Chicago-ish reference for "normal" clutch operation?

[Otter74]

I have no real reason to think there is anything wrong, per se, with the operation of my car's clutch. Compared to when I bought the car, new coupler and shift-linkage bushings and a new cable have dramatically improved the feel and ease of shifting.

But since my 911 is the only one I have ever driven, I have no idea how it compares to any other stock SC. This came to mind yesterday when I went for a drive with my SO and her dad and his '67 MGB GT, and we traded cars. The BGT has a marvelous clutch and shifter - clutch is low-effort and easy to modulate, and the shifter is mechanical and direct with short throws.

My 911 has a much heavier pedal effort and the take-up is noticeably more difficult to modulate for a smooth launch (though I would not call it difficult in absolute terms.) Is there anyone in Chicago-ish with a nice 915-box car who would be willing to trade cars for a short drive together? I'm curious to know what other cars feel like.

[DRACO A5OG]

Question, when you did your last clutch job did you make sure wrench or you replaced the pressure plate?

Some shops opt to re-use the old pressure plate as it will work but the tensil strength weakens over time and causes the pedal throw to be heavy and over work the helper arm. The other side effect is it will put allot of load on the bearing bracket post evidenced by deformation and groves on the helper arm pivot point.

I just did a clutch job, thorough one with pressure plate, even balanced the flywheel and pressure plate for extra measure.

I got to tell you my clutch never felt so light and almost like a modern car except for how the pedal angle is, but that is another topic .

[Otter74]

The clutch was replaced by the PO in 2005 when the transmission and engine were rebuilt, 30k miles ago. Looking at the invoice, I see a line for 'clutch kit' and 'flywheel bolts' but not one for a flywheel, so I'm guessing it wasn't replaced.

Now that you mention this I remmember reading it. Still, for all I know my car is normal - I just don't know 'cause I don't have any reference. The clutch is noticeably heavier than that on my Fiat Spider, Sentra SE-R or the BGT, all with cable clutches, but those are cars with significantly lower-powered engines.

[DRACO A5OG]

Well, if $600-1100, the "clutch kit" should include the new pressure plate.

[Otter74]

Yeah, it was 975, so it sounds safe to assume the car got a new pressure plate.

[DRACO A5OG]

Have you taken a look at the omega spring aka helper arm spring? Not sure if you have one but most if not all do not service this part regularly as it is a maintenance item. If I were you, I would remove the clutch arm, helper arm, and Omega spring and clean all the pivot points.

If the helper arm does not drop out then you have some rust up in it, should be cleaned and use high heat bearing grease, high heat is important because standard grease will just melt off. Ask me how I know.

Then I would take a look at the Omega spring, the hooked section that pivots on the trans mounted "bearing bracket" that SS stub. See if there are deep groves or pitting. Signs of it not being lubed. I used a polishing stone to smooth mine out. This made a world of difference but sadly my bearing bracket needs replacing after all the years of service it deformed.

Just lube in these areas will lighten the clutch throw.

Don't forget to lube the spring up front at the pedal cluster and the clevis, another neglected lube point.

[Otter74]

Originally Posted by DRACO A5OG

Have you taken a look at the omega spring aka helper arm spring? Not sure if you have one but most if not all do not service this part regularly as it is a maintenance item. If I were you, I would remove the clutch arm, helper arm, and Omega spring and clean all the pivot points.

If the helper arm does not drop out then you have some rust up in it, should be cleaned and use high heat bearing grease, high heat is important because standard grease will just melt off. Ask me how I know.

Then I would take a look at the Omega spring, the hooked section that pivots on the trans mounted "bearing bracket" that SS stub. See if there are deep groves or pitting. Signs of it not being lubed. I used a polishing stone to smooth mine out. This made a world of difference but sadly my bearing bracket needs replacing after all the years of service it deformed.

Just lube in these areas will lighten the clutch throw.

Don't forget to lube the spring up front at the pedal cluster and the clevis, another neglected lube point.

Sounds like not a bad idea to do even if everything is OK - didn't think of it when I replaced the cable!

[OsoMoore]

I'm in Milwaukee, and I rebuilt my SC's 1st and 2nd gear two summers ago. If you are up this direction I'd be happy to let you check out my transmission and clutch feel.

[Otter74]

OsoMoore,

Thanks - I'm likely to take you up on it. I've been planning to go up there on a coming weekend for the Harley museum or the art museum or both.

[Jack Stands]

If you are interested, the Chicago Region of the PCA is having a concours on the Prominade in Bolingbrook this weekend. Check the Chicago Region PCA website for times and details as there should be some cars to compare with.

My Targa is up in Wisconsin right now, so I'm unable to help. Otherwise, Perfect Power in Buffalo Grove or Midwest Eurosport in Bensenville are both reliable shops to help you.

[OsoMoore]

Originally Posted by Otter74

OsoMoore,

Thanks - I'm likely to take you up on it. I've been planning to go up there on a coming weekend for the Harley museum or the art museum or both.

They museum is fantastic, especially the room with open engines. Shoot me a PM when you have a date chosen and we'll set something up.

[DRACO A5OG]

Pelicans to the rescue, LOVE IT!

[Otter74]

Thanks to OsoMoore for kindly offering to let me check his car out. I was up in Milwaukee this weekend to go fro a drive and check out the Italian Car & Motorcycle Show, and took the opportunity to stop by afterwards and we swapped cars for a bit.

Normal clutch, nothing significantly different from his car. But I do really like that Seine GateShift with short shifter, and the 930 steering wheel

[DRACO A5OG]

Oh good, did you also lube the pivot points?

[Otter74]

No, I haven't had time for that yet, but the next time I can make the time I'll lube everything and also jury-rig a stop to substitute for the one that's on the foot board that I don't have. I can avoid pushing the pedal too far by feel (stop when pedal pressure starts to drop) but it does require a bit of concentration. I'd like to take it to Detroit this weekend, and maybe I can make time one evening this week.

[OsoMoore]

Originally Posted by Otter74

Thanks to OsoMoore for kindly offering to let me check his car out. I was up in Milwaukee this weekend to go fro a drive and check out the Italian Car & Motorcycle Show, and took the opportunity to stop by afterwards and we swapped cars for a bit.

Normal clutch, nothing significantly different from his car. But I do really like that Seine GateShift with short shifter, and the 930 steering wheel

It was a fun time. Also neat to see a megasquirt setup first hand. Soooo different from the CIS. And it leaves a lot of space to work on the engine.

[DRACO A5OG]

Originally Posted by Otter74

No, I haven't had time for that yet, but the next time I can make the time I'll lube everything and also jury-rig a stop to substitute for the one that's on the foot board that I don't have. I can avoid pushing the pedal too far by feel (stop when pedal pressure starts to drop) but it does require a bit of concentration. I'd like to take it to Detroit this weekend, and maybe I can make time one evening this week.

Well, get a helper to press the clutch so you can lube behind the Omega ring's pivot area. Ask them to notice the difference after lubrication.

Wow, you have sensitive feet. I am a neanderthal, keep hitting the stop, thank goodness I switched to aluminum boards

[Otter74]

Draco,

Yeah, I guess my leg muscles are sensitive It's like the last inch of pedal travel that the effort drops off slightly.

What do you mean by 'behind' the Omega spring pivot? And what kind of grease is appropriate for these lube points? E.g. clutch shaft, omega spring, etc. Is something like the EP moly grease I use for suspension bushings and such fine? I assume the clutch clevis and cable bousing should get a lithium spray or something else light like that.