firemn131

So whats your opinion?

Crank travel is waaayy out 1.27MM
Crank shows high temp indications
Block is chewed up.

I released preload when I bought it.
Most damage seems to have happened during PO.

I have been getting clean oil changes and running strong for 2 years.

Do you see any issue with me putting it back together and running it as is?

If block and crank are already toast, what have I got to lose?
Will there be collateral damage to other high end parts?
IE Heads, valve train, transmission.

I plan on another engine, just not soon.

All opinions are greatly appreciated.

John

Ducman82

another thread? :-P get a used one and rebuild. if you "know its going to die" i doubt you will drive it much. and why waste the time re installing a junk engine?

firemn131

Ducman,

Relatively easy to reinstall the engine. Low $$
Maybe others can afford to just buy another engine, but I cant at this time. I have most everything to do a great rebuild, but not the time.

I think I can install, wait for the inevitable and do an amazing rebuild as time and $$ make themselves available.
All the while collect data and info on the progression of a Total thrust bearing failure. This would include oil pressure, temp changes, starting issues, etc..
I see it as potentially having a great opportunity to help others along the way.

The purpose of the additional thread was to solicit advise.
Didn't know it was going to cause heart ache.

Ducman82

no heart ache implied. just curious.

firemn131

Cool, I don't post enough to be as forum savvy as I need.

Feel free to keep me straight.
LOL

These forums have helped me in so many ways!
I appreciate all feedback

Randy V

Your thrust bearing is loose? As long as you don't lose it you should be fine.

linderpat

I like the idea of you running it to failure, and taking reliable data measurements during the process. It could be valuable information, and nobody else has ever volunteered to do it. Your downside is quite big, though, as you may end up ruining many good parts that you could have used on the new engine, which could end-up costing you more. Not to mention that you will not be able to predict when, how and most importantly where the thing may decide to go on you. It may not be very opportune time.

firemn131

Linderpat,
I think that most of the damage has already been done, and during previous ownership. There is so much play now that I should be relatively successful in finding the mid point to prevent any further grinding. The other bearing surfaces will continue to suffer due to previous galling or contamination, but I think I can minimize with frequent oil changes and diligence and light weight oil.
I don't expect to use the pistons or any other part of the engine assembly on the new rebuild that I will get in the future. I may end up wearing the cams, but as of now they look great. I hope to keep the heads.
I haven't been able to drive it because of life's business for almost 2 years, so I am anxious to get it on the road even if it is the swansong. Kinda like, if you know when the last time you spend with family or an old girlfriend. You would make the last visits more memorable. I will only drive local, and have AAA on speed dial.

anonymousagain

as it gets progressively worse, it will heat up and chew up more, until it grinds a new position for the crank "out of travel". My experience was ~30mi until noticable power drop, then ~3mi to stall. Release/reposition after towing it home allowed it to run like normal for ~1/2mi. Not much service. Remove and replace with LS swap.

True, no other components were injured, but "from what I could see" verification is far from trustworthy.

Jfrahm

There is a short block on ebay for $1K, a complete engine for $1700. Not too bad. If that's too much or you are interested in what happens next it would be something to replace the thrust bearing and run it.
Can a custom or oversize thrust bearing be obtained?

Sapientoni

I have one now that was seized when I bought it. I swapped everything over to an 86 block. Had to grind off a bump in the valley. Sum bitch hasn't run yet!! It's hit a lick or two. Had to use the flexplate from the 86 block and starter bracket. I'm thinking of welding up the damaged block and then machining it back. SMOKEY YUNICK said the biggest advantage to aluminum block over cast was the ability to weld repair damages. Anyhow, that's my suggestion. Might require align boring. I'll try to pull the thing out and examine it with pics to post this weekend if possible.

Sapientoni

RE: hasn't run yet. I've checked everything I know, and I thought I knew everything as I worked on my own 928s for 30 yrs. I'm missing some little detail. I remember some guy had a souped up 928 engine on EBAY for $24,000 and was flaming the shop that built it. It, too, would not run and it was built on an earlier block.

Rob Edwards

Not sure how much welding ol' Smokey did on Reynolds 390...

FredR

A further consideration in all of this is that the forces that wrecked the motor for the most part have been removed when you released the clamp. that your motor has no thrust bearing proper is a fact and in all probability the main bearing faces on that centre main journal have also been wiped- do you experience a lower than normal oil pressure at tickover when warm [normally about 2 barg]?

Almost certainly the thrust bearing will have spun in its housing and that more than anything is what causes end of service life as it invariably cracks the webs the main bearing sits in. The flex plate itself will tend to resist axial movement of the crank providing the load is not too high but I suspect the crank will end up hammering itself axially in some kind of resonance.
My GTS motor had damage to the rear crank thrust face, the thrust bearing, the thrust bearing seat has small cracks and the web walls were ground in a bit. I had the GTS crank thrust face reworked and with a std thrust bearing it would have left a crank end float of 0.5mm albeit mostly on one side. However, if the motor still runs with 1.3mm float then logic says 0.5mm end float can work even though the factory wear limit is 0.4mm. I have heard that thrust bearings are available in a plus 0.2mm format. So, I have a GTS crank with excessive end float and I often wonder if it may just be viable in a rebuilt engine albeit the nitriding layer is probably lost on that face.

With that amount of end float I expect you will see the crank pulley wobbling about.

When I purchased my GTS I knew what was going on and that the motor was history. Whether my crank,rods and pistons can ever go back into a motor remains to be seen. All I can say is tha tit sounds as though your motor is as damaged as mine was and there was no way I would run a motor like that- but that is me and I had my pretty good 1990 S4 motor to play with already.

Keep the lateral thinking rolling.

Rgds

Fred

SMTCapeCod

I like your plan. If you can slap it back together and have a decent summer, whatheheck? Sounds better to me that getting into the other alternative which will be under-resourced from time and other perspectives. Clamp it, run heavy oil and maybe one or other iteration of super slick snake oil for good measure.
Speaking of which I think the O/C should cove one or more oil analyses, so we have a datapoint for what it looks like at various stages.