89 5.0 Mustang

Hey everyone its been a while since I have posted on here but got kinda a stupid question maybe but I want to make sure I'm ok. So I have a 95 cobra and I have a 50oz imbalanced harmonic balancer and a ram aluminum flywheel with a 50 oz internal balance. I guess I have 2 questions. 1 being what does it exactly mean when something is imbalanced and or why would they do that. Question 2. Being would I make a big problem when I install my flywheel or was I correct that one is 50oz imbalanced and the other is 50oz internal balanced? So I can do the install and not have any crazy vibrations or motor problems in the future. Any help is appreciated! Thanks, Steve

Bubba 95SN

They are one in the same. What you are saying is balancer has a 50oz weight-the flywheel has a 50oz weight. 95 5.0 uses 50oz.

67mustang302

Not exactly. The oz imbalance is actually based on force at a given rotation iirc, but the weight itself is not "as advertised" as it were. Also, in the later 302's the flywheel used a 50oz balance factor and the balancer uses a 34oz imbalance factor(which is referred to as the 50oz balance, earlier 302's and all 351W used a 28/28 factor). It's done to help balance out harmonic frequencies that are generated from the winding and unwinding of the crank as power is applied and it rotates, as well as the increase and decrease in crank acceleration due to power being unevenly applied to it(a characteristic of ALL piston engines).

There are internally balanced or 0 balanced setups, where all the balance control is in the crankshaft, and the flywheel and balancer have a 0oz imbalance, however it's difficult and expensive to achieve, since it often requires the drilling out of holes in the crankshaft to install heavy metal weights(such as tungsten) to get the balance correct.

Here are some articles dealing specifically with that, however much of the information is quite advanced and goes far beyond what we're discussing in regards to depth. But, the information is there if you want to learn.

http://www.epi-eng.com/piston_engine...on_engines.htm

http://www.epi-eng.com/piston_engine..._absorbers.htm

89 5.0 Mustang

Ok cool so. Basically from what I got was that I should be totally fine. I heard from someone that it was a bad idea to do an aluminum flywheel just because of the just like was said the power from winding and unwinding and that could cause my pistons to start becomeing bad or worn quickly? Opinions? I'm also planning an an aluminum driveshaft. I don't see why it would be a bad idea but who knows while we are on the topic might as wellask. Thanks! Steve

67mustang302

Shouldn't be. Others run them without issues. Also, keep in mind that AL DS's are weaker than steel(often weaker than stock) but are better at controlling vibrations, especially those encountered when using numerically higher gears.

DeltaElite121

Don't do an aluminum flywheel if you drive it alot on the street. Obviously it's lighter, and that's going to change the driving characteristics. Not saying it's incapable of driving, but you probably won't like it so much because it will change the "feel".

89 5.0 Mustang

I thought about the weakness but I figured that they would have thought about that but u do have a great point. Do u know if iwill feel the dif with an aluminum flywheel obviously I will have quicker revving but will I feel the difference? And may be a stupid question but would any one recomend locktight on. Aluminum flywheel bolts?

89 5.0 Mustang

Wat is so different about the driving characteristics. Its my weekend warriar so its not my dd atleast.

DeltaElite121

Aluminum flywheels have their place, but because of the change in weight (and inertia due to the weight change) this can change the way your engine responds entirely, and it will. There's really no reason to mess with your flywheel unless you have something like a huge power curve from 4500-7500RPM's and all kinds of modifications done that would support using one - then I could understand it because an aluminum flywheel will get you to your desired RPM range much faster than if you had a steel flywheel (however this can really go both ways because if you had idle - 5500, this could potentially hurt you). This will make it very different to drive when engaging/disengaging the clutch because of the flywheel inertia difference. Some also argue the structural integrity of the flywheel under serious power conditions because of it's composition, but that's debatable. I would also keep in mind the gear ratios you're running as well.

Not trying to make a pun, but it's seriously all about balance. Lighter doesn't always mean better, but it can be given the right circumstances.

mjr46

Care to explain what driving characteristics will change??? and please use first hand experience/examples of your own not the "I heard/ I read on the internet" BS that exists..................I have 2 rides with aluminum flywheels and the only thing they did was improve the ride all the way around.