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Clutch adjustment on 2 plate'ers

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Old 09-12-2008, 03:06 PM
  #136  
mark kibort
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Well, I was at the shop fixing a crack in the frame where the sway bar mounts attaches and did some measurements for you . Just to confirm the process.

It turns out that my crude measurements of the "H" window of 1.8mm, is actually 1.5mm. So, this means, in some cases, pushing the "H" all the way back will reach the factory manual spec. However, this is not correct for some. In fact, there are several issues that can cause the clutch to drag when these things are pushed all the way back as i have reported earlier.
You said you put in two feeler gauges of .040 each? thats near 2mm. I dont see how that is possible unless the ears are bent or you might have misread them to be .040" when they are actually .40mm. (kidding)

anyway, you did say you ended up with a gap with the two feeler gauges of near .080". thats still way too much. It doesn take much to adjust the clutch intermediate plate, anything will be an improvement by closing the gap. I just estimated mine to be under 1mm and it actually is more like .5 to .75mm. (so is Scots)

I was out again today and the car has never shifted better! Its really great to be able to downshift into 1st without care and toggle between 1st and reverse with ease!

So, confirm the "H" gap to the rear, close it down to under 1mm, say, .5 to .75mm. Remember there is nothing to push the "H"s rearward except the force of the flat springs. If they are moving the "H" back, then clearly the interemediate plate is bad. However if you still have a large visual gap, its too big.

scots is working fine, mine is better than ever and ive been beating on the car for a week now!

mk


Originally Posted by OBehave
Well Mark not so fast,
All was good until this morning.After about 20 miles or so of normal driving,upshifting and downshifting,I started having problems again dragging and not able to put it into gear.I was able to get it to work by either shutting off the engine or sometimes running lights.I haven't put it on the lift yet but I will let you know what happens.
What a bitch this is becoming. Ed
Old 09-12-2008, 03:12 PM
  #137  
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Originally Posted by mark kibort

scots is working fine, mine is better than ever and ive been beating on the car for a week now!

mk
That is so much better than all the beating on the chest ....
Old 09-12-2008, 03:14 PM
  #138  
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Greg,

Manual is kind of confusing, right to the point of having two sets of tollerance ranges. If the "H" pads are resting on the flywheel side, then you have a maximum gap of, (i just measured it with a dial indicator) of 1.5mm. (interesting, just the outer tollerance of the spec) BUT, by understanding the mechanism, you can see what has happened here. First of all, he still has way too much of a gap. second, as I mentioned before, there is NOTHING acting on the "H" pads when there is a 1mm gap, besides the flat spring (agreed). that force is miniscule. no matter how fast you push the clutch in, or how far you push it in , will it create any greater force on the "H" adjusters to the rear. So, it aint going anywhere unless there are dynamic forces during high rpm engagement that moves the pressure plate floater surface. Next, if the intermediate plate is allowed to move too far rearward, and it doesnt take much, it will drag. simple, you are right! So, the spec of 1mm to .7mm as i have used seems to work well.
Ill make you a side bet that mine doesnt change over the next 2 race weekend or the rest of the season.

Originally Posted by GregBBRD
Imagine that! I'm so surprized.

I'm not sure how the workshop manual instructions got so confused. Its not like it is hard to read or interpret!

"The forks of the stop brackets (the "H" pieces) must rest on the stop of the intermediate plate on the flywheel end on both sides. This will produce a gap of 0.7 to 1.0mm or 1.2 to 1.5mm."

Come on guys...that's really clear. There's even a sketch right there, showing what they mean....with the dimensions pointing at the gap.

It's not like this is the first one I've even fussed with....I have literally done hundreds of these things, in the past 20 years. If the gap is too big....the clutch is not going to work. If you have the wrong discs with the wrong intermediate plate...its not going to work. You might be able to make it work for today, but the customer is going to be back tomorrow with a dragging clutch! Keep screwing with it and you will also need new syncros.
Old 09-12-2008, 03:18 PM
  #139  
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This could be a solution too. Scots was REAL bad, made worse as his slave and master were bad. after replacing them, it worked, but just like it always did , marginal. When we did the "close the gap to under 1mm trick" , it worked and was amazing! He now is downshifting the old bugger into second like he never could before. I wish i found this all out 2 years ago, when his transmission was a lot newer!

