Lightened flywheel - clutch adjustment

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phaetn
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Your car is a: 1974 Fiat Spider 1800
Location: Ottawa, ON Canada

Lightened flywheel - clutch adjustment

Post by phaetn »

As part of a recent engine rebuild (almost back on the road!) I had my flywheel lightened. I see some say it may not be a great thing for street use as it spools down too quickly. Too late to put that material back on. :)

Anyhoo, my clutch pedal bites very close to the floor and I'd like to be higher (there's a bit of a catch in the free play at the top of the travel, too, so I may have to replace the cable). Can I just keep tightening the clutch cable to raise the engagement point? (I know technically this is disengaging the clutch and that often the term is confused between the actual clutch and the pedal and which is "dis/engaged").

I don't want to put too much pressure on the throwout bearing. I know with less flywheel material the clutch arm is going to sit differently...

It's been a long road and I've missed the car, but this COVID year when I haven't had to drive to work in the Spring was definitely the year to do the work!!

With thanks and cheers,
phaetn
1974 CS1
32/36 DFEV; CompuTronix ign.
9.8:1 c/r; 40/80 intake cam w/ Isky springs
Vicks' SS header & adj. cam pulleys
A/R's progressive coils, Koni Yellow dampers
205/50-15s on CD-66 style rims
Momo wheel, Corbeau seats w/ 5 pt belt
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Nut124
Posts: 748
Joined: Wed Oct 25, 2017 6:39 pm
Your car is a: 1978 124 Spider 1800

Re: Lightened flywheel - clutch adjustment

Post by Nut124 »

You should adjust the clutch normally. The nut is the adjustment assuming the cable is OK and properly installed.

Did you weight your flywheel before/after? Any lightening should not remove material from the friction face. The face should only be touched if needed to restore the surface after wear.
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: Lightened flywheel - clutch adjustment

Post by 18Fiatsandcounting »

In addition to what Nut said above, I'll add this:

The pedal travel distance between starting to engage and starting to release is related to the wear of the clutch disc. With a brand new clutch disc, this distance can be pretty far, and as the disc wears, the distance gets smaller and smaller until eventually the clutch starts slipping. My recollection is that a new clutch (when properly adjusted) can start to engage a couple inches from the floorboard. My '71 with a well worn clutch starts to engage well past halfway towards the full up position, and one of these days I'll need to replace it.

In any event, you want about an inch of free play at the top of the pedal travel before the clutch starts to disengage. This is the critical measurement, so I'd set that and see how it behaves.

-Bryan
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phaetn
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Posts: 575
Joined: Thu Jan 02, 2014 7:42 pm
Your car is a: 1974 Fiat Spider 1800
Location: Ottawa, ON Canada

Re: Lightened flywheel - clutch adjustment

Post by phaetn »

Thanks for the replies - that's a big help!

I've adjusted for about 1" free travel at the top of the clutch travel, like I normally do. That's quite a ways down the threading of the clutch cable, but so be it.

I suppose it's the new clutch that is grabbing right away (barely off the floor mat) that I'm not used to... I'm sure I'll become accustomed eventually. :)

Thanks again and cheers,
phaetn
1974 CS1
32/36 DFEV; CompuTronix ign.
9.8:1 c/r; 40/80 intake cam w/ Isky springs
Vicks' SS header & adj. cam pulleys
A/R's progressive coils, Koni Yellow dampers
205/50-15s on CD-66 style rims
Momo wheel, Corbeau seats w/ 5 pt belt
pics and HD vids
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: Lightened flywheel - clutch adjustment

Post by 18Fiatsandcounting »

A new clutch can feel kinda "odd" until the parts wear in a bit, plus it's likely different from what you were used to. I'd give it a couple weeks, then see how it feels.

-Bryan
maxm50
Posts: 107
Joined: Sun Jul 07, 2019 12:12 am
Your car is a: 1981 Fiat Spider
Location: Sebastopol, CA

Re: Lightened flywheel - clutch adjustment

Post by maxm50 »

More importantly, how do you like the lightened flywheel?!? How much weight was taken off?
1981 Fiat Spider 2000
2011 BMW 335i M-Sport
1971 Honda CB450 Twin
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