Different Clutch Pivot Arms

[Jay Laifman]

I'm happy to say that I'm driving my Alpine again. It's been a long COVID lock up, and some time before that as well. So now I'm thinking of something that has been bothering me.

My first Alpine was a very late SV with fine spline transmission. That thing shifted like butter. I'm now on my fourth transmission since then.

(my original fine spline driveshaft broke and back in the late 70s, pre-internet, we couldn't find a replacement. So we found a used course spline and put it in, with a replacement course spline tranny. I then replaced that with a rebuilt OD trans. That trans blew up. And now I have an NOS OD transmission from a later Rapier that was converted to fit Alpine).

Ok, that all said, not one of the other three transmissions have shifted like butter. Always a little notchy. Many many years ago - on this site and maybe on others - I tried to figure out why. Please don't bother suggesting bleeding or mismatched master/slave. Back then, when I last explored it, I came to learn that there were different pivot arms. Not very different, but a little different. This created a slightly different ratio, which would mean that the throwout bearing might not move as far. I suspected this could be the difference because I did swap pivot arms (and thankfully I do still have that original pivot arm). There were also different pivot arm stands - some a little taller than others.

I also changed the clutch. I don't know if the clutch I had was taller or the same as my late SV clutch. Of course the clutch plate was different with the different splines.

So I'm wondering (1) is it actually rare that Alpine boxes are smooth as butter - and my late SV was unique? (2) has anyone done a bigger study of the different pivot arms and have a better idea of if they might have an impact? (3) or anyone know if there are other parts that might have changed that contributed to this - like bell housings or clutches. (4) Oh, I also switched to the roller bearing TOB when this happened - so could the roller bearing TOB not be as tall and cause the clutch not to depress as much?

And I guess (5) does anyone have any idea which height pivot arm stands and which pivot arms go with which clutches and which cars?

 

[alpine_64]

Jay, my SII alpine has had 2 trans in my ownership ( 1996 on) the first a full sync OD oit of a hillman.. Beautiful shift, light precise and very smooth.
I replaced that with a full sync OD in 2007.. Also very smooth and easy.

My fathers late SIVGT had a full sync OD trans original to the car that was notchy but also very worn. It was rebuilt in 2004... It had stiffer detent springs put in which made it firmer to select and a bit stiff...
Other alpines i've driven with decent trans have always been very smooth and precise... I.ve greased the shifter and linkage and find that keeps selector movement smooth.

 

[puff4]

I rebuilt my own SV OD gearbox about 25 years ago and it’s always been smooth as butter ever since. Nicest gearbox I’ve had in all my 49 LBCs over the years. It’s jus a very robust and good design (apart from that stupid spline).

 

[Jay Laifman]

So either I have had a series of bad transmissions - or I somehow mismatched stands, pivot arm, or TOB - and others just happened to have their original matched sets and never happened to see there was a difference.

I'm still hoping that someone has information on determining the right matches.

I can assure you I held different height stands and different length pivot arms in my hands. Not by much. But maybe just enough for no notchiness.

 

[mikephillips]

Yep they are different as production moved on. The early Alpines, and I can't say when it changed, used the shorter pedestal. Why?? well the clutch pressure plate assembly was slightly shorter height. The later Alpines used a taller pressure plate so had the slightly taller pedestal. Last time I checked the taller clutch was what was available so that is what should be and probably is in your car . As for the pivot arm, there were at least 2 different ones as the early cars used a larger throwout bearing so the arms were farther apart. Later, perhaps with the pressure plate change, they went to a smaller diameter throwout. To be sure you have what should match for the assembly, the throwout should contact the pressure plate when the arm is more or less 90 degrees to the clutch assembly, which means parallel to the firewall and steering link above it.

 

[Jay Laifman]

Thanks Mike. That was my basic recollection. The thing is that the parts that I selected from were a very late SV box and a SIV or SV box.

I think my big problem is that it does work fine - just not perfect. So I'm not inclined to remove the transmission just to swap. Taking out the OD transmission is not particularly easy.

