Might need motor replaced

[MRM]

I might be in the market for a used or rebuilt Chevy 4.3, w engine code, 99-?
Anyone have a good experience in north Ga with a used/rebuilt company or installer?
I could install it myself.

I was going to replace the rod bearings myself. I paid someone to try. It held up for about 3 mo of light use. The knock is back.
I don't know if they measured the bearings or used a standard set.
The knock came back intermittent so I suppose it could be something else.
I might drop the pan and "verify" or increase the torque slightly.
Anyway I don't have any bottom end experience.
Anyone "save" an engine like this? It is a low use truck.
Cheers

 

[Boz1911]

I wouldn't advise on increasing the torque. If anything drop a main also while you're there and have look see. Measure the crank before you buy anything. I have heard of people replacing the main bearings while the crank is still in the car, not something I'd want to do though

 

[MRM]

Yeah. I should have done the rod bearings myself...
I would have measured them.
I wonder if it is worth a try still.

I don't think I would want to try the main bearings.

 

[tas6691]

put a crank kit in it if the top end is strong. Can do it in frame most likely

 

[libertysteeth]

What's the oil pressure?

 

[jeep78]

Plastigauge the mains and rod bearings to see what you have.

It used to be standard practice to replace bearings in the field when they got loose.

It is probably still in the maintenance manual on that model vehicle, if not, I am sure I have the min/max and field reject on the running clearances.

I did this to an engine 5 years ago, and the knock never returned, plus oil pressure is staying normal.

Is that a countershaft engine? Are you sure it is rod knock you are hearing? Check timing chain slack while you are at it. When I had to rebearing my engine, I had 18 degrees of slack in my timing chain.

 

[MRM]

The engine has 200k on it. No top end problems.
I bet I would have to pull it to install a crank kit. I'm outdoors so that might be a little aggressive.
I would almost rather buy a short block if I was going to go that far.

 

[MRM]

Oil pressure is good. Same as it always was.
The knock went away when warm before the first repair attempt.
Now it is back and faint when warm.
It came back intermittent which I find odd.

 

[tas6691]

I would look for a lower mileage used motor personaly

 

[MRM]

Excellent. This gives me hope.
How difficult is rolling in the main bearings?
I asked for the plastigauge at the parts store when I was going to do it. They were clueless.
Good idea, just gauge them all.
I am not sure if it has the countershaft

What's the oil pressure?

Plastigauge the mains and rod bearings to see what you have.

It used to be standard practice to replace bearings in the field when they got loose.

It is probably still in the maintenance manual on that model vehicle, if not, I am sure I have the min/max and field reject on the running clearances.

I did this to an engine 5 years ago, and the knock never returned, plus oil pressure is staying normal.

Is that a countershaft engine? Are you sure it is rod knock you are hearing? Check timing chain slack while you are at it. When I had to rebearing my engine, I had 18 degrees of slack in my timing chain.