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The S2 and S3 Clutches have 100 teeth on the intermediate plate. This clutches can't easily converted to later one disc solutions and are really expensive as Greg pointed out.
Getting the teeth for the injection trigger and the starter ring gear was a real challenge!
And, as you say, expensive.
The "first" flywheel cost me over $10,000 with engineering, programming, and prototyping.
And we still had some issues with the ring gear that had to be solved....
Early cars, < 86 need the development of the suppliers most, pressure plate and intermediate plate were long nla, before this the release bearing and Porsche is very slow in changing this situation.
So, having payable solutions is life saving for rough cars.
To all 928 clutch developers:
Here's some pictures of a one of the clutches from one of our custom/flywheel packages with 5,000 miles on it.
This is my 4th "iteration" of a clutch for a 928 which will hold the torque of my biggest engines and still be super smooth.
This clutch was combined with my custom flywheel/T/O bearing mount/and custom clutch short shaft, behind a very healthy 5.9 liter street driven stroker (zero track miles.)
At this rate of wear, it will take 15,000 miles just to get all 4 friction surfaces broken in.
Probably the "last" clutch any high performance/regular 928 will ever need.
I think this is your target...make a clutch/flywheel/T/O bearing/T/O bearing mount/input shaft/all associated hardware, clutch lines, etc. that is butter smooth, bulletproof, holds over 800ft.lbs., and cheaper.
Let me know if you need any help.
Always will to lend a hand.
Close-up of clutch friction surface after 5,000 miles. Less than 50% broken in. Entire clutch surface of one disc, after 5,000 miles. Less than 50% broken in. Intermediate plate of clutch, after 5,000 miles. Can barely tell the difference from brand new.
My first observation of that minimal wear could be a a tribute to the driver. Let my son drive it if you really want to check durability! My second observation is why is the clutch out at 5000 miles?
My first observation of that minimal wear could be a a tribute to the driver. Let my son drive it if you really want to check durability! My second observation is why is the clutch out at 5000 miles?
"Younger" manual transmission drivers are generally harder on both clutches, transmissions, and sometimes engines.
I know I certainly was....
It's part of the "learning curve."
We test/inspect all the pieces we make, so others don't have to do this. This clutch was removed for a through and detailed inspection and replaced with an identical unit, so we had ample time to do this inspection.
Because it was deemed to still be in virtually brand new condition, yet could not be resold as new, various pieces of it were used in our single disc clutch development program.
This is just one piece of the equation we use to make highly functional and reliable pieces, for 928's.
"Younger" manual transmission drivers are generally harder on both clutches, transmissions, and sometimes engines.
I know I certainly was....
It's part of the "learning curve."
We test/inspect all the pieces we make, so others don't have to do this. This clutch was removed for a through and detailed inspection and replaced with an identical unit, so we had ample time to do this inspection.
Because it was deemed to still be in virtually brand new condition, yet could not be resold as new, various pieces of it were used in our single disc clutch development program.
This is just one piece of the equation we use to make highly functional and reliable pieces, for 928's.
Sound like field testing on customers to me. That's OK so long as they expect it and are willing to participate.
No-one want a car in the shop that doesn't have to be there, no-one want's there car in the shop if it doesn't have to be there.
I'm calling BS on this this one. Not sure we're getting the whole story. Sound like narrative to me.
Last edited by icsamerica; 02-03-2023 at 02:49 PM.
Sound like field testing on customers to me. That's OK so long as they expect it and are willing to participate.
No-one want a car in the shop that doesn't have to be there, no-one want's there car in the shop if it doesn't have to be there.
I'm calling BS on this this one. Not sure we're getting the whole story. Sound like narrative to me.
I believe this was the clutch from the monster Stroker motor car that Greg recently finished. They were doing suspension and other component development on it and taking things apart after X # of track hours to check wear, adjust valving etc. If that's this clutch, the customer was fully aware and working closely with Greg to make the car 100% for it's use case.
I believe this was the clutch from the monster Stroker motor car that Greg recently finished. They were doing suspension and other component development on it and taking things apart after X # of track hours to check wear, adjust valving etc. If that's this clutch, the customer was fully aware and working closely with Greg to make the car 100% for it's use case.
That wear pattern may indicate the disk may not be sitting flat and is not wearing evenly. I think after 5000 miles it should be worn evenly when using an organic disc. That's not a feature, it may be a bug. And it's a'part so there was a problem. What exactly needs to be inspected if all is working well? In any case I'm sure GB will figure it out.
