Gsrob

What exactly was the issue? I've spent around the same on mine but before the timing belt and v/c service. That's next on my DIY repair list. I've been steadily accumulating tools and re-tooling from past vehicles.

Airbag

Well Rob you would have to go back and read the thread .. But basically I covered it with Salt and left it in a steam bath for 7 months ...

All 4 springs broken , calipers seized, pads fell off backing plates,starter motor seized, alternator seized, rear view mirror fell off .. wiring harness coroded, muffler falling off, Aluminum wheels bonded on to hubs. . When you looked at the suspention it looked like it belonged on the Titanic after 100 years under water. I was at a local Porsche get together and there was a facory tech there. he told me the rumour was you couldnt kill an Audi .. I had obviously dispelled the myth ..


apparently not

CRuby

SO back to my rebuild discussion, & some updates that seem to substantiates the no-kill (just wound) rumor. It's been bugging me that since engine is out of car I should check lower end bearings. Wanted to change upper & lower oil pan gaskets anyway, so I decided to plastigage the rod & crank bearings while I was there. All rod bearings & crank bearings 2,3,4 , all tested to be within new clearance specifications. That was good news! All journals looked pristine. Slight visual wear discoloration on most bearings, but no detectable scatches & plastigage flattening pretty uniform. I didn't test crank bearing #1 because cap supports pivot pin for oil pump chain tensioner, & I didn't want to bother pulling front pulley to get tensioner out.

So here's some real data that shows the lower end bearings can hold up well as long as you don't run dirty oil or no oil.

Now over the hump & on our way back to reassembly.

Airbag

Well now we know why we hear of 'Bottom End" so Little. it would seem the Germans have quite a robust Bottom End. ...

CRuby

Well said! Robust bottom end. Top end (valve covers) doesn't seem to be doing as good. Any C5 owners familar with cracks in VC's?
Both PS & DS valve covers have cracks as noted by the dashed red lines. I've seen some pics of other used ones & they seem to have similar cracks. Wondering if others have seen similar cracks on their VC's?

Audi1969

as stated by other members, it is not necessary to touch the inside of your STOCK block if you are showing good numbers, on compression test. Most importantly its your oil changes from now on that will keep good numbers . once you open that block your car will never be the same. spend your money somewere else there is a lot more you can do

SloopJohnB@mac.com

R U sure those are cracks? Look like mold marks to me…are they into the metal or above the metal? Never seen cracks before like that.

CRuby

Audi1969: With ~170K miles on the car, & engine/tranny out for clutch, & other items, I chose not to replace crank/rod bearings & rings. This based on 1st on data, & 2nd on guidance/experience of this & other forums. As for car never being the same after opening block, well I hope you're partially correct. I doubt checking bearing gaps will lead to any problems, but I do expect changing oil pan seals & rear main seals/gasket will fix my leaky engine.

SloopJohnB: I'm certain they are cracks, but convincing others seems a bit more difficult, since this seems not to be a common problem. Casting mold lines would be present from the day they were made, & as you suggest, they would generally be raised surfaces/edges. My son & I have had valve covers off several times in the past, chasing misfire issues. (PO switched cam chain tensioners, L-R to R-L & it took some time to figure that out.) I know these crack-like indications would have caught my eye before. I've looked at these many times using 10X magnification & it is definitely parted/cracked metal. The "cracks" appear to follow an interior (oil side) casting stress concentration, which is exactly beneath the top edges of the raised coil pads. Anyway, whether anyone else believes they are cracks is up to them. For me, they are, & the new valve covers I bought don't have any crack-like indications.

FYI, just installed engine & tranny back into Audi today. Still lots of bolts to tighten, but making progress.

SloopJohnB@mac.com

Good for you! Look forward to hearing it's working again.

CRuby

OK. Time to eat crow!
I took the valve cover pictured above (post 25) in to the materials lab where I work & the failure analysis metalurgist looked at it under much higher magnification than my 10X jeweler glass. Most of the long red-dashed lines regions in prior pic are not cracks, but are evidence of casting parting lines. SloopJohnB, +1. However, there are several areas that branch off the parting lines that are really cracks. These are branches off red rectangle below cyl. 6 (on right), & on hump for TB on left side of pic (not marked). What I was considering secondary striations are also not cracks, but rather appear to be slight scuffs/scratches done by some some external operation. The metalurgist speculated that the scuffing is only evident adjacent to regions of this parting line, likely because of finishing process used to buff off the excess mold line during manufacture.
Anyway, I thought I should followup on this topic, since I left it stating I believed they were cracks. Most (but not all) of them are not.
Crow tastes like chicken.