HELP rod knocking

[SALTYcracker]

I have a 99 Yukon Denali and I just replaced the damaged rod bearings and didn't see any other damage but the engine is still making noise the rod is still knocking please help

 

[strutaeng]

Give us more to the story please. Are you the original owner or you just bought the truck? Service history?

Do you have any idea why the rods started knocking? How did those bearings look? If the engine ate a bearing, that material ran through the entire engine and it's probably going to need a complete teardown and rebuild.

We won't be able to diagnose based solely on your description of the issue. Most likely needs a rebuild.

 

[tom3]

You would have needed to check clearances with the new bearings when installing. Plastigage is usually good enough to see if there's a problem that would some machine work. I'd guess a crank jpurnal was worn undersize

 

[SALTYcracker]

Give us more to the story please. Are you the original owner or you just bought the truck? Service history?

Do you have any idea why the rods started knocking? How did those bearings look? If the engine ate a bearing, that material ran through the entire engine and it's probably going to need a complete teardown and rebuild.

We won't be able to diagnose based solely on your description of the issue. Most likely needs a rebuild.

Thanks for the reply,

The motor burns oil, it's an old truck with at least 3 previous owners. It ran low on oil one day, I didn't think to check it for a week or so. that's when the motor started to knock slightly. When I made it to the house I heard the bearing jingling and clanking and the rod knocking, I'm thinking the ring is bad and my piston is making the noise because it now sounds like the noise is coming from the top of the motor. I had a recent oil change before this, and before that the truck sat for probably 5 years.
It's all I have though and I'm trying to tackle this quickly.

 

[SALTYcracker]

You would have needed to check clearances with the new bearings when installing. Plastigage is usually good enough to see if there's a problem that would some machine work. I'd guess a crank jpurnal was worn undersize

Maybe I could go back with a thicker bearing then if the journal was worn, it really didn't look too bad though to my eyes at least.

 

[strutaeng]

Thanks for the reply,

The motor burns oil, it's an old truck with at least 3 previous owners. It ran low on oil one day, I didn't think to check it for a week or so. that's when the motor started to knock slightly. When I made it to the house I heard the bearing jingling and clanking and the rod knocking, I'm thinking the ring is bad and my piston is making the noise because it now sounds like the noise is coming from the top of the motor. I had a recent oil change before this, and before that the truck sat for probably 5 years.
It's all I have though and I'm trying to tackle this quickly.

Oh man, sorry to hear that. That makes sense now.

Is this your only vehicle to get to work or school? If so, I understand you are trying to get it running, but I would just swap another junkyard motor and keep on driving. These vehicles are so old and not many folks are driving and fixing them anymore. Demand on these engines is very low and so are prices. Around here they go for $300-$500. Swap it in one weekend.

Watch one of those YT videos of the guys tearing down engines that ran low on oil. Metal to metal contact pretty much wrecks every single part inside. Cranks, rods, pistons, oil pumps, camshaft, lifters, valve train. It looks sad.

 

[SALTYcracker]

Oh man, sorry to hear that. That makes sense now.

Is this your only vehicle to get to work or school? If so, I understand you are trying to get it running, but I would just swap another junkyard motor and keep on driving. These vehicles are so old and not many folks are driving and fixing them anymore. Demand on these engines is very low and so are prices. Around here they go for $300-$500. Swap it in one weekend.

Watch one of those YT videos of the guys tearing down engines that ran low on oil. Metal to metal contact pretty much wrecks every single part inside. Cranks, rods, pistons, oil pumps, camshaft, lifters, valve train. It looks sad.

Yeah she's my only way of getting around and I was supposed to start a new job Monday. Looks like I'm battling another set back now. Is the way of life I suppose, just my luck. Thanks for the advice.

 

[Eman85]

WOW! This is like a trip down memory lane back when I was young. I had a rod bearing spin and didn't have money for more than a patch repair. I polished the crank with fine emery cloth and tried an oversized bearing which was too tight. I used a standard bearing and ran the rod cap across a file to tighten up the gap. Laugh all you want it stayed together for quite some time before I was able to change motors.

 

[SALTYcracker]

WOW! This is like a trip down memory lane back when I was young. I had a rod bearing spin and didn't have money for more than a patch repair. I polished the crank with fine emery cloth and tried an oversized bearing which was too tight. I used a standard bearing and ran the rod cap across a file to tighten up the gap. Laugh all you want it stayed together for quite some time before I was able to change motors.

That's exactly what happened with this lol. Maybe I need to polish up the rod cap and see if that helps. Guess I'll drain the oil out AGAIN