924Board.org

headstrong2740 · Joined: 29 Apr 2010 Posts: 111 Location: Moline IL

Ok guys its been a while since i have been on here.

I have isolated the random death to a relay by my battary... and so far have been un able ot figure why it keeps tripping... still searching it.

But the issue i have at hand is getting troublesome and worrys me.

I have a massive vibration coming from the car while i am driving.... When it revs up to about 3000 rpms it is very noticable and then goes away around 3600 and comes back at 4800 and stays... and its does it regardless of speed.

Ill describe the sound i get as this.... ever hear a heat shield rattle bad? Sounds like that.. but the heat shields are not on the car... so i know its not that

When i have it in park and rev the motor it still does it as well.

I reved it several times while being under it (some one else pushes pedal)
and it at first seeme to come from the flywheel (flexplate). I pulled hte starter and rotated the motor and looked at both wheels and seem to be fine...

upon further investigation you can really feel the vibration coming from the torq tube.... is it possible my bearings have gone bad?

Any on else have this issue and am i looking at a torq tube rebuild? What bearing are recommended? I saw a rebuild thread and they guy had his stolen but was told there was two different types you could use, but one created more drag so i would figure the less drag ones would be better.. but who knows... let me know what you guys think and if you think im over looking at something else
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1987 924s "Enzo"
2002 1.8t VW Passat
http://porsche924resto.shutterfly.com/ - follow the progress of "Enzo"

headstrong2740 · Joined: 29 Apr 2010 Posts: 111 Location: Moline IL

I do know that USUALLY when a bearing goes bad its more of a whine

Also what is that rubber wheel disc thingy that bolts up to the flexplate? You know... the one that has the rubber center (massive) with the shaft sticking out it...

What is it for?

I remember it was starting to show a little dry cracking in it when i was putting the motor back in.

Im wondering if this is causing my probelm as well... .. thought i would add that info as well..

Let me know if anyone else has/had this issue and what your thoughts are
_________________
1987 924s "Enzo"
2002 1.8t VW Passat
http://porsche924resto.shutterfly.com/ - follow the progress of "Enzo"

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

You've probably lost the rubber-centered portion of your clutch disc. Though, I don't know if they vibrate when they fail so much as they clunk.

You could try putting the car in gear, engine off and rear wheels blocked and have a friend try and turn the motor (make sure to turn it the proper direction!) while you watch the clutch disc area to see if the rubber is moving around.

You could simply have blown motor mounts as well.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

headstrong2740 · Joined: 29 Apr 2010 Posts: 111 Location: Moline IL

the motor mounts do not appear to have any issues. The motor has no play in it if i try to rock it by hand and barely moves on start up or under a load from flicking the throttle

Im starting to lean more and more toward the bearings in the torq tube because While driving i have been paying very close attention to the noise and im noticing a bearing whine under all the vibration noise i get

If the bearing has worked its way back on the shaft that would explain the hard start issue i have form time to time... the motor cranks then hits a spot were it feels like the engine stops turning for less than a second and then contiunes one full rotation and does it again before firing off

I think that with the bearing back farther.. there is more play in the shaft and would allow for some minor binding while trying to turn over...

Correct me if im wrong... (I HAVE AN AUTO) But the shaft in the torq tube turns continuously with the motor at all times since the transmission is in the rear

so this makes me more certain that alot of my issues i have are tied into the same issue

Any one know of a good place to find a dampner (the rubber disk)? Also where can the bearings be purchased from? Part numbers would be nice... not sure if the 6006ZB number is correct that i found elsewhere
_________________
1987 924s "Enzo"
2002 1.8t VW Passat
http://porsche924resto.shutterfly.com/ - follow the progress of "Enzo"

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

On the "stops while cranking" check your speed/ref sensors and their wiring.

The damper plates are still available new at $1000+. Some people have swapped in a manual disc and pressure plate (likely a bit hard on the gearbox).

Torque tube rebuild instructions are HERE.

Spec to check motor mount height (lack of engine rocking is immaterial) is HERE.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

headstrong2740 · Joined: 29 Apr 2010 Posts: 111 Location: Moline IL

According to the motor mount thing.. i should be feeling a vibration or knock on startup and shut down and a hard vibration at idle... i dont have any of these symptoms... its only at 3000+ RPM's

Ill still check them, but again i do not think this is my issue...

As for the manual clutch swap? how does that work since i dont quite understand how that would swap out the damper... The just bolt in the pressure plate, clutch, and bearing and just dont hook it up since it automatic?
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1987 924s "Enzo"
2002 1.8t VW Passat
http://porsche924resto.shutterfly.com/ - follow the progress of "Enzo"

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

The damper connects the crank via the flywheel to the driveshaft. A clutch and pressure plate (no throwout bearing or actuating mechanism) does the same, albeit without the benefit of all that rubber, which is designed to isolate the tranny from engine vibrations.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

headstrong2740 · Joined: 29 Apr 2010 Posts: 111 Location: Moline IL

so basically your saying i could eliminate the rubber and attach the flywheel and such (using a ford mustang (mid 80's) clutch kit non 5.0) and would replace that... then i just need to rebuild the TORQ tube and go from there...

The car will be down this winter for a week or so anyway for all new suspension so this will get tacked on as well... as well as new brakes and wheel bearings and possibly CV Shafts.. but we will see on those.

Ill check mounts as well too and replace if needed
_________________
1987 924s "Enzo"
2002 1.8t VW Passat
http://porsche924resto.shutterfly.com/ - follow the progress of "Enzo"

headstrong2740 · Joined: 29 Apr 2010 Posts: 111 Location: Moline IL

Im probably going to go the route od swapping in clutch parts for the Rubber.. so any suggestions on the right clutch pressure plate and such i need to replace the rubber damper would help...

i am trying to figure that out my self reading through several threads baout the different clutches that can be used... and i got to say,... its confusing at best

LOL

_________________
1987 924s "Enzo"
2002 1.8t VW Passat
http://porsche924resto.shutterfly.com/ - follow the progress of "Enzo"