View Full Version : Crankshaft and Flywheel Lightened ??

02-14-2003, 12:53 AM
Hi people! I'm wondering what you think of lightening Crankshafts and Flywheels, do you think they are worth doing ???

If you cut weight on your crankshaft and balance it, do you have to do the flywheel as well, for the whole thing to be balanced ??

If you could only do one, which one would you do, crankshaft or flywheel ??? or do you think it's worth doing both of them ??? or maybe it's too risky ??? how much more can an engine efficency improve by doing this ??? around 10% or less than that ???

please let me know what you think ...

I'm already working on a "Big Valve" re-worked cylinder head, a mild street camshaft, 87mm linner kit, dellorto 40 DHLA sidedraft carbs, Headers and a TR6 exhaust sys. to improve air flow. graemlins/crazyeyes.gif

02-14-2003, 12:56 AM
If anybody has a picture of a Lightened Flywheel or any sort of literature that can help me do the job a bit better please sent it to the following email address: "p_vernon@hotmail.com"

thanks ...

02-14-2003, 01:19 AM
If you get the flywheel lightened, you get the advantage of faster throttle response. The downside is the need to keep the gas on when you take off, no more just letting the clutch out and pulling out. I like the fact I have a car I can set the idle down to 300rpm on, it just sounds so neat. The flywheel should be balanced when cut, but if you don't do the crank, the assembly isn't balanced.(not any better than the factory) Now is the fun part, the local machine shop will love you. If you want to do this to get the high revs, this pistons and rods must also be balanced. Then the crank. And the flywheel. And the harmonic balancer(front pulley) Then they get balanced as an assembly. Now you need a head, valves and springs, retainers, cam, intake, carbs, ignition and exhaust that can make use of it. Balancing an engine doesn't really give you ponies, its the fact that you can wind it out that does.
Your engine will be as fast as your wallet. The trick is to match everything. Too big of a cam, and the exhaust and carbs are useless.
Harmony of components is Nirvana, young grasshopper. images/icons/grin.gif

02-23-2003, 03:00 PM
Paul, Clint has a good point, you should look at the overall assembly.Balance the crankshaft the rods and the flywheel so that the whole thing is right. This is done AFTER any other work such as lightening the flywheel.It is no trick at all to lose 7 or 8 lbs from the stock flywheel which gets you quicker reving but loses some ability to resist stalling. If you can afford it the stock rods should be scrapped in favor of the carrillo rods(much lighter&stronger)this lets the engine rev even more without adverse effects.
MD(mad dog)

02-23-2003, 11:00 PM
Yes, both Clint and MD are correct.

However, if you are looking for a "quick/cheap" way to add some rpm's, then a lightened flywheel and perhaps an underdrive pulley (some like them, some don't... i haven't used one, yet), will help it spin up a little quicker.

best of luck!