Aluminum flywheel?

I run a lightened aluminum flywheel on my PI Motorsports Windsor 427 stroker with no problems so far, other than that everyone who gets into the car to drive it for the first time stalls it. Once you realize you have to give it a few rpm to get going, you're fine.

Yup same here. The car is a blast to drive though and has great response.

Blaine

thanks guys, I think I will go aluminum, yep.
thanks again,
Daniel

427 CI stroker and aluminum FW here and no problems as far as I'm concerned. Light car + low first gear + big displacement = No problem. Even with a somewhat lumpy cam. At least as far as clutching from a standing stop.

Where I notice it most is when you're just ambling along through the earlier gears at low Rs. The Rs drop off faster with the lighter flywheel so you have to be a little quicker on the clutch as you grab the next gear in order to have a smooth transition. Not an issue at higher Rs of course and accelerationwize you can appreciate the lighter mass when you come on the sweet spot in the cam.

Kelly

This is something I'm looking at!
I need a flywheel that is safe to 8000 rpm but im looking at something in the middle of a steel vs aluminum, any info?

Mark

Isn't there an aluminum clutch cover (pressure plate) for the Cleveland also?

With the 2.20 first gear I would be doubtful that a big port 351 would be happy on the street with an aluminum flywheel. The car isn't that light. If it was 2,000 pounds with driver that would be a different story. You're going to have to slip the clutch a lot to get it moving.

A 427 is a different animal.

I was ambivalent about recommending the use of aluminum flywheels in the Pantera, but driving Jim Cozzolino's GT5 (which was equipped with an aluminum flywheel) put an end to my concerns. Frankly I couldn't detect an adverse effect in the drivablity of his Pantera.

I drove Jim's Pantera on dry asphalt. There may very well be some applications were the alloy flywheel may create problems, such as driving in bad weather on wet or icy asphalt. It may not be the best idea for a daily driver that will see use on wet roads. Jim drove his Pantera daily, but he lives in the Phoenix area, not exactly the wettest climate.

cowboy from hell

I fully agree George. I have an aluminum flywheel coupled to a std cube motor, mildly warmed over with crane H272-2 cam, air gap intake and Edelbock heads doing 329 rwhp. I was amazed how little change there was. From what I had read I expected the worst. You do need to be a bit slower with the clutch in stop and go driving but you become used to it immediately.

regards...Mark

No argument from me.

I am only trying to supply what I know about it.
Hey? What is it 5 say great and 1 says caution?
That is an overwhelming yes to me. Do it.

There is only one 351c car that I can think of over the last 30 years of that didn't go back to an iron or steel flywheel. Maybe 6 cars in total. The one car that hasn't is a track car.

To me that speaks volumes.

Nothing like the sound of an engine with real radical cam and a light aluminum flywheel. Music to my ears! When I was a kid I had Chevy small block with the 65 375 HP FI solid lifter cam and it sounded mean. The light flywheel let it rev super quick and drop RPM really fast.

Mike

I love the great responses, thanks again, definitly aluminum!!!!!!

Daniel

hey, as long as we are on the subject, MME wants to make it a 408cu, 4" stroke, I was under the impression that a great compromise stroke was 3.75" witch would let you rev safely 6500-7000 rpms. and still have plenty of horsepower. Iam thinking on the path that big stroke makes big torque and breaks things big.
What your thoughts?
Thanks guys
Daniel

ps MME is using CHI heads and intake
custom solid roller cam
11:1 compression
studded top to bottom

I'm running 427 Windsor based motor with aluminum flywheel no regrets

I have ran my MME engine (360ci Yates heads 670hp) in both my Pantera and now my GT40 with an aluminum flywheel with absolutely no regrets.

Ron

quote:

Originally posted by Daniel #9191:
... MME wants to make it a 408cu, 4" stroke, I was under the impression that a great compromise stroke was 3.75" witch would let you rev safely 6500-7000 rpms. and still have plenty of horsepower. Iam thinking on the path that big stroke makes big torque and breaks things big.What your thoughts ...

Daniel,

Mark has a lot of experience with the 408 Clevelands. He's sold a bunch of them, and some are being run very hard. He's got a masters in mechanical engineering and a ton of experience. He's the expert, that's why you're doing business with him. Why second guess him?

The 4" stroke will not limit rpm, the big concern is the extra thrust on the thin Cleveland cylinder walls. But Mark machines the blocks very precisely and is using pistons designed & specified by him to address these concerns (offset wrist pins).

My advice is to tell him how you plan to use the motor, express your concerns, and then listen to his reply & explanation very very carefully.

cowboy from hell

Daniel
I too have an MME 408c, I went with the aluminum flywheel also... Rev's so much better, but besides that, it's so easy to work with when you gotta lift it... oh ya and by the way, it dyno'd @586hp.... Your going to have sooo much fun!

