The cons of a lightened fly wheel

[joshbl]

I'm after a lighter fly wheel, but not one which has been lightened. Let me show you why;

http://i76.photobucket.com/albums/j21/iheartmx83/780-034.jpg

http://i76.photobucket.com/albums/j21/iheartmx83/780-039.jpg

http://i76.photobucket.com/albums/j21/iheartmx83/780-050.jpg

The ones with holes drilled in are the worst offenders.

 

[gtsnissanb]

Oh dear that looks awful what happened? I know whats happened but why? My flywheel once came loose on my sx scary times didn't do any damage luckily

 

[Eliot]

It would be like a circular saw at that speed!

 

[Grevs]

ouch :O

 

[martinb]

you cant base your whole analysis on a photo of some ones lightened fly destructing everything as solid evidence there dodgy!!

we also dont know who ligtened it or whether it was balanced afterwards(doubtful)

i could find millions of things wrong that you shouldnt do

ive never had a problem, neither has frank or scopez or anyone else to be fair

its like saying if you eat eggs your get samonella poisning!:suspect:

 

[Deano400]

I believe that was a Skyline with a machined flywheel doing drag runs. They probably just machined too much off, but it's not as uncommon an occurrence as most people might believe.

 

[miah686]

this is ugly never saw a thing like that happened before you definitely got a dodgy job mate

 

[Scott]

http://www.youtube.com/watch?v=n0TxZFDLa3w

 

[nathgun]

wow.. never seen that happen before that crx is crazy!!

 

[gtsnissanb]

I believe that was a Skyline with a machined flywheel doing drag runs. They probably just machined too much off, but it's not as uncommon an occurrence as most people might believe.

Looks like a r32/s13 interior but I'm sure champagne red was r32 colour, and it's rwd so it'll be a gts/t

 

[frank]

The ones with holes drilled in are the worst offenders.

like the £500 jun one fwn which does,nt have the steel band/gear ring hot shrinked around it for extra strength (like the oem one)
there are a few clutches that explode on the topfuel drag cars tho eh

 

[joshbl]

I'm talking about Standard fly wheels that people have dodgily lightened themselves Frank. Most are fine but it's people like me who have no idea and get drill happy Flywheels that are designed to be light are just fine

 

[Low Rider]

Lightening a standard cast iron flywheel is a risk and is not something I would do personally. If done correctly however it can be safe but due to the much lower tensile strength, lightening should be considered carefully.

Since the JUN flywheel is made from high strength steel already, the benefit of a shrunk on steel ring will have little effect. For a cast flywheel, this may add some additional pre stress to the flywheel, but judging by the dimensions of the ring I would question the magnitude and would not use this as a contingency factor when lightening a cost iron flywheel.

One could state that a flywheel will fail when the tensile strength of the material is exceeded, but a failure could also be down to fracture mechanics. Things can work for a period of time and seem ok, then suddenly fail.

Generally if you stick with large radii and don't go too mental you should be ok. The general rule of thumb on a cast flywheel is to limit yourself to a minimum thickness of 10mm. I personally have no qualms about spending out on a steel flywheel. I have one and the piece of mind is worth it to me, especially when the passenger compartment is in the firing line

 

[gtsnissanb]

Also worth noting ALWAYS use new flywheel bolts, they ain't designed to be reused

 

[Low Rider]

Also worth noting ALWAYS use new flywheel bolts, they ain't designed to be reused

Nissan bolts are re-useable, they are not TTY fasteners.

 

[gtsnissanb]

Nissan bolts are re-useable, they are not TTY fasteners.

I've always been told that Nissan flywheel bolts need changing, plus I've had first hand experience of the bolts coming loose on my car so they get changed! Why would you not change them? It's like not changing head bolts when swapping head gaskets

 

[Scott]

I've always re used flywheels bolts on the SR20s we've had open. Never had a problem.

 

[gtsnissanb]

I've always re used flywheels bolts on the SR20s we've had open. Never had a problem.

My sr20det nearly threw it's flywheel off when I reused my bolts torqued up correctly, and locktite still came loose, I prefere to be over safe than over sorry

 

[Low Rider]

I've always been told that Nissan flywheel bolts need changing, plus I've had first hand experience of the bolts coming loose on my car so they get changed! Why would you not change them? It's like not changing head bolts when swapping head gaskets

I wasn't disputing the fact that they shouldn't be changed, only that the do not have to be changed. Personally, I use ARP fasteners, better quality steel, rolled threads etc and far more cost effective than Nissan OEM bolts, they are pricey!!

As long as all of the mating surfaces are clean, un-damaged and free from previous traces of locktite AND thoroughly degreased, (plenty of acetone), there shouldn't be any cases of things coming loose down there.

 

[davew]

Ah, my first post on the forum :laugh:

BTW, you don't need new flywheel bolts on a K10 or K11 Micra - fact

Oh and the flywheel pictured (obviously not a Micra flywheel) has not got a "steel band shrunk onto it" - it is a billet steel flywheel.

There is no problem whatsoever in lightening flywheels so long as some basic rules are followed - keep all sections to 10mm minimum - no sharp corners or undercuts - dynamic balance afterwards.

(Y)(Y)(Y)

 

[davew]

..... and as one of the most prolific K10 Micra engine builders in the Uk, I've balanced dozens of Micra flywheels and used hundreds of secondhand flywheel bolts and have yet to suffer a failure (not wishing to tempt.....)

 

[gtsnissanb]

Ah, my first post on the forum :laugh:

BTW, you don't need new flywheel bolts on a K10 or K11 Micra - fact

Oh and the flywheel pictured (obviously not a Micra flywheel) has not got a "steel band shrunk onto it" - it is a billet steel flywheel.

There is no problem whatsoever in lightening flywheels so long as some basic rules are followed - keep all sections to 10mm minimum - no sharp corners or undercuts - dynamic balance afterwards.

(Y)(Y)(Y)

Lol welcome

 

[gtsnissanb]

..... and as one of the most prolific K10 Micra engine builders in the Uk, I've balanced dozens of Micra flywheels and used hundreds of secondhand flywheel bolts and have yet to suffer a failure (not wishing to tempt.....)

Get some pics up of your stuff will be very interesting to see

 

[davew]

I will if I get chance. Keep hearing about the forum from customers and was prompted today to join. Someone with a March had picked my name up from somewhere on here and rang for a bit of advice.]

See my site (never up to date tho'!): www.dw-engineservices.co.uk

 

[karlj]

if only i had the money

 

[Shaun]

that CRX would of won though