First time rebuilding engine - need advice from experienced folks

Kornilov

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Rebuilding an Audi 2.0 TSI engine. Have it torn down to the block, have cleaned block, had crank polished at the machine shop and honed cylinders.

I just got the new bearings & bolts in and went to start mocking things up for re-assembly in the lower end. When I went to look at the area where the lower main bearing sits, I saw a lot wear and scratches. Nothing that I can feel with my finger, but none the less, they are there:

49849732318_4d74737161_b.jpg
IMG_2879 by emanookian, on Flickr

49850267531_870960d13c_b.jpg
IMG_2878 by emanookian, on Flickr

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IMG_2877 by emanookian, on Flickr
 

Kornilov

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So the question is, is this a concern? If I put new bearings in there, would it be ok or do I need to address the wear marks? This is not a build for power just to get back to OEM specs for a daily driver. The original issue was the the oil pump failed and flooded metal particles through the engine - that's likely where the gouges comes from.
 

Blkkbgt

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With that much surface area showing damage I would seriously consider having the mains align honed. If it were just a few spots I'd install the bearing and go.

One thing you could try is to take a new razor blade and gently scrap the areas and see if any metal collects on the blade. Go up and away from the oil hole to keep metal out of the main galley. You can also plug the hole with and ear plug to help keep metal out. Leave it very proud of the saddle so that it's not forgotten. If metal collects on the blade you really need to have the mains cut because the bore is most likely out of round due to the damage.
 
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IronSnake

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The part that sticks out to me, is what appears to be heat spots. Cross hatching looks present, but you definitely have abnormal wear. I agree with the above, and worst case get a line hone down the mains to clean it up.
 

BigPoppa

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Nothing rotates on there (the crank rides on a film of oil between it and the bearing), so as long as the clearances are good when you put the bearings in, you should be fine. As said above, it looks like normal varnish, but you paid for a block cleaning and I've never got a block back from cleaning that looked that dirty.
 

derklug

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The lower end on Audi 2.0s is the last place you need to worry about. What you see really is not a problem. The bearings go in there and don't move. Having the cylinders honed should get rid of your oil consumption, spend the money to get the cam alignment kit as that is where I see most guys go wrong.
 

Kornilov

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Nothing rotates on there (the crank rides on a film of oil between it and the bearing), so as long as the clearances are good when you put the bearings in, you should be fine. As said above, it looks like normal varnish, but you paid for a block cleaning and I've never got a block back from cleaning that looked that dirty.

Lol. Sorry if I wasn't clear - I didn't pay for the block to be cleaned - I hosed it off in the driveway, brushed off the major gunk, and hit it with a couple coats of high temp engine paint. Then I honed the cylinders.

The only thing I paid the machine shop to do was polish the crank - which they did do a great job of.

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IMG_2844 by emanookian, on Flickr
 
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Kornilov

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Ok so, here's some more to the story. Before I decided to rebuild the engine that was in the car, I plucked a junkyard engine out of a 2007 Passat (the Audi A4 and Passat of the era share the same engine except for minor accessories, oil pan, and mounts) with the intention of dropping the JY engine into the car to get it back on the road quickly. However, I ultimately decided to go down the rebuild road.

Now I have the choice of one block or the other.
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IMG_2881 by emanookian, on Flickr

Tonight I cleaned up the JY block and honed the cylinders. But discovered the #3 cylinder has this bit of a gouge. Its just deep enough that I can feel it with the skin of my finger but not deep enough to catch a nail on (this is after 40 passes with the ball hone):

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IMG_2883 by emanookian, on Flickr

The rest of the cylinders look damn good:
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IMG_2882 by emanookian, on Flickr

The bottom of the JY motor looks good too - none of the same scratches/gouges that the original block has.

So my inclination is to go with the JY block even though the #3 cylinder has a decent size scratch.

Given the choice between blocks, which would you go with?
 

Kornilov

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For the record - the original motor wasn't consuming oil. The cause of failure was the balance shaft in the oil pump assembly failed, causing the gears on the balance shaft to grind into the gears of the oil pump shaft, reducing the performance of the oil pump AND flooding the engine with metal laced oil. Between the oil pump working at reduced PSI and the tons of metal debris in the oil, the main and road bearings got scored and gouge to shit.
 

ShelbyGT5HUN

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I'm no expert, but the honing you did, looks too parallel to the cylinder bores there should be more of a crosshatch effect those honing marks look too parallel to each other. Could run into oil consumption issues?
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BigPoppa

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I'm no expert, but the honing you did, looks too parallel to the cylinder bores there should be more of a crosshatch effect those honing marks look too parallel to each other. Could run into oil consumption issues?View attachment 1638721
This.

That comes from moving it in and out too slow. Run it in and out faster until you see good cross hatching.
 

screamngdave

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What you are calling "scratches" in the main bearing saddles are from where the block was line honed at manufacturing/machining plant and aren't a concern. You can use some brakecleaner and a scotch bright pad(I would use the red pad) to clean off the oil varnish that's there. I would definitely re-hone the cylinders because your patter is wayyyy to parallel and will lead to oil consumption and ring sealing issues. I would also suggest you check the bore with a Dial Bore Gauge to make sure you haven't opened the hole up to much and to also make sure it hasn't become tapered. Just my .02 and hope it helps.
 

Kornilov

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Thanks everyone for your input. So after mulling it over a couple of days, I will go with the original block and I will re-hone the cylinders to get a better crosshatch.
 

Kornilov

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Thanks fellas,

Re-honed the cylinders on the original block today and got a little better crosshatching going:

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IMG_2893 by emanookian, on Flickr

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IMG_2889 by emanookian, on Flickr

If the weather holds up tomorrow, I will wash the block again and then start checking & fitting the bottom end for re-assembly again.
 

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