I thought about the extention of the slave technique, but after the H gap was closed, it solved the problem.

under 1mm is the trick. more like .7mm

mk

Originally Posted by BrendanC
The mention from Greg about getting more extension from the slave cylinder was interesting. I wonder if some of the issues are that your slave cylinder is not extending enough? Are your clutch pieces new? ( I did not see that info in your posts)
Old 09-12-2008, 03:22 PM
  #140  
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Kibort do you just not see things like this ?? ..............."Well Mark not so fast,
All was good until this morning.After about 20 miles or so of normal driving,upshifting and downshifting,I started having problems again dragging and not able to put it into gear.I was able to get it to work by either shutting off the engine or sometimes running lights.I haven't put it on the lift yet but I will let you know what happens.
What a bitch this is becoming. Ed " ..... Frankly you tend to use "facts" much as a drunk uses a lamppost ....more for support than illumination.
Old 09-12-2008, 03:24 PM
  #141  
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Here you provide two dimensions that I have a hard time believing.
2.2mm starting out and 2.0mm is what you ended up with. maybe there is some variance with the "H" adjusters between years, I dont know. However, the good news is that you were closing the gap slightly and it barely worked. The bad news is that you didnt close the gap enough. Mine is well under 1mm, probabably just under .7mm. It workes create and you can see mine due to the peak hole, that the int. plate moves back via its springs to release the flywheel. No dragging.

I would be curious how the 2.2mm measurement happened, but thats ok. It really doesnt matter. move the "H" adjusters almost until they tough and make the slightest of gaps you can make. that will be enough. Or use a feeler gauge with a .020" number on it.

mk

Originally Posted by OBehave
I was just trying to understand in simplified terms what Gregg was saying just so I can understand better.
As far as all of the various techniques that I have read here,I have tried them all.I tried pushing them fully rearward and could not get it into gear,then I tried to center the Int.Plate with a winch on the release arm,and problem was better but still there although driveable.But after asking you about your version of adjusting,I dropped my lower bellhousing once more and without releasing the lever,I put 2 pieces of .040 thick steel under the H and pushed them forward.The gap that was there before I started was approx. .090 inches. I put it all back together and had NO PROBLEMS. It never shifted that good since I owned the car.The clutch in the car was replaced over 2 years ago before I bought it but there was always issues.The car has been sitting apart for 2 years because I was doing Koni's and springs,motor mount and a bunch of other stuff as well as a complete hydraulic clutch system top to bottom.
I have only put about 50 miles on it since the adjustment but there is a definite feel that makes me believe we got it licked.Thanks Mark, and everyone else for debating and explaining these issues. Ed.
Old 09-12-2008, 03:29 PM
  #142  
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Originally Posted by mark kibort
Well, I was at the shop fixing a crack in the frame where the sway bar mounts attaches and did some measurements for you . Just to confirm the process.

It turns out that my crude measurements of the "H" window of 1.8mm, is actually 1.5mm. So, this means, in some cases, pushing the "H" all the way back will reach the factory manual spec. However, this is not correct for some. In fact, there are several issues that can cause the clutch to drag when these things are pushed all the way back as i have reported earlier.
You said you put in two feeler gauges of .040 each? thats near 2mm. I dont see how that is possible unless the ears are bent or you might have misread them to be .040" when they are actually .40mm. (kidding)

anyway, you did say you ended up with a gap with the two feeler gauges of near .080". thats still way too much. It doesn take much to adjust the clutch intermediate plate, anything will be an improvement by closing the gap. I just estimated mine to be under 1mm and it actually is more like .5 to .75mm. (so is Scots)

I was out again today and the car has never shifted better! Its really great to be able to downshift into 1st without care and toggle between 1st and reverse with ease!

