Noise and "rough" running w and w/o clutch pressed

[wwdwgs]

Hello, everyone.
Symptom - when I start my 924S ('87 w/ 74K Mi), I feel "extra" noise and shaking (feels like rough idling).
When I press the clutch (in Neutral), the noise and vibration lessen a bit in a couple of seconds.
This happens when the engine is cold. I didn't expreriment on the warm engine.
There is no visible vibration seen on drivetrain, engine or exhaust system.
I think that the source comes from the ball bearings inside the torque tube.

Prior work was done in last 3-4 years: Engine mounts (fluid filled, but aftermarket), Timing and Balance Belts and associated rollers, WP, Transaxle with new seals (except driveshaft seal) and fresh gear oil (GL-4).

The other components are "as is" - I didn't replace or repair any other parts of the drivetrain or the eingine. Clutch could be original or replaced by previous owner. The driveshaft doesn't have a play, which happens with deteriorated rubber clutch.

What are your related experieces, thougths and suggestions about my problem?

And, Happy New Year to everyone.

[944 Ecology]

The test for bad bearings in the torque is as follows:

1) Remove two bolts holding the coupler and move back towards the transaxle input shaft, enough that the torque tube driveshaft and the transaxle are decoupled.

2) Have a friend depress the clutch pedal (alternatively, use a broomstick to hold the clutch pedal depressed.)

3) The drive shaft should now be free to rotate. Rotate the driveshaft and listen for noisy or dry bearings. It helps to be in a very quiet place (e.g. a garage with the doors closed). Use a mechanics stethoscope to help isolate the noise.

[wwdwgs]

I see...Thanks, George.

[walfreyydo]

I also suspect torque tube bearings.

If confirmed bad, look up Bud Hoffman on facebook, he rebuilds them.

You can also try the DIY route, which I did (in hindsight I would have purchased a rebuilt unit instead)

[wwdwgs]

walfreyydo,
I had watched several videos of how these torque tubes are rebuilt.
If the tube will be out, then the clutch and transaxle input shaft seal are good candidates for servicing.
Maybe, the exhaust gaskets, too.
Updated shifter?, if I'll have enough funds.
Fun....
Thank you guys, for support and Happy New Year to all!!!!

[walfreyydo]

If you are dropping the torque tube then yes, you'll want to consider doing a lot of while you are in there tasks, including rear main seal, clutch, pilot bearing, throwout bearing, clutch fork bearing, which is what I did when I did my TT bearing rebuild.

Additionally, since youll be dropping the rear suspension, you should also consider if now is the time to upgrade or re-index your torsion bar, and upgrade or update all your rear end bushings (torsion tube carrier bushings, spring plate bushings, rear sway bushings). Which is also what I did.

[Monkey Wrench]

if I buy bearings I just go to a bearing retailer then i can pick the brand.

if you have one out look for the bearing number, these are standard parts, not proprietary parts. most bearings are metric. In a Porsche they will be for sure. if someone else has a bearing lying around, they could have a look, it is almost always on the bearing itself. avoid made in China ones.

Porsche never made the bearings, they are just a re-seller with a high price tag.

Trivia, but Volvo was originally a bearing manufacturer,
and I don't speak Swedish but evidently Volvo means "I roll"

[wwdwgs]

MW,
Thanks. Volvo rolled too far and ended up in China.

[Monkey Wrench]

Agree, Ive owned a 122 several 240's and 740's, Great cars, they dint change everythign every year. that made service work a lot more practical.

Then I went to a tech session with Volvo when they came out with the 850. it was loaded with unnecessary wiring and gizmos that in my opinion don't need to be a part of any car I own. so I gave up at that point on anything newer. I think a lot of makers transitioned at the same time to a planned obsolescence ideal. I own 5 cars all with ashtrays and no airbags so I'm golden ;-)
the rest can go tot he dealer and pay to have them change oil because most can't do even that by themselves. The Porsha 944 isn't so bad, Id rather it not have a sunroof or AC or seta heaters other stuff I don't need. Volvo also included that garbage around the same date.

