Newbie needs clutch/transmission help?

[k_dub]

Over about the last year I have been working toward getting my first Porsche on the road. I started with a '75 911S which I quickly discovered was not worth the effort to first the body issues with, but the motor and transmission worked great. I then stumbled across a complete 1980 911SC that had the motor and tranny parted from it so I decided that I'd put the 2.7 I had into that. I know it my be sacrilege, but it seemed like a good idea.

After many discoveries of what is different between the two cars, I finally got the 2.7 in running and all of the bits working. I was out for my first drive in it over this weekend and everything was working great (except for a small ignition issue, for another time). I was coming to a stop when I slipped off the clutch and made a very hard downshift into second. I'm sure some people can guess what came next, lovely aroma of clutch and from then on I have had a bad vibration in reverse and first gear.

I've done some reading on the other threads and see that it could be everything from glazed clutch disks to loose motor mounts to torque tube issues.

Before I dive into this I was hoping to get some advise on the best route to go through troubleshooting this.

[Oh Haha]

Welcome to Pelican.

By "hard downshift" what do you mean? Did it grind going into gear?

[Flat6pac]

Sounds like a rubber hub clutch on the 2.7 disintergrated. Leftovers from days gone by.
Bruce

[k_dub]

Originally Posted by Oh Haha

Welcome to Pelican.

By "hard downshift" what do you mean? Did it grind going into gear?

To clarify, it didn't grind, but the RPMs were around idle and I basically dumped the clutch doing 30-40 MPH.

As for the rubber centered clutch, I had the transmission off before I put everything back together because I was considering replacing the clutch before putting it in the car and I from looking at pictures it didn't look like a rubber one. I could be wrong though.

[k_dub]

I also just realized that I made a mistake in my description, the vibration only happens when I'm engaging the clutch, when it's in gear there isn't continued vibration.

[Oh Haha]

I would check your clutch cable adjustment. Does the clutch engage at the same spot that it did before?

[k_dub]

Yes, the clutch still engages at the same spot, only there is a pretty hard vibration from just after I feel the clutch starting to engage until it's fully engaged.

[OldTee]

Clutch chatter = worn clutch disk.

Try this. Put it in second, add some power and slip the clutch. Let it cool. If you still have the problem buy a new clutch disk.

[DRACO A5OG]

Originally Posted by k_dub

Yes, the clutch still engages at the same spot, only there is a pretty hard vibration from just after I feel the clutch starting to engage until it's fully engaged.

It should engage in middle of the pedal travel. Where does your clutch engage and how is the pedal height?

[k_dub]

Clutch engages closer to the end of the pedal travel. Not sure I know what you mean about pedal height?

[DRACO A5OG]

It must engage at middle of the path. You need to adjust the clutch cable at the trans. It must be 25MM ( +/- 0.5MM), the difference between pressed and unpressed lengths. See Bentley or Waynes book or even the Haynes Guide.

In your car, look down at your brake foot pedal's height. Your clutch foot pedal must be the same height.

[k_dub]

Thanks everyone for the great advise. I tried a bunch of the stuff late in the week to see if anything would help but nothing sounded right so I decided I'd just open it up and take a look and this is what I found.


I guess it was a little more serious than I thought. But after a quick jump down to my friends a Nineapart, a new clutch disk and pressure, and everything is back to normal. Pedal engages about half way through the stroke and the car pulls great.

Thanks again and we'll see what my next adventure brings.

[DRACO A5OG]

Oh my down to the studs, good grief . Glad you finally found the culprit.

Now enjoy Brother!