Questions about resurfacing flywheel 2000cc

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Odoyle
Posts: 440
Joined: Mon Dec 01, 2014 10:06 pm
Your car is a: 1983 Pinafarina Spider
Location: CA

Questions about resurfacing flywheel 2000cc

Post by Odoyle »

I have what appears to be the original valeo clutch removed from my 83 spider, and look like its worn down to the higher set of rivets on the plate. The clutch has been working with no problems, but since I'm rebuilding the trans, and it looks a little worn, I want to replace the clutch disk and possibly resurface the flywheel. I want to reuse the pressure plate because it is balanced to the flywheel already, so should I resurface the flywheel?

I have a new pressure plate and clutch disk made by CO.ME. which says "If machining of the flywheel is undertaken ensure that the same amount of the material is removed from both the friction and mounting surfaces, and machining or grinding must be made respecting the surface finish included between 2.4 and 2.8 Ra with CONCAVITY from the center to the outside included between 0.0 and 0.8 like about 2 degrees inclination." (CO.ME.)

Does that mean that the flywheel and the pressure plate must have the same amount of material removed from both to do this correctly? Maybe I'm interpreting that wrong? Would love to hear your guys thoughts.
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engineerted
Posts: 531
Joined: Tue Feb 21, 2006 9:57 pm
Your car is a: 1974 124 spider
Location: Farmington Hills, MI

Re: Questions about resurfacing flywheel 2000cc

Post by engineerted »

No, it just mean you need to maintain the step on the fly wheel as the friction surface is not flat to the mounting surface for the pressure plate cover.
Ted
1978 124 Spider, Complete Restoration
1974 Fiat 124 F Production Race car
18Fiatsandcounting
Posts: 3798
Joined: Fri Mar 15, 2019 11:23 pm
Your car is a: 1969 and 1971 124 spiders
Location: San Francisco Bay Area

Re: Questions about resurfacing flywheel 2000cc

Post by 18Fiatsandcounting »

Hmmm, I would have assumed that the flywheel surface was flat, but after some Googling, it appears that some flywheel designs are concave or convex to help the clutch engage and disengage more smoothly (certain Jeeps for example). If your flywheel is like that, I would either go over it by hand with some light emery paper, or make darn sure your machine shops knows how to interpret the instructions from CO.ME and carry them out. Some online automotive forums give examples of folks who had to go get a new flywheel after their machine shop mistakenly machined everything flat and then the clutch didn't work right.

Concavity in the flywheel can be a sign of warping (excessive heat), but not always. If it ain't broke, don't fix it??

-Bryan
80spiddy
Posts: 180
Joined: Thu Mar 05, 2015 8:06 pm
Your car is a: 1980 spider 2000

Re: Questions about resurfacing flywheel 2000cc

Post by 80spiddy »

I work in a machine shop. I ground my flywheel flat on one of our grinders. Installed new pressure plate. All works flawless. Not sure why all the hoopla on the specs.
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Daddio
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Joined: Thu Nov 16, 2017 1:29 am
Your car is a: 72 124 Coupe 2L project
Location: Portland OR

Re: Questions about resurfacing flywheel 2000cc

Post by Daddio »

Agree with EngineerTed, step must be maintained for proper 'grab' and disc life.
Jeff Aurand
Portland, OR
'72 124 Sport Coupe
'86 Bertone X "Anna"
'70 Volvo 145 "Edna", since 1989
'87 Maserati Biturbo Spyder 2800i
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