(Possible) Victim of the Clutch Inspection Chasm

[argiopeweb]

In the process of replacing battery cables in my 924S, I've inadvertently lost the bell housing nut. I remember a faint "tink", and I'm 99% sure that it didn't hit the ground. Magnet has turned up nothing either in or out of the bell housing, dropping the starter and manually turning the engine over has turned up nothing. No sounds, no apparent binding; I have absolutely nothing other than Murphy's Law to say it's in there.

And so, I've turned to tradespace analysis. What I need to know is: What are the potential worst-case consequences of leaving a nut in the clutch housing? It's going to be an absolutely gastly quantity of work to do the 3/4 clutch job necessary, particularly as the car is my daily driver/sole means of motorized transport and has already been down in excess of a week for upgrades/maintenance. But I'm really trying not to let that influence me.

[9FF]

I don't think anyone would advise you to leave it in there and take a chance, it's up to you alone and I feel your pain having gone through a similar issue.

Worst case: damage to flywheel ring gear, starter motor, sensors and sensor pick-ups, clutch. Could damage anything in there basically and the damage could leave you stranded at the roadside.

I would buy/borrow a scope and keep looking and make sure it's not in one of the crevices under the intake manifold first.

[argiopeweb]

Thanks 9FF. Confirms the unfortunate truth. Oh well... I guess I didn't have anything too important planned for this Saturday...

[CatsEyes]

You'd be amazed how much space there is in around there for things to get lost in, other than inside that little hole. A magnet and a mirror together can be helpful.

Good luck!

[mytrplseven]

I feel your pain. I read a lot of posts about covering the holes near the sensors on the 944 when working up there and I put a rag in the hole and then taped over it for good measure. Good thing, too since I did drop a nut while attaching the battery ground cable to the top of the bellhousing. I guess it's possible for a nut that size to fall into the pressure plate, but looking back on the install, I'm not so sure. A dental mirror and flashlight looking into the lower clutch inspection hole might help but I'd do anything short of pulling it apart again to find that little bas---d. Maybe pick the car up and shake it?

[argiopeweb]

In the event that I do end up needing to do this, is is normally necessary to have to remove the pressure plate? If so, this project is going to be even more delayed while I wait to get a clutch alignment tool shipped in (unless I overnight it, of course... Hmm...)

[mikepellegrini]

Whether or not you need to remove the pressure plate is determined by where/when you find what fell in there.

The clutch alignment tool is available in your nearest auto parts store. If I remember correctly, it interchanges with a Ford tool. You just need the same diameter and number of splines.

Clutch Alignment Tool (Spline count = 23; Pilot diameter = 14.9 mm; Spline diameter = 25.4 mm) 911, C2/4, 993 (1987-98), 911/C2/993 Turbo, 944/944 Turbo/968 (I'm assuming a 924S is the same).

[Porsche37]

What! No one has hears of high pressure air? If you want it out throttle a little air in the bottom inspection hole or from the top speed sensor fitting. Better than a whole weekend dropping the transmission.

[89-944NA]

I too have felt that pain of a lost fastener in the bellhousing....have someone rotate the engine while you look in the inspection hole.

Had I done this, I would have seen the bolt trapped in the side of the pressure plate (one of those openings in the side of the pp where the spring strap connects the pp housing to the friction surface), and used a pair of needle nose pliers to reach in and removed it. Since I didn't try this, I pulled everything involved in doing a turbo clutch, only to find it in a place that was easily accessable from the inspection hole.

[89-944NA]

Originally Posted by mikepellegrini

Whether or not you need to remove the pressure plate is determined by where/when you find what fell in there.

The clutch alignment tool is available in your nearest auto parts store. If I remember correctly, it interchanges with a Ford tool. You just need the same diameter and number of splines.

Clutch Alignment Tool (Spline count = 23; Pilot diameter = 14.9 mm; Spline diameter = 25.4 mm) 911, C2/4, 993 (1987-98), 911/C2/993 Turbo, 944/944 Turbo/968 (I'm assuming a 924S is the same).

Yes, it's a FORD alignment tool, available at any auto parts store.

[89-944NA]

Originally Posted by Porsche37

What! No one has hears of high pressure air? If you want it out throttle a little air in the bottom inspection hole or from the top speed sensor fitting. Better than a whole weekend dropping the transmission.

Air didn't work in my case, since the bolt was trapped by the spring strap.

[argiopeweb]

Dredging this back up seemed more sensible than a new thread... I've gotten off everything down to the flywheel and haven't found my nut (you'll recall it might not have been in there in the first place). Is it possible it could actually be behind the flywheel? Since I'm already there and will be ordering new bolts for the pressure plate, are there any gotchas that would make me not want to take it off?

[John_AZ]

wow...

If you are ready to remove the flywheel, you need a high quality 10mm 12 point/triple square/cheesehead/XZN wrench.

The flywheel bolts are a one time item--they stretch.

You should replace the RMS-rear main seal. Elring is best. Do a search on the proper installation technique and depth of seal in the block.
TechnoDuck has just posted he will rent you the Porsche OEM seal press.

Polish the flywheel to get rid of any burn marks. If it is scored deeply--have it machined.

Since you cannot find the nut, I have found a couple washers/rings/nuts in the canyon to the left of the TDC view hole by the orange pen. I use a Harbor Freight expandable magnet wand to probe the area.



GL
John

[argiopeweb]

Flywheel bolt replacement is why I mentioned I'm already ordering pressure plate bolts (apparently I neglected to finish that thought).

RMS, flywheel, clutch and pressure plate were all replaced in August 2009 and have ~12k miles on them. Will I still need to do RMS?

I've played around in that cavern you pointed out quite a bit. I'll give it another go with the magner and see what I find.

[John_AZ]

I think there will be a chorus of "DO IT" in the background, but probably NO unless you see a path of oil down the pan.

Replace the pilot bearing.

GL
John

[argiopeweb]

hehe... The more I talk to y'all the more things I find I need to do. If I don't find that nut on the engine in the morning tomorrow, I'll go ahead and grab an RMS and pilot bearing and just get them done while I have the flywheel off.

Thanks for the continued help.

[John_AZ]

I would not change the RMS unless you see the oil path.

3 years and low mileage ......leave it alone.

John

[argiopeweb]

Sounds like a plan. I'll hold off my order till after I get the flywheel off tomorrow evening (assuming it's necessary).

[CatsEyes]

Keep at it with that magnet on the bendable pole!

You may also find your local electronics-type store has small mirrors on bendable sticks: that can help too. You might spot something that's in too tight for the wand to reach.