Clutch adjustment on 2 plate'ers
09-25-2008, 06:46 PM
#181
Team Owner
OB remember the throw out bearing is spinning all the time at ening speed, so they usually either rust out or fail due to a lack of lubricant, now if someone could put a zerk fitting or some other system on the TOB and have a service of lubing it every oil change then my guess there would be a whole lot less failures.
By the way the water get into the clutch/TOB/pilot bearing from the top where the clutch pivots on the bell housing. Plug this hole before you wash the engine
By the way the water get into the clutch/TOB/pilot bearing from the top where the clutch pivots on the bell housing. Plug this hole before you wash the engine
09-26-2008, 09:52 AM
#182
Former Vendor
OB remember the throw out bearing is spinning all the time at ening speed, so they usually either rust out or fail due to a lack of lubricant, now if someone could put a zerk fitting or some other system on the TOB and have a service of lubing it every oil change then my guess there would be a whole lot less failures.
By the way the water get into the clutch/TOB/pilot bearing from the top where the clutch pivots on the bell housing. Plug this hole before you wash the engine
By the way the water get into the clutch/TOB/pilot bearing from the top where the clutch pivots on the bell housing. Plug this hole before you wash the engine
Good idea on covering that gaping hole in the upper bellhousing.
Thanks.Ed
10-06-2008, 02:16 AM
#183
Rennlist Member
Thread Starter
well, 2 races later and a bunch of street miles, its still holding. However your read on the problem is dead on. Scots is moving like "obehave's" we had to adjust his after every single session. We think it was his very chattery clutch.(very grabby), but after shifting duringt the races, the forces, vibrations or just the pressure plate flexing in the springs, moved his very loose adjusters.
Ill take that nickel in 5 pennies when i see you in LA sometime.
I think the 1/8" roll pin like i show might be a way to fix this for a while. certainly it will keep it from moving.
mk
Ill take that nickel in 5 pennies when i see you in LA sometime.
I think the 1/8" roll pin like i show might be a way to fix this for a while. certainly it will keep it from moving.
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.
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.
10-06-2008, 06:56 PM
#184
Rennlist Member
Thread Starter
You would have laughed at the race. Scot's car has the same problem you have. Those adjusters are just too loose. we had to lift the car and adjust after ever session. Thankfully, i make those peek hole hatches to make adjustment a snap. however, it moved in the race. Mine was fine, but Scots was moving. I have done some more testing of a "Pinning" idea on my old intermediate plate. a 1/8" hole with a roll pin solves the problem. easy to do, through our inspection and adjustment hole and will be very perminant. when adjusted perfectly, it shifts like a dream. under racing conditions, there is enough torque/flex in the adjustment springs (flat springs) that it forces the adjusters to move back and there is residual drag on the pressure plate and disc. if pinned at .75mm, it will stop that from happening. You have heard of pinning the rear end, now its pinning the intermediate "H" plates!
[QUOTE=OBehave;5845569]
[QUOTE=OBehave;5845569]
10-07-2008, 01:49 PM
#185
Rennlist Member
Thread Starter
I bought some 1/8" roll pins and a drift and we are going to attack Scots moving "H" adjusters.
I see no reason why this is not a perminant fix that will hold. I have a dummy Intermediate plate that ive tested on and just the drilling alone stiffens the friction coupling of the "H" adjuster. the pin will work fine i imagine. I also found a long drill bit that can drill the hole without removing the bell housing (a big, no, HUGE pain with the devek msds headers)
I have a picture of where the hole is going to go, and what it will look like. Hey, we could even make it like a porken tool, where there is a bunch of holes drilled and some type of screw.............wait...... maybe ill just drill and tap a long screw hole in there. Nah, thats too fancy.
