[fat50]

Hi All,
A friend at work just had his SBC rebuilt and it was balanced using his steel flywheel. Now he has decided to go with an aluminum one. He doesn't want to tear in to a fresh rebuild to have it re-balanced. Now for the question.....

Can he take the aluminum flywheel and have the balance matched to the steel one?






Thanks,
Chris

[454me]

Unless its a stroker or a 400 the flywheel shouldnt have been balanced with it. The small blocks except the 400 were internally balanced.

[RCastle]

Why does he want to swap if it is all balanced with the stell piece?Is it broke?Weight difference will be minimal. I have heard yaking about the weight of flywhellsand the enertia of them changing things but I can not see how it helps.The engine will rev the same either way,steel or aluminum.

[454me]

I would think that it would rev quicker with aluminum. Less mass to get spinning. I would think the torque would be better with steel. More weight to stop. I cant see why i would want aluminum. I think they would be less durable than steel. But then I have never had one.

[LilSmoke]

If u have a heavy car, a steel flywheel will help to get the car moving, If its light,like a early vette or a vega or an anglia, it will help to control wheel spin and rev quicker. Aluminum flywheels have a bronze insert on the mating surface. their are many different weights for both to tune the car with. 4 and 5 sp cars are always changing weights for the track cond. the only drawback to aluminum is the bronze tends to crack if subjected to alot of heat after awhile,eventhough it can be swapped out .

[jimfulco]

A heavier flywheel makes it easier to start off from a dead stop without causing the engine to stumble. The engine will still rev to the same speed, but it will take it a little longer to get there.

[RCastle]

I can not see a lighter flywheel doing it .If we were talking about a piece of metal that weighed upwards of 35 + pounds,maybe.But if you have even a low horsepower engine,spinning something with a weight difference of 3 to 4 pounds??

[dmc12mk3]

Originally posted by RCastle
I can not see a lighter flywheel doing it .If we were talking about a piece of metal that weighed upwards of 35 + pounds,maybe.But if you have even a low horsepower engine,spinning something with a weight difference of 3 to 4 pounds??

Its a weight difference with a considerable amount of leverage behind it. Hold a half gallon jug of water (~4 lbs) and throw a few shadow punches with it. You can illustrate to yourself how a minor reduction in mass (putting down the jug) allows your arms to move a lot more quickly.

Reducing the flywheel mass increases the ease at which the engine revs (significantly) and also allows for a lot more engine braking when you lift your gas peddle.

[johnsongrass1]

3-4 pounds?

Any quality single disk aluminum piece will reduce rotating intertia by less than half a stock typr. You'll accerate faster, stop sooner, with more throttle control and response. Not to mention free up power. Down side, hard to get a heavy vehicle moving, less clutch life overall.

[RCastle]

What I am saying is that I can not see it mattering on any typical 350 HP street car.As stated in the first question.This guy has had a rotating assembely balanced with a steel flywheel..So now he is going to throw off the balance job.Ounces count in a balance job,so pounds will definently.I still think it is bunk.As for the arm and 4 lbs. of water in a jug.My arm does not put out 350 HP of power,useless argument.Just checking on something,Taken from a Summit catalog for a CSR Performance


"Machined from virtually unbreakable .187" thick chromemoly steel,these CSR Torque Master flexplates have a gold iradate finish and a fixture welded ring gear to ensure minumum runout.Each flexplate is SFI approved and weighs about 3 to 4 pounds heavier than stock to help improve your reaction and 0-60 times.NOTE: CSR recommends balancing the flexplate with your rotating assembely.





So which one is it,lighter spins faster or heavier spins faster? Now lets not get all pissed at Ron,cause I am not a believer of the flywheel issue.

[BOBCRMAN@aol.com]

Those are specs of a FLEX PLATE. Not a flywheel. Apples and Oranges...

My buddy and I campained a 66 396 SSChevelle back when it was new. These cars are not noted for wheel well room so we were limited to about a 10" tire. We tried f-wheels from stock weight to 35 lbs. And one aluminum. The heavy wheel= Explode the M&H Racemasters off the line. Big block torque helps carry the engine thru the load. Terrible 1/4 mile time. 25 lb.= Controllable wheelspin, good forward motion, torque carries thru rpm range. Best 1/4 mile times.. Aluminum= Leave the line at over 1000 rpm higher than steel wheel, bog motor. Terrible 1/4 mile time. The only way to launch car is on borrowed 7" tires. Bog motor off the line and spin the tires top of each gear. Throw away aluminum wheel..... Not good on 3400 lb. car with big end torque.

I also tried an Aluminum wheel on my big block Nova street car. I thought it would give me an advantage with the street tires (L-60 15's) HATED it. poor driveability. Wasted a good Hays disk in about three weeks. Back to a thirty lb. wheel.

[RCastle]

The picture clearly shows a flywheel,they just wrote it in as a flexplate.



Ever grenade a bellhouisng? I have nevr of course,just curious what the Pucker Factor of that is from someone with firsthand expierence.

[BOBCRMAN@aol.com]

I was at Lapeer Dragway one Sunday, when a 55-57 Chevy grenaded a flywheel. 2/3rds of it went up into the air (out of site) then came down about 10 feet behind the spectators seating. Struck a new Chevy sedan about mid hood and destroyed the top of the cars motor/waterpump radiator area.

I was racing on opening day at Manistee County Dragway, a 57 Chevy blew a f-wheel and a piece hit and killed a young spectator. A bad way to start out a race track!!

When I was in High school. We were street racing one Saturday evening when a 64 Corvette blew about 1/2 a stock flywheel thru the furniture store window. Didn't do the Vette bodywork any good. Nobody got hurt, but we all remembered it for years!!