Mine is an early 85 so it probably has less unnecessary crap. now every car needs a computer screen, I get enough screen time without having one staring me in the face when I'm driving too.


it sounds like you isolated it by listening , when the car is rolling in gear the shaft is turning if you take it out of gear I suspect the clutch and driveshaft are disconnected from both ends so maybe you can hear it slowing down or stopping. I suspect when its disconnected at both ends it will roll to a stop.

a think I've done is to jack up the back wheels and drive it like that and peer underneath , there are some obvious safety concerns with doing this . like don't let the back wheels get you and make sure it isn't going to fall off the jack stands and drive over you.

but it did help me understand things a bit better when i had driveshaft issues.

another thing I found helpful just jack up one back wheel a little block the car up safely now you can rotate that tire with your foot or get a helper to twist it back and forth engine in gear.

then you can feel things like play in CV joints etc. the freeplay of the wheel equals all the play which is stacked up, splines, hubs gears bearings diff, etc. I feel it is a very quick way to assess how worn out a car is. If you had a bearing that was completely bunned , like for example it it lost its rollers , then you might see the driveshaft move weirdly, or similar. I wonder if you can grab that coupling and shake it to detect any slop? I've never had mine all apart, something to look foreword to , If I pull the transaxle I think Id like to pull the tank and recoat it ,POR 15 makes a good kit for that. it requires turning the tank all about to disperse it. the tank won't come out easily with the transaxle installed.
ones later than my early 85 went to a plastic tank. ( I think) if yours does have a metal tank it could be worth removing the sending unit to see in there? then decide if the tank is ok as is or maybe yours is plastic.

I've owned cars where the throw-out bearing got noisy then it would make noises when the clutch is depressed. I'm suspecting mine has a broken rubber mounted clutch plate , Ithnk there are aftermarket ones, I dont wanto rplace it with another porsche rubber mounted one if I can find a way around that.

the previous owner said it made a clunk going into second, it could be something else like synchromesh issues.. Ill have to fix it enough to drive it then i can assess more. a while back someone posted info comparing the Porsche 944 axle shafts to ones from I think it was a VW van and found them interchangeable.. it seemed like if I change the CV joints I may as well just change the whole axles.. you might check prices or see if yours have a lot of freeplay.. You can also take them apart and grease them, careful because the orientation of parts does matter it may affect its balance. If you are pulling the transaxle you are going in there anyway.. so its a chance to spend more money ;-) likely you can find Chinese parts that will work or spend a bit more , on Porsche ones, they are likely better quality.


what I equate all this to is the swing of a hammer, if you have several sources of play int he drivetrain , then ever tine you take your foot off the gas or step on it, that freeplay reverses, with more slop its' like giving a hammer a longer swing and then you have a harder impact.. more free play means the parts wear out faster. If its all good and tight it's also more comfortable especially when you need to drive at 5 miles an hour with traffic.



my early 85 944 leaked its fuel then when parked I think it dumped any fuel left near the filter, 6 months later. rotten rubber hoses. a leaking gas tank can be very dangerous. had a friend who tripped up on his trouble light when he was draining the fuel in a bucket, it changed his life a lot , serious burns.. not fun, so be careful about leaking fuel and maybe consider looking around for things like that too.

with the fuel lines it might add up and there is a option to convert it to other types of parts like the brightly colored anodized aluminum fittings, If it's a really show car Id go with OEM or have them made up. I checked locally and no one had a hydraulic crimper tool for the metric lines, the hydraulics shop that I often deal with wouldn't help with that.. there is a member here who can make OEM style ones up.. a place that does sell the aluminum fittings said its fine to convert them over and you can use marine grade hose, I guess its a choice to make.

[wwdwgs]

MW,
the tank is metal, I cleaned it through the sender unit hole.
Your clutch could be original (read - with the rubber center). The rubber degrades and there is a slop when the clutch is engaged with a metal thud. The slop can be checked by rotating the drive shaft inside the transaxle bell nousing - remove the trepezoid-shaped plastic access cover, reach in and twist the shaft. My other Porsche had about 90 degree play. The new replacement clutches are spring-loaded - no one makes them with the rubber centers.
The drive shaft is on four ball bearings inside the torque tube, so, even if one ball bearing has a play, the others will keep it "tight".

[Monkey Wrench]

Thanks for that info. my whole restoration got delayed a lot just because everything else I own broke down , such is life. I've accumulated enough parts to have a go at things so plan to get it going then Ill be where you are pulling the transaxle to do the clutch etc.

I think , for me, it is likely what the previous owner described as a "clunk in second" may well be the clutch rubber issue but I'd like to actually drive it so I know if the tranny is ok otherwise.
Im a millwright and I fix all sorts of machines , but not cars, as a profession so changing bearings is stuff that doesn't really upset me.

It makes sense to change all 4 and Id' look for a recognizable brand of bearing. I'm seeing a lot of equipment failures created by Chinese bearings breaking down way before their time is due. If you look at them physically they seem fine and some manufacturers may be ok but its so hard to tell.

I remember my dad telling me he was in a bearing maker facility and they had a system where they drop the balls , and the bounce and have to land in a small hole. if they miss the hole they get rejected as it is assumed they are imperfect and rejected by quality control.