Mk
I see no reason why this is not a perminant fix that will hold. I have a dummy Intermediate plate that ive tested on and just the drilling alone stiffens the friction coupling of the "H" adjuster. the pin will work fine i imagine. I also found a long drill bit that can drill the hole without removing the bell housing (a big, no, HUGE pain with the devek msds headers)
I have a picture of where the hole is going to go, and what it will look like. Hey, we could even make it like a porken tool, where there is a bunch of holes drilled and some type of screw.............wait...... maybe ill just drill and tap a long screw hole in there
. Nah, thats too fancy.Mk
10-11-2008, 01:29 PM
#186
Rennlist Member
Thread Starter
Looks like an easy perninant fix.
1. adjust the H adjusters through the hatch in the bell housing (or remove it)
2. drill hole through H near rivet axis with long drill bit, or normal drill bit if bell housing cover is off
3 put roll pin in hole
4 use drift to hammer roll pin through hole
5. (Optional) dremel off excess roll pin
Note: both a 1/8" drill bit and 1/8" roll pin and 3/32" version will work.
mk
1. adjust the H adjusters through the hatch in the bell housing (or remove it)
2. drill hole through H near rivet axis with long drill bit, or normal drill bit if bell housing cover is off
3 put roll pin in hole
4 use drift to hammer roll pin through hole
5. (Optional) dremel off excess roll pin
Note: both a 1/8" drill bit and 1/8" roll pin and 3/32" version will work.
mk
10-12-2008, 05:23 PM
#187
Rennlist Member
Thread Starter
Greg, no nickel???
In the end, it looks like these intermediate plates can get loose, and that is a big issue. the spring is strong enough to move the H adjusters around if it is really loose , and you have some vibration as a catalyst. Mine survived the higher pressure, pressure plate, so that is not a factor as the adjustment done before the Sears Point race has held even through a double race weekend at Laguna and a bunch of street driving.
we are going to "Pin" Scots this week and i have no doubts it is going to hold fine.
mk
In the end, it looks like these intermediate plates can get loose, and that is a big issue. the spring is strong enough to move the H adjusters around if it is really loose , and you have some vibration as a catalyst. Mine survived the higher pressure, pressure plate, so that is not a factor as the adjustment done before the Sears Point race has held even through a double race weekend at Laguna and a bunch of street driving.
we are going to "Pin" Scots this week and i have no doubts it is going to hold fine.
mk
10-17-2008, 01:58 AM
#188
Rennlist Member
Thread Starter
We just "Pinned" Scot's intermediate plate today. Looks like it worked like a charm, and the "H" adjusters are not going to move anymore.
04-27-2009, 08:46 PM
#189
Rennlist Member
Thread Starter
clutch intermediate plate still working well on the Holbert car (even with the new high pressure plate) Great after 12 race days on the new engine!
Scot had a new clutch put in and I advised the shop how to adjust the intermediate plate. sure, it ran fine to the track, but after a few sessions, it shifted notchy and was tough to get into 1st or reverse. fortunately, we had the little window he cut. (and Greg, we have cleaned up the bell housing hole )
Of course, the gap was near 2mm. I moved it toward 1mm on all 3 "H" tabs and he was good to go. the car shifted well and no problems getting it into gear the rest of the weekend, including after the race.
the drilled intermediate plate didnt work out too well, because the drilling was hard and only on once side of the H adjuster. If my adjusters become lose like Scots, ill adjust the intermediate plate and then disassemble and hit each one with a mig welder and re-assemble!
mk
Scot had a new clutch put in and I advised the shop how to adjust the intermediate plate. sure, it ran fine to the track, but after a few sessions, it shifted notchy and was tough to get into 1st or reverse. fortunately, we had the little window he cut. (and Greg, we have cleaned up the bell housing hole
)Of course, the gap was near 2mm. I moved it toward 1mm on all 3 "H" tabs and he was good to go. the car shifted well and no problems getting it into gear the rest of the weekend, including after the race.
the drilled intermediate plate didnt work out too well, because the drilling was hard and only on once side of the H adjuster. If my adjusters become lose like Scots, ill adjust the intermediate plate and then disassemble and hit each one with a mig welder and re-assemble!
mk
06-27-2009, 10:09 PM
#190
Instructor
I also have the dreaded "difficult clutch release problem" ('83 928S) which I attempted to cure by the - move them all the way back -method several years ago.
