Inliners International Forums General Discussion Drive Train Aluminum flywheel

I know at least one of us here is running an aluminum flywheel and didn't see much of a difference in performance. I've been told by someone else that "it wound up like a V8" after the installation and they were very impressed (all stock except for Tremec OD trans).
I'd like a few more opinions on whether or not it's worth putting in? Would it help mileage as well?
Btw, this is in my '67 Chevy 1/2T 250 with a T-5.

No I don't feel it would help mpgs in any way. I have ran a alum flywheel myself. Yes the rpms do come up a touch faster. BUT You also Lose rpms Fast once you let off the gas.It does not hold the Rpms Between shifts Like a Steel one does.
So this is my 2cent input.

PS mind you mine was not a daily driver at the time I was trying out the Alum flywheel.

I have been running a Schiefer aluminum flywheel for several years, first with my stock three speed transmission than last year when I installed my T-5.
I have not been impressed with the added performance, if any, with either transmission and may have to go back to the steel flywheel. I am finding quite a bit of fine aluminum dust and/or powder inside of my bell housing as of late. In fact, I never had that problem with the three speed and 37 clutch, but with the T-5 and the Astro clutch, it seems I'm slowly loosing my flywheel a little at a time. This is something I never expected. I have no idea what is causing this problem.
I'm sorry, I didn't mean to hi-jack this thread with my problem, but it seemed like a good time to share the performance opinion and mention the other problem.

Joe

Joe, you're who I was referring to with my first line. I did a search and saw your post. Thank you for responding on this one! Even without that problem, do you still think it's not really worth putting in?

I just wonder if your problem is normal, being that AL is a softer material?

Well the alum dust your finding is not comming from the face ,Because the alum flywheel should have a Steel clutch facing. For the disk to ride on. I know My Ram Alum flywheel was Built that way.For you to be having them shavings/dust Something is not right Or is Lose.

Here is a link to a dyno test before and after installation of an aluminum flywheel and clutch in a Corvette. Dyno test of an aluminum flywheel.

The reported gains in torque and horsepower agree faily well with "back-of-the-envelope" calculations. As the dyno tests were conducted on an inertial dyno in a fairly high gear, even greater gains would have been observed if the acceleration would have been allowed to be greater, either with a lower inertial load or by running in a lower gear. Conversely, if the test would have been run on a steady-state dyno no gains would have been observed, as the torque (and HP) increase is proprtional only to the rotational acceleration (e.g., change in RPM per second) times the mass moment of inertia of the rotating hardware.

If you are looking for a lighter flywheel you don't need to spend all the money for an aluminum one. GM Performance Parts has a 15 lb lightweight wheel for the small block Chevy that is nodular iron. It is available only in the 153 tooth 12 3/4 inch size that takes the 10.4" clutch. You can get it for the earlier engines with a 2 piece rear seal or for the 87 and later jobs with the 1 piece seal and smaller crank flange so be sure to specify the earlier one for your 250.

If your truck now has the 14 inch 168 tooth wheel then you will also be into it for a new clutch & pressure plate as well as a starter and may need to drill and tap the necessary hole for the starter bolt. Some blocks had both sets of holes already tapped. Only you can decide if all that is worth any potentially small gains in performance.

Larry -

Give me some ideas what to look for. Is it possible that because the Astro clutch is a different size than the 37 clutch, the Astro clutch has to seat? I'm just thinking out loud here. Anybody got any ideas?
Any and all suggestions are appreciated!

Joe

The GM Performance part # is 14085720 for the 153 tooth 12-3/4" 15lb flywheel if anyone else is interested.

Anyone know the weight of the original flywheel?

Original would be around 30-35 lbs approx.
MBHD

All clutchs have to seat. Just some??????? take a little more time then others.(miles wise that is)

Now take my Ram set-up as a example.( a 6 finger disk and a long style Pressure plate)All I have to do to seat it Is load it one time Maybe?? twice
at the Most ( against the brake) And i am good to
go. NOW Most street set-up again useing Center force as a example,They call for ruffly 500 miles
Before trying to Hammer down on it. I tryed to race this set-up at one time and it didn't even Make four passes Before it was toast.That is how i found out about their 500 mile deal.

That flywheel #14085720 is 163.80 plus 10-15% shipping from gmpartsdirect.com.

regards,
Leon

Thanks Leon, it may be worth trying for that price. I have to pull my trans anyway for the rebuild so it won't be any more effort...

I have an aluminum flywheel in my mustang, and I don't like it for street driving at all. It shudders at stop lights and has no pull off the line. Wind it up and it spins up much quicker though. I wouldn't run one for street. Only for road racing/ autocrossing type stuff. Drag racers use heavy flywheels, and a heavier one smooths out your motor and decreases rpm drops between shifts.