Alusil block cylinder wear?

Hey guys

I am rebuilding my 07 s6 engine which needs a new block. I purchased this 07 s8 block as a replacement and it seems that each cylinder has light scoring as shown. Engine has 60,000 miles on it. Cylinder walls feel smooth to the touch with no noticable gouging (cannot hook my finger nail on the discolored parts of the cyinders). Is this normal wear? The good cylinders on my S6 did not look like this at 100,000 miles. Any advise as to weather this is a suitable replacement block?

Mine 130k looked different either. It had just a bit of discoloration, but nothing similar to this. It might be a writeoff, but we’ll see what others say.

Sad circumstance of using Audi’s ridiculous 10k oil changes. Gets the car through warranty but not a couple hundred thousand miles. Long or filled for life oil changes for the transmissions and differentials is bad too.

Hi. My S6 2006 runs beautifully. Has very similar looking cylinders 9-10. 73k miles. Here’s a photo. You can hone alusil blocks with “Sonnen AN-30”. Look up alusil honing. I didn’t do it to mine at this time.

If you have means to check compression, maybe try that before writing off the block.

OK, will definitely do a compression test before attempting the Alusil Honing. I’ve seen this done before and might do some tests on my other block. Some people have had good results from this. Some mixed info on whether or not guys are re ringing after alusil honing. Even saw a video of a guy that had success doing this with the pistons still in.

According to my service history, the first owner didn’t change the oils for the first 100k km. They had it serviced regularly at the dealership (“Longlife” service), but the oil change box was never ticked. Then the next marking is “engine change”. I find that somewhat amusing.

Honestly doesn’t seem that bad. Looks like 60k miles with no carbon clean. Potentially little bits of carbon following the piston down, then rebounds gets caught on the ring and scores the edge of the wall. I’d say at worst hone and rering the pistons, I would do that anyways though even if it still had good compression.

Not sure if it had good compression, I purchased this block from a wrecker in Illinois and had it shipped to a US address and picked it up. Unfortunately, I didn’t get to inspect it. The car it was in had some front end damage (not terrible) and was probably written off. After some new developements (I will post something about this shortly), I’m going to strip the block and going to try the Sunnen Paste and rering, maybe salvage the block.

Ok, so new development. 2 pistons (#2 and #7 which are opposite each other) are missing carbon build up on the edges where the scoring is. These 2 cylinders have more scoring than the others. I’m thinking oil is getting by the rings on these 2 cylinders. Upon further inspection, when I turn the crank and these pistons are travelling on the down stroke, I push on the top of the piston and there is a clunking sound. There is maybe a 1/6 to 1/8 of play. This happens on both of these pistons but none of the other pistons. Maybe bad rod bearings or wrist pin issue??

Here is a link to a video of the piston vertical play and some photos of the top of the pistons.

Anyways, tearing down the block, attempting the Sunnen AN-30 and reringing seems inevitable.

A few questions for you guys that I’ve heard mixed opinions on:

  1. Has anyone tried honing/reconditioning cylinders with the Sunnen AN-30?
  2. Are there special rings required for Alusil Blocks or will standard rings work? The factory ones are super expensive.
  3. Any suppliers for the Sunnen AN-30 in Canada? I do have a US address to ship to as well.

Thanks guys!

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Are you looking at Ring set part # 07L198151
Definitely looks like you need to inspect the Rod bearings. I’ve seen a few V10’s and RS5 V8’s (same Rods) have the bearings go bad, not sure if it is an oiling issue or undersized for the stresses. For the Rod bearings I’d highly recommend you go with Kings bearings rather than OEM. King bearings are the industry best for Rod & Main bearings. High Tech coating and all.
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You are correct on the piston ring part number. I’ll check out the King bearings. I tore down the bottom of the engine and it seems the bearings are done as you said. I just need to confirm that these will fit. The S6 is not listed for this item on the King website. Thanks for the info!

Yep, bearings non existent. Will have to tear down further and inspect the crank and remaining connecting rods, etc.

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Hate to see that as with that kind of play there is almost certainly crankshaft rod journal damage.

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