engine not turning over
04-12-2017, 11:50 PM
#16
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Yes. Pry bar. Would not move more than .003 inch. Tried and tried.
I can turn it over with the pry bar on the fly wheel but the starter will only crank a little then it stops.
Yes. That looks like metal in the oil filter.
I can turn it over with the pry bar on the fly wheel but the starter will only crank a little then it stops.
Yes. That looks like metal in the oil filter.
04-13-2017, 05:51 AM
#17
Rennlist Member
The oil filter display is a bit worrisome - have you considered taking an oil sample and sending it off for lab analysis?
The crank end float you are advising is also suspect but not in the usual sense. TBF usually displays excessive crank end float - the end float you quote is unusually "tight" at 0.07mm assuming I converted the number correctly- healthy engines show about 0.2mm end float.
When TBF occurs some nasty things happen, the norm being that the thrust face of the bearing thins, the rear most thrust face of the crank also can grind out, white metal melts and seizes the bearing to the crank and then the thrust bearing itself spins in the crankcase causing the casing to crack - if it goes that far then it is usually "game set and match".
The only thing I can think of that might explain your measurement is if this damage profile has occurred and then somewhat unusually the white metal that melted has then solidified and locked the thrust bearing in such a position that end float is constricted. I would have thought that the probability of such happening is low to non existant but..?
Because of personal experiences in this problem area I tend to follow all documented cases of TBF, I have never come across such a scenario happening previously but maybe others have?
That you can manually turn the engine over and yet the starter motor cannot also seems a bit unusual. Even your photo is a bit perplexing in that on the one hand the clamp looks quite a long way down the splined section typical in TBF cases] and yet if anything, the photo suggests that the flexplate is slightly bowed in the opposite direction to that expected with TBF noting that where the clamp body bolts to the plates there appears to be a bit of a gap also suggesting distortion of the plates in the opposite direction to that expected when TBF occurs.
Judging by the dearth of input to your post, I suspect our friends are just as puzzled about your case as I am. If you do not mind me asking, how did you determine end float to be only 3 thou? Whereas it remains a possibility, more investigation is needed to conclude that TBF has in fact occurred so keep a positive mindeset until such is established as a fact.
I would also suggest you take a look at the rear couping bolt, check if it is tight [or too loose], remove the bolt and ensure that it looks in good condition, not gnarled up and that the detente in the shaft aligns with the bolt hole.
The crank end float you are advising is also suspect but not in the usual sense. TBF usually displays excessive crank end float - the end float you quote is unusually "tight" at 0.07mm assuming I converted the number correctly- healthy engines show about 0.2mm end float.
When TBF occurs some nasty things happen, the norm being that the thrust face of the bearing thins, the rear most thrust face of the crank also can grind out, white metal melts and seizes the bearing to the crank and then the thrust bearing itself spins in the crankcase causing the casing to crack - if it goes that far then it is usually "game set and match".
The only thing I can think of that might explain your measurement is if this damage profile has occurred and then somewhat unusually the white metal that melted has then solidified and locked the thrust bearing in such a position that end float is constricted. I would have thought that the probability of such happening is low to non existant but..?
Because of personal experiences in this problem area I tend to follow all documented cases of TBF, I have never come across such a scenario happening previously but maybe others have?
That you can manually turn the engine over and yet the starter motor cannot also seems a bit unusual. Even your photo is a bit perplexing in that on the one hand the clamp looks quite a long way down the splined section typical in TBF cases] and yet if anything, the photo suggests that the flexplate is slightly bowed in the opposite direction to that expected with TBF noting that where the clamp body bolts to the plates there appears to be a bit of a gap also suggesting distortion of the plates in the opposite direction to that expected when TBF occurs.
Judging by the dearth of input to your post, I suspect our friends are just as puzzled about your case as I am. If you do not mind me asking, how did you determine end float to be only 3 thou? Whereas it remains a possibility, more investigation is needed to conclude that TBF has in fact occurred so keep a positive mindeset until such is established as a fact.
I would also suggest you take a look at the rear couping bolt, check if it is tight [or too loose], remove the bolt and ensure that it looks in good condition, not gnarled up and that the detente in the shaft aligns with the bolt hole.
04-13-2017, 11:10 AM
#18
Captain Obvious
Super User
Super User
You could have excess carbon in the combustion chamber that dropped down on top of the piston and causing the engine feel like it's sized up. Or something else that's foreign in the combustion chamber. As bizarre as his sounds, I've seen this with my own eyes happen to a 928. It was documented either here or another Porsche forum.