thats a good point! there might be a little cusion that is provided during up and downshifts that insulates the transmission from the instataneous forces of shifting and downshifting maybe this is why anderson has toasted two transmissions recently.

mk

 

More details to follow....

 

I wanted to bump this thread and get some more ideas and see if you guys have some answers for the questions to follow.

Ive started to collect parts from a few different earlier cars. I have a brand new 86 intermediate plate if i decide to upgrade to a SPEC dual disc and possibly an aluminum flywheel. This is the expensive option and i am still not sure i will install the NEW intermediate plate and may just resell it. The cheap option is basically the entire clutch assembly from an 84 Euro including the flywheel, bellhousing cover, arm, mid plate, pressure plate, disc's and slave cylinder. This is the cheap option being thats its used but maybe what i use to install as an exploratory setup and if i like it then i may just leave it and sell the current GTS setup, or upgrade it further and buy an aluminum flywheel, and spec stage 2 clutch kit and install the new mid plate and have all brand new stuff.

I have a couple questions about the components though and what will work. Apparently the clutch disc's and PP's are pretty much interchangeable from 80-86. The flywheel and midplate however seem to be another story. I had thought i could use the 84 flywheel and just press on an S4 automatic timing ring onto it. But if the 84 flywheel is anything like the 90 flywheel, the teeth are cast into the wheel and cannot be removed. Being that they have a different number of teeth this could prove to be a problem and i may need a different flywheel. I assume one from an 80-82 that had no ring on it. But if i have to buy another flywheel i may just buy an aluminum one and call it a day.

The other issue i have is with the midplate. The new 86 plate has the starter ring on it so i assume thats fine for me, but is it?

From what ive learned thus far, I will need to swap the following from the 84 into my car to get the DD setup to work.

1) Flywheel with 60 tooth S4 timing ring
a) aluminum version from Carl, case closed $530
b) 80-82 flywheel + S4 auto timing ring $100-$200?
c) 84 Euro flywheel as is (doubtful) or 84 flywheel with different timing ring (if they can be swapped?)

2) 84 lower clutch cover, why is this cover different from an S4 cover?

3) 84 clutch slave cylinder (Still not sure why i need to change slaves?)

4) GTS clutch arm (Already in the car, apparently it can be used with a DD)

5) 80-86 clutch kit with T/O bearing, discs and PP

6) intermediate plate with a starter ring (a few options here)
a) new 86 mid plate
b) used 84 mid plate (Should be the same as above correct? just used)
c) or do i need an 80-82 mid plate, if so why? whats different?

7) intermediate drive shaft (I think they never changed, so mine should be good)

8) intermediate shaft tube
a) original spec is the plastic tube
b) later GTS metal tube (This should work correct, isnt this preferred?)

9) pilot bearing (these are the same, no change needed)

10) ........

I think that pretty much covers every part from the end of the engine to the front of the torque tube.

I guess I would like to turn this thread into a how to, for doing a dual disc conversion. There is some information out there, but there are differences with early clutch setup's such as 80-82 and 83-86. I wasnt aware of what years to look for so maybe we can figure this out once and for all.

I would like to hear from those that have done the conversion or those that are familiar with the earlier DD clutch setup's. Ive never seen one so I could use some answers.

Thanks in advance.

PS: I am looking for an S4 timing ring, if you have one, or know someone that has one laying around, please let me know.

 

You need an 85/86 flywheel to press on the 87+ timing ring from an automatic flywheel.

The 84 will require shimming and welding the timing ring. Not ideal unless you know someone who will do it.

I've not done the conversion, but will be interested in one of your intermediate plate if you stay with a single disc system.

 

I was looking at Stan's thread and found the following

2) Apparently the 90 lower clutch cover can still be used, but there still seems to be some debate on this

3) The 90 Slave cylinder should be fine if i either cut down my rod, or i would think i can use the stock rod from the 84 slave with the 90 cylinder itself. This eliminates the need to crack open the line. So thats good.

4) I think Louie said that the latest clutch arm is too big and interferes with the dual disc pressure plate

I guess i will have everything so i can just kinda play with it like Legos and see what fits and what works. I need to buy some new PP to flywheel bolts and need to read up on adjusting the early clutches. I guess you can adjust the mid plate, i will crack open the WSM.

As for flywheels, is the 84 Euro the same as the 85/86? It appears that the 84-86 Euro had the same flywheel, and it too had a timing ring. So maybe an 84 US and ROW are different flywheels. I dont know, maybe someone can clarify. I think its a possibility because Carl lists a 100 tooth timing ring for 85/86 US and 84-86 Euro, any ideas?

 

I dont know how close the 84 flywheel is compared to the 85 US, but what i can tell you is that 928intl sent me a 85 flywheel and 87 timing ring already attached and spot welded. the rest of the stuff was 82 . old bell housing, 84 used intermediate plate, new 84 clutch set, and the 82 slave cylinder. this way, you can mount the starter directly to the bell housing. pretty convenient.

mk

 

Is the starter gear attached to the intermediate plate on the 82?

I think one type of intermediate plate doesn't have the starter ring, maybe its a 78-79.

What did you pay for the 85 plate with S4 timing ring on it?

 

The starter ring is attached.

 

So what's the difference between 80-82 intermediate plates and 83-86 intermediate plates? or is there none?

Clutch kits are apparently the same, but flywheels are different, at least US 85/86 is different from earlier versions. Is that because of the timing ring and the engine management changed?

 

I had the intermediate plate up in my attic from a clutch change on my 84 many years ago. (when i was into changing everything, good or bad). glad i did, as now those things are pretty expensive.

the flywheel with the timing ring was about $400 if i remember correctly.

mk

 

If anyone has a 5spd flywheel for sale, please let me know and I'll take it off your hands.
Thanks,
Kevin

 

UPDATE:

I found a complete dual disc setup from an 84 Euro (THANKS LESLIE!) and will be installing that shortly after making a few modifications.

I was very anxious to weigh the new items and got the flywheel, clutch's, mid plate, pressure plate and throw out bearing and release arm put together and on the scale and came out with 37 lbs!

Very happy with this, I think I will stick with the factory flywheel and not bother with the lighter aluminum version which is 5 lbs lighter. I wanted to get to the 35lb target of 1 lbs of rotating mass per every 100 lbs of the car. I am within 2 so will stick with this. If i ever want to dump some more money into the car I will look for Carl's aluminum flywheel but since the stock steel version meets my goal, i am sticking with that.

I will make notes on what other changes need to be made. I am hopeful that only the slave cylinder rod needs to be changed so i wont have to break into the clutch hydraulics. We will see. There are also a few other items that may or may not need to be swapped and i will document those in this thread or another.

 

Hey, so where's the follow up here? How'd it go?

Trying to recall whether my '83 Euro should be sporting single or dual disc. Is there a VIN cutoff?

 

howd it go.......DAMMIT!

i got it all together, had all the parts ready.......and sold the damn car!

but i still strongly believe in the concept and the next GT that i buy will have thic clutch mod done as my first or second mod behind an x-pipe.

accumulating all the parts is a PITA though, mid plates are hard to find, although they are STILL available new from Porsche but are about $800. The mid plate is the one part thats tough to find, clutch kits are all over the place and the flywheel i would suggest buying from Carl as it is a real PITA to collect the stuff to make the hybrid flywheel that i ended up with. Carl's is lighter too by 5lb which would give you a 32lb weight as opposed to the 51 of the factory stuff.

 

Finding the neccesary parts is not all that hard - both 928 International and us at 928 Motorsports have conversion kits that will provide everything you need.