Flywheel integrity

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K.O. SWINGER

K.O. SWINGER

Meeting in the alley since 1976
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My question is at what point you step away from a iron flywheel. The question is not related to power but strength of a iron flywheel. Assuming a Duc iron flywheel is in perfect shape what horsepower or RPM range do you feel it's time to move to a superior material.
 
More information is needed. What car, what engine, what HP, what's the usage, street car, race car, combination of both? Your question leaves us to guess at the combination.
 
K.O. SWINGER said:
My question is at what point you step away from a iron flywheel. The question is not related to power but strength of a iron flywheel. Assuming a Duc iron flywheel is in perfect shape what horsepower or RPM range do you feel it's time to move to a superior material.
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If you are making any power and have any gear (I say over 375 HP and more than a 3.73 gear) you need an aluminum flywheel. You don’t need that rotational weight.
 
You can (and they have) blown up flywheels with a stock Chev 283 4bbl. All it has to do is see enough abuse, slippage, and heat, and then a little bit of RPM. A hydraulic lifter v8 capable of 5-6K is all it takes. There has been flywheels come apart in TRUCKS
 
yellow rose said:
If it’s 15 pounds it’s probably ok. If it’s 30 pounds it better be a low HP tall geared combo.
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Says 27 lb, and I have one that's working fine in my decent HP, over-cammed, 3.91 geared combo... and a Lakewood scattershield!

Anyway the OP wanted to know at what point he should discard the cast iron wheel. My recommendation is: immediately.
 
I understand the dangers of an exploding flywheel but in 40 years of Street racing I have only seen one flywheel come apart and actually I was very young and I believe it was a fastener problem and not the flywheel actually failing also thousands and thousands of iron flywheels have been used over the years
 
K.O. SWINGER said:
I understand the dangers of an exploding flywheel but in 40 years of Street racing I have only seen one flywheel come apart and actually I was very young and I believe it was a fastener problem and not the flywheel actually failing also thousands and thousands of iron flywheels have been used over the years
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Those weren’t 40 or 50 years old then either. It also depends on the clutch you run. If you are generating a lot of heat you need something better.

Like I said above, most anything today needs an aluminum flywheel. All that mass (lets say 30 pounds) that far away from the centerline of the crank imparts a huge amount of shock to the drivetrain/chassis/tire and unless you need that (you do if you have a very small displacement, heavy car or both) you’ll just beat the crap out of the tire and make it harder to tune the chassis.
 
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DrCharles said:
What? should that be "shock", maybe?

My 451's low-end torque is quite weak with a 272 cam, so the extra mass helps there. Wouldn't a lighter flywheel require higher rpm at launch?
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LOL...my fingers aren’t working too good today. I fixed it.

With 451 inches I can’t imagine you need more flywheel weight. Unless you have a 3.23 gear or something and the car is heavy...like 3800 pounds or more.
 
Why I've run this in my Bee since 1979, after watching my GF at the time's brother lose a right foot in his '66 GTO.
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Ask Ronny Brown, when his flywheel exploded back in the late sixties a piece hit the ground & ricocheted up. It hit someone standing on the outside of the rails at the starting line in the neck, they bled out before the paramedics could help him. Ronny was running stock eliminator & clutch cans were suggested, but not required back then. Shortly after that incident, clutch cans became MANDATORY for any stick shifted car.
 
"I was there" This happened as I recall in the summer of 66 or 67. Two of us had taken my beater 57 Chev to the old Deer Park WA drags. It was a cold windy day. We had gone back to my car to warm up, which was parked with others "drive in movie style" along the spectator fence. For some reason I'd gotten in the pass side and was looking through a program which my friend had bought. He started to yell and I looked up "Ron's blew a clutch!!!" and I could see junk coming down out of the bottom

Seconds later, BLAM!!! A piece of PP about 2" square had come between the two cars, and put a long almost horizontal gouge into the rear side fender of a 58-59? Cad parked next to us, and lay smoking in the grass. I had that piece for a long time, I wish I could find it.

Ronsgasser.jpg


RonsDriveIn140ChevyGasser-vi.jpg
 
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