4K Engine,Flywheel Getting Lightened,,Help Plz :)

[Mezz///]

Hey guys :) I'm running a 4k with :

*Port job head with match port to manifold and exhaust

*extractors

*heavy lumpy cam

*down draft weber 26/27

 

I am wanting to lighten fly wheel to see what acceleration I can get out of it..

 

Does anyone know how much I should ask for when I get it lightened?

 

How much should it weight if I want more acceleration and response down low,without loosing too much torque?

 

Any one done this to their k motor b4?

Mezz///

[philbey]

It's not simply about weight, it's about where they remove it from. A kilo off the centre might not be as effective as .2 from the outside.

 

Tell your machinist what the application is: street, race etc. tell him whether you are going to fit a scatter shield into the bell housing or not. Let him make the decision based on that info and he will machine based on the design of the flywheel.

Edited December 30, 2011 by philbey

[altezzaclub]

The best way is to mill it off radially, the cheapest is to lathe it off circumferentially.

 

Take a couple of Kg off it, I'm sure you can take off more but at some stage it gets weak. You need enough to support the ring gear and the pressure plate pulling the rim backwards against the center. Here is mine compard to the auto flex-plate it replaced.

[Mezz///]

I love you guys,..no seriously!! I'm very appreciative of your time,as those things you both said,I had no idea of..so now this little k engine is going to be a happy little vegimite ;) thanks guys

[SLO-030]

The best way is to mill it off radially, the cheapest is to lathe it off circumferentially.

 

May I ask why?

[altezzaclub]

Radially you can make it thicker where the pressure plate bolts go in. Its a comparison of a spoked wheel versus a disc wheel really, and you can put your 'spokes' where the stres is greatest.

 

On the 'front' face in the lower photo above you would mill out the metal between the bolt holes down to the clutch plate face, it doesn't do anything. This is nice-

[SLO-030]

Good point Rob. However, considering it's only a cast flywheel. Personally I would stop machining it before it got to the point where the space between bolt holes would be machined out.

 

A billet flywheel however.... :guns:

[altezzaclub]

That's why I reckon a couple of Kg is fine, I think mine went from 8 to 6kg. In the end you need some decent steel to make something like that one above.

 

I haven't heard of a 4K one flying apart mind you, usually the big stories involve Skylines or similar... I wonder what filfrederick used in his 4K-16valve at 9600rpm?

[Mezz///]

Wow that flywheel would be making that thing rev so quick..I guess it can get risky,..although ya never know unless ya try it. ;)

[philbey]

Keep in mind that spoking a flywheel like that will make it harder to balance. But yeh you take as much off the outer, don't touch the middle unless you have a scatter shield.

 

I haven't heard of one flying apart either and frankly I don't want to. Be the first haha.

 

The guy I bought my dellortos off was also selling a jun ally flywheel, 3kgms. No way I would run an aluminum fly in a streetcar though, it is only a matter of time before it blows haha.

[styler]

Chromoly is the only way to go for a very light flywheel ie under half the weight

but as has been said its where its gets removed that counts most which is the outside

which has more material as well so it all works out but be aware all cast - if stock,

lightened or badly lightened are more prone to fly apart if used under racing conditions,

a scatter shield around the bellhousing would be a good idea.

[Mezz///]

Ok guys,..I'm hearing this scatter shield a lot. Think I need to do one then. Do ya buy them or make them up?

I'm going to get it lighten tomorrow ;)

thanks again guys. Great little thread that's helpful as for us fellas who like to play :)

[philbey]

With a minor lightening and a shot peening, I wouldn't worry much. Skimming a bit off the outer will be fine, when you start cutting chunks out or taking it out of the guts, then it gets scary.

 

Scattershield, 6mm plate in the inside of the bell housing.should do it?

[Trev]

I haven't heard of one flying apart either and frankly I don't want to. Be the first haha.

 

The one and I hope only time I have ever had a flywheel let go:

 

http://www.rollaclub.com/board/topic/13692-random-photo-thread/page__view__findpost__p__264540

[philbey]

Man looks like a lucky fail!

 

That disc out of the centre, was it roughly the same diameter as the mating face on the crankshaft? Makes sense, that's where the highest load from the clutch pressure Will be concentrated.

 

I had a flywheel shear all it's bolts once. Dug a groove on the inside of the bel housing....