Have spent quite a bit of time reading this thread and would like to thank mainly Mark, but also the others (who actually contributed something) for helping me to finally understand what is going on with this double disk mechanism.
I plan on making a large, neat inspection hole in bell housing, reassemble, depress and hold clutch down, then adjust the H's for maximum free play. This will eliminate the objections that were raised re the Devek method, and should also compensate for possible variable wear issues on different cars.
Perhaps someone could explain why Porsche designed this system with such small tolerances. Why not design the slave cylinder to move 1 1/4" instead of 1" and design the intermediate plate to move back 3mm instead of 1mm?
Have spent quite a bit of time reading this thread and would like to thank mainly Mark, but also the others (who actually contributed something) for helping me to finally understand what is going on with this double disk mechanism.
I plan on making a large, neat inspection hole in bell housing, reassemble, depress and hold clutch down, then adjust the H's for maximum free play. This will eliminate the objections that were raised re the Devek method, and should also compensate for possible variable wear issues on different cars.
Perhaps someone could explain why Porsche designed this system with such small tolerances. Why not design the slave cylinder to move 1 1/4" instead of 1" and design the intermediate plate to move back 3mm instead of 1mm?
06-28-2009, 01:47 PM
#191
Drifting
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Marton
06-28-2009, 04:09 PM
#192
Instructor
Finally solved
I Had my doubts, but decided to extend the travel of the clutch by removing the rubber bumper and a small amount of metal from the contact points as suggested before doing the cutout modification and adjustment.
Had to lengthen the pushrod with a threaded bushing because it was on its last threads on pedal lever, but made the adjustment and was sure to remove as much play as prudent.
To my surprise, the car now shifts without ANY resistance. Remember, I had my H's adjusted all the way back, so as Mark stated, the rear disk was contacting the pressure plate. The small amount of extra movement gained was enough to free the rear disk.
Marton, I was thinking the same thing about having the slave sleeved, although I don't think 20% would be needed. If someone can supply the diameters of the master and clutch bores, I could calculate the difference needed to extend the throw the extra 1/4" need to solve the problem thoroughly. I don't think the slave extends to it full extent normally.
Also, if anyone knows where sleeving can be ordered (I remember reading about a source in Hemmings years ago) would appreciate a post.
Had to lengthen the pushrod with a threaded bushing because it was on its last threads on pedal lever, but made the adjustment and was sure to remove as much play as prudent.
To my surprise, the car now shifts without ANY resistance. Remember, I had my H's adjusted all the way back, so as Mark stated, the rear disk was contacting the pressure plate. The small amount of extra movement gained was enough to free the rear disk.
Marton, I was thinking the same thing about having the slave sleeved, although I don't think 20% would be needed. If someone can supply the diameters of the master and clutch bores, I could calculate the difference needed to extend the throw the extra 1/4" need to solve the problem thoroughly. I don't think the slave extends to it full extent normally.
Also, if anyone knows where sleeving can be ordered (I remember reading about a source in Hemmings years ago) would appreciate a post.
06-28-2009, 05:58 PM
#193
Rennlist Member
Thread Starter
keep in mind, you totally reduce the flat springs on the intermediate plate to "non-functional" when the adjusters are all the way back. you might not have the quick release for speedy shfiting, and a possiblity of of clutch drag on the front discs as the springs loose most all of there tension. what you did is a good idea to make sure it always releases, but you should close up the gap a little to get some function out of the flat springs of the intermediate plate. It pulls the intermediate plate back from the flywheel and front disc when the pressue plate is pulled on. The entire exersize here is to find that small gap that allows the int pate to retreat off the front disc and flywheel and also not keep in contact with the pressure plate and disc.
Interesting mod though. Nice job.
Interesting mod though. Nice job.
I Had my doubts, but decided to extend the travel of the clutch by removing the rubber bumper and a small amount of metal from the contact points as suggested before doing the cutout modification and adjustment.
Had to lengthen the pushrod with a threaded bushing because it was on its last threads on pedal lever, but made the adjustment and was sure to remove as much play as prudent.
