dcmelik

87 S4 auto US left-drive version. I have the bell housing off and I noticed that the coupler bolt (pinch bolt?) allen head is facing upward. I *could* get an allen wrench on it, but I'd like to torque it to spec (59-66 foot-pounds) and have the bolt head facing downard. Is this is the one where if I release it, the TT snaps back?

Will hand cranking the engine at the crankshaft bolt accomplish this? Or must something else be done . . . Thanks in advance.

David Cmelik
87 S4 auto "indischrot"
01 986 5sp "seal grey metallic"
00 BMW 323i black on red

Ed Scherer

That'll work. A few months ago when I did mine, though, I just blipped the starter and got lucky on the first try.

Mrmerlin

Hi you need a 27 mm deep sockt to turn the crankshaft ONLY turn the crank in the direction of rotation IE facing the engine turn clockwise, if the pinch bolt is facing up put a mark on the crank and turn it till the mark is opposite then you should have the pinch bolt facing the correct way, also look for an orange dust near the clamping collar this indicates the shaft has been moving in its splines and if there are any marks on the pinch bolt it should be replaced I torqued my bolt to 66 ft lb book recommended up from the 61, before you loosen the collar bolt look carefully at the flex plate see if it looks like the 3 fingers of the plate are bowed towards the flywheel, this is a quick indication of a problem of the flex plate moving forward

Mrmerlin

And of course you could try to blip it with the starter, to save time put a mark on the opposite side of the crank pulley so you see your results from the top

dcmelik

Thank you mrmerlin and ed for answering my question about the coupler/pinch bolt on the drive shaft re: flexplate inspection. Car is buttoned back up. Here are my findings.

The flexplate showed visible distortion before release. Driveshaft splines showing before release: 9 mm. Driveshaft splines showing after release: 4 mm. No more distortion showing on the flexplate after release.

I think I helped myself here and, more importantly, you all helped me save an engine block. For now.

Many thanks.

David Cmelik
87 928 S4 "indischrot"
01 986 5 sp "seal grey metallic"
00 BMW 323i black on red

Mrmerlin

UH,glad you got things put back together But........ did you check end float on the crankshaft, this is done by prying on the flywheel and seeing how much the crank moves forwards and backwards, this is part of the reason to release the clamp on the driveshaft ,what did you torque the clamp bolt to?did you pry the crank all the way back and then tighten the clamp? Also the limits are new bearings .110 to.312mm wear limit is .40mm if you have a digital vernier caliper open to .40mm then swap over the readout to inches if you dont have any feeler gauges or better still a dial indicator this is preferred

dcmelik

No, I followed the instructions here:

http://members.rennlist.com/v1uhoh/9...earticleTH.pdf

which does not discuss prying the crank all the way back before tightening the clamp. I do not understand the following: "Also the limits are new bearings .110 to .312 mm wear limit is .40 mm . . . "

I used a ruler and measured 9 mm of spline showing and, when I released the pinch bolt, now 4 mm are showing. Sheepishly, I admit I did not torque the pinch bolt using a torque wrench (a big no-no to purists) but I did apply what I considered to be 60 pounds of pressure on a one foot bar that extended my Allen wrench. The reason for this is sheer laziness and perhaps I will pay dearly for it.

But my torque wrench is toast after having used it foolishly for a breaker bar in another 928's past life. I have not yet replaced it. I will have to get another one and, the way I see it, I will be checking this quite frequently (a good friend here in Iowa says he checks it every 3-4 months and his is a daily driver). Next time I check this, I will use a torque wrench and get the torque figures exactly.

If anything, I exceeded 66 foot-pounds. Is it possible to over-tighten? I don't know. In previous write-ups, Constantine indicates that tests do not indicate wisdom of over tightening by ten percent to try and stop the forward migration.

David Cmelik
87 928 S4 auto "indischrot"
01 986 5sp "seal grey metallic"
00 BMW 323i black on red

Earl Gillstrom

David,

Do the "Loctite Fix" and you won't have to worry about Thrust Bearing Failure. http://members.rennlist.com/captearlg/loctitefix.html

ew928

Torque wrenches are a dime a dozen at Harbor Freight.
http://www.harborfreight.com/cpi/cta...Itemnumber=807

The 1/2" drive one is even cheaper. Search for torque wrench.
Been using their 1/2" drive to do the lug nuts.
Use a calibrated or one of the beam wrenches to check the new wrench for accuracy if
you need higher accuracy.

Ernest (NYC) May your block live a long life.

dcmelik

I have a strange noise coming from the undercarriage. It's like a knocking although I couldn't distinguish it from a rotational noise. It does not increase with RPMs.

The sound is new since I did the flexplate inspection.

It's either exhaust or I've really screwed something up with the flywheel/TT.

Christine (my better half) says I'm a dork and it is just exhaust ("like when you put the Borla on wrong before on the other 928 and had to tighten it up"). It's an awful sound. And combined with the smoke (presumably from the flavored kerosine I used to loosen the exhaust bolts-- in this case "PB Blaster") I thought I had really gone and done it. Jury is still out. Letting it cool off in the garage before I go back out and inspect the exhaust bolts. Perhaps a cool one is in order beforehand.

David Cmelik
87 928S4 auto "indischrot"
01 986 5sp "seal grey metallic"
00 BMW 323i black on red

928drvr86.5

I noticed with my 928 specialists modular crossover on my 86.5 i no longer need to lower the exhaust to remove the flywheel cover, this makes checking the TT clamp about a 10 minute job.

928drvr86.5

maybe you can convince Christine to buy you a modular crossover, the time you save by not having to drop the exhaust each time you check the TT clamp could then be spent with her.

dcmelik

I've raised the car on jack stands and carefully started the motor getting down to ground level with my ears (but not getting under the car) and even putting a broom stick on the exhaust system and, alternatively, the bell housing to try and see where the noise is coming from (thinking that the noise is coming from a vibration I will be able to feel).

I'm starting to second guess my work and wonder if I've done something worse rather than good.

Will an overly *loose* pinch/coupler bolt and, ergo, a migrating TT shaft produce a metallic rotational noise or is it more likely that I've disturbed something in the exhaust system now that is rattling around where the mod X pipe should be. Thanks in advance.

Edit: The noise gives a final hurah as I shut off the engine and it does sound like rattling in the cats. So I did a search for "noise" and TBF and found the posts on *rear* pinch bolt adjustment. I have never done this so I'm hoping this is all it is. Also, I found the rivet issue mentioned but not discussed in the archives. Anyone know where there is a write up on the rivet issue and the *rear* pinch bolt adjustment procedure?
David Cmelik
87 928S4 auto "indischrot"
01 986 5sp "seal grey metallic"
00 BMW 323i black on red

Mrmerlin

Hi I would first look at the front heat shields then the O2 sensor wires as they could have been moved, did you by chance leave the O2 sensor disconnected from the header pipes? and it may be rattling on the pipe?

Earl Gillstrom

David,

A loose rear pinch bolt will usually "rattle" at idle speed and in neutral and the noise will go away as you rev up, or put in gear. There is no adjustment for thr rear pinch bolt. It is in a notch in the drive shaft. Loctite it and tighten to 66ftlb. If you don't loctite it, you have to tighten it every oil change.