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Hot Rods Are there long term effects for too heavy of a flywheel?

Discussion in 'The Hokey Ass Message Board' started by Roothawg, Mar 1, 2016.

  1. Roothawg
    Joined: Mar 14, 2001
    Posts: 26,030

    Roothawg
    Member

    I have an old vintage Hayes flywheel for a stick. It's a heavier flywheel for drag racing. Any long term effects on bearing life etc? I would love to run it if possible.
     
  2. gimpyshotrods
    Joined: May 20, 2009
    Posts: 24,533

    gimpyshotrods
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    How heavy is heavy?
     
  3. cavman
    Joined: Mar 23, 2005
    Posts: 698

    cavman
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    I would think that if it is in balance there would be no problem. The Nomad in my avatar had a 41# flywheel on a built 265" sbc, and it worked real well with the exception of it was rather slow to get higher revs out of it.
     
  4. RB35
    Joined: Dec 15, 2006
    Posts: 971

    RB35
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    Flathead flywheels are pretty heavy to begin with and only run on 3 mains, but I'm not racing.
    I would thing having a good balanced ***'y would be the key to longevity and a good inspection (magnaflux?) of the wheel and blowproof b-housing. Wouldn't want that coming through the floor.
     
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  5. BOBCRMAN
    Joined: Nov 10, 2005
    Posts: 846

    BOBCRMAN
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    from Holly

    You didn't state what engine you have.. But, I used to get in industrial flatheads for rebuilds, back in the day. Some with flywheels you could barely lift (even when I was forty+ years younger) and no bearing damage after years of 2800-3400 rpm. almost constant use.
     
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  6. Blues4U
    Joined: Oct 1, 2015
    Posts: 8,081

    Blues4U
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    from So Cal

    I always thought flywheels were lightened for racing. You should see some of the flywheels they run on tractors, too heavy to lift by hand.
     
  7. Roothawg
    Joined: Mar 14, 2001
    Posts: 26,030

    Roothawg
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    I just weighed it. 45#.
    It's a 265 Chevy, balanced bottom end with forged domed pistons. I was planning a 5 speed behind it for fun factor. The heavier flywheels tend to help launch lighter cars with small cubic inches or so they say...
     
  8. squirrel
    Joined: Sep 23, 2004
    Posts: 60,019

    squirrel
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    launches harder if you rev it and drop the clutch. when the engine slows, the flywheel gives up energy. When it revs back up, the engine puts energy back into the flywheel.

    The net gain/loss depends on the rpm through the lights, vs the launch rpm. If they're pretty close, then it doesn't matter how heavy the flywheel is--it will end up with the same energy is starts with. Energy is conserved. If the final RPM is a bunch higher than the initial RPM, then you have to add more energy to a heavier flywheel, energy that is not going to accelerating the car.

    That's the physics lesson. But the actual results will depend on a lot of other variables.

    as far as bearing wear, etc, there should be negligible difference, ***uming it's balanced properly.
     
  9. kbgreen
    Joined: Jan 12, 2014
    Posts: 359

    kbgreen
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    The physics suggest to me that the forces in action to make it spin from a dead start are a function of the acceleration which is a low value thus negligible. Once spinning, changing the rpm is also a matter of acceleration (not velocity) which again are low so again likely to be negligible. The upside is that a heavy flywheel will make an engine seem to run smoother because the larger rotating m*** is less affected by small vibrations like a misfire, etc. The downside as noted caveman is the rpm response time is lengthened. Regarding safety, I think any flywheel of any weight that disintegrates and flies through your floor boards is dangerous. Can't say that a heavier flywheel is more dangerous, they all are when they fail.
     
  10. aaggie
    Joined: Nov 21, 2009
    Posts: 2,530

    aaggie
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    Years ago I had a 301 Chevy with Rochester Fuel Injection, Duntov cam and fairly high compression Jahns pistons. I built the engine for a '57 Belair that weighed around 3300 pounds and it was tough to launch without revving to 5K. I pulled out the Aluminun flywheel and replaced it with a stock Chevy 11" ***embly that probably was close to 50 pounds and it would launch at 2K. The only problem was it took longer to rev up. That clutch ***embly was still in the car when I sold it three years later and held up to the abuse. I say run it.
     
  11. El Caballo
    Joined: Mar 3, 2001
    Posts: 6,334

    El Caballo
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    from Houston TX

    Flywheel lightening and its impact on engine performance.-- Read more at: https://www.torquecars.com/tuning/flywheel-lightening.php - (c) TorqueCars

    This was a pretty interesting read on this topic, it really depends upon how you plan to use the car. They like the idea of lightening the driveshaft, lots of rotational m*** there.
     
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  12. Roothawg
    Joined: Mar 14, 2001
    Posts: 26,030

    Roothawg
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    It's a street car. The history is this. The motor was in dads C/Gas car. It held a National record for a few months. I know it is nothing compared to today's motors, but it is as traditional as it gets. A 1955 265 with a tripower and a stick. The flywheel was mated to it when it set the record. It was also the first motor we ran in the Fly.
     
