Thrust Bearing Fail. WHAT HAVE I GOT TO LOSE?
#61
Instructor
I have an early 86 engine I was planning on putting in my 84. It is partially disassembled but looks ok from what I can see. You can have it if you can get it up there from Mississippi.
#62
Rennlist Member
John,
There is a magic number for end float when lots of metal is in contact viz the crank webs and the block- once that number has been reached it will continue to grind metal but chances are end float will not change any time soon because of the large surface area in contact. The amount of metal being churned out will be huge and what happens eventually remains to be seen.
The original GTS motor in my example was at 1.3mm end float- my guess is that is the magic number! It will be interesting to see if there is any coating left on your piston walls
There is a magic number for end float when lots of metal is in contact viz the crank webs and the block- once that number has been reached it will continue to grind metal but chances are end float will not change any time soon because of the large surface area in contact. The amount of metal being churned out will be huge and what happens eventually remains to be seen.
The original GTS motor in my example was at 1.3mm end float- my guess is that is the magic number! It will be interesting to see if there is any coating left on your piston walls
#64
Rennlist Member
Thread Starter
Not sure what to do with the grinder. Scrap, coffee table?
New engine is in transit. Car still runs but very noticeable grinding on start after sitting for a week or so.
will reuse very little from this motor depending on what the new heads look like. Will work the engine while keeping it a driver. 968 will get on the road as soon as I get my arm out of a sling and rehab allows me to turn wrenches.
New engine is in transit. Car still runs but very noticeable grinding on start after sitting for a week or so.
will reuse very little from this motor depending on what the new heads look like. Will work the engine while keeping it a driver. 968 will get on the road as soon as I get my arm out of a sling and rehab allows me to turn wrenches.
#65
Rennlist Member
Thread Starter
Update
I am at a crossroads of sort, so this post is more of a way to sort out my head. Sorry for the rant....
Pulled the replacement engine apart and found cylinder gouges and piston damage in #4. It ate something. The thrust travel is perfect and engine looks to have been maintained fairly well. Not sure what to do at this point.
Waiting on the vendor to give me their suggestion.
Options are;
** Keep the accessories and vendor replaces with a known good short block. Continue with reconditioning the heads. Preferred
* Replace the long block (re-assemble with cam shafts out and properly stored) ship it all back.
* Wait another 2 years to save up and hopefully find a good short block.
* Check the engine in my 89 and if good, part it out to save the 87, or vice versa and save the 89. Really hate to salvage either of these. The 87 is really well sorted.
I just got the 89.
Other options if vendor doesn't help that require funding that wife probably won’t smile about. For the first time today, she has questioned the amount of $$ that this car is threatening.
* Ship to Greg B., Sleeve the bad cylinder, new piston.
* Re-bore and oversize block/pistons.
* Sleeve the whole block.
* Tear down my TBF motor to see if it has good cylinders/pistons and debate if the thrust bearing can be replaced with block repair. A very slippery slope! some of this may be done local??
* Move to Anaheim and see if Greg will:
A. Adopt me,
B. let me work as 56-year-old unpaid gopher.
* Give up on the 928's sell off the daily driver 968 find another hobby. Was going to sell the 968 anyway to fund the repaint on one of the 928's.
I have to say that falling into the 928 community has been one of the most rewarding things that I have ever done. With the help from the vendors (928Rus, 928Intl, 928MS) and the many listers especially Greg B, the Doc's, Kibort, Soontobered84 (way too many to list) this been a great diversion from the stressors of life as a DoD flunky.
More to come.
Pulled the replacement engine apart and found cylinder gouges and piston damage in #4. It ate something. The thrust travel is perfect and engine looks to have been maintained fairly well. Not sure what to do at this point.
Waiting on the vendor to give me their suggestion.
Options are;
** Keep the accessories and vendor replaces with a known good short block. Continue with reconditioning the heads. Preferred
* Replace the long block (re-assemble with cam shafts out and properly stored) ship it all back.
* Wait another 2 years to save up and hopefully find a good short block.
* Check the engine in my 89 and if good, part it out to save the 87, or vice versa and save the 89. Really hate to salvage either of these. The 87 is really well sorted.
