964 clutch options and "while in there" items
 

Well, the time to drop the engine from my 964 Carrera 4 for the first time is here at last. I do not plan to rebuild the engine at this time as, other than some oil weeping, it is a phenomenal powerplant that does not need to be messed with. It still goes faster on the track than its driver is comfortable with, it idles well, etc. Maybe I can even fix the oil weeping while I'm at it, if it's something easy.

Right now I am researching, shopping, and budgeting. There are three basic questions here:

1. Which clutch setup should I get?
2. Should I replace the pressure plate and/or flywheel?
3. What else should I do while the engine is out?

My primary rule whenever I do something on the car is to keep it legal for its PCA Club Racing stock class. I don't race but this seems like a good rule to keep from sliding all the way down the slippery slope. Relating to the flywheel and clutch, rule 1.L says that I can replace the DMF with a single-mass flywheel and that the clutch disk must be the stock diameter (which appears to be 240mm, am I right?). It goes on to suggest a 964 RS flywheel as a suitable replacement.

Options abound. Some are easier to understand than others. The obvious choices are:

a. Stock clutch disk is $176. Pressure plate is $593. DMF is $920. It's possible to just do the clutch disk, but my car has 164,000 miles on it and likely has the original DMF and pressure plate. Dropping the engine is a major chore on the C4. So I'm disinclined to just replace the disk and have to drop it again.

b. Same as (a) but with a sportier clutch disk. Recommendations?

c. Carrera Cup conversion kit is $2,079 plus a $450 performance chip to keep the idle stable. A lot of people say that you lose street drivability going this way. But how much do you lose? Is it harder to drive than with a nearly worn-out clutch disk?

d. Centerforce clutch package from Pelican is $1,180.

e. Patrick Motorsports has all sorts of parts. It looks like the starting point is a LWF at $535 plus conversion kit at $523 plus clutch disk of your choice plus a pressure plate of your choice, either the $1,060 sport/race version or the $598 lightweight/cup version.


Then, the while I'm in there items. Here is my list so far:

i. Replace gaskets on oil temperature switches, breather lid, oil temperature sensor, oil pressure sender, remote temperature sensor, and their 'lid' (perelet's oil leaks & fixes thread recommended items underneath the intake assembly)
ii. Fuel injectors
iii. Clutch master and slave cylinders and slave cylinder hydraulic hose
iv. Ignition wires (anyone have experience with the $169 DIY kit sold by Pelican?)
v. Engine sound pad (or just leave it out?)
vi. Power steering belt (should have done it when I had the pump off to replace the seal where it meets the camshaft)
vii. Distributor belt
viii. A/C belt, which is nearly worn out and totally pointless since the A/C on the car doesn't really work; maybe just pull the A/C out of the car at this point?
ix. Rebuilt alternator
x. Rebuilt starter
xi. Valve adjustment
xii. Strip and refinish valve covers
xiii. Strip and refinish engine cooling fan
xiv. Engine carrier reinforcement
xv. Engine mounts (Euro RS or is there a better option?)
xvi. Transmission mounts (what exactly is required for this?)
xvii. Strip and refinish engine tin
xviii. Heater blower bypass
xix. Clean out the engine bay from all of the years of spilled oil from the times I've removed the filter without puncturing it first, leaked oil from the breather area, road dust, and so on

Anything inexpensive that I have forgotten?


I'm not going to start buying parts or doing any work for a couple of months, but I want to know what I'm in for before I begin. Thanks!

One more option Mid-Weight flywheel kits - Rennlist Discussion Forums

Thanks for the tip! That decides that issue.

And now I am thinking that it's a long winter and I am already removing the engine, so maybe a re-seal or even rebuild is not the worst idea. Does anyone have tips on the bill of materials to disassemble and reassemble the engine? The workshop manual says which parts should always be replaced, and then Pelican sells three gasket kits which appear to possibly (but maybe not, hard to tell) include all of those items. I don't want to buy two of anything if I can help it.

Then I need to find a machine shop qualified to work on the various pieces of the engine. I'd be going at least 600 miles to get to one, I think, so I may as well ask here which shops do a good job for a fair price and are easy to work with remotely by shipping parts and talking on the phone or by e-mail about what is needed.

Slippery slope...but the car deserves it, right? :)

I don't think you exactly need the mid-weight flywheel.

I have a 996 GT3 RS clutch and lightweight flywheel (11lbs?). I do not have a chip. I don't have A/C either. Further the engine has been freshly tuned, ignition, ISV, all good. It takes a minute to balance out the idle when cold, but it hasn't stalled once.

It sounds like you'll have a similar setup to me. If you end up needing a chip to prevent stalling, you get the benefit of the 'optimized' timings.

Is the GT3 setup hard to adapt to the 964 engine and transmission? What parts are required to convert? Clutch, pressure plate, and flywheel or is there more to it? Thanks.