So, confirm the "H" gap to the rear, close it down to under 1mm, say, .5 to .75mm. Remember there is nothing to push the "H"s rearward except the force of the flat springs. If they are moving the "H" back, then clearly the interemediate plate is bad. However if you still have a large visual gap, its too big.

scots is working fine, mine is better than ever and ive been beating on the car for a week now!

mk
Mark,
I put 1-.040" shim under each side of the "H" for a total of 2.
.040" is .001" or .0254mm bigger than 1 mm.
I just got out from under the car and all 3 "H"'s are equally the same gap except now the gap is larger than .040". It is .075" or 1.905mm.So all 3 have gotten larger equally by .035" or .889mm. after roughly 65 miles of average driving,meaning no race type abuse.Funny thing is that it really came without any kind of warning or noise etc.
Ed
Old 09-12-2008, 03:32 PM
  #143  
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Originally Posted by mark kibort
Here you provide two dimensions that I have a hard time believing.
2.2mm starting out and 2.0mm is what you ended up with. maybe there is some variance with the "H" adjusters between years, I dont know. However, the good news is that you were closing the gap slightly and it barely worked. The bad news is that you didnt close the gap enough. Mine is well under 1mm, probabably just under .7mm. It workes create and you can see mine due to the peak hole, that the int. plate moves back via its springs to release the flywheel. No dragging.

I would be curious how the 2.2mm measurement happened, but thats ok. It really doesnt matter. move the "H" adjusters almost until they tough and make the slightest of gaps you can make. that will be enough. Or use a feeler gauge with a .020" number on it.

mk
Dearest Mark,
Kindly refer to post# 142 Thank You.
Old 09-12-2008, 03:40 PM
  #144  
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Originally Posted by GregBBRD
Imagine that! I'm so surprized.

I'm not sure how the workshop manual instructions got so confused. Its not like it is hard to read or interpret!

"The forks of the stop brackets (the "H" pieces) must rest on the stop of the intermediate plate on the flywheel end on both sides. This will produce a gap of 0.7 to 1.0mm or 1.2 to 1.5mm."

Come on guys...that's really clear. There's even a sketch right there, showing what they mean....with the dimensions pointing at the gap.

It's not like this is the first one I've even fussed with....I have literally done hundreds of these things, in the past 20 years. If the gap is too big....the clutch is not going to work. If you have the wrong discs with the wrong intermediate plate...its not going to work. You might be able to make it work for today, but the customer is going to be back tomorrow with a dragging clutch! Keep screwing with it and you will also need new syncros.
Hey Greg any chance I could get a reply to my question in post 125?
Thanks.Ed.
Old 09-12-2008, 03:55 PM
  #145  
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Ed, got it. didnt put 2 and 2 together and understand you were using separate feeler gauges on each side.
so, you adjusted them to near 1mm.

So, if they moved, the "H"'s might be worn, or floating themselves with little friction. did they seem to move easily? remember the only thng to push them back would be the spring of the intermediate plate.

again, i would move them closed if i didnt suspect that they were really weak.
if the gap is greater than 1.5, that is interesting, as was poste by Greg, the max distance in the gap should be 1.5. (i verified this too ) 1.9mm is pretty big Id like to see a picture of that.

If it were me, (close your ears Greg), i would close the gap to .7mm and put a tack weld right on the "H" adjuster and the plate behind it.

a weld could buy you a couple of years of safe operation when the clutch disc wears enough on the inside to not make proper contact. From what i have seen on some pretty old set ups, it might cure the problem for a long long time with little downside risk. But, thats me. Shade tree racer mechanic.

sounds like a legitimate issue with the int. plate. if those adjsusters can move around as you move them with a screwdriver, and its easy with little friction, thats probably the issue.


On the picture below, i would put a tack weld right above the little piece of spiderweb and the H adjuster behind it.

mk


Originally Posted by OBehave
Mark,
I put 1-.040" shim under each side of the "H" for a total of 2.
.040" is .001" or .0254mm bigger than 1 mm.
I just got out from under the car and all 3 "H"'s are equally the same gap except now the gap is larger than .040". It is .075" or 1.905mm.So all 3 have gotten larger equally by .035" or .889mm. after roughly 65 miles of average driving,meaning no race type abuse.Funny thing is that it really came without any kind of warning or noise etc.
Ed
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Old 09-12-2008, 04:46 PM
  #146  
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Concerning the gap at the slave rod, did you check to see if the clutch MC had the proper preload?

Dennis
Old 09-12-2008, 05:00 PM
  #147  
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isnt there a movement spec that shows how far the slave should push? I measure mine at a little over 1". I dont have the exact dimensions, but it works.

