rod bearing?

[INCase]

Ok. finally got the old girl Case 800 running with new LP heads and newer/better manifolds (gas).

Here"s the PRoblem... now that its quieter I can hear a pretty good rattle/knocking/clatter sound in the lower end. Its not real loud but can be heard especially on the right side not as loud on the left. Its mainly near the front of the engine near #1. I pulled the wires off the plugs as I read in an ooold post that that can help determine if its a rod knock. The noise did not change at all with the spark plugs disabled. The soundis also still there with an increase in speed (just sounds like a faster rattle/clatter). I did drain the oil. The 1st oil to come out was kinda watery/sluggy mix and is somewhat black/grayish in color with a little gas smell. It had cracked heads and I knew it was getting some water in the oil that way and do not know how long the previous owner ran it that way. I pulled the pan and pulled #1 and #4 caps off. The picture is from the #1. #4 looks a little better (less grooves).

What does a rod or main bearing knock sound like? Would bad cam bearings make that sound?

Thanks for any and all feedback and help.

 

[Paul from MI]

Rod bearings usually knock worse at an idle or when you rev the engine, then back off quickly to an idle. Main bearings tend to knock more under a load at low rpm. From the looks of the bearing, it's just plain worn out. It's worn clear thru the babbitt and into the bronze backing. Many times a bearing this bad will have also damaged the crank. I would check the journals for size and roundness before proceeding. You may need to grind the crank before putting in new bearings. Cam bearing have to be pretty bad before they make much noise. Probably time for a majoer overhaul.
Good luck,
Paul

 

[noncompos]

I agree 100% with Paul. I will add that loose rods (worn rod bearing) tends to have a distintly higher metallic clattering noise than loose mains, which tend to be a lower pitched deeper thumping sound. AS Paul says, rods tend to clatter when engine sitting (trans in neutral) and engine revved, clattering as engine revs pick up, and when engine pulling load and gas backed off, like cresting a hilltop. Mains tend to sound under engine loading( pulling). Cam bearings I have no experience with.
I do find it unusual that pulling a plug wire didn't alter the sound at all if it was a loose rod (I assume you pulled all the plug wires one by one). But it's immaterial; I'd guess the engine was run too long with bad oil, and EVERYTHING needs to be checked. With sympathy, Bud

 

[caterpillar guy]

Cam bearings will show a low oil pressure reading on the oil gauge usually in addition to the rods&mains If the oil pressure picks up at inceased engine speed that is rods&mains but if it stays lower all the time at an idle and higher engine speeds it is probably cam bearings. They take a special tool to change.

 

[INCase]

Yes. Pulled 1 wire at a time. The rattle/clatter sounded like it was closer to the CAM area but upon visual inspection the CAM/lifters ect look ok. What are you refering to as "everything"? I"m new to engine lower end work. Thanks for the help.

 

[noncompos]

You commented the oil was "watery/sluggy" and "black and grayish" (and probably with the grayish streaky through the blackish?)that it also smelled of gas,and that you didn't know how long the previous owner ran it that way.
It sounds like it was run (no telling how long, but too long) with both water and gas contamination of the oil, which means reduced lubricating and cooling qualities, which means that every moving part that was supposedly being lubricated and cooled by the oil may have suffered excessive wear and overheating, and as a result may be susceptible to premature failure. Which, in turn, means that, to be safe, you should check everything supposedly oiled: pistons, rings, cyl walls, valve train, cam, ad nauseum, for evidence (like your insert) of wear, scoring and/or overheating. With sympathy, Bud