I just bought some rotors for a Volvo they came with outer races as the bearings are incorporated, but they are made in China rotors, but not the cheapest ones. slotted ones. Ill knock the races out and install ones that come in a set from a familiar brand.

Id normally change tapered bearings as a set, so I was surprised they had races pre- installed but then I figured maybe the factory needed the races to spin them on, to machine the rotors accurately.
shortly after mine was made (88) volvo went to a hub design where it uses one large bearing and a big nut rather than the traditional castellated nut with cotter pin.

I came to the realization that this also means that the rotor can have runout caused by things lie dirt between the rotor and its mating face. The older style did not have that mating face so it is actually probably better but the rotors cost more to make.

way back the country of origin meant a lot, ANY older machine in made in Germany seemed to be very well made, I did a lot of work with German Heidelberg printing presses and they are the very best of quality. extremely precision very good quality castings. I went there, very impressive facility. The castings are all made by them, in Germany

These days I don't know , the quality control seems to be less related to country of origin and since a lot of vendors with recognizable brands went to China in the race to the bottom, basing quality upon branding and country of origin may not always be a very reliable way to make sound judgments.

Sorry I did stray pretty far off topic.

sometimes if you order bearings it may refer to the Porsche part number but not give info on the bearing brand.. so then its a crapshoot, likely Porsche chooses a decent brand.

If you call up a bearing retailer with the actual bearing number or look online you can probably find the same bearing ( dimensionally) made by quite a number of manufacturers
All I'm saying ( in too many words ;-)
is you do have choices on the brand of bearing you choose. Because they are so hard to get to , its a consideration.

[wwdwgs]

MW,
This is how the "rubber" clutch looks like without rubber. Those three "tongues" move axially and hit corresponding "tongues", thus making a metal clanking noise. You can drive with the clutch in such a condition, you just have to be very smooth in engaging and disengaging the clutch and smooth with the gas pedal, too.

[wwdwgs]

MW,
for your viewing pleasure: DRIVESHAFT PLAY

[Monkey Wrench]

thanks for the video. I'm sure mine is bad too, and I do expect it'll be in my future to change it. rubber simply has a shelf life and it expired

I will verify this is the case with mine. Ill need to remove the starter to lock the ring gear to change the belts so Ill check closer that when do get there, a bit cold out now.

I guess by the time you get in there to access it no one would want to put the same disc back but I have to wonder how the car would feel if it were simply welded solid, I know usually clutches have the springs instead.

it was once possible to re-line them but finding places to do that is becoming harder. the shop I used got closed , likely due to asbestos issues.

I did get them to turn some drums for my old Volvo and they fitted new material to my shoes, since they had removed some from the drum they put thicker material and they also arced them properly. that's a way t get thicker pads in there.. neat trick I thought.

I liked their work so much I took a spare set of drums and old shoes, and got them to make me a spare set the same way. He would do clutches too, a lot of their work was commercial trucks.

I did see the friction material alone somewhere and wondered about riveting new stuff on. Probably possible, but likely a job best avoided. I think if I could rivet them
then turning them true isn't so hard. It is a bit unusual these days to need to do that sort of thing.


I was not previously aware that if I ordered a new OEM one, it would not be rubber, Do the replacement OEM ones have springs? is it a Fitchtel and Sachs? or Sachs? I've seen them used in Volvos and it sounds European, or possibly Germán made. I think its common for most automakers to buy the clutches from a maker of such.
Maybe this one was actually made by Porsche? or a special factory order perhaps.

has anyone successfully cross referenced to the clutch of some other car that could be a more reasonably priced alternative and a direct fit?

this page shows some similar ones but I do not see anything that fits a early 85.

https://www.sachsperformance.com/en/clutch-kit-and-performance-clutch-sachs-performance-navigator

Pelican doesn't ship to Canada. I could renew my passport to drive 20 mins across the line and open a US postal box to support them, I'm not knocking buying parts from Pelican. The 16V ones seem more common in the aftermarket , these older ones, less so.

the racers surely must have already worked this out somehow.

I will test my car beforre I go ripping all that apart, but I can see this as being really anoying when driving at 5 miles an hour where the car is constantly changing from "being driven, to driving" in that situation its constantly changing and the clutch would be bothersome and annoying I think.. once you are going down the road or oin a highway I suspect its less of a bother because than its not reversing like that.

its basically acting like a hammer , pounding on gears, CV joints etc. and of course the gentle driving would help not destroy things too quickly. the springs or rubber are probably there to reduce the "hammer blow", "shock load" is a better term.

