clutch adjustment time or OK?

Jim - It is difficult to determine whether the clutch pedal "feels" appropriate from a type written description. Perhaps a few rambling comments will help.

The adjustment rod connecting the release-bearing lever and the clutch cable pivot bracket should always have a bit of play. This is owing to the play in the end-ball-linkages. Indeed, if there is no play present, then it is inappropriately adjusted to provide preload to the lever which implies that the throw-out (release) bearing is in constant contact with the pressure plate....a bad thing.

The release bearing lever should have a minute amount of play. You should be able to wiggle it a bit, which insures that it is not constantly in contact with the pressure plate.

As far as the adjusting rod and the tight lock nuts, I am sure that you realize that one side of the rod has a left-hand thread and the other has a right-hand thread. Make sure that you are turning the nuts appropriately.

Good luck.

Jim S.

 

Jim,
Does not sound quite right. Is the helper spring adjusted according to the book? Is the helper spring there?
The double coil spring that is above the clutch linkage should preload the clutch fork a little OUT with no pedal pressure. The adjustments for this spring are the bracket on the cam cap and the double screw down at the clutch. The spring cam cap and double screw are set with a new clutch and after severe wear. Fine free pedal adjustment is at the two ends of the clutch cable. Move either clevis to get the release point where you want it off the floor. The top cable end is the UP stop. I added a spacer here to get the free pedal lower. Simple aluminum U crimped over the band. There is supposed to be a coil spring at the clutch pedal that preloads cable and linkage. My spring has broken a number of times from fatigue and I stopped replacing it. There is no play in the clutch flex cable. The geometry shown in the Owners Manual is what you must have to get the delightfully light clutch that makes the car so much fun to drive. 2 to 10 mm offset is fine. Less than 2 is a problem. Set the geometry with the fork just touching the throwout bearing and all should be good. Go very slow on the double screw and adjust spring to match. See my Dino Saga 060205
http://ferrarichat.com/forum/showthread.php?t=92598
for more discussion, photos and a drawing. Good luck.
John

 

Jim - your description of the pivot bracket being vertical, and the "over center" feel, is exactly as you want it. If this is adjusted so that you get help (from the large spring) all of the time, then it will lead to constant pressure on the release bearing against the pressure plate. The helper spring should be pulling the release bearing AWAY from the pressure plate for the first few millimeters of travel, and THEN it helps you overcome the pressure plate force once the release bearing touches the pressure plate fingers.

John - my foot pedal spring recently broke. I ordered a new one from GT Parts, and they sent a "factory" piece. It seems too short. I had to add a loop to get it to span the gap between the pedal and the bracket. Without my added loop the spring was stretched beyond normal when in the rest position. If I were to step on the pedal, the spring would be stretched way beyond what seemed reasonable.

Jim S.

 

Jim and Jim S.,
Adjusting the clutch unfortunately has 3 adjustments and an illustration that would work fine for an engine on a stand but is completely worthless when the engine is in the car. Here is what we have:

Clutch Pedal, pivoted in the middle. A small spring pulls the pedal UP and PUSHES the cable.
Push/Pull cable that goes back to the engine
3 point Rotary Lever that connects the Push/Pull cable to a Helper Spring and the Clutch mechanism.
Double coil Helper Spring. Under roughly 75 lb. static compression. Pushes DOWN on lever.
Adjustable Push/Pull screw from the Rotary Lever to the clutch Throwout Lever.
Throwout Lever, PUSHED to disengage the clutch(pedal down), PULLED to lift lever off throwout bearing.

Three adjustments are:
Top cable clevis. This is the UP pedal stop and sets cable length. A pedal spring PUSHES cable to insure throwout lever lifts off of throwout bearing when Offset is near zero.
Bottom cable clevis. Works with upper clevis to adjust Helper Spring offset at Pedal Up.
Double Screw. Adjusts throwout mechanism to match Cable/Lever mechanism.

The Rotary Lever mechanism should be adjusted to always keep some Helper Spring tension on the Push/ Pull cable. The Pedal spring supplies enough force to overcome friction if Offset is very low. There should never be an "over center" pedal feel. I have adjusted my offset to feel right for me. The Helper Spring gives me a firmer up pedal and still nice down pedal with 10 mm offset. If the long arm is vertical it is similar to mine but maybe too much or too little. Maybe someone tried to adjust to the Owners Manual illustration without realizing the orientation of the illustration. Maybe need a new illustration.
John

 

Decided to do the mirror drawing while it was fresh in my mind. Printed my old post first which is a copy of the Ferrari drawing. Printed that photo on thin paper, put it on the scanner upside down, set brightness down and contrast up. Got a useable reverse. Redid text and numbers and freshened the alignment lines. Put new drawing on old main text. Not too bad. The top part of the drawing is what you see when you open the engine cover and look inside. You can put a straight edge between the lever(bell crank) pivot and the upper spring pivot and guess the offset. The lower spring pivot centerline must be on the left side of the line. Pictures are small because that was all Rob let us have way back in '96.
John
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I made the spacer from 1/16" half hard aluminum. Cut a strip as wide as the height you need and 6" long. Wrap the strip around a socket held in a vise. Takes a couple of tries to get the right size socket. Only have to do 30 degrees at a time, loosen vise, rotate things, tighten and bend some more. Start at the very beginning of the strip. When circle is done, cut strip deliberately leaving a small gap. Makes a nice tube that is a spring fit on cable. I should have done the same thing down on the engine but was lazy. Note that moving the sheath can move the stop for the clutch pedal. I wrapped a piece of the aluminum strip around the inner cable to compensate. Crimped tight. Has lasted just fine. I leave off the rubber boot up top.
John

 

Sounds like we have a new clutch expert. Great! If you want to feel a real difference, pop the top of the helper spring loose and try the clutch. No fun at all. Clever helper design but must be adjusted. Thanks to Dave for swapping my drawings. This thread might help a lot of folks.
John

 

This image is so kindly helpful maestro