I think the clutch disk on mine is a 996 RS part number but the flywheel in the package is a 964 part and essentially everything else. Perhaps a more knowledgable member can confirm.

I just installed the mid weight setup on my car. It has a more mechanical feel than the old dual mass. No stalling issues but it does take more effort to depress the clutch pedal...not sure why that would be the case but I wish I could easily change the pedal effort.

Regarding the GT3 setup:

The Carrera Cup flywheel/clutch conversion kit that Pelican sells (PEL-FWC-C2C4N) consists of the following parts:

928.102.151.01.M260 flywheel bolt x 9
944.116.080.01.M38 release bearing
950.116.813.30.M157 guide tube
964.102.239.31.M157 flywheel
964.114.143.31.M260 ring gear
964.116.028.90.M38 pressure plate
900.067.103.01.M260 ring gear bolt x 9
996.116.015.32.M38 clutch disc
931.102.111.00.M34 pilot bearing

If you tell Pelican you have a 2007 GT3RS and shop for clutch parts, you will find:

928.102.151.01.M260 flywheel bolt (same)
944.116.080.01.M38 release bearing (same)
964.102.239.31.M894 or .M157 flywheel (same)
950.116.813.30.M157 guide tube (same)
964.114.143.31.M260 ring gear (same)
996.116.027.51.M38 pressure plate (different)
900.067.103.01.M260 ring gear bolt (same)
996.116.015.32.M38 clutch disc (same)
931.102.111.00.M34 pilot bearing (same)

So they really must not be that hard to match up if the only different part is the pressure plate.


Regarding the midweight setup:

I'm glad to hear from someone actually driving with this. Did you notice any difference in throttle response?

All the g50 clutches are interchangeable after about 1990. The lightweight flywheel must be matched to a sprung hub disc and matching TOB,while the DMF one is solid hub(the torsion is taken up by the rubber in the DMF.)but the pressure plates are the same dimensions and interchangeable.The GT3 RS clutch springs are about 30% stiffer than the std 964 one .The 993 standard PP is about 10% stiffer than the 964 and equal or very close to the 964RS one.
I recall reading The clubsport 993 in Europe uses the stock 993 PP but the SMF combo otherwise.
I wouldn,t use a turbo or GT3 PP unless you have a very strong left leg and need the extra clamping power. The std setup can last 100,000 mi so it is usually adequate.
For street use aside from the possible stalling issues with a LWF the biggest annoyance is the gear rattle you hear below about 3000RPM.
Andreas ? something posted a pressure plate list on Rennlist I found several years ago
If upgrading for the street I would use a std 993 replacement set in a 964 ,same disc slightly stiffer PP

After some delay (new garage finally got doors and then it was cold; finally got some heat and maybe even some time to work), the car is up on jack stands and the oil is drained. I pulled the fuel pump fuse to kill the engine before draining the oil, so the fuel lines should not have much or any pressure. Disconnected the battery and started on the engine drop process.

Note on the pressure plate: The 993 Euro RS part number is the same as Pelican sends with the 964 Carrera Cup kit. So that seems like a very reasonable choice.

So here's the question: When I drop the engine, is there any reason to (or not to) remove the heat exchangers first? I'll be working on jack stands and I have an ATV jack to lower the engine. I've removed the heat exchangers a couple times before, so I know it's not hard to do. The question is if it gains (or loses) anything in the engine removal process.

This the kit you are looking at? Its seems very comprehensive

the 993RS used the same dual mass flywheel and clutch as the regular 993s

The 993RS/CS and 993 Cup used the 964RS/Cup single mass flywheel and spring centered clutch that you want to use, My memory is fading but I seem to recall that early 964C4 also used this setup but I could be misremembering.

The exhaust is usually left on for most drops

Bill: Thanks for the response. I'm looking at the equivalent of the Pelican Carrera Cup conversion kit, although from separate parts since there are a couple of options to save some money by getting a different brand from what comes in the kit.

It is indeed comprehensive, but with over 160,000 miles on the car and an unknown history prior to about 140,000 miles I have no shame in replacing more of the clutch mechanism than needed. I'll be doing the clutch slave cylinder and fluid hose and a couple other items while I have the car apart. My 'optional' list runs from new engine mounts up to a total rebuild depending on whether I can figure out how to put the latter on my 1040 Schedule A.

It sounds like the 993 RS pressure plate must work the same with a DMF as with a SMF. I know that the 1989 Carrera 4 was different from the later version but I don't know the exact differences. it certainly could be as you suggested. I have a 1990 so, barring any surprises when I separate the engine and transmission, I ought to have the DMF setup.

How much of the exhaust should be left on? It seems to me that removing the secondary muffler and catalytic converter should provide clearance for the engine to drop, leaving the primary muffler (or in my case the bypass) in the car unless it and the bumper need to come out for clearance.

