Ok MrMerlin and everyone else, I'll do that exactly this week. I'm just trying to figure out the jackstands situation cuz I'm limited in space. To remove the crossmember and the steering column, can I have the car mounted up on the wheels? Or does this create load that will separate the crossmember bolts and make it harder to install crossmember? Is it best to lift to hold car up by its jack points for this?
RV II

 

Jack points.

See:
http://liftbars.com/

 

Uhh your talking about removing the front cross member? this to replace the bearing?

This isnt how this job of replacing the bearings is done,
the engine is pulled out then placed on a stand then the girdle is removed then the crank is removed and sent off for cleaning polishing .

BUT first if your sure of the measurement you have taken,
then there isnt any need to replace the bearing.

This is why its been suggested to take the readings again to be sure of what you have

 

Merlin, I was just going to look at condition of bearing and block. But I will do that and then take reading at the same time just to be sure. Ill take pics and post them for you guys to put your sense. Thanks for all the pointers to everyone! Ill keep you guys posted.

RVII

 

RVII,

When you say you restart it (after it dies), do you mean you restart it right after it dies?
If so, I think it's not the thrust bearing. If it would be the TB, it would not crank right after it dies.
Like James says in thread #6, you would need to wait until it cools down before restarting it.

Like many guys said it's an essential thing to do to release the preload on the flex plate like you did
and mesure the crank end play to make sure everything's good.

https://rennlist.com/forums/928-foru...pictorial.html

http://www.dwaynesgarage.norcal928.o...0Procedure.htm

 

@ Bert,
What I meant to say is that my car restarts without any issues when it died on me the few times.
I already have released the load on the plate, 3/16's of an inch to exact. And the play at the fly wheel is 0.24 mm which what all links sent to me and what everyone else says, falls in the range that it needs to be.
But a few have recommended to remeasure and I want to drop oil pan not to change out TB but to look at the block and TB. Then take pics and post them to you guys to verify whatever damage might have occurred.
Thanks for the links and concern and I will keep you guys posted.
RV II
1987 928 S4
Black/Red

 

This does not fit thrust bearing failure. When that is the problem, the engine dies when warm but is HARD to restart until it cools down. It acts as if the battery is discharged or the starter is bad - the starter turns slowly due to increased load from partial seizure of the bearing that caused the engine to die. What you describe sounds more like failure of the idle stabilizer valve, with the idle speed fluctuating high and low, then dies sometimes, but starter cranks normally. I would verify your crank endplay. If really 0.009", that's just fine. I don't know where the metal in the oil came from. Is it magnetic (sorry if you already answered that)?

Also, if you pull the pan and look at the block, don't be alarmed if you see some machining of the block. You might initially think it is from the crank throws hitting the block, but if you look carefully the crank will not have matching wear and the marks don't quite line up. That is factory machining. Scared me initially when I did my pan gasket.

Some threads relevant to crank endplay.

Measuring: https://rennlist.com/forums/928-foru...pictorial.html
PKlamp: https://rennlist.com/forums/928-foru...xperience.html

 

The wear limit is .4mm. .24 is just about perfect in a NEW engine (Porsche spec is .15 - .32mm

I agree 100% that this does not indicate TBF. You need to investigate more. The thrust bearing wear you show (and is accurate if you know how to use calipers correctly , have a good quality set of same,and somebody held the crank in each direction as you took the measurements) is normal. A dial indicator is an easier way to check for this condition, though.

 

Just curious, how did you determine there was "a good amount of metallic debris" in your oil?

Such as:
1) Visually inspecting the the dipstick for glitter like sparkles?
2) Drained the oil and filter funnel it?

Just like measuring end play, trying to rule in or rule out items are only as good as the diagnostic procedure.

I know in private planes, my father in law, as part of his annual inspection, would send out used oil samples to a lab for analysis. It was pretty amazing the amount of information relative to engine health they could predict based on levels of contamination. I'm guessing the same/similar service is available for automotive engines. Might be worth looking into.

If it were me, I would want to rule in or out thrust bearing wear ASAP for both peace of mind and plan of action. Like others have said, if your endplay is accurately measured and within spec, then most likely can rule that out. Whew.

Then you are back to what did you see in your oil? Try to solve that mystery.

Then you are back to your original question about engine cut out at idle... which could be as simple as a dirty ISV (idle stabilizer valve)... which is not the easy item under the hood to get your hands on.

Hopefully you dodged the big bullet and wish you luck solving/repairing the rest.

 

I am going out on a limb - you don't have TBF.

I would start by following Dwayne's write-up on testing for air leaks before dropping the oil pan. I just completed a full top end engine refresh and all my idling and running issues disappeared - including a drive line rattle I assumed a torque tube rebuild.

 

A top end refresh eliminated a drive line rattle?

 

I know that sounds crazy, but even after I replaced the OPG and MM the rattle from the TT persisted. It would go away when I pushed in the clutch. The whole driveline shook.

Yesterday when I took it out for its maiden post top end refresh even with the console out there was no noise from the TT. Top end refresh included cam cover gaskets, chain tensioner pads, oil pins, all the hoses including the fuel lines, rebuilt injectors, hall sensor, CPS sensors, knock sensors, rebuild a injector clip on the harness and CPS connector on the harness, as well. At idle the engine is so still it looks like it is not even on. Just amazing. Used to stall coming up to a stop sign when I put it into neutral - gone. Idle is rock steady.

So, before setting your hair on fire screaming TBF it might be useful to properly diagnose issues raised by the OP. ;-)