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Clutch replacement maybe in forecast for upcoming winter for my 61 fuelie, and pre-planning some possible changes. Thinking of changing out extremely heavy flywheel to aluminum flywheel. Looking for benefits, suggestions, experiences, etc.
Appreciate it, rustylugnuts
Last edited by rustylugnuts; 07-21-2014 at 12:05 PM.
Keep the stock one... I drove my friend's 59 which had an aluminum flywheel. I had to keep up the RPMS as I let out the clutch. I must have stalled the car three times within two miles before I could even drive it. What an experience... I guess if you got used to using it then no problem. I do not think he has had any issues with it (installed since the late 80s). Lots of noise too...
I guess it would all be what you're looking for. If the car is geared pretty low, you would probably not notice much in the way of having to rev the motor up more to get it moving- (not as much stored energy). The motor would rev faster, but looking at your car, that probably doesn't matter to you. It is hard for me to lose my old race car line of thinking. On a related note- I knew a guy who was running an aluminum flywheel behind a high winding small block- when he would dump the clutch at 9500, you could practically feel the thump when the car launched. It would jerk the motor back down to about 7000. Weirdest sound I had ever heard one make! Worked good though.
I never had much interest in aluminum flywheels but I got talked into one on my 459 cu in, 4.25 in. stroke Cobra motor. I don't have an A to B comparison but for a fairly long stroke motor it revs like a small block and is very smooth. Until I got use to the transmission I found myself taking off in 3rd several times and the only reason I knew so is because the engine didn't rev up to where I needed to shift up. I guess it depends on your motor size, gearing and vehicle weight. Smaller motor and moderate to high gearing and a steel flywheel is still probably better.
I guess it would all be what you're looking for. If the car is geared pretty low, you would probably not notice much in the way of having to rev the motor up more to get it moving- (not as much stored energy). The motor would rev faster, but looking at your car, that probably doesn't matter to you. It is hard for me to lose my old race car line of thinking. On a related note- I knew a guy who was running an aluminum flywheel behind a high winding small block- when he would dump the clutch at 9500, you could practically feel the thump when the car launched. It would jerk the motor back down to about 7000. Weirdest sound I had ever heard one make! Worked good though.
On a massive displacement engine, which can continually produce plenty of torque, an alum flywheel is fine. But for street driving with a small displacement (ie 283) engine, the inertia that is retained by the spinning of the greater weight of the stock style flywheel will be much more compatable on the street.
Now, with that said, if you are regularly involved in road racing where the rpm is kept high, an alum flywheel is the better choice.
Oh, and yes, I have personal experience with an alum flywheel. MANY years ago when the 56 had a 327, it also had an alum flywheel. It didn't take long for it to come off and get replaced with a stock style 168 teeth flywheel. It's been under the workbench for over 35yrs. I'll never use it again. It's too good to throw away, but a lucky winner could have it for the price of shipping.
I had a Schiefer aluminum wheel in my 265/240 '56 Bel Air. Worked fine after I got used to it. Didn't matter how it was geared.
I had the light L 88 Flywheel in my '69 Z 28. Worked fine after I got used to it.
I am putting a L 88 light wheel in my L 84 powered '65 Chevy II and I'm sure it'll be fine when I get used to it!
When you get used to it, you don't have to rev the engine any more than normal, you just have to be a little more precise in modulating the clutch and gas pedal motion.
If you do a lot of stop/go driving, well.......................?
On a massive displacement engine, which can continually produce plenty of torque, an alum flywheel is fine. But for street driving with a small displacement (ie 283) engine, the inertia that is retained by the spinning of the greater weight of the stock style flywheel will be much more compatable on the street.
Now, with that said, if you are regularly involved in road racing where the rpm is kept high, an alum flywheel is the better choice.
Oh, and yes, I have personal experience with an alum flywheel. MANY years ago when the 56 had a 327, it also had an alum flywheel. It didn't take long for it to come off and get replaced with a stock style 168 teeth flywheel. It's been under the workbench for over 35yrs. I'll never use it again. It's too good to throw away, but a lucky winner could have it for the price of shipping.
I once tried a lightweight aluminum pressure plate assembly. Other than not being able to shift the trans quickly- it wouldn't release cleanly- it sure did rev fast though.
From what I have seen there are also a wide range of aluminum flywheels weights. Some are very light, less than 10 lb. But some are kind of medium weight - like 20 lbs. So there may be a compromise available - depending on your vehicle and type of driving you do as pointed out above.
I've got a 15 lb GM nodular iron flywheel in my 327. GM Part 14085720. I've had it in the car since '08 and have 24K miles on her. No noise but I did have to learn to "get used to it"...meeting the gas and clutch engagement. Ya' don't ride the clutch for sure, just let her out and go.
Initially, she was installed when the motor was rebuilt and mated to the original Muncie M20 wide ratiio. Since December of 2012, flywheel was refaced and mated to a Keisler SS700 close ratio 5 speed. No issues.
The GM L88 flywheel weights about 16 lb, and is a better choice than aluminum for a street car.
This flywheel does like lower gears (4:11, 4.56), or a five speed with a similar compound first gear ratio for street use, but I didn't have any problems with 3.55 gears and a L79 327..
IMO, it is too light for a very large displacement motor with low rotating mass crankshaft and rods, as you can get low RPM surge with a C1 leaf spring suspension. I doubt it would be a problem on a c2 car. But you don't have 400+ CI motor, anyway.
I have a Hays aluminum 11 pounds that was installed with my 5 speed and car will drive away from a stop without hardly any gas. Just rolls out. Prefect!! The 3.37 first gear in the RS500 helps that a lot. It is a 327 L-79 with EFI. Couple thousand miles no problem and no noise.
I just switched to an L88 flywheel in the 65. The engine is a 355 and about 425 hp. Lots of torque as well. The stock flywheel weighed in at 29 lbs on the digital bathroom scale. 17 lbs for the L88 one. The engine revs much quicker and I don't find it hard to pull away at all. I like it. That said I have a RG 5 spd with 3.27 1st gear and 3.08 rear.
I have a Hays aluminum 11 pounds that was installed with my 5 speed and car will drive away from a stop without hardly any gas. Just rolls out. Prefect!! The 3.37 first gear in the RS500 helps that a lot. It is a 327 L-79 with EFI. Couple thousand miles no problem and no noise.
I have an aluminum flywheel in my track car. It's the best modification I've made to the car. It revs so fast that I have to shift about 30 ft. earlier than I did with the stock flywheel.
I'm not sure why you would need one on the street though.
Here's an article I wrote a while back on aluminum flywheels. Here's one I wrote on clutches.
Richard Newton
Last edited by rfn026; 07-22-2014 at 08:18 AM.
Reason: sp
the 425 HP 396 65 corvette had the light weight GM flywheel and that is why they were so quick.
I understand the reason they were quick is because of no friction in the valve train because the valve springs stayed broke. A guy told me once he fixed this problem by using 100 LL gas. Problem gone. Yep!
07-21-2014, 12:00 PM
Stock Flywheel VS. Aluminum
On a related note- I knew a guy who was running an aluminum flywheel behind a high winding small block- when he would dump the clutch at 9500, you could practically feel the thump when the car launched. It would jerk the motor back down to about 7000. Weirdest sound I had ever heard one make! Worked good though.
I once tried a lightweight aluminum pressure plate assembly. Other than not being able to shift the trans quickly- it wouldn't release cleanly- it sure did rev fast though.
