I have a problem, I have a bad knocking noise in my bottom end that I thought to be the main bearings. I just got everything apart, I had the new .020" sized bearings ordered and ready, (as opposed to the .010" bearings currently in there) and I am looking at them. Do these look like they are wearing wrong and could be my bottom end knocking noise? Or am I hearing connecting rod bearings instead? I just dont wanna put in the new bearings and find out it isn't going to fix my problem. I measured the main journals and found they were .018 smaller than original. I used a digital vernier, so maybe I am off a tad.Any help is greatly appreciated, and I need a quick answer because I have to have this job done tonight so I can drive it to work tommorow lol. Sorry for the bad pics, it's the best I can come up with. As you can see in the second and third pics, the bearing isnt wearing on the sides much at all.

 

Those look OK to me. Not exactly "brand new"; but certainly not "knocking", either.

I'd say your knock is elsewhere.

In fact, looking at those, it looks near impossible to me that you have any bearing problem at all. I see no evidence of metal shavings in the oil or low oil pressure. Just some normal used bearings, with some miles on them.

 

Thats the thing, they only have about 5000kms on them. I just pulled a connecting rod cap and those bearings are wearing perfectly. This is what I am talking about, this lighter area is the coating that comes on the ebarings from the factory. Usually it wears off right away. Also I wiped all the oil away, there are no shavings in it though anyways.

 

Right; that's what I'm saying. They look fine. Put them back together, because your problem is not there.

Look at your flex plate. REAL carefully. Around the crank flange bolt holes.

 

Here are some more pics of another bearing cap I popped off. I'd say something is wrong.











I am pretty positive it isnt the flexplate. I have been debating it and asking everyone about it for weeks now and everything points to a bottom end knock. It even sounds like it's coming more from the oil pan area.

 

Looks fine to me. In fact, looks like the crank hasn't even touched in the center there, like maybe somebody over-tightened the oil pump bolt at some point in the past. There's NOTHING wrong with that bearing though.

How bout that flex plate?

 

See this is what I think is happening, the crank is moving around because the bearings are too big, so the crank is sloppy, and is moving side to side and up and down and all around when the engine is running and revving up. It is bouncing off the various points on the bearing and making those wear spots and leaving other spots untouched. Here is an illustration:

 

what do the other half of the bearings look like?

 

Just pulled one, the other halfs are even worse, the crank has hardly touched them. They only have light scratchs.

 

There's no wear on those spots, because installed bearings aren't round. The clearance is wider parallel to the parting line than it is perpendicular.

It's also normal for the lower bearing half to wear sooner than the top, since that's the direction all the force is applied in.

Nothing wrong with those bearings.

 

They're fine. They ARE NOT your knock.

How bout that flex plate?

 

You said you're running .010" under bearings and the crank measures .018" under?
How accurate do you think that digital vernier is? Try measuring your feeler gauges to be sure. It should be within .003" at least, and that would mean you're in trouble.
I only saw your first picture in this thread, there are no others showing. Am I missing something?

 

see i can clearly see copper in those bearings... i just pulled a set out of my new long block that had 80,000 original miles that werent anywhere near the copper

 

The crank is stamped M .010 which I am told means the mains have been turned down .010, it also says T .010, what does that mean? I don't wanna put the wrong bearings in again, please help. I just plastigauged the .020" bearings and came out with .003" clearance. Sounds about right eh?

 

M 010 is probably "mains undersize .010", and T 010 is probably "throws undersize .010", which is pretty standard.

 

What of my plastigauge reading? would they have turned it down another .010 at one time and not stamped it?

 

It's certainly possible. Personally I wouldn't trust plastigauge for anything and I'd measure the journals with a real measurement tool.

 

I think plastigauge is good to .001" accuracy or so, most likely better than the caliper, assuming you're using it right.
If you're using the .0005-.003" plastigauge, and it shows .003", you could have .012" clearance and it's not even touching.

You're using the green plastigauge? Try the larger stuff, red I think?

Or, if you want to be sure, walk into a machine shop with the crank and ask them "WTF?". They can whip out a .0001" accurate micrometer and give you a real good measurement for free if you ask nicely. Or slip the guy $10 or something for his troubles.

 

Are you seriously going to run 020 under bearings on a worn out 010 under crank without having machined it to that size? Holy crap! Advance auto parts can get you a reman crank kit for around $150, with new bearings --

 

When I thought it was a flexplate, everyone said bottom end. Now that I suspect bottom end and have ruled out the flexplate, everyone says flexplate. My car has zero oil pressure with the .010's, and I don't want to run it like that.

 

Had to search your other posts.

I'd ditch the crank and start over. You may have damaged that thing running the wrong bearings. I'd also have someone check the rods (its possible your vernier is correct) to make sure those wrong bearings didnt ruin the big end of the rod. Probably unlikely but at least check it.

 

http://www.youtube.com/watch?v=dGNnlh93Vfw

A quick sound clip of the engine knock, it's hard to hear unless you listen real closely or have selective hearing.