That should be qualified with the statement that this is an analog odo with a history of being broken, so in reality it's TMU.



While it's nice to have gotten vindication for the spiraling out of control engine tear down, it's pretty disappointing to see copper on the #1 main bearing at this indicated mileage. What does this wear pattern say about what's going on in this engine?

Also, should there be this much copper showing on the thrust bearing in a 5spd?

 

Looks as though you need some root cause analysis here. Did you measure the crank end float as a matter of interest?

The thrust bearing looks well wiped as does your main bearing but as to why is what needs to be determined. Oil pump issue?

Plenty of support around.

Rgds

Fred

 

I got to the point in the tear down where I was going to replace bearings anyway, so unfortunately I did not check end play. The oil pressure was fine before tear down, lowest pressure was about 1.5 bar indicated in stop-and-go traffic on a sweltering day. Oil pump looked good but had a ton of axial play.

 

which side of the thrust bearing, front or back of the engine ??

 

Front. The bearing in the lower cradle is worse than the top. Guessing the PO was a clutch rider.

 

Was that the pressure at idle or with some revs? At idle it seems a bit low but not that bad. Did oil pressure recover to normal full pressure by the time you hit around 3k rpm?

I have also been somewhat concerned about the warnings Greg Brown has given concerning the state of the engine dampers as they age and lose the ability to do what they were intended to. If your oil pressure was satisfactory one wonders if the damper might be a contributing factor?

Rgds

Fred

 

That low pressure was only on the hottest days in the worst traffic. Typically, it idled at 3 and shot back up to 5 with any throttle.

With the localized damage, damper was on my mind too...

 

Completely normal thrust bearing....actually pretty nice! Note that the entire surface hasn't worn away the coating. The stock coating on the flanges of the trust bearing is very thin.
There is no soft layer to absorb dirt and particles, like on the faces of the bearings. They get into the "copper" immediately. (This part of the bearing must be hard to control the endplay forces.)

The wear on the front bearing is caused by crankshaft harmonics, in my opinion. The stock dampers had the rubber connector between the two metal pieces get too hard to transfer the harmonics about 15 years ago.

 

Can I get on the list for your damper kit before you get deluged with orders?

 

Get in line! I'm on Greg's waiting list myself at the moment.

 

Making another "batch" right now....fairly high volume piece, even for the tiny 928 world.

Main bearings used to come out of these engines looking pretty good....I reused many sets.

Now they all look like yours...or worse. The cars that run at higher rpms really beat them up....along with the block and cradle.

 

I was suspicious of the front bearing as soon a I saw the photo.

Looks like you might have a new customer!

Something we should all be paying attention to before it is too late for the bearing [I suspect].

 

Would a 50K engine that hasn't been used for 20 years share the same problem?

 

Difficult to know....depends on how and where it was stored.

 

What type and viscosity of oil was used in this engine?