I'd add the clutch master cylinder too.

Also take a long hard look at the clutch release arm, the bushings tend to go at awkward times and will do a lot of damage when they fail. I replaced mine w/ a 997 GT3Cup part, 997.116.086.90

You can't use the 993RS dual mass parts w/ single mass parts, they are incompatible. You have to go all one or the other. It's possible that they just mislabeled it as RS when it should be RS/CS or Cup, most of these parts have been superseded w/ 997GT3RS parts anyway

Thanks for the tip. Does the pressure plate really change between the SMF and DMF setups? Pelican's item number for the kit is PEL-FWC-C2C4N. The pressure plate included is part 964-116-028-090-M38. The PET lists this as the normal part number for 92- and an alternative part for -91 cars. Or I could be the victim of my own misunderstanding or a catalog error.

Yes, the clutch used w/ the SMF has springs, the one for DMF doesn't
This is a SMF clutch disk from a 993RS/CS
http://forums.pelicanparts.com/uploa...1423000480.jpg

This is a 996DMF setup 964/993 would be similar
http://i275.photobucket.com/albums/j...sclutchkit.jpg

I know that the single-mass flywheel requires a spring-dampened clutch disc while the dual-mass flywheel requires an undampened clutch disc. Can you help me understand the difference in the pressure plate?

You are correct the pressure plate itself is the same in both setups

the 993tt and 997GT3RS have greater clamping force and can be used too

Thanks - I thought I was losing my mind for a moment there. :)

Any experience with those parts? I don't think my little 964 will ever put out such torque as to benefit from greater clamping force than it already has. Or, at least, the cost of modifying the engine to reach that level of torque would make a GT3RS pressure plate a drop in the bucket. But the GT3RS part seems to cost the same or even a few dollars less than the 964 Cup part, so unless we're talking about the pedal effort difference being enough to make my left leg disproportionately hefty, I could just as well go with the upgraded one.

That's the problem with these cars. There are too many possibilities for anyone to have tried them all. Except maybe Bill Verburg. Thanks again for weighing in on this one, Bill. :)

Ari, over Christmas holidays I dropped my engine to do minor here and there. Then right before I put it back I went to adjust valves and discovered that I have broken head bolt (<<<<--- check yours). Minor drop converted to major fun.

Things that you list all make sense. Do allow for s%^&t to happen. I'll do complete writeup once I put car together, here are few notes.

1. Leave heat exchangers on (you can keep whole exhaust):

https://dl.dropboxusercontent.com/u/...d/IMG_0098.jpg

2. To do clutch etc all you need is ATV jack and few floor jacks:
https://dl.dropboxusercontent.com/u/...d/IMG_0168.jpg


you'll have access to pretty much everything except exhaust side, you can do exhaust gaskets etc when you'll put it back in the car.


3. If s%^&t will happen. You'll need engine lift and yoke and more deliberate tools:

https://dl.dropboxusercontent.com/u/...d/IMG_0360.jpg

4. Depending on level of s%^&t you'll end up taking many pieces apart, I ended up here:

https://dl.dropboxusercontent.com/u/...d/IMG_0545.jpg

https://dl.dropboxusercontent.com/u/...d/IMG_0514.jpg

Important notes:
1. Read factory manual 1st
2. See #1
3. You can read internet after you do #1

Measure everything. Compare to factory specs. I have 78K miles on my car, you have 2x more - some things may be worn and need replacement.

Oleg: Thanks. I am definitely allowing for everything to go wrong. I've run a budget for a complete rebuild of the engine and, while I don't know if it's a pill I WANT to swallow, I know that if I have to I CAN swallow it. I adjusted valves not that long ago (while following your other advice to fix numerous oil leaks, although there are a few stragglers, probably from the breather or the through-bolts) and the studs were all okay, but I don't want to make any assumptions and will check everything I have access to.

I didn't have the energy in me to pull off enough junk to access the spark plugs and do a leak-down test while the engine was still warm. So I'll do that when it's cold. The PPI leak-down I had done indicated all signs good except some leakage (12 or 14%) on cylinder #4, which they didn't bother to identify as being through the rings or one of the valves. So I'll be watching for that. It's possible that just being driven for the 4 years since then will have tightened that cylinder up--but equally possible that it's now looser along with its friends and neighbors. So we'll see where the numbers are and where the air is going and decide whether and how far to rebuild.

It appears that you're just doing a top-end rebuild. How did you decide to do that? It seems to me like the top is the expensive half of the rebuild, so if you go that far it is not much more expensive or time-consuming to split the case. But I'm a complete novice and would really like to understand your thought process.

I'm trying to remain positive and conservative at the same time. It probably comes across as passive-aggressive: Just the clutch one day, total overhaul the next. But that's how it goes with a Porsche, it seems.