[wwdwgs]

MW.
Crossreferenced clutches - a disk from ford bronco 2 can be fitted (riveted with spacers)... Balancing could be an issue.
early 944 is the same as "late" 924S (1987-1988)
I drove with deteriorated rubber clutch for a couple of months - smoothness is the key. The Sachs clutch kit was about 488.99 when I bought it a couple of years ago.

[Monkey Wrench]

summitt racing seems to have a range of them for the bronco II - 23 splines, the price seems to jump up a lot if I search for 944 clutches but here are some terms Im not so familiar with stage 1 stage 2 and such, maybe it refers to how much has been done to make more HP

yes, when I had my Volvo motor balanced they included the flywheel along with he crank, I think pistons and rods were balanced separately I cant; remember if I sent the clutch and pressure plate along with the other parts for balancing. it was a new F and S one. the disk isn't coupled to the crank obviously but that whole pressure plate is bolted to the flywheel so its probably a part of the rotating weight of the crank, in essence.

but I guess if you go swapping out the flywheel then the balance is lost. Its likely initially balanced with the crank in the factory.

I kept mine heavy because I'm not racing and enjoy the weight. I sent the parts in and they did the balancing , it wasn't that much and I felt it was well worthwhile after as it sounded way better at the higher revs.. That car has a driveshaft with 3 u-joints, I shortened it about a foot to install an overdrive so had that balanced as a unit as well. the way the torque tube is, it's probably best left alone. Ive heard lots of stories where people have unknowingly pulled out the driveshaft and put it back in some other arrangement, then to find it vibrated later.

maybe there is benefit in paint marking the splines to get the coupling or torque tube back in the same orientation in case it was all factory balanced as a unit? it may not matter much, that balancing will be separate anyway.. the parts that disenguage are their own assembly. so any parts that turn wiht the crank are part of the crank's balance and any parts that turn wiht the driveshaft are a separate entity and the disk might just be part of the driveshaft's balance.. I might be a little off but the pressure plate assembly bolts to the flywheel , I think


a while back someone posted a link to a video, it was a German guy who explained that the axle shafts can be put back incorrectly and it would affect balance, He obviously knew his stuff, what he said made sense, and my take was it would still work if you got that wrong and some may not realize it affected anything

If its just about tracking the orientation its likely best not to change it because that only requires being a bit perceptive and making some marks.. Ill normally use a centerpunch and a paint marker as well, so then they can't get washed off..

if there is a correct, and a wrong way the correct way wouldn't really be any more labor. The thing is if you don't mark stuff or know it matters , then then once its apart you wont know where it was , then potentially the balance gets lost, how much of it matters, with reference to the torque tube etc, I'm not entirely sure of all that..

what you paid seems within reason. I don't really intend to try to increase performance in my 944 Most likely just keep it stock.

I guess the racing clutches might need more pedal pressure and what I'd really want is basically just what's stock and normal. too heavy may just amount to a back-ache in traffic.

the linings are riveted on but where would the spacers go? was it to basically make the friction material itself thicker? something to do with the offset of the throwout bearing carrier maybe?

Im ok doing a little machining, my lathe at home is only 9" but the one at work has a larger swing so I could spin the disk if that was needed. my brother just bought a 12 foot long monster size lathe.
I assume if I can get it for $500-ish, then It's not really worth trying to customize it. if its a lot more then maybe it is. im seeing some with prices a lot higher.

I think without other mods its best to trust that the factory engineers thought out the ratio of spring pressure and found a decent happy place. too heavy is probably like buying shoes that are too big and hoping bigger feet will make you run faster ;-)

[wwdwgs]

MW,
forget about stage 1-2-3, you need stage 0 )))) Simple.
This is how the bronco/944 clutch looks - with "bean-shaped" spacers affixed with 3 rivets:

[Monkey Wrench]

did you need to modify the bronco II one to make it work? I see the riveted bean shaped spacers , I don't get whey they need to be there.

[Monkey Wrench]

I think this is the right one in Pelican's stuff.. for my early 85 non turbo 8 valve

https://www.pelicanparts.com/More_Info/95111691100.htm?pn=951-116-911-00-M38
892 US dollars I guess,, the OEM one seems to be a whopping 2 grand.. OUCH ! with transition to Canuck bucks that's 25 % more than I paid for the whole car lol..

this one also seems right $635.49 at auto atlanta
SACHS CLUTCH REPAIR KIT
R94411691100 - Replacement/Accessory

the second one is also Sachs, but has 6 springs , 3 sizes, maybe the different springs , I'm not sure if the different springs prevent resonation or perhaps as they are compressed more, the tension is increased..

yes Ill probably stay at stage 0 ;-)

[wwdwgs]

MW,
Try Rock "oto".