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Flywheel
- Thread starter bberwick
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Keoke
Great Pumpkin
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Hi bberwick, Gregs response is correct. on the big healey the ring gear is a separate piece that can be replaced on the existing flywheel by preheating it. However, I suggest you have it replaced by a knowledgeable mechanic as it is tricky. Additionally,from your description yours needs replacing.--Fwiw---Keoke
Hi BB,
Keoke and Greg are right. In my opinion, I would change the starter drive as well.
I once changed the ring gear on my old Ford 8N tractor. Accidently put it on backwards, reheated it, removed it, replaced it and guess what, it would no longer shrink tight! Welded it, but please don't treat your Healey like that. Sarge
Keoke and Greg are right. In my opinion, I would change the starter drive as well.
I once changed the ring gear on my old Ford 8N tractor. Accidently put it on backwards, reheated it, removed it, replaced it and guess what, it would no longer shrink tight! Welded it, but please don't treat your Healey like that. Sarge
you might want to check out PAECO engines. I have their 2005 catelogue and it shows both ring gears and flywheels. On a 100-6/300 the ring gear is listed for $137. They also have lightened flywheels as well if you choose to replace yours. They have a 9.0 pound or a 12.5 pound flywheel made from aluminum. Take a look at their website. www.PAECO.COM. I haven't used them. Myabe somebody else has
BB,
Exercise caution if you plan to use a light flywheel. Two very knowledgable Healey mechanics that I spoke with when rebuilding my BJ7 indicated that unless you plan to "race" your Healey it might be advisable to leave the flywheel stock. Apparently a lightened flywheel makes it difficult to "launch" the Healey from a stationary position, i.e. you must have higher revs before releaseing the clutch.
Exercise caution if you plan to use a light flywheel. Two very knowledgable Healey mechanics that I spoke with when rebuilding my BJ7 indicated that unless you plan to "race" your Healey it might be advisable to leave the flywheel stock. Apparently a lightened flywheel makes it difficult to "launch" the Healey from a stationary position, i.e. you must have higher revs before releaseing the clutch.
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[ QUOTE ]
If your going to lighten the flywheel, take the metal out of the centre!, helps keep the torque !
[/ QUOTE ]
Helps keep the torque AND defeats the purpose of lightening the flywheel in the first place. The purpose is to reduce the inertia of the rotating mass. Metal removed from a larger radius has much more effect than metal removed nearer the center. If you don't wish to reduce the inertia - torque, don't remove any metal.
D
If your going to lighten the flywheel, take the metal out of the centre!, helps keep the torque !
[/ QUOTE ]
Helps keep the torque AND defeats the purpose of lightening the flywheel in the first place. The purpose is to reduce the inertia of the rotating mass. Metal removed from a larger radius has much more effect than metal removed nearer the center. If you don't wish to reduce the inertia - torque, don't remove any metal.
D
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Re: Flywheel - torque
Maybe we should back up a bit.
A flywheel cannot increase engine torque. It can only provide stored energy due to it's rotational inertia, or moment of inertia, (resistance to rotational speed changes). This is useful when engaging the clutch to get things moving, as the stored energy of the flywheel reduces the engine torque required to get things moving during clutch engagement. It momentarily increases APPARENT torque during clutch engagement.
Flywheel inertia helps smooth out the power pulses of the engine & give a smoother idle, but we aren't going there.
OTOH, this same rotational inertia resists engine speed changes such as acceleration or deceleration. A flywheel with less inertia will allow engine speed changes more quickly but at the expense of having less stored energy to get the car rolling when the clutch is first engaged. We have all observed Formula One cars & such taking off from a pit stop. Their very light, small diameter flywheels require a great deal of clutch slipping to get under way from a stop. Very little stored energy.
On to center of mass - The formula for rotational inertia is basically, inertia = a constant X mass X radius of the mass squared. You can see where the radius of the flywheel mass squared, has a far greater affect on inertia "stored energy & resistance to rotational speed change" than the overall mass of the flywheel.
Since the object of lightening a flywheel is to reduce it's inertia for quicker throttle response, material removed from the outer diameter has a far greater benefit than metal removed from nearer the center. (Much greater radius squared). To repeat, apparent torque cannot be kept the same & still have the benefit of reduced inertia.
There is no great benefit from removing mass near the center of the flywheel & it may even seriously weaken it.
D
Maybe we should back up a bit.
A flywheel cannot increase engine torque. It can only provide stored energy due to it's rotational inertia, or moment of inertia, (resistance to rotational speed changes). This is useful when engaging the clutch to get things moving, as the stored energy of the flywheel reduces the engine torque required to get things moving during clutch engagement. It momentarily increases APPARENT torque during clutch engagement.
Flywheel inertia helps smooth out the power pulses of the engine & give a smoother idle, but we aren't going there.
OTOH, this same rotational inertia resists engine speed changes such as acceleration or deceleration. A flywheel with less inertia will allow engine speed changes more quickly but at the expense of having less stored energy to get the car rolling when the clutch is first engaged. We have all observed Formula One cars & such taking off from a pit stop. Their very light, small diameter flywheels require a great deal of clutch slipping to get under way from a stop. Very little stored energy.
On to center of mass - The formula for rotational inertia is basically, inertia = a constant X mass X radius of the mass squared. You can see where the radius of the flywheel mass squared, has a far greater affect on inertia "stored energy & resistance to rotational speed change" than the overall mass of the flywheel.
Since the object of lightening a flywheel is to reduce it's inertia for quicker throttle response, material removed from the outer diameter has a far greater benefit than metal removed from nearer the center. (Much greater radius squared). To repeat, apparent torque cannot be kept the same & still have the benefit of reduced inertia.
There is no great benefit from removing mass near the center of the flywheel & it may even seriously weaken it.
D
JamesWilson
Yoda
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A practical counter-example:
Ice skaters spin faster when they hold their arms close to their sides. MORE mass is then in the "middle". With their arms extended they slow- the mass is further "out". Same turning force and the same mass, but the distribution yields less speed.
Ice skaters spin faster when they hold their arms close to their sides. MORE mass is then in the "middle". With their arms extended they slow- the mass is further "out". Same turning force and the same mass, but the distribution yields less speed.