911/01 and 901/13 Clutch Forks

[keitho64]

First the background - The car had a 2.2T motor and 911/01 5-speed with 215mm flywheel, clutch and pressure plate which I ran for the last 4 years, covered about 8,000 miles and had no problems. The 911/01 trans would grind on occassion going into 2 and the oil had a lot of material in it. I figure I will rebuild my 2.2 and the 911/01 for future use.

I purchased a new 215mm pressure plate, clutch, throw-out bearing and pilot bearing. The flywheel has been cleaned up and it is ready to go.

For now I was goint to install a 901/13 gearbox that I have and when I mated it up to the motor the throw-out bearing will not touch the pressure plate.

In searching the archives of Pelican I think I came up with a solution to my problem.

The first pictures are of the 911 gearbox that was connected to the 2.2 motor.



This picture shows the clutch fork and associated parts that came off the car and were working.

Edit - The part number on the fork is 9011167120R



The next series of pictures are from the 901/13 gearbox, this combination will not actuate the clutch. Here is the fork mounted with the new throw-out bearing.



Here is the clutch pivot ball that was on the 901/13.



Here are the clutch fork and associated parts that do not seem to work.

Edit - The part number on the fork is 9011167111R


OK More to come in the next post...

[keitho64]

Here are some pictures I hijacked from other threads on Pelican.



and two



Is it possible that I need items 2, 3, 4, and 5 in order to work with the 901/13 box?

I am trying to use this gearbox and take the time to get the 911/01 rebuilt. The car has been down to long and I want to get it on the road. I would prefer not to put the 911/01 in until it can be checked out. I am sure it needs some work but I am afraid if I use it this summer it would be damaged beyond reasonable repair.

Thanks again for all the help.

[keitho64]

OK to test my theory I bolted the original 911/01 trans and used the fork that was with it and the clutch works fine.

The 901/13 will not operate the clutch and I am think the trans I have has the wrong fork. The fork from the 911/01 will not work as the pivot ball is in a different spot. Finally it looks like someone may have 'modified' the fork from the 911/01 trans to work. I can see some welds on it and am wondering if it was changed.

[Zeke]

Forgive me if I forgot something here, but doesn't the 901 push and the 911 pull?

[Shoepop]

Milt is correct, the 911/01 uses a pull set up the 901/13 a push. To install the 901/13 you will need a different T/O bearing, fork, clutch cable and not sure off top of my head what else. The upside to the 911/01 is you can upgrade to a 225MM clutch if you choose, that entails new fly wheel, disc, T/O bearing and pressure plate.

[keitho64]

I think this whole push pull thing has me confused. Both forks are actuated the same way; the cable pulls the fork toward the front of the car when you press on the clutch. On the 911/01 trans it all works fine. I added a washer under the ball and then installed the trans. When I did this I was able to get it close but still not enough to full engage the clutch. On both transmissions the throw-out bearing pushes against the pressure plate to actuate the clutch while being pulled by the cable. This is why I think they are both the same but I have something wrong on the fork with the 901/13 transmission.

I guess I am still a little confused as to what is wrong and how to make this work.

[Grady Clay]

Keith,

Here may be the issue.

In the first image below, the pull-type pivot used for the 225 mm
clutch has been replaced with the ball pivot (red arrow) used
with the 215 mm clutch. The problem is the pivot needs to be
relocated to the red “X”.




You can see the difference with the 901/13. Note the position of
the push-type ball (green arrow). To convert the 901/13 to a
225 mm pull-type clutch the pivot needs to be repositioned
farther outboard (green “X”).







What I think you have is a PO did this mod, found it didn’t work
properly (because of the wrong position of the ball-pivot) and
then modified the clutch arm. You need to compare the arm to
a known original. It is also possible there is another mod.


As an aside, (yellow arrow) this is too much grease. You want
only enough grease the have the surfaces lightly covered with
no excess. When that grease falls off, it will contaminate the
clutch.

Another issue is there is a significant difference between the
clutch release bearing guide tube push-type to pull-type. The
push type is 40.5 mm long and the pull-type (’70-’71) is 50.0 mm.



Another area requiring only slight grease are the splines on the
input shaft (external) and clutch disc (internal). This is best done
with the guide tube off and test fit the disc on the shaft, wiping
off any excess. I like to test “feel” the fit dry first. One key to
great clutch operation is the disc easily floating on the input
shaft. I have even used valve grinding compound to smooth
the surfaces.

Best,
Grady

[JWest]

Originally posted by keitho64
Both forks are actuated the same way; the cable pulls the fork toward the front of the car when you press on the clutch.

The fork is pushed in opposite directions between 901 and 911.

It is hard to understand without seeing it, but the type 911 uses a pull clutch. The end of the cable is solidly mounted, and the cable conduit is allowed to move, pushing the fork toward the rear of the car when the pedal is depressed.

The throwout bearing is mounted to the pressure plate in a 911 and pulls the center of the beville spring away from the engine for disengagement. This is opposite the 901 clutch that pushes the center of the pressure plate toward the engine to release.

[keitho64]

On the first post I added the part numbers on the forks. Both start with 901. Does that mean these are the right type forks for the 901 style ...

