Rod Bearing Failure Analysis
- Thread starter Taylor
- Start date
- Status
Probably ran on 5W-20.
If you get a little piece of sand in the oil, it'll rip right through that thin film of 5W-20.
If you get a little piece of sand in the oil, it'll rip right through that thin film of 5W-20.
Originally Posted By: Merkava_4
Probably ran on 5W-20.
If you get a little piece of sand in the oil, it'll rip right through that thin film of 5W-20.
And your thinking it wouldn't do that to a 30w or 40w oil?
Tell us why. And also explain that bit you said about how oil closes up ring gaps, too.
I'm all ears...
Probably ran on 5W-20.
If you get a little piece of sand in the oil, it'll rip right through that thin film of 5W-20.
And your thinking it wouldn't do that to a 30w or 40w oil?
Tell us why. And also explain that bit you said about how oil closes up ring gaps, too.
I'm all ears...
Last edited:
Just from the picture it looks like the tabs were not nested properly, possibly in backwards.
My first thought was they were installed bone dry.
My first thought was they were installed bone dry.
Taylor,
I don't believe the bearing spun.
I don't see any problem with the pictures of the connecting rods. Sometimes the quality of the machine work is less than optimal and the final sizing is a bit rough. This is actually quite normal.
I don't see any extensive wear on the bearing.
I don't see where you've posted any measurements of bearing clearances. I can't help you without good data.
However, it looks to me like the bearings are not the issue, from the pictures I currently see. Could be a piston pin knock, or piston slap.
Please post DATA so I can help.
I don't believe the bearing spun.
I don't see any problem with the pictures of the connecting rods. Sometimes the quality of the machine work is less than optimal and the final sizing is a bit rough. This is actually quite normal.
I don't see any extensive wear on the bearing.
I don't see where you've posted any measurements of bearing clearances. I can't help you without good data.
However, it looks to me like the bearings are not the issue, from the pictures I currently see. Could be a piston pin knock, or piston slap.
Please post DATA so I can help.
This is classic bearing wear. No knock at all. But from an engine that is known to have bearing issues. Looks nothing like yours.
Here is a classic spun bearing:
Here is a classic spun bearing:
The debris in the bearings is a bit much. But, that's not all that unusual either. Modern bearings are designed to allow particulates small debris to embed in the bearing shell and allow continued operation without impact on engine life. Looks like they did their job properly.
Originally Posted By: Cujet
Taylor,
I don't believe the bearing spun.
I don't see any problem with the pictures of the connecting rods. Sometimes the quality of the machine work is less than optimal and the final sizing is a bit rough. This is actually quite normal.
I don't see any extensive wear on the bearing.
I don't see where you've posted any measurements of bearing clearances. I can't help you without good data.
However, it looks to me like the bearings are not the issue, from the pictures I currently see. Could be a piston pin knock, or piston slap.
Please post DATA so I can help.
I'm inclined to agree with you. If the bearing had spun, the tab would have been long gone and the outside of the shell would have been toast. The wear marks on the I.D. of the bearing posted look semi normal to me. In fact, I've seen a lot worse operate normally before tear down.
Without hearing any knocking noise pre tear down, I also agree that it could be piston slap or wrist pin noise. I've heard some pretty chattery 4.7's- even when they were hot, and it definitely wasn't rod knock.
Taylor,
I don't believe the bearing spun.
I don't see any problem with the pictures of the connecting rods. Sometimes the quality of the machine work is less than optimal and the final sizing is a bit rough. This is actually quite normal.
I don't see any extensive wear on the bearing.
I don't see where you've posted any measurements of bearing clearances. I can't help you without good data.
However, it looks to me like the bearings are not the issue, from the pictures I currently see. Could be a piston pin knock, or piston slap.
Please post DATA so I can help.
I'm inclined to agree with you. If the bearing had spun, the tab would have been long gone and the outside of the shell would have been toast. The wear marks on the I.D. of the bearing posted look semi normal to me. In fact, I've seen a lot worse operate normally before tear down.
