More light flywheels

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rridge
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More light flywheels

Post by rridge » Mon Sep 11, 2017 12:52 pm

Carl's recent post prompted me to dig out a lightened flywheel I've had in my stash for many years. I believe it is a lightened 2L wheel done by PBS but I have no documentation and would appreciate any validation. Here's the specs. Diameter without ring gear is 273mm. The center hole is 35mm. The bolt holes take 12mm bolts. The backside is dished from a radius of 73mm to 125mm and cut to a depth of 5mm. The weight is 14lbs give or take a couple of oz. Two pictures attached.
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Light flywheel - front (1).jpg
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Light flywheel - rear (1).jpg
Light flywheel - rear (1).jpg (119.09 KiB) Viewed 201 times
Richard
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Re: More light flywheels

Post by SimcaBertone66 » Mon Sep 11, 2017 10:54 pm

I still have my original "assault Weapon: lightened stock flywheel... I get a weight on it ... and report back :ugeek:
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Re: More light flywheels

Post by vandor » Wed Sep 13, 2017 12:36 am

12mm bolt holes means it's a very late 1800 or 2 liter. 13-14 lbs is the normal weight for a lightened stock flywheel.
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friedman
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Re: More light flywheels

Post by friedman » Wed Sep 13, 2017 8:30 am

My lightened flywheel weighs about 14.5 pounds.
Carl in Virginia
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Re: More light flywheels

Post by rridge » Wed Sep 13, 2017 9:38 am

In poking around for flywheel specs I looked in the late factory service manual that Bradley recently posted for the DS Spiders in the library. Actually it covers all U.S. bound Spiders 1975 to the end, though I have not yet directly compared it to my 1982 Fiat NA manual. The manual suggests that the flywheel and crank be balanced as a unit whenever the flywheel is replaced. It shows a simple blade edge static rig for doing so.
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Re: More light flywheels

Post by friedman » Wed Sep 13, 2017 12:35 pm

The spec world meets reality. I can't imagine anyone except a racer building a high rev motor would go to the trouble of pulling the crank out of the motor to balance the flywheel with it. I have done many motors with a flywheel from another Fiat motor and not resulting vibration. I have done a lot of 1500 motor swaps into 1300 Xs, 128s and a 128 SL which required the 1300 flywheel and never noticed vibration.

The only time I ran into a problem was when I replaced the clutch on my Miata. The flywheel is not indexed to the crank like it is on the Fiat TC motor and I didn't know I had to mark the flywheel so it would go back on the same way. When everything was put back together the motor never was a smooth as it was before the clutch job.
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Re: More light flywheels, for real //

Post by SimcaBertone66 » Wed Sep 20, 2017 5:26 pm

134564_424173394308756_1102016018_o.jpg
134564_424173394308756_1102016018_o.jpg (291.2 KiB) Viewed 67 times
Millers Mule Machine , believe he uses a Fiat brake disc for the steel friction surface
ARP flywheel bolts, heavy dowels for pressure plate,
Its for sale .... with engine attached :lol:
Joe DeGasperis
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