MG Sports Cars

Never thought I'd be replacing the V8 in my car this soon. I have removed the '95 SBC roller motor from my car and am building a new engine. I think you guys have warned me that at some point I'd want to go faster and you're right!

Among the many questions I have, can you guys let me know if there is a down side to using an aluminum flywheel? I purchased the Hays 20-330, that weighs 11 lbs. I think a stock flywheel is about 30 lbs. A nice weight savings over the stock unit.
Many years ago, I ran a lightened flywheel in my Fiat Spider. That, combined with a mild cam, Weber, headers, really made that Spider fly. I did not run an aluminum flywheel in my Fiat, it was machined down by a Fiat specialist.

I also have Trick Flow twisted wedge heads, that will take about 50lbs off the weight of my SBC, and offer more power than the stock heads.

I will try to post some pics and the rest of the specs of my new engine soon. Thanks in advance for your feedback.

Brad

Not in a light car with plenty of horsepower. Go for it. I would want some protection such as some sort of scattershield plate if you don't have room (not likely) for a blowproof bellhousing, though.

I think Carl is right. An aluminum flywheel doesn't carry as much energy at low rpm as steel or cast and in a heavy car you might tend to stall unless you apply a few rpm's leaving a red light, but a light car like a MG shouldn't be a problem. I have used them in the past and considered one for my 302 but 28oz aluminum flywheels are not as plentiful, and not cost effective for my application, so I went with steel billet. I have a friend with a hole at the back of his 65 Mustang hood because his aluminum flywheel exploded; I would consider Carl's recommendation on the bellhousing too.


Paul

I've used aluminum flywheels on my last 3 V8 builds, including my current dry sump motor (all of them well over 325 HP). I've never had one explode, come apart, or in any other way fail under normal use (and that includes some pretty hard running). I use them less for weight savings and more because I prefer their responsiveness and the nearly immediate drop in RPM when off the throttle. Could be my success with them has to do with staying away from the cheap ones or just luck. Hard to say.

Though it can happen, I've never had one blow up either and my friends may have been of low quality, lord knows I've got a few low quality friends :-) at least according to my daughter. It might have just had a flaw, who knows, it did happen at a drag strip. I think the chances of a failure during normal road use are low too but If I had to buy a bellhousing anyway I might consider it. I like the responsiveness as well and as I'm not pleased with some choices I made when building my current motor, I'm considering a 331 stroker in the future and it will probably have an aluminum flywheel. I guess "The Tool Man" is right, there's no such thing as enough horsepower.



Paul

Do not use a cast aluminum flywheel for any performance application, make certain it is billet, and it should be fine. The lighter weight is a distinct advantage. You only need enough inertia to launch the car, and with the SBC you already have that even with no flywheel at all. While you are at it, you can also get a pressure plate with an aluminum pressure ring, which gets rid of a lot more weight. Worst possible handicap? It may not move out when you drop the clutch without giving it some gas.

Jim

I am not the burn-out type of driver, never have been. Hard launches are rare for me, but I do recall the quick response of a lightened flywheel. I am thinking the weight savings plus the quick response is a nice combo to have.

Thanks for your responses and expertise. I hope to have this all together by July, looking forward to meeting you guys!

Brad

Brad the sole purpose of an aluminum flywheel is to let the engine rev quicker to get on the power band of a particular cam.
Cams with wide LS and long duration have a higher rpm power bands.

Cast aluminum flywheels are a thing of the past Have not seen one in about 40 years. Hayes has very good aluminum flywheels with a steel insert for the clutch, there are others out there just as good and most are NHRA approved.

Everything is a domino effect. Want to rev even quicker use a twin disc 6" or 8" clutch from 10,000 rpm (brand name) very light.

I'm using a 12 pound aluminum fly wheel with my ls1 engine. It rev's quickly and comes back down quick also. It is great for auto crossing. I don't use the brakes that much, throttle up and off for braking effect.