Without hearing any knocking noise pre tear down, I also agree that it could be piston slap or wrist pin noise. I've heard some pretty chattery 4.7's- even when they were hot, and it definitely wasn't rod knock.
Originally Posted By: Cujet
Taylor,
I don't believe the bearing spun.
I don't see any problem with the pictures of the connecting rods. Sometimes the quality of the machine work is less than optimal and the final sizing is a bit rough. This is actually quite normal.
You summed it up better than I.
Taylor,
I don't believe the bearing spun.
I don't see any problem with the pictures of the connecting rods. Sometimes the quality of the machine work is less than optimal and the final sizing is a bit rough. This is actually quite normal.
You summed it up better than I.
Originally Posted By: The_Eric
Originally Posted By: Cujet
Taylor,
I don't believe the bearing spun.
I don't see any problem with the pictures of the connecting rods. Sometimes the quality of the machine work is less than optimal and the final sizing is a bit rough. This is actually quite normal.
I don't see any extensive wear on the bearing.
I don't see where you've posted any measurements of bearing clearances. I can't help you without good data.
However, it looks to me like the bearings are not the issue, from the pictures I currently see. Could be a piston pin knock, or piston slap.
Please post DATA so I can help.
I'm inclined to agree with you. If the bearing had spun, the tab would have been long gone and the outside of the shell would have been toast. The wear marks on the I.D. of the bearing posted look semi normal to me. In fact, I've seen a lot worse operate normally before tear down.
Without hearing any knocking noise pre tear down, I also agree that it could be piston slap or wrist pin noise. I've heard some pretty chattery 4.7's- even when they were hot, and it definitely wasn't rod knock.
You catch the video?
Originally Posted By: Cujet
Taylor,
I don't believe the bearing spun.
I don't see any problem with the pictures of the connecting rods. Sometimes the quality of the machine work is less than optimal and the final sizing is a bit rough. This is actually quite normal.
I don't see any extensive wear on the bearing.
I don't see where you've posted any measurements of bearing clearances. I can't help you without good data.
However, it looks to me like the bearings are not the issue, from the pictures I currently see. Could be a piston pin knock, or piston slap.
Please post DATA so I can help.
I'm inclined to agree with you. If the bearing had spun, the tab would have been long gone and the outside of the shell would have been toast. The wear marks on the I.D. of the bearing posted look semi normal to me. In fact, I've seen a lot worse operate normally before tear down.
Without hearing any knocking noise pre tear down, I also agree that it could be piston slap or wrist pin noise. I've heard some pretty chattery 4.7's- even when they were hot, and it definitely wasn't rod knock.
You catch the video?
Heard the video. Not much info there. I hear some noise. Could be valves could be a broken flex plate on the transmission. It's not very helpful without a left-right, up down microphone movement around the engine.
In the first picture is that tab damaged? You say you suspected #3 and/or #5 were either of those rod caps put on backwards? If you follow me, not the bearing in the cap backwards but the cap itself on the rod if that's even possible on this engine.
These bearings didn't spin that's for sure otherwise the half shell with the oil hole would not be still in the rod side, it would be all over the place but the machining looks terrible.
Are all the rods and caps like the one in the picture? Are any of those ridges deep enough to hang you fingernail on?
If someone did the rod bearings from under the vehicle it would be easy to put a cap on backward.
It looks to me like they were dirty putting it together or they didn't lube the bearing shells but that wouldn't cause a knock.
Instead of pulling the engine you could just do some plastiguage to get a rough idea.
Honestly I have no idea what is normal and not with this engine I am just bouncing ideas around in my head.
The bearings don't look like what you would find in an engine with a knocking rod but like you say did someone just put these in and if so why and what did the ones taken out look like.
These bearings didn't spin that's for sure otherwise the half shell with the oil hole would not be still in the rod side, it would be all over the place but the machining looks terrible.
Are all the rods and caps like the one in the picture? Are any of those ridges deep enough to hang you fingernail on?
If someone did the rod bearings from under the vehicle it would be easy to put a cap on backward.