It's not a Ford 351C in a Pantera but the physics still apply. A while
back I ran the numbers for switching from an iron to aluminum flywheel
for my Triumph TR8. The effect was surprisingly large. There are a
couple of approaches to doing the math. The more rigorous approach is
to calculate the polar moment of inertia for the two different flywheels,
adjust for the square of the overall gearing (transmission, final drive
and tires) and convert to an equivalent linear inertia. The second
method (the one I chose) is to start with a known linear to rotational
equivalent and ratio from there. The known relationship I used is a
solid disk rolling on its edge. It has an effective inertia exactly
1.5 times what it would be if it wasn't rotating. That means the
rotational component is 50% of the linear component. Adjust for the
square in gearing and you have the answer. I wrote a little Fortran
program to do the calculations. I assumed a 12" diameter flywheel
which is the Buick/Rover diameter, less the ring gear. The circumerence
of a circle is the diameter multiplied by pi. So if you roll the
flywheel along the ground it will move 37.7 linear inches per
revolution (= pi * 12). A 205/50/15 has a diameter of approximately
23.1 inches. My TR8's final drive ratio is 3.45:1 and first gear is
3.32:1 so one revolution of the flywheel results in the Triumph TR8
moving around 6.3 inches. Ratio the squares and take half
((37.7/6.3)**2)/2 = 17.9. So each pound removed from the flywheel
(equally across the face) is the same as about 18 pounds of weight
removed from the car when in first gear. So if you remove ten pounds
from the flywheel (equally across the face), the result is equivalent
to removing 180 pounds of vehicle weight in first gear. The effect
goes down for each higher gear, of course. Removing weight farther
from the rotational axis has a more pronounced effect. If the weight
is removed from the outside of the flywheel only, the effect is about
2.78 times as strong since a solid disk has a radius of gyration of
0.6 times the radius (1.0/0.6)**2 is 2.78). 2.78 * 180 is 500 lbs
equivalent weight reduction. A non-trivial effect, particularly
in a lightweight car. I ran the numbers a couple of ways to
illustrate. For my TR8, assuming a 3.45:1 final drive ratio,
205/50/15 tires and LT77 gear ratios of:

1st 3.32:1
2nd 2.09:1
3rd 1.40:1
4th 1.00:1
5th 0.83:1

along with flywheel weights of:

stock flywheel - 32 lbs
lightened steel - 22 lbs
aluminum - 11 lbs

The engine in the TR8 is essentially a Buick 215 aluminum V8 from the
early 1960's. The stock flywheels in those had a big ring around the
perimeter. Lightening the flywheel by milling off the ring is similar
to removing the mass from the perimeter (from 32 to 22 lbs). In the
numbers below, I didn't do it that way but a more accurate approach for
the aluminum flywheel would be to assume a reduction of 22 to 11 lbs
equally across the face and add that to the difference of the 32 to
22 lbs across the perimeter. In any event, a lighter flywheel looks
like a good thing to do for performance. Here are the numbers:

32 to 22 lbs (across face assumption):
1st 177.5 lbs
2nd 70.3 lbs
3rd 31.6 lbs
4th 16.1 lbs
5th 11.1 lbs

32 to 22 lbs (perimeter reduction assumption):
1st 493.4 lbs
2nd 195.5 lbs
3rd 87.7 lbs
4th 44.8 lbs
5th 30.8 lbs

32 to 11 lbs (across face assumption):
1st 372.7 lbs
2nd 147.7 lbs
3rd 66.3 lbs
4th 33.8 lbs
5th 23.3 lbs

32 to 11 lbs (perimeter reduction assumption):
1st 1036.1 lbs
2nd 410.6 lbs
3rd 184.2 lbs
4th 94.0 lbs
5th 64.8 lbs

Rotational inertia is mass multiplied by the distance from the
rotational axis (integrated over the surface). The effect is
stronger farther away from the hub. The best is from the
perimeter. Equally across the face is less effective and near
the hub is the least effective. In my example, dropping 21 lbs
from the perimeter is equivalent to over 1000 lbs reduction in
weight in first gear. Dropping the same mass the face is equivalent
to 372.7 lbs.

Reducing the flywheel inertia does reduce the stored energy for
start from a stop. Torque follows displacement. Little engine
in big car with tall gearing needs more stored inertia at start.
Big engine in little car with short gearing can get away with
much less stored inertia. On the street with a ligter flywheel,
you may need to use more RPM and clutch slip. On the strip, you
may bog if you don't have enough excess torque at the rear tires
(more traction than engine/gearing). Remember that HP is the
measure of how much potential torque you can have at the rear
tires via gearing. If you have enough power to overcome your
traction, then a heavy flywheel is a loser.

Dan Jones

Hi guys, I am close to having my engine parts collected and had been considering MME for the build. Has he relocated and has anyone been in touch with him? Has anyone had him build an engine with EFI? Thanks Dave Ferrato

Dan, Thanks for taking the time to provide a techincal answer to this debate about flywheels.
Your response has value because it is based on sceince and math not an opinion. When I post information it is also based on sceince and sound engineering ... I feel responsible to the Pantera community to keep our cars safe, reliable and yeild good performance. I hope to see more responses like yours in the future.

So Jon, because you believe only opinions that provide science and math in the answer is of any value, I guess we should discount 99% of every post on the forum. That’s a shame.. A simple answer to question doesn’t mean it had no value or that it’s incorrect. But I’m glad you take the responsibility to keep us safe.

Now, now...one mans science is another mans witchcraft.

When I think of scientific evidence I hink of Carl Sagen saying "biwyons and biwyons".

Sorry everyone, I did not mean to be so absolute about the science or use the word "opinion" in a negative way. Yes, opinions are a big part of the forum and contribute to advice. Sometimes I feel opinions are not supported by sound judgment and could be unsafe or technically misleading.

OK, but do have data to support your opinion?

I'll buy that... I know all those years I raced, it was always "hows that feel now." (Thanks Jon)