HAMB drags [just for funzies] and possibly a little fun at our local 1/8 mile track on $10 Friday nite.
99% of my driving will be on the street and some road-tripping.
PS...the flywheel is aluminum with a bronze insert.......... not used, it's a new one.

 

I must ask the question... with a stock engine it would seem like the stress on the rest of the engine would be more extreme. and possibly break things more often?

 

New is good. I just don't want to be the one that gets sent out to find your toes and you know it'll be me or Mikey.

 

That effect is nearly worth the price of admission. The near-instant revving of the motor makes them sound like a all-out race motor. But note I said 'nearly'...

One downside not mentioned is vibration. Years ago I owned a '67 Cougar with a bored-and-stroked 455" FE/four-speed/3.50 gears and I got a deal on an aluminum flywheel while I was assembling the motor. Now, this motor had huge torque so drivability wasn't big issue but with a smaller motor with less torque it could be unless you're running pretty steep rear gears. In 'normal' street driving, I didn't really notice it other than it required a bit more 'finesse' when starting from a stop. But drop the hammer and the vibration would loosen your fillings when the motor was in full cry. A heavy flywheel not only stores energy, but also smooths the impact of the individual firing impulses. For a illustration of this, look at the size/weight of Harley flywheels. How bad this will be will depend on many factors (a very good balance job should be mandatory), but you'll get some no matter what. Not an issue on a sprint car, but if you have a heavy right foot you may be spending a lot of time tightening small fasteners back up....

 

my experiences are 1/4 mile
11# wheels to 60# ones...
both have different reasons launch/hook and rev's, per your DRAG cars requirement.
as others have stated quick rev's (both up-n-back down) with Aluminum.

 

My experience has been with Stock Eliminator drag race cars. Every car I know of that went to a lighter flywheel, lowered the E.T. including mine. A heavy flywheel does produce inertia that carries a car off the line or through the gear change but keep in mind that after the leave or the gear change, the engine has to accelerate. Light weight bottom end / driveline components will accelerate faster. I would think on a street car if the clutch is out and you wack the throttle, the vehicle with the light weight flywheel will accelerate faster than one with a heavy flywheel. If you want to side step the clutch and smoke the tires,you would be better off with a heavy flywheel. A light flywheel is also easier on the driveline. If you don't beat on your car you may not even notice the difference.

 

More than a few aluminum flywheels for me...
My 304" flathead in '32 Five window hiboy (2300 lbs., thereabouts) had a 12 lb. aluminum Weber flywheel, 10" Auburn clutch. Fast up-n-back down, literally fell on its face out of the hole. No 'normal driving', or it would stall on takeoff. Very hard to drive...but OH, the Power!

I took over payments on a '63 Impala 409, close ratio Muncie, 2 E-series AFBs, Jardine headers, and a General Kinetics 'cheater' cam, solid lifters, 4.56 rear.
I just HAD to replace the flywheel with a Schieffer 14 lb.? aluminum wheel.
Even the 4.56 didn't save it...car was too heavy. Sure sounded scary with that fast rev, though... then right back down. Sounded like 14:1 compression ratio. LOL

The worst example was the '50 Olds Cpe I got from an older guy: '57 J-2, '37 LaSalle box, (he knocked out low and 2nd 3 times, got discouraged, and sold me the car for $600. This was in '60.)
I tore out the LaSalle, fixed it, (cluster pin bore was oblonged .050"!) installing a new Schieffer aluminum wheel at the same time. 3.78 rear...
You never saw a long-legged Olds fall on its face comin' outa the gate like that one.
If they were measuring 60 ft. time back then, you'd have had time to start a conversation!
Right off, I could see what a mistake that was...
Back in went the steel (about 30 lb.) wheel, and the difference was applaudable!
Rev engine to 3200, just slip the clutch, then wide open throttle...ZOOOOM! Low gear would be used up at the end of the leap...also had a meaner second...

The bald truth is to use a 12 lb. aluminum wheel in a car that's lighter than 2,000 lbs.
Truth reluctantly accepted by an old 'Die Hard'...
I have a new Schieffer aluminum flywheel for my 283" Chevy mill, built the engine 'to 1959 fast street specs', Duntov 12/18 cam, 3 Rochesters, Powr.Pak heads, matched ports.
'39 box behind it, to go into my 'glass turtleback '24 T. (leftovers)

 

Im going to try a light alu flywheel in my model a coupé, with a bored 265 (283) ...
3 speed, Hope the hotrod is light enough. Going to try a 12 inch clutch too

 

LOL that kind of defeats the purpose of a light flywheel.

Sorry I just wanted to say that.

You'll be sure that we know if it works or doesn't though right? I used to run smaller clutches like in the 10-11" range. Will be interesting to see how it works out.

 

I think the clutch is the same weight as the 11", but I Will check it up ;-)
I compared the profile, and the 12" is little more slim. Anyways, as a rookie (me), I just got that awsome flywheel and needed to try it out, Hope for some smiling results :-D

 

@jho Has been running an aluminum flywheel in his FE powered Model A Coupe for a while now. He seems to like it --- may bring it up the next time you run into him, @Rocky

Malcolm