[Zeke]

Originally posted by keitho64
I think this whole push pull thing has me confused. Both forks are actuated the same way; the cable pulls the fork toward the front of the car when you press on the clutch. On the 911/01 trans it all works fine. I added a washer under the ball and then installed the trans. When I did this I was able to get it close but still not enough to full engage the clutch. On both transmissions the throw-out bearing pushes against the pressure plate to actuate the clutch while being pulled by the cable. This is why I think they are both the same but I have something wrong on the fork with the 901/13 transmission.

This could be, but normally a 911 bolted to a 2.2 is a pull clutch. IOW, the cable housing itself is what moves the arm. The arm is moved towards the rear of the car; the end of the cable is stationary. On the 901, the end of the cable pulls the arm towards the front of the car, pushing the fingers on the pressure plate. Look at your cable carefully.

Better yet, snap some digies and let us see.

EDIT: Well I was typing and Grady had posted his info. Obviously, you want to look into what he is saying.

[keitho64]

OK I just got off the phone with Grady. From what we can tell the PO modified the fork to work with the early style clutch. My 901/13 transmission is missing the large washer between the case and the ball pivot. I am heading out right now, but will post some more pictures when I get home. I will provide shots of the differences in the forks I have.

As for the flywheel I do have it connected the right way. The washer does go between the bolts and the flywheel with the flywheel right against the crank.

Stay tuned more to come....

[Grady Clay]

I think we may have solved the problem.

First, the arm has been cut and welded to “fix” the mal-placed
push-type ball pivot. It didn’t work, the clutch didn’t release
fully and ate the syncros in the type 911/01 transmission.

As it turns out the ball pivot on the 901/13 transmission doesn’t
have the thick copper sealing washer (901.116.773.01) under
the pivot ball. Can someone measure the dimensions of this
washer? The lack of this washer is probably the reason why
the OE 2.0 arm isn’t operating correctly.

For reference, here is the 2.0 ’65-’69 215 mm configuration. Not
shown are the washer 901.116.773.01 and the pivot ball
901.116.771.01 and the updated version 901.116.772.11.


© 1969, Dr. Ing h.c. F. Porsche K.G.

Keith, you should also replace the white plastic cup, #5 above
and the two black plastic #9s. Inspect #6 for wear.


There is some unclear info in this thread and possibly another
we need to clean up. I’ll try and figure that out.

Never should the washer be between the crank and flywheel.

Best,
Grady

[keitho64]

Well it looks like both transmissions are using the pull type configuation. It seems that the PO modified a fork to work with the 911/01 which was in the car. So I have a 901/13 and a 911/01 which are using the pull type clutch. Assuming that by pull type I mean the cable is pulling the fork toward the front of the car. OK a few more pictures.


On the left is the 901/13 and on the right is the 911/01




Here is a close up of the 911/01 trans with the fork and throw-out bearing installed



Here is a close up of the 901/13 trans with the fork and throw-out bearing installed



more pictures in the next reply.

[keitho64]

Here is a side view of the fork on the 911/01 transmission, as you can see it is setup to be pulled by the cable. Again it was in this configuration that the car has been running for the last 4 years.



Here is a side view of the fork on the 901/13 transmission. Again this is setup to be pulled by the cable.



Here are the two forks removed. On the left the 901/13 and on the right the 911/01. Niether of these had a washer under the ball pivot.





I think if I can find the washer, part number 90111677301 that Grady referenced I will be good. I did try installing a washer under the ball pivot on the 901/13 transmission and is was almost good enough.

I hope others will find all of this information useful.

Grady, thank you again for your assistance, it was a pleasure talking to you. I will post more as soon as I find the washer.

If anyone has the washer that goes under the ball pivot on the 901 trans I am looking for the dimensions so I can try to find one locally. I will call the dealer tomorrow to see if they have, or can get, one.

[JWest]

Interesting mod that was performed. Just for consistency, the type of clutch you have is called a "push clutch" as the convention refers to the pressure plate itself.

[keitho64]

James, thanks for the clarification on the push.

Yes the more I looked at what was done the more amazed I have become at the handy work some will go through.

[pello3602]

Just read your post' and i am now really confused !! Inherited a 911/01 trans with no cable fitted and with the fork positioned as though it would be a pull configuration. I have been told this is incorrect and have repositioned it the opposite way,but how does the clutch cable now work ? Can anyone please help as i'm desperate to get my project moving,pics would be a fantastic help ?

[Grady Clay]

pello3602
First, WELCOME to the Pelican 911 Technical Forum
You will find a lot of help here.



Please post some images of your transmission and clutch linkage pieces as above.

As you can see, there is more than ‘just a bit’ to all this.

With some good images, we can get your 911/01 to operate properly.

What chassis is it going into? Pictures please.

Best,
Grady

[pello3602]

Hi, Have the pictures as you suggested. The chassis is an early 1973 Targa. The clutch cable has not been photographed as it has been removed from the vehicle and will be replaced with new. Please can you or someone explain the route of the cable and whether it is a push or pull fork. Thanks.

[pello3602]

Forgot to say, Targa is a 911e. Trans is married to a vw 2.0l aircooled engine.