That fact that Ed's H adjusters moved just on the pressure of those little flat springs, is not a good sign. however, another fix might be to put a end cap or something on the slave shaft so that the pressure plate is pulled back just a bit further as hacker mentioned. Id be torn on doing that or a quick spot weld.
mk

Originally Posted by Dennis Wilson
Concerning the gap at the slave rod, did you check to see if the clutch MC had the proper preload?

Dennis
Old 09-12-2008, 05:11 PM
  #148  
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Mark,

I wonder if Porsche changed the WSM in 91 to compensate for the wear. The old clutch pedal rod adjustment called for a gap between the rod and master cylinder, whereas the new technique calls for pushing the rod in until the piston stops moving, then compressing the piston one more revolution of the rod. This should move the slave rod forward and reduce or eliminate the gap. Sure beats welding bits on to the rod.

Concerning the H adjusters, I only have experience with single plate clutches. Thank goodness.

Dennis
Old 09-12-2008, 05:15 PM
  #149  
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Originally Posted by mark kibort
Ed, got it. didnt put 2 and 2 together and understand you were using separate feeler gauges on each side.
so, you adjusted them to near 1mm.

So, if they moved, the "H"'s might be worn, or floating themselves with little friction. did they seem to move easily? remember the only thng to push them back would be the spring of the intermediate plate.

again, i would move them closed if i didnt suspect that they were really weak.
if the gap is greater than 1.5, that is interesting, as was poste by Greg, the max distance in the gap should be 1.5. (i verified this too ) 1.9mm is pretty big Id like to see a picture of that.

If it were me, (close your ears Greg), i would close the gap to .7mm and put a tack weld right on the "H" adjuster and the plate behind it.

a weld could buy you a couple of years of safe operation when the clutch disc wears enough on the inside to not make proper contact. From what i have seen on some pretty old set ups, it might cure the problem for a long long time with little downside risk. But, thats me. Shade tree racer mechanic.

sounds like a legitimate issue with the int. plate. if those adjsusters can move around as you move them with a screwdriver, and its easy with little friction, thats probably the issue.


On the picture below, i would put a tack weld right above the little piece of spiderweb and the H adjuster behind it.

mk
Mark:

I'll take that bet. Put me down for a nickel. No welding, no further adjusting, no messing with it. You jack it up and have a tool or even a popsicle stick anywhere near the "axe hole"......you pay.

We're in slightly different worlds. If I welded on a customer's worn out intermediate plate and it screwed up....I'd get to buy him a brand new one when it failed. In my world, if you touch it....you are then responsible forever! Nice thought, but I really have no reason to make someone else's worn out crap....mine. It is different when you are messing around in the garage with you own crap.

Now, if you'd make some little pieces to fit over the ends of the "H" adjuster, on the flywheel side, that acted like shims, so that the "H" piece can't move any more towards the rear.....I'm interested.
Old 09-12-2008, 05:21 PM
  #150  
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You're On!! You're down for a nickel.

Its sealed up with the aluminum cover plate with high temp rtv and thats how it will stay.

anyone else?

Hmmm, a shim on the back side....... not a bad idea either! can i use that popsicle stick? How about drilling a small hole and driving a dowel as a stop gap part?

As far as you giving the shade tree advice, I totally understand. a new Int plate would be the solution, but the fix sure seems easy with a quick spot weld or shim/stop gap modification.

Edit: Here you go. a 1/8th hole and stick a roll pin in the hole! DONE!

mk



Originally Posted by GregBBRD
Mark:

I'll take that bet. Put me down for a nickel. No welding, no further adjusting, no messing with it. You jack it up and have a tool or even a popsicle stick anywhere near the "axe hole"......you pay.

We're in slightly different worlds. If I welded on a customer's worn out intermediate plate and it screwed up....I'd get to buy him a brand new one when it failed. In my world, if you touch it....you are then responsible forever! Nice thought, but I really have no reason to make someone else's worn out crap....mine. It is different when you are messing around in the garage with you own crap.

Now, if you'd make some little pieces to fit over the ends of the "H" adjuster, on the flywheel side, that acted like shims, so that the "H" piece can't move any more towards the rear.....I'm interested.
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