I just got the 89.
Other options if vendor doesn't help that require funding that wife probably won’t smile about. For the first time today, she has questioned the amount of $$ that this car is threatening.
* Ship to Greg B., Sleeve the bad cylinder, new piston.
* Re-bore and oversize block/pistons.
* Sleeve the whole block.
* Tear down my TBF motor to see if it has good cylinders/pistons and debate if the thrust bearing can be replaced with block repair. A very slippery slope! some of this may be done local??
* Move to Anaheim and see if Greg will:
A. Adopt me,
B. let me work as 56-year-old unpaid gopher.
* Give up on the 928's sell off the daily driver 968 find another hobby. Was going to sell the 968 anyway to fund the repaint on one of the 928's.
I have to say that falling into the 928 community has been one of the most rewarding things that I have ever done. With the help from the vendors (928Rus, 928Intl, 928MS) and the many listers especially Greg B, the Doc's, Kibort, Soontobered84 (way too many to list) this been a great diversion from the stressors of life as a DoD flunky.
More to come.
#66
Rennlist Member
Brett Jenkins had a S4 engine for sale...cheap. You may want to PM him.
#67
Three Wheelin'
What ever way you go, take the oil cooler off & flush it completely until there is no sign of anything in it- best done on a parts washer with a pump, let it run .By running the TB failure motor, you have a big chance that the cooler has junk in it.
#68
Rennlist Member
Thread Starter
Hey Jim,
Yea that's the plan.
If I use any of these oil components they will get "sanitized".
Not really looking forward to having two engines taken apart. Garage real-estate is at a prime now.
Besides a short block swap from the vendor, I am looking into the sleeving process for one piston at this point.
fact finding on the Alusil block specs now for my machinist.
Thanks
Appreciate the input.
`
Yea that's the plan.
If I use any of these oil components they will get "sanitized".
Not really looking forward to having two engines taken apart. Garage real-estate is at a prime now.
Besides a short block swap from the vendor, I am looking into the sleeving process for one piston at this point.
fact finding on the Alusil block specs now for my machinist.
Thanks
Appreciate the input.
`
#69
Take everything apart, and start there.
#70
Rennlist Member
So, one good path for you would be to bore+ hone any bad cyls out and go with the oversized pistons that Greg has. A couple of questions about this approach:
-Is your damage too deep for this approach?
-How many cyls would need it?
-Where is the nearest shop that can do it?
-How much would bore+hone+deck+piston cost on that block?
-Is your damage too deep for this approach?
-How many cyls would need it?
-Where is the nearest shop that can do it?
-How much would bore+hone+deck+piston cost on that block?
#71
Rennlist Member
Thread Starter
Well,
Going to split the block when I get back from travel next week.
I haven't found a local shop that has done this, but my machinist is pretty sharp and has the proper tooling. So that is probably how I will go.
Bore out the gouges and see if it will support an oversized piston. If not, then sleeve it.
And away we go.
Going to split the block when I get back from travel next week.
I haven't found a local shop that has done this, but my machinist is pretty sharp and has the proper tooling. So that is probably how I will go.
Bore out the gouges and see if it will support an oversized piston. If not, then sleeve it.
And away we go.
#72
Rennlist Member
Thread Starter
Update
Well, finished assembling the “new” short block.
overbored 1 cylinder, all new bearings, rings, and rebuilt the heads.
Just began pulling the old engine out. So it begins.
While beginning the removal, I noticed several of the Silicone vacuum lines had split. They look nice but don’t hold up (2years).
overbored 1 cylinder, all new bearings, rings, and rebuilt the heads.
Just began pulling the old engine out. So it begins.
While beginning the removal, I noticed several of the Silicone vacuum lines had split. They look nice but don’t hold up (2years).
#75
Rennlist Member
Thread Starter
Final crank float measurement,,,,
wait for it...……………….
1.89 MM.
Nominal is .40
still ran pretty good.
It will be interesting to see what the internals look like.
wait for it...……………….
1.89 MM.
Nominal is .40
still ran pretty good.
It will be interesting to see what the internals look like.