Rod bearings scored?

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doogievlg

doogievlg

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I pulled my engine part last night and I found that my main bearings are smoked so this is not a huge deal but I was curious. Anybody have an idea of what may cause this?

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doogievlg said:
I pulled my engine part last night and I found that my main bearings are smoked so this is not a huge deal but I was curious. Anybody have an idea of what may cause this?

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When the scratches are uniform like that it tells me the crank grinder didn't do his job. What you are seeing is marks in the bearing from scratches on the rod throws.
 
After looking at your main bearings in the other thread, and seeing the surface material flaking off of them, I am inclined to think that there has been main bearing surface materials going up into the rods. It is one of 2 places where that crud would go.....

The small scratches and the dark wear area in the middle look pretty typical to me. The spots are probably the other crud from the mains. I don't see anything awful there.

The mains sure are worn out and deteriorated.... that looked unusually poor.
 
yellow rose said:
When the scratches are uniform like that it tells me the crank grinder didn't do his job. What you are seeing is marks in the bearing from scratches on the rod throws.
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The engine will be going to a different machinest for sure. I double checked every tolerance in the short block and everything looked dead on.
 
nm9stheham said:
After looking at your main bearings in the other thread, and seeing the surface material flaking off of them, I am inclined to think that there has been main bearing surface materials going up into the rods. It is one of 2 places where that crud would go.....

The small scratches and the dark wear area in the middle look pretty typical to me. The spots are probably the other crud from the mains. I don't see anything awful there.

The mains sure are worn out and deteriorated.... that looked unusually poor.
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The main bearings are absolutely trashed. Only one rod bearing that had significant wear.

271A8857-EBF7-45B7-834F-01217715FC0B.jpeg
 
See if you can relate which main and its bearings fed to this rod bearing. A lot of something was coming up into this rod bearing. That's pretty nasty looking.
 
That one score almost in the center of that first one looks like they didn't chamfer the oil hole in the journal good. Those holes should be re-chamfered to remove any sharp edges that could score the bearings like that. That's a kindergarten machinist's mistake. Find another machine shop.
 
nm9stheham said:
See if you can relate which main and its bearings fed to this rod bearing. A lot of something was coming up into this rod bearing. That's pretty nasty looking.
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I set all bearings back in the pistons they came out of and kept the rod bearings in order and some I just sat back on the journal. I plan on taking the bearings up with the block and crank to the machinest.
 
didnt you recently rebuild that?
 
At this point it really does not matter too much though. Even if I reuse that same crank I will have it reground and they will be assembling the short block.
 
dukeboy_318 said:
didnt you recently rebuild that?
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Motor was rebuilt in 2013. Could something as simple as oil pump failure cause this?

I did not have an oil pressure gauge on the car but I cut the filter open and found the metal then threw a oil pressure gauge on it right away.

I’ll be installing a permanent oil pressure gauge when the engine goes back in.
 
doogievlg said:
Motor was rebuilt in 2013. Could something as simple as oil pump failure cause this?

I did not have an oil pressure gauge on the car but I cut the filter open and found the metal then threw a oil pressure gauge on it right away.

I’ll be installing a permanent oil pressure gauge when the engine goes back in.
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yep, very easily. heck, a clogged oil passage or even a restricted one can cause it.
 
doogievlg said:
The engine will be going to a different machinest for sure. I double checked every tolerance in the short block and everything looked dead on.
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I'll ask the question.........every thing looked dead on "what"?? Do you have a list of the clearances you measured?
Did this thing detonate much? How long was it in service? It doesn't look like it was running happy!
 
JBurch said:
I'll ask the question.........every thing looked dead on "what"?? Do you have a list of the clearances you measured?
Did this thing detonate much? How long was it in service? It doesn't look like it was running happy!
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The measurements were dead on the specs that came out of a book on Chrysler small block engines. I can dig that info up when I get home but they were exactly the same as the numbers listed. No detonation that I noticed. I was fairly conservative with my timing with 16 initial and 34 total. See above comments about the engine life. As far as mileage goes in those 4 years I would say maybe 2000.
 
Bearings are 4 years old, and maybe 2000 miles and they look like that!!!! You've got some basic fundamental issues going on. I will guess ( I could be wrong ) a start at improper clearances, ie too tight. They may have been right on the money as listed in the manual and the manual probably spec'ed out clearances in the range of .0005 to .0025, anything in that range would be "right on the money" and that's not a bad thing depending on intended purpose; Grandma going to the store, OR stand on it once and a while, entertain yourself, go to the track and stand on it. Grandma would be happy at .001 even .0015 clearance; stand on it thrill at .0015 clearance and the crank most likely will bite the bearings, .0025 to .003 would be better. I learned this one over a decade ago on a 360 I had put together, it ran about a 1/2 hour total wasn't bearing failure it was something else but I had to tear the engine completely down and found every bearing marked up ( should have kept them for garage art ). In trying to learn what happened and why, an acquaintance looked at them and stated the clearance was too tight ( I had them at .0017 to .0022 ) and he then said "loose don't break", I took my crank back to grinder and had .001 taken off, I carry 20 psi hot idle and 75 when I'm into it, std pump, hp spring, Shell Rotella 15/45.
 
JBurch said:
Bearings are 4 years old, and maybe 2000 miles and they look like that!!!! You've got some basic fundamental issues going on. I will guess ( I could be wrong ) a start at improper clearances, ie too tight. They may have been right on the money as listed in the manual and the manual probably spec'ed out clearances in the range of .0005 to .0025, anything in that range would be "right on the money" and that's not a bad thing depending on intended purpose; Grandma going to the store, OR stand on it once and a while, entertain yourself, go to the track and stand on it. Grandma would be happy at .001 even .0015 clearance; stand on it thrill at .0015 clearance and the crank most likely will bite the bearings, .0025 to .003 would be better. I learned this one over a decade ago on a 360 I had put together, it ran about a 1/2 hour total wasn't bearing failure it was something else but I had to tear the engine completely down and found every bearing marked up ( should have kept them for garage art ). In trying to learn what happened and why, an acquaintance looked at them and stated the clearance was too tight ( I had them at .0017 to .0022 ) and he then said "loose don't break", I took my crank back to grinder and had .001 taken off, I carry 20 psi hot idle and 75 when I'm into it, std pump, hp spring, Shell Rotella 15/45.
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What exactly is a fundamental issue? Took the car to the track three times and highest I shifted was 6200 rpm. 9 passes
 
on the second pic with the heavy wear off to one side I would check if that rod is bent or twisted.
 
doogievlg said:
What exactly is a fundamental issue? Took the car to the track three times and highest I shifted was 6200 rpm. 9 passes
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I'm just saying that in 4 years, approximately 2000 miles ( average 500 miles a year ), 9 trips down the track and bearings look like they do, something very basic from the beginning was not right, and at this point it's all wild speculation. If you're building another engine, I hope it turns out better than this one; good luck.
 
JBurch said:
I'm just saying that in 4 years, approximately 2000 miles ( average 500 miles a year ), 9 trips down the track and bearings look like they do, something very basic from the beginning was not right, and at this point it's all wild speculation. If you're building another engine, I hope it turns out better than this one; good luck.
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Wasn’t my first and certainly won’t be my last. Things happen.
 
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