To my surprise, the car now shifts without ANY resistance. Remember, I had my H's adjusted all the way back, so as Mark stated, the rear disk was contacting the pressure plate. The small amount of extra movement gained was enough to free the rear disk.
Marton, I was thinking the same thing about having the slave sleeved, although I don't think 20% would be needed. If someone can supply the diameters of the master and clutch bores, I could calculate the difference needed to extend the throw the extra 1/4" need to solve the problem thoroughly. I don't think the slave extends to it full extent normally.
Also, if anyone knows where sleeving can be ordered (I remember reading about a source in Hemmings years ago) would appreciate a post.
Had to lengthen the pushrod with a threaded bushing because it was on its last threads on pedal lever, but made the adjustment and was sure to remove as much play as prudent.
To my surprise, the car now shifts without ANY resistance. Remember, I had my H's adjusted all the way back, so as Mark stated, the rear disk was contacting the pressure plate. The small amount of extra movement gained was enough to free the rear disk.
Marton, I was thinking the same thing about having the slave sleeved, although I don't think 20% would be needed. If someone can supply the diameters of the master and clutch bores, I could calculate the difference needed to extend the throw the extra 1/4" need to solve the problem thoroughly. I don't think the slave extends to it full extent normally.
Also, if anyone knows where sleeving can be ordered (I remember reading about a source in Hemmings years ago) would appreciate a post.
05-12-2015, 04:12 AM
#194
Its better than before, even with the stock clutch. Its not going anywhere! Understanding what all the components do, helped in setting it up. It took a while , but it all makes sense now. they dont move, unless they (the H adjusters) are loose. since they are not loose, there is nothing acting on the floating intermediate plate adjusters except the spring pressure, which is minimal. I dont think anyone took the time to really understand these little gysmos. the manual is right, and the 1mm gap is what is needed so that you alow for 1mm of release of the front disc off the flywheel and whatever that leaves you with for the rear disc and pressure plate. more than 1mm starts to press on the rear disc and pressure plate and makes them drag against each other spinning the drive shaft so you cant get the car in gear, unless you turn it off.
Its not black magic like it started out looking like. with the cut out, you can actually see the pressure plate move back from its own spring presure when you press the clutch pedal in. If it is too close, you run the risk of it dragging. however, too big of a gap, and it positions the intermediate plate too close to the pressure plate.
That is what I've seen, and I bet JV had this issue as well as what scot is going to see tomorrow.
mk
Its not black magic like it started out looking like. with the cut out, you can actually see the pressure plate move back from its own spring presure when you press the clutch pedal in. If it is too close, you run the risk of it dragging. however, too big of a gap, and it positions the intermediate plate too close to the pressure plate.
That is what I've seen, and I bet JV had this issue as well as what scot is going to see tomorrow.
mk
1. I can test the action of the IP by pushing down on the disc towards flywheel side - movement should be 1mm according to you and WSM.
2. I can bolt the whole pack up and see if it looks ok.
Of course I might screw the setting up when putting the pack, but I will give it a try. Thanks for the detailed post.
Christian
05-12-2015, 04:26 AM
#195
Rennlist Member
Thread Starter
Mark, I think I will give this a go with the clutch out of the car.
1. I can test the action of the IP by pushing down on the disc towards flywheel side - movement should be 1mm according to you and WSM.
2. I can bolt the whole pack up and see if it looks ok.
Of course I might screw the setting up when putting the pack, but I will give it a try. Thanks for the detailed post.
Christian
1. I can test the action of the IP by pushing down on the disc towards flywheel side - movement should be 1mm according to you and WSM.
2. I can bolt the whole pack up and see if it looks ok.
Of course I might screw the setting up when putting the pack, but I will give it a try. Thanks for the detailed post.
Christian
On the bench, the INT plate is spring loaded to the rear contact point of the H adjusters. when its assembled , you only want it to move 1mm or so. the H adjusters can move near .5" , so it will be a crap shoot.
just do it the right way and there will be no doubt that you will get the adjustment right.