Ideal Flywheel Weight?

[BlownMGB-V8]

You could take a good bit of weight off that flywheel yet. I've seen skeletonised steel flywheels  down around 15 lbs easy. Anything outside of the PP attachments and the clutch face is only to attach the ring gear. Almost all of that could be machined away. The clutch surface does not have to be more than 3/8" thick, the web to the crank could be thinner than that and have holes. There could be holes in the clutch face as well.

Note, the PP is available with an aluminum pressure ring at a reasonable price:
https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=aluminum+pressure+plate&tbm=shop&spd=12350264774748369425

Jim

[BMC]

Although this thread was started two years ago, I thought I would give a simple and short weigh in.


First, it is not just the crankshaft that makes up the rotating weight. It is anything spinning inside and outside the engine including the crankshaft, big ends, balancer, timing chain, camshaft and everything. The further out, the more it will effect things= outer edge of the flywheel and the balancer are good items to point out.

I have used steel and aluminum flywheels and have seen no negative effect on engines that are essentially built to use on the street.

I hear and read from many people who most likely have zero experience with very light flywheels who believe with all their heart that a light flywheel is doom and gloom, especially the MG and other people in the as-it-were factory built car crowd. Some believe that a little weight off the factory flywheel is okay but not too much. My experience says otherwise but it is something that costs money and there are some other items that money is better spent on first.

My personal 3.4L powered MGB and an S10 pickup I have both have aluminum flywheels- no problems. Although everything was identical on both vehicles, it was actually more noticeable on the S10!

Speaking of the S10, with the pickup weighing in at around 2,800 pounds, adding a 200 pound fibreglass top, driver, passenger, fuel, a few spares, my very tiny tandem axle trailer and an MGB V6 to the trailer, the GVW is somewhere around 7,200 lbs. The only time I noticed any change was when pulling away from a dead stop at the top of any hill. This usually at a stop light coming off the freeway. I have to slip the clutch for an extra second- but then again, the rear end gearing is so tall (high speed) that it needed to be slipped at that point anyways. The power of that engine in that truck going down the road is not effected negatively either but it does not have the braking power in that small vehicle to stop the trailer but that's a different story.

Point is- weight of a flywheel under many circumstances I believe can be lighter than the average internet mechanic realizes. As others have said, your findings may differ.

-BMC.

[roverman]

Anyone using one ?  Late oem Corvette/ others ? I'm told less "lurch" ?  Like a highly effective torsional hub, in the clutch disk ?