Also, as I said, my box is NOS - except for what had to be swapped to make the later box fit. I know that included the first motion shaft. I don't know what else went with that. So there is a chance that the very thing that was causing the notchiness in the last box just got swapped into the new one! It really is mostly 1st that has the notchiness. Maybe a little in 2nd.

 

[mikephillips]

First gear and maybe some second could indicate that the first/second sliding hub, shift fork or syncros are slightly worn so not making a clean engagement too. Hard to say without being there to hear and try it.

 

[Jay Laifman]

Hi Mike. I'm wondering if this symptom would help shine more light on it. It also doesn't like going into R. But, if I slide it into 1st before going into R, then it slides right into R.

Also, I found my old notes on it and noticed that I measured the clutch slave movement, and I had full movement, plus some. And I spoke to Rick. He suggested that I might have a warped clutch disk so it was causing friction and never fully releasing. I wonder if he knows of that being a problem.

 

[mikephillips]

Could be a slight warp to the clutch disc causing it to not fully disengage and be pulled a bit by the flywheel or pressure plate. If you go to reverse, which is a non syncro gear then to neutral for a few seconds before releasing the clutch, does the difficulty return, meaning the input shaft is starting to rotate again?? First is fully syncro on the late IV and all V transmissions so even with that should engage without a problem. My thought is that the root cause may be a worn syncro hub and/or rings causing it to not easily line up when there is some motion rather than syncing the input and main shaft gears together.

 

[Tim R]

Over the years we have had numerous problems with different height pivot pedestals and arms. On one car the engine and gearbox were in and out every weekend for ages as we tried to sort things out. That turned out to be a clutch plate that had a 5mm over length centre boss and it would never have worked properly. One of the problems that we have had is that we relied on 'specialists' who assured us that parts were correct, when they weren't. Both of the clutches in the photo were supposed to be for a Series V. We had different height pedestals which were meant to be standard Series V and it was (to put it mildly) a nightmare. In future we will have clutch parts re-conditioned and only replace them when we are 100% certain that they are identical to what is in the car and working correctly now.

Tim R

 

[Jay Laifman]

Thanks Mike and Tim.

Actually Tim, now that you mention it, I remember now that the pressure plate and cover did not look like others I've seen - or those you picture above. It was more of straight sides, with like a 90* corner at the rim/edge. I remember thinking it was different, but assuming that Sunbeam Specialities knew what it was sending, and it looked so nice, I kind of assumed maybe it was a nicer alternative. Now on hindsight, I have no idea what it was, or how it measured. Maybe something is wrong there.

This is not a Sunbeam one - in fact it's a Porsche one. But the sides looked more like this:

 

[Jay Laifman]

Well, it looks like I have it solved. The problem looks like it was human error. As everyone knows, the pedals are adjustable in and out. I just went and checked, and found that when I had the pedal in the lower position, the pedal would bottom out against the firewall (n0 carpet) before the clutch master had full stroke. When I had the pedal in the upper position, the clutch would get full stroke. Three test drives seemed to show that the prior problems are gone. Of course, I have no idea how much wear I got from not having full release all these years. Fortunately, I don't think that I have put that many miles on since I got this clutch.

Thanks to Mike for talking through some of the possibilities with me.

 

[Jay Laifman]

I should add that my clutch travel needs may not be the same as others. I have a different clutch in there. Rick was supplying it for a period of time. He doesn't have details on it anymore. It could be that that clutch was not as tall.

Interestingly I actually have the 3/4" master. So I already have further travel than stock (and I did measure it and confirmed I did.

I also swapped the TOB fork before this happened because I had a few and decided the one in there was the least worn one. But I did know it had a SLIGHTLY different angle in the bend. Maybe that was enough to pull the TOB back enough that I needed even more stroke. (Or admittedly, it might have angled the TOB in. I just don't know). I'm pretty sure the pedestal I used was the exact same height. But I can't swear to it.

 

[mikephillips]

Glad to help. It can be difficult now that we're at the point where so many bits have been "adapted" to work and so many don't know what was original or not.