It looks to me like they were dirty putting it together or they didn't lube the bearing shells but that wouldn't cause a knock.
Instead of pulling the engine you could just do some plastiguage to get a rough idea.
Honestly I have no idea what is normal and not with this engine I am just bouncing ideas around in my head.
The bearings don't look like what you would find in an engine with a knocking rod but like you say did someone just put these in and if so why and what did the ones taken out look like.
I had done that as well, I'll see if I can find it. It at first I thought it was coming from the top end near cyl's 3&5. But when under the jeep, it was also loud from the oil pan. I pulled the head covers, 13 failed lash adjusters. Pulled the timing chain cover, and the drivers secondary was quite loose.
In laws in town today, so looks like I won't be pulling the motor until tomorrow.
In laws in town today, so looks like I won't be pulling the motor until tomorrow.
Originally Posted By: Trav
In the first picture is that tab damaged? You say you suspected #3 and/or #5 were either of those rod caps put on backwards? If you follow me, not the bearing in the cap backwards but the cap itself on the rod if that's even possible on this engine.
These bearings didn't spin that's for sure otherwise the half shell with the oil hole would not be still in the rod side, it would be all over the place but the machining looks terrible.
Are all the rods and caps like the one in the picture? Are any of those ridges deep enough to hang you fingernail on?
If someone did the rod bearings from under the vehicle it would be easy to put a cap on backward.
It looks to me like they were dirty putting it together or they didn't lube the bearing shells but that wouldn't cause a knock.
Instead of pulling the engine you could just do some plastiguage to get a rough idea.
Honestly I have no idea what is normal and not with this engine I am just bouncing ideas around in my head.
The bearings don't look like what you would find in an engine with a knocking rod but like you say did someone just put these in and if so why and what did the ones taken out look like.
No the tag wasn't wiped, and yes all rods/caps are the same. Some of the scratches do hang a nail on the rods/caps. They are fractured rods, so I don't even know if they'd go on backwards, and if so, I think it would have shown on those cyl's.
In the first picture is that tab damaged? You say you suspected #3 and/or #5 were either of those rod caps put on backwards? If you follow me, not the bearing in the cap backwards but the cap itself on the rod if that's even possible on this engine.
These bearings didn't spin that's for sure otherwise the half shell with the oil hole would not be still in the rod side, it would be all over the place but the machining looks terrible.
Are all the rods and caps like the one in the picture? Are any of those ridges deep enough to hang you fingernail on?
If someone did the rod bearings from under the vehicle it would be easy to put a cap on backward.
It looks to me like they were dirty putting it together or they didn't lube the bearing shells but that wouldn't cause a knock.
Instead of pulling the engine you could just do some plastiguage to get a rough idea.
Honestly I have no idea what is normal and not with this engine I am just bouncing ideas around in my head.
The bearings don't look like what you would find in an engine with a knocking rod but like you say did someone just put these in and if so why and what did the ones taken out look like.
No the tag wasn't wiped, and yes all rods/caps are the same. Some of the scratches do hang a nail on the rods/caps. They are fractured rods, so I don't even know if they'd go on backwards, and if so, I think it would have shown on those cyl's.
Should be noted that in these videos, the exhaust manifold studs at the number 7 cyl were snapped and at that cyl it was leaking exhaust, when I pulled it, the gasket was clean around the rest of the cyl's suggesting they weren't leaking. Just noting this due to the fact it may affect the resonation of the knock.
That's what I was wondering if in fact it was #3 and 5 if those were the caps.
Chances are there the bearings are not the source of the noise.
I never saw machining like that behind the shell, they are usually honed to a fairly decent finish but who knows they may not need to be and there may be even some advantage to it.
Its sounds like your on to something though with the other parts.
Chances are there the bearings are not the source of the noise.
I never saw machining like that behind the shell, they are usually honed to a fairly decent finish but who knows they may not need to be and there may be even some advantage to it.
Its sounds like your on to something though with the other parts.
- Status
Similar threads
