uh oh tbf
#1
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uh oh tbf
well as my luck always runs it is no different with my 928. my 89 s4 has tbf. the end play is 75 thou.... i was told about 20 thou is abou the max or .4mm. anyone have any history on this. the car does run and the pressure has been taken off the flex plate. where do i go from here. the guy that sold me the car has offered 20/hr labor to make the repair if i fork out the money for the parts. he wants to short block it. but with all that aluminum running through the engine i can't see heads being in that great of shape.... i got 3500 in the car as it sits, new LH unit, the car will need paint and a complete interior yet after i make this repair. What would you guys do? it has 110k on the ticker and the AT transmission condition is unknown. I bough this as a toy to play with in my spare time, but this is a little deeper than i wanted to get.
#2
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OH SPIT! I would string up the seller by his cohones. He KNEW it! and he bent you. As for remediation, well, I would want to be made whole, no matter what it cost. Going that route will involve court, et-al. Part out and start again.
What a bastardo.
Doc
What a bastardo.
Doc
#4
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75/1000 is about 1.9mm. Several times larger than factory 0.4mm limit but still too small for thrust bearing side to be worn away fully. Also there should be enough side play on connecting rods upper end for that rods and pistons could be all ok. So with some luck oil filter has collected all loose metal away from circulation and nothing except #3 bearing is really worn. I wouldn't give up just yet.
#6
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If I was in your shoes I'd read Erkka's post again. An '89 shouldn't be parted out. Made into a track car maybe, but not parted out. It would be interesting to the entire community to know if a motor with that much end-play (but, not enough to chew the block) can be fixed and made whole again.
Of course, if you do part it..... I'd be interested in some of the parts.
Of course, if you do part it..... I'd be interested in some of the parts.
#7
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I wholly agree with Erkka: if the crank throws haven't gone through the thrust bearing and into the girdle of the block, then a fresh set of mains may be all that is required.
That is still a complete engine removal, etc.
That is still a complete engine removal, etc.
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#8
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I agree with Erkka almost.
At 2mm the conrods shouldn't quite have used up all the end play but it will be close.
At 2mm the crank throws may well have hit the block but that is not a real big deal and can be ignored.
What can't be ignored and unfortunately what I've seen in the TBF'd motors that I have looked at is that the centre main bearing shell will probably have spun against the thrust face of the block and will probably have neatly machined about 1mm off the rear thrust face of the block journal. This would need to be built back up to restore the thickness of the journal.
The Top end of the engine should be OK. The oil filter should have caught most of the alu filings.
Jon in NZ
PS TBF engine I dismantled had no sign of Alu in the heads just lots in the sump.
At 2mm the conrods shouldn't quite have used up all the end play but it will be close.
At 2mm the crank throws may well have hit the block but that is not a real big deal and can be ignored.
What can't be ignored and unfortunately what I've seen in the TBF'd motors that I have looked at is that the centre main bearing shell will probably have spun against the thrust face of the block and will probably have neatly machined about 1mm off the rear thrust face of the block journal. This would need to be built back up to restore the thickness of the journal.
The Top end of the engine should be OK. The oil filter should have caught most of the alu filings.
Jon in NZ
PS TBF engine I dismantled had no sign of Alu in the heads just lots in the sump.
#9
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i just don't know
i really don't feel like doin this. i am going to spend who knows how much just findong out what it needs. the car still needs interior, trans shape is not known. if some one wants a project i would trade an 84 or newer that runs and drives, this is my second shark i will not drive. the car is cosmetically a mess and now also mechanically a mess.... i just do not see a reason to continue. i'v just had it. i know its my fault i just put way too much trust in people. " yeah its mechanically fine, its all electrical" yeah ok....
#10
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Originally Posted by Shark Attack
i really don't feel like doin this. i am going to spend who knows how much just findong out what it needs. the car still needs interior, trans shape is not known. if some one wants a project i would trade an 84 or newer that runs and drives, this is my second shark i will not drive. the car is cosmetically a mess and now also mechanically a mess.... i just do not see a reason to continue. i'v just had it. i know its my fault i just put way too much trust in people. " yeah its mechanically fine, its all electrical" yeah ok....
#13
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Originally Posted by Shark Attack
Erie PA - 6000.00
Well, that just isn't going to happen in your lifetime. I bought a running, driving, but needs minor work car for $6000. If all the soft stuff is hashed up too, then parting it is harder too. Most of the stuff guys need is the soft stuff that goes bad over time. I think you're in a world of hurt financially.
If you want to start hacking at it, you can expose the bottom end with about 3 hours of work. Start the motor mount job, expose the oil pan, pull it and you can have a look see at the crank girdle. This will give you enough info to decide if the block is possibly saveable. If it's not, just put the oil pan back on a decide what to do. If it is, you can decide if you want to pull the engine and redo the bottom end.
Bummer.
Doc
#14
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Sometimes the truth hurts.
I used to think that a timing belt failure was the achilles' heel of the 928, but I'm now starting to think it may be thrust bearing failure - both of which can be abbreviated with TBF. Coincidence? I think not. Thrust Bearing Failure I think is by far the more catastrophic of the 2, but timing belt failure is more common. Either way, they're both pretty bad.
I used to think that a timing belt failure was the achilles' heel of the 928, but I'm now starting to think it may be thrust bearing failure - both of which can be abbreviated with TBF. Coincidence? I think not. Thrust Bearing Failure I think is by far the more catastrophic of the 2, but timing belt failure is more common. Either way, they're both pretty bad.
#15
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sorry doc
it seems every one comes out of the woodwork to want the car. I don't know what i am going to do with it at this point, someone asked what i would take for it and right now in a hurry, unsure where i want to go with it, i would take 6000.00 remember somebady asked. i didnt offer. i am leaning twards fixing it. looks like about 5K to do the job right with a short block. you asked.....6k is the number, maybe 2k by next summer if i get board with it.