Wow! Look At All Those Pieces.......
 

Well, First off I gotta say a big Thanks to Don @ EBS.Was just going to do a re-ring & valve job,but after talking to Don,he convinced me I really should split the case & go thru the bottom end.Has 156,000 on it.He was right on the money!Everything looked very good except for a couple rod bearings were just starting to show wear.I think so anyway.If I just had done the top end,one of those rods would have surely went in short order.

Here are a few pics, I would like a few opinions from some of the more senior members out there on the condition of bearing wear.

Not sure if things are totally clear in every shot.http://forums.pelicanparts.com/uploa...1117853641.jpg http://forums.pelicanparts.com/uploa...1117853664.jpg http://forums.pelicanparts.com/uploa...1117853697.jpg http://forums.pelicanparts.com/uploa...1117854024.jpg http://forums.pelicanparts.com/uploa...1117854044.jpg http://forums.pelicanparts.com/uploa...1117854149.jpg http://forums.pelicanparts.com/uploa...1117854178.jpg

This is gonna get interesting.........

Cylinder 3&4 do not look quite right - the bearing looks scratched. That may warrant a closer look at the crank. I would recommend getting it magnafluxed and micropolished at this point.

The other bearings look like they have some wear, but nothing too excessive.

Definitely replace the intermediate shaft bearings, they are showing copper - not good

Your mains look fine. However, since you have the case split already, I would replace them - it is real cheap insurance.

AFJuvat

With the exception of the scratched bearing they are all appear to be in good shape. There is no reason why the scratched one would have been likely to fail since most of the bearing surface is still intact.

Its not unusual to see that kind of bearing damage when a piece of debris travels through the oiling system and finds its way to the bearing. Thats why bearing surfaces are made out of babbit after all.

That being said at 150K miles its a good time to go through the bottom end anyways. You never know what might be getting out of spec till you check to be sure.

Speaking of that, have you measured the crank journals yet? Chances are its probably still in spec.

350, Haven't gotten to checking the crank dimensions yet,but is on my looong list of things to do.All bearings, rod, main & inter.shaft are being replaced while apart.along with timing chains, guides,etc.In the pictures,the top row are the upper half (rod half) bearings.Any thought on the dark splotches right near the center of each bearing shell?There is no roughness or any edges to be felt on any marks.Everything is as smooth as can be?The crank looks very good also,no visible cuts,grooves,marks.I will post some #'s when I get things measered up.

That interesting little spot is from the heavy loading that occurs as the side of the journal where the oil hole is passes by the bearing during the compression stroke.

As the folling pic shows my 930 had the same marks at the 130K mile mark.

http://forums.pelicanparts.com/uploa...1117896214.jpg

I still need to learn how to spell.........Maybe next month!

350,
I can see the beginning of the lines like are showing on mine on yours,I was more referring to the black looking discoloration on the top row of bearings.

Thanks for the input.....

By the way,I'm an ex-motocrosser & have built many modified race bikes & the inside of the cases,castings & such remind me very much of how 2 strokes are designed & built.Amazining that Porsche has been building these for so long without alot of major redesigning or changes.
More evolutionary,rather than revolutionary.

I thought you were talking about the dot at the center of the top bearing.