This thread is getting a bit off track, It's a call to collaboration for a different type of product and solution. Open source and collaborative. Lower cost and effective. I'd appreciate some focus and less thread pollution.
Last edited by icsamerica; 02-03-2023 at 03:03 PM.
We need a list of tasks and deliverables.
Then people can contribute within those bounds.
I’m willing to contribute since I will be in this clutch area soon enough. I have some decent measuring tools and some parts laying around.
I believe this was the clutch from the monster Stroker motor car that Greg recently finished. They were doing suspension and other component development on it and taking things apart after X # of track hours to check wear, adjust valving etc. If that's this clutch, the customer was fully aware and working closely with Greg to make the car 100% for it's use case.
Actually, this clutch is out of Jim Corenman's 5.9 liter GT.
Jim was very much involved in the design of this clutch (and did a large percentage of the prototyping), he received the very first clutch and associated prototype flywheel, input shaft, T/O bearing (and other pieces.)
Since Jim lives in the FAR Northwest and we were trying to write clutch installation instructions, he decided to not drive 2,000 miles to my shop, but rather to "swap out" the clutch at his house and give me some feedback about removal and installation.
I sent him a completely new clutch/associated pieces, so I could have this one back, for inspection.
That wear pattern may indicate the disk may not be sitting flat and is not wearing evenly. I think after 5000 miles it should be worn evenly when using an organic disc. That's not a feature, it may be a bug. And it's a'part so there was a problem. What exactly needs to be inspected if all is working well? In any case I'm sure GB will figure it out.
This thread is getting a bit off track, It's a call to collaboration for a different type of product and solution. Open source and collaborative. Lower cost and effective. I'd appreciate some focus and less thread pollution.
I certainly did not make any the clutch pieces and the engineers at Tilton, when they inspected this clutch, thought that all the pieces were exemplary.
Perhaps Tilton Engineering could use some of your expert advice....805-688-2353.
In terms of "thread pollution", everything I've posted is to help with your clutch development and help you define your "target" (I even mentioned that I would be willing to offer any help I could, in post #18).
I've already mentioned and am certain that cheaper and better clutches (than stock or my own), would be extremely well received, in the 928 community.
I've reread the entire thread and would submit that the "thread pollution" seems to be completely coming/solely from you, at your continual attempts to attack me and my proven products....
This thread is getting a bit off track, It's a call to collaboration for a different type of product and solution. Open source and collaborative. Lower cost and effective. I'd appreciate some focus and less thread pollution.
For the record, the first derogatory comment in this thread was from you when you said Greg had a "narrative" and "that we weren't getting the whole story".
There's no reason Greg should be excluded from this collaborative effort even if what we're trying to do here is different from his offering, as he may have valuable insight and experience to contribute.
If you would just leave your closing paragraph or last sentences off your posts, these threads wouldn't degarade like they do. I'll leave it at that and we can get back to discussing clutches.
We need a list of tasks and deliverables.
Then people can contribute within those bounds.
I’m willing to contribute since I will be in this clutch area soon enough. I have some decent measuring tools and some parts laying around.
Early stages, At this point I could use...
Flywheels for re-drillng, I have an early one en-route, a late flywheel in any condition would be helpful
Bell housing, Early and late for EZK trigger alignment, I have an early one coming but could use a lower cover to mock up with as well.
Intermediate shaft and clamp
Someone familiar with Solidworks to make the trigger wheels and new flywheels
Someone with a sympathetic ear for low production projects at a flywheel manufacturer, I already reached out to Findanza, I've used many of their items in the past with good results.
Someone with a lathe and some experience to redrill OE flywheels would be very helpful.
Someone with an early CIS or Ljetronic 928 (no trigger wheel) to do some field testing to start.
Wanna help DM me. I'm willing to pay for parts / shipping. I expect nothing for free but would appreciate anything offered parts, time or technical expertise.
I believe this was the clutch from the monster Stroker motor car that Greg recently finished. They were doing suspension and other component development on it and taking things apart after X # of track hours to check wear, adjust valving etc. If that's this clutch, the customer was fully aware and working closely with Greg to make the car 100% for it's use case.
The first derogatory action was to use this thread as a basis to advertise a different product with a different level of service that's completely unrelated to open source development and collaboration. (post 12)
01-30-2023, 05:14 PM
