Swapping out rod bearings without taking engine out

[mycarsucks]

I have a 94 gp with what sounds like the beginning of a rod knock when the engine is warmed up, i know on a 3800 you can swap out the barings with the motor still in the car by pushing the top bearing around the crank journal and out. Is this possible with the 3100 and what do I need to do to take the oil pan.

[mycarsucks]

 

 

[mycarsucks]

has anyone else changed out the bearings with the motor in the car successfully? I cant find any other threads on this site, and I don't have the time or money to replace the engine.

[94 olds vert]

If it is knocking, you likely need to replace or rebuild the engine. 

[mycarsucks]

9 minutes ago, 94 olds vert said:

If it is knocking, you likely need to replace or rebuild the engine. 

It just started knocking, It was only running for 20 minutes or so once it started. I have swapped bearings into motors that had worse knock than this and it turned out just fine, I'm just wondering if it is possible with these cars to drop the oil pan completely or does the subframe need to be removed.

[94 olds vert]

1 minute ago, mycarsucks said:

It just started knocking, It was only running for 20 minutes or so once it started. I have swapped bearings into motors that had worse knock than this and it turned out just fine, I'm just wondering if it is possible with these cars to drop the oil pan completely or does the subframe need to be removed.

The subframe is in the way. In order to remove the oil pan, the subframe will have to be removed. 

[mycarsucks]

 

 

Really? You cant just lower it at an angle and wiggle it out?

5 minutes ago, 94 olds vert said:

The subframe is in the way. In order to remove the oil pan, the subframe will have to be removed. 

[94 olds vert]

17 minutes ago, mycarsucks said:

 

 

Really? You cant just lower it at an angle and wiggle it out?

It appears you can raise the engine enough to clear the oil pan with the subframe in place on a 3100. 

[55trucker]

My 1st thought is ....what has caused a bearing started to knocking? They don't do so because they like to.......

The most obvious answer would be ......poor oil pressure.

which bearing is the one that has the knock? Front of the engine or rear.......

 

[mycarsucks]

Just now, 55trucker said:

My 1st thought is ....what has caused a bearing started to knocