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Technical => Engine Tech => Topic started by: BogusSVO on February 17, 2010, 01:11:10 PM

Title: How to lighten a stock cast iron Flywheel
Post by: BogusSVO on February 17, 2010, 01:11:10 PM
How to lighten a stock cast iron flywheel



Start with your stock flywheel, In my case, 2.3L Turbo Ford

(http://i261.photobucket.com/albums/ii49/BogusSVO/flywheel/DSCF3813.jpg)

Its weighs in at 20.5Lbs

Lets see how much weight can be cut off….



Next is to remove the clutch plate alignment pins….

(http://i261.photobucket.com/albums/ii49/BogusSVO/flywheel/DSCF3815.jpg)

A slide hammer works well

(http://i261.photobucket.com/albums/ii49/BogusSVO/flywheel/DSCF3814.jpg)

Mount the flywheel upside down, on the flywheel grinder

(http://i261.photobucket.com/albums/ii49/BogusSVO/flywheel/DSCF3817.jpg)

 Start buy cutting the excess cast iron down to the ring gear..
(http://i261.photobucket.com/albums/ii49/BogusSVO/flywheel/DSCF3818.jpg)

 Once that was flush, I weighed the flywheel again, that reduced the weight by .75 lbs (12 oz) now 19.75 lbs

Time to thin the fat from behind the ring gear…

(http://i261.photobucket.com/albums/ii49/BogusSVO/flywheel/DSCF3819.jpg)

 each pass, this machine cuts only .005-.008 off…

(http://i261.photobucket.com/albums/ii49/BogusSVO/flywheel/DSCF3818.jpg)


 the final weight is now 17.75 Lbs 

I removed a total of 2.75lbs…. This should help the engine rev a bit faster, with out giving up too much torque..
Title: How to lighten a stock cast iron Flywheel
Post by: Ductape91 on February 17, 2010, 06:08:41 PM
can someone who has done this on a street driven car and has some drive time with it shed some light here as ive been told to NOT lighten a cast iron flywheel for any reason, perticularly if you dont know what your doing?
Title: How to lighten a stock cast iron Flywheel
Post by: jcassity on February 17, 2010, 11:02:58 PM
:rollin:
yeah,, tell my left eyebrow that!!!
20 stitches later working under the bronco.

Anyone know how much a those f150 5speed (1991 or so) flywheels weigh?)

 hurt coming straight down on my head,, ring gear first lol.

Had to change ring gears twice before i figured out someone used the wrong flex plate...modified the AOD flex plate to accept the standard starter.

what a bitch.
Title: How to lighten a stock cast iron Flywheel
Post by: HAVI on February 17, 2010, 11:46:08 PM
Try a 345 IH flywheel.  Knocked me dizzy for a few minutes.

Good friend of mine's dad balances flywheels and cranks for a second job for the local dirt trackers and such.  key word is balance here.
Title: How to lighten a stock cast iron Flywheel
Post by: t3skidoo on February 18, 2010, 12:08:37 AM
Isn't the easiest way to lighten a 2.3 flywheel is to replace it with one from an escort?

Knew a guy that lightened his flywheel by drilling holes in it.  He didn't seem to like his feet that much.  Your way looks better.


Ductape91,

the flywheel "stores momentum"*, which makes it easier for a driver to move from a standstill in a car/engine combo like the TC.  The tradeoff is the cost in engine acceleration.  (*don't use this explanation in front of your science teacher)

The only car I know of from the factory without a flywheel is the McLaren F1.
(http://www.supercars.dk/cars/mclaren/wallpaper-mclaren-f1.jpg)
Title: How to lighten a stock cast iron Flywheel
Post by: thunderjet302 on February 18, 2010, 12:35:55 AM
Don't you have to have the flywheel rebalanced?
Title: How to lighten a stock cast iron Flywheel
Post by: BogusSVO on February 18, 2010, 10:42:29 AM
the last 4 flywheels I have had balanced after lighting them were out about 2 grams, the Interal balanced engines  (most 4 cyl) do not seem to have issues as much as the external balanced engines ( 302 350 ect)

you have to be carfull of where and how much you remove so not to weaken the flywheel so behind the cluch disk you tend not to cut much.

yes you can replace the flywheel from a 2.3 with an escort, but you have to drill new clutch plate mounting holes.
Title: How to lighten a stock cast iron Flywheel
Post by: 88CougarGT on February 18, 2010, 11:45:11 AM
http://www.streetfire.net/video/Trans-AM-Clutch-Explodes_727191.htm

That video is about enough to convince me never to mess with a flywheel.  His was just the pressure plate, but I like my toes.  Granted the kid was an idiot.  But still, wow.
Title: How to lighten a stock cast iron Flywheel
Post by: Cougar8775 on February 18, 2010, 12:53:40 PM
wow and they were laughing bout it like it was a huge joke.
Title: How to lighten a stock cast iron Flywheel
Post by: grutinator on February 18, 2010, 12:57:14 PM
Quote from: t3skidoo;310599

The only car I know of from the factory without a flywheel is the McLaren F1.




that pic is not a McLaren
Title: How to lighten a stock cast iron Flywheel
Post by: BogusSVO on February 18, 2010, 01:43:42 PM
yep the driver is lucky.....

but I am not saying to do this on a 700+hp engine..... this would be ok for one up too  maybe 400 hp and a red line of about 7000 rpm
Title: How to lighten a stock cast iron Flywheel
Post by: Ductape91 on February 18, 2010, 06:18:42 PM
Quote from: t3skidoo;310599


The only car I know of from the factory without a flywheel is the McLaren F1.
(http://www.supercars.dk/cars/mclaren/wallpaper-mclaren-f1.jpg)


i understand what a flywheel does, that much i understand.
i was told to not lighten a cast iron flywheel because they are more likely to crack and explode from heat stress and shock(dropping the clutch)even on low powered motors.
im no expert so figured it wouldnt hurt to ask.


also im sure the car posted was a pagini zonda :P
Title: How to lighten a stock cast iron Flywheel
Post by: t3skidoo on February 18, 2010, 11:09:02 PM
DOH! that's what I get for posting just before sleepy time.

(http://kappakstur.is/assets/mclaren/mclaren_family.jpg)

Better?
Title: How to lighten a stock cast iron Flywheel
Post by: dominator on February 19, 2010, 08:09:39 AM
What an idiot,620hp i think not.
You could plainly tell he was slipping the clutch to max rpm,what did he expect.
It's only gonna get so red lol.
Title: How to lighten a stock cast iron Flywheel
Post by: BogusSVO on February 20, 2010, 01:12:02 PM
well...... some people have more money than sense
Title: How to lighten a stock cast iron Flywheel
Post by: 88CougarGT on February 22, 2010, 09:26:08 AM
Quote from: BogusSVO;310839
well...... some people have more money than sense


Someday I hope to be one of those people. :D