  13. Engine man
    Joined: Jan 30, 2011
    Posts: 3,480

    Engine man
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    from Wisconsin

    While a driveshaft might have some m***, it's a small diameter so it's not a big contributor.
     
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  14. squirrel
    Joined: Sep 23, 2004
    Posts: 60,019

    squirrel
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    it's lasted 60 years, and now you're worried if it's gonna be able to survive a few more p***es? :)
     
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  15. Roothawg
    Joined: Mar 14, 2001
    Posts: 26,030

    Roothawg
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    Well, it's been mostly a 1/4 mile at a time.....not a lot of miles to check for reliability.
     
  16. gimpyshotrods
    Joined: May 20, 2009
    Posts: 24,533

    gimpyshotrods
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    I've had heavy flywheels my whole life. My discs are bulging, and I have stenosis.

    Sent from my SM-G900T using H.A.M.B. mobile app
     
  17. El Caballo
    Joined: Mar 3, 2001
    Posts: 6,334

    El Caballo
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    from Houston TX

    You should see a doctor about that.

    The-face-you-make--When-you-sEe-a-doctor-touching-your-Vent-meme-31820.jpg
     
  18. Roothawg
    Joined: Mar 14, 2001
    Posts: 26,030

    Roothawg
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    I haven't priced a explosion proof bellhousing in a long time. Wow! They have gone up.
     
  19. belair
    Joined: Jul 10, 2006
    Posts: 9,036

    belair
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    I dropped one on my foot once. I wish it had been lighter.
     
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  20. Well Root here is some food for thought, there are companies marketing heavier flywheels for Harleys these days. I have spent my life making the lower ends lighter. "light bike light lower end" was the term when I was coming up. The heavier flywheels are to get the heavy pigs (baggers) that are so popular with the, "all I ever really wanted was a Harley," crowd going down the road.

    A heavier flywheel will help you launch or get rolling with a load, The draw back is that any weight on your drive train takes torque to turn. If you don't put an engine that makes a lot of torque in front of it you will note that the parasite is keeping you from reaching your rev potential. In a perfect world a heavy flywheel will be mounted behind a torque monster as opposed to a revver and have tall gears behind it. The heavier wheel will help you pull away at an intersection and the tall gears will get you down the road.
     
  21. Roothawg
    Joined: Mar 14, 2001
    Posts: 26,030

    Roothawg
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    I was pondering a 5 speed and a 3.90 gear.
     
  22. Well that will work I suppose as long as your sweet spot is down low. You already know what I am going to say because you know me but someone does not. You never ever want your cruising range to be below where you engine starts to climb up on the cam, IE starts to build torque.

    I don't know that it matters but I pulled a 283 out of an old GM dump truck once, it was built on a 2 ton ch***is. The flywheel was by far the heaviest Small Block flywheel I have ever touched. I didn't weigh it but it was a two handed flywheel to be sure.
     
  23. Truckedup
    Joined: Jul 25, 2006
    Posts: 4,660

    Truckedup
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    Stock Chevy flywheels I weighed were about 30 pounds.. There are probably other stock wheels of a different weight. A heavier flywheel won't drop as much RPM between slower shifts..and the engine will run smoother at low speeds..
     
  24. Roothawg
    Joined: Mar 14, 2001
    Posts: 26,030

    Roothawg
    Member

    I am on the hunt for a WC T-5 from a V8 car if anyone stumbles across one.
     
  25. Gene Boul
    Joined: Feb 9, 2006
    Posts: 805

    Gene Boul

    Maybe on you if you keep picking it up!
     
  26. Gene Boul
    Joined: Feb 9, 2006
    Posts: 805

    Gene Boul

    Back in the "day" heavy g***ers and modifies ran really really heavy wheels. We're talking about 12, 13 or 14 pound cars. i.e. 268" small blocks that weighed 3750 pounds or more. I ran a 268" DM/P with a 40 pound wheel but my car certainly wasn't an exception there where many others with wheels 50+.
     
  27. DDDenny
    Joined: Feb 6, 2015
    Posts: 22,542

    DDDenny
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    from oregon

    Feel fortunate that you don't need the one for early (64-67)Chevy 11's.
     
  28. desotot
    Joined: Jan 29, 2008
    Posts: 2,049

    desotot
    Member

    But if the flywheel is real heavy and your rings are worn out it could take several minutes for your engine to stop spinning when you shut it off. Just sayin
     
  29. Roothawg
    Joined: Mar 14, 2001
    Posts: 26,030

    Roothawg
    Member

    Yeah, it could freewheel for a while.......;)
     
  30. bobss396
    Joined: Aug 27, 2008
    Posts: 18,752

    bobss396
    Member

    I'm running a truck flywheel in my Ford, been using the same set up for eons in various cars. Fairly heavy compared to some I suppose. With a stock engine it contributed to the smooth engine idle. And the clutch had a very nice engagement. My current one uses a Zoom clutch, the PP was balanced to the flywheel.
     

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