LeMans71

I have made a deal to purchase an '89 S2 (about 90K miles) and have a couple of questions for you 944 vets:

-There is some "slack" in the driveline on this car, both on accel and decel. The mechanic who did the PPI says he thinks it's probably "looseness" in the original rubber-centered clutch, but I wonder about ring/pinion wear. There is no noise associated with it, just a noticeable delay in the transfer of power from engine to rear wheel(s). Thoughts?

-It is not an LSD transaxle, but I'd like it to be. Depending on the answer to my first question, I may be looking for an LSD trans to swap in, or to rebuild the original trans, possibly with an LSD carrier if I can find one. (I'd like to keep it "stock" for autocross purposes, too - so I'm talking about an original Porsche LSD.) So - other than part # and carrier, is there a difference between the LSD/non-LSD trans housings/internals? Can a LSD carrier be swapped into a non-LSD housing? If I were to buy an entire LSD trans, which years/models would be compatible (i.e., differences between NA, Turbo, 16-valve transaxles, and years?).

I'm excited about the car - my first Porsche. It needs some immediate maintenance (belts and rollers, chain tensioner, etc.), and some that can be done a bit later, but I did my homework and got a PPI, and all that has been factored into the price. Thanks in advance for your help.

Scott

JakeS2

Hi Scott!
Congrats on your new car. The loosness might be from the original clutch which is the so-called rubber-duck. Transmissions on these are pretty reliable if taken proper care (you know, gearbox oil change etc...)..

The LSD is a bit of q question. The original one these car tend to have not as sophiticated as recent LSD units. What I am talking here is that people are selling LSD trannies with $2k but with $2k you can get a good 2nd hand tranny PLUS quaife differential. Now quaife is whole new ball game as it's a TorSen unit, not based of friction plates. If you do clutch job you need to take out the transmission ; well it's not such a big operation to put in an aftemarket LSD unit then..

Sorry to say but only transmissions that fit your S2 are from S2 or 968 series. Well of course anything from the 944 family bolts right in but the gear ratios of f.ex 951 (944 turbo) won't work at optimal level with your car (your "beef" is the low-mid torque, turbo and 944S are higher revving engines).

LeMans71

Thanks, Jarko - the car needs some love, it's been shuffled around a lot in its life so far, but hopefully now it will be home.

I'm hoping that it is the clutch - even with minimal maintenance, I can't imagine a ring/pinion going bad after only 90K. Thanks very much for the transaxle info - I hadn't considered the different gear ratios, but that makes a lot of sense - big difference between 150 lb-ft of torque in an NA vs. 210 lb-ft in an S2. I'm aware of the Quaife and some other LSD units and will look into those - I was hoping for a Porsche unit to keep the car legal for Stock class autocrossing - don't know about PCA, but in SCCA an aftermarket diff would bump you up in class (to Modified, I think). I'm an autoX newbie, anyway, so I probably won't need to even worry about having LSD for a couple more seasons - if I can solve the driveline lash issue with a new clutch I'll take my time and research the LSD question further.

Thanks,
Scott

rmconner80

I bet it needs a new clutch. I got an S in November, my first Porsche, and it had the same thing. Kind of a "clunk". If you get the clunk, that is the metal safety tabs on the clutch disc. The rubber center breaks down and disconnects, leaving those metal tabs to spin and catch on acceleration or deceleration. This is a "limp home" type safety thing... it is stressful to the transmission to continue to drive it in this state.

Really, if you are on the original clutch and you are going to do events... that clutch disc will likely break down in the first couple of minutes anyway. The rubber is 19 years old! In other words, you need to factor a spring centered clutch disc into your budget.

LeMans71

rm, I believe you are correct. Picked up the car last night and drove it home, and I'm quite confident that it is the clutch. I definitely heard/felt the 'clunk' you are referring to. So, I'll add "new clutch" to my list of required maintenance, and scratch off "transaxle rebuild" for the time being. Thanks! Any advice regarding other components I should replace while I've got the driveline pulled apart? Clutch actuation seems fine, just wondering if I can count on the master/slave cylinder, etc. lasting the life of a second clutch.

Thanks,
Scott

rmconner80

From what I have heard, the slave and master cylinder usually go before the clutch. So if you are on the originals, I say replace. This is however something you may want to do after or before the clutch job. If I'm not mistaken, they're pretty much independent in terms of work and getting to them.

Clutch replacement is a bear but you can do it.

I am by no means an expert, but when you do the clutch, I suggest:

1) Rear Main Seal replacement (also known as a flywheel seal or rear crank seal)
2) New clutch disc, pressure plate, and throwout bearing
3) All new flywheel bolts / pressure plate bolts
4) Resurface the flywheel (factory specs are in the FSM)
5) Have the shop balance or "match" the pressure plate / clutch / flywheel assmembly. I didn't; now I have a irritating vibration in the driveline at 2900 - 3300 rpms
6) New pilot bearing, throwout guide tube, cross shaft, & release lever shaft bearings
7) new cv axle bolts (don't reuse the old ones; use blue loctite to secure)
8) Optional - If there is slop in the shifter, rebuild shift lever while you've got it out (replace sound absorber too if you like - it will be in shreds)
9) Optional - rubber exhaust hangers will probably be fried by now, so new ones may be a good idea.

Inspect the cv boots for tears. Optional repack or rebuild if needed.

yes, that's a lot of parts, it's not cheap, and it's perhaps excessive "while you are in there" mentality. However, as you'll soon find, you do not want to have to do this ever again on your car, much less a couple months later if something you had opportunity to replace new goes bad.

LeMans71

rm, thank you very much - your reply will be great guidance for my planning/parts buying.

Another quick question - what's a good source for the service manuals? In my research so far, it looks like the most affordable option is the reprints sold by 944Online, @ $145 for the set (minus the Turbo volume). Any other good options that you know of? I understand the manuals are available on CD, but I haven't found a source, and I have an iMac so I don't know if the CDs would be compatible (??? - I'm not very computer savvy).

Thanks,
Scott

L8_apex

LeMans -

Let me also welcome you to the S2 house. Thank you for rescuing the can and giving it a good home!

I've not dealt with the LSD/clutch/transaxle issues you're exploring - so I can't offer any help or comment.

I do know that for the S2, you'll likely want the Turbo Volume of the 944 Manual. The S2 has a lot of mechanical similarities with the '44 Turbo (e.g, suspension, brakes, etc.). The pre-'89 944 information in the Manual for these areas I have found to be generally informative, but will not match up with your car.

LeMans71

Bob, thanks for the welcome. It does feel kind of like a rescue - the guy I bought the car from had bought it to "flip" it (with the intent of charging the expected "Porsche tax"), and it's been through several auctions, etc., etc. After some negotiation/education about the need for immediate maintenance, and the consequences of ongoing neglect, a more appropriate price was agreed upon. It has a few cosmetic challenges (front seat seams pulling apart, and clear coat burn-through on top of the passenger rear fender flare), but I think underneath it all it's a good solid car that deserves a stable home after 20 years.

Pretty sure the problem I described is the clutch, as the symptoms are exactly as Jarko and RM describe above. A replacement is scheduled, after I finish the belts and cam chain tensioner - might as well earn all my 944 mechanic merit badges right off the bat!!!

Great point about the Turbo supplement - I guess it's logical that it would be helpful, since the car is basically a Turbo with the 3.0L 16V swapped in! I hadn't thought that one through, but I will make sure that I get a copy of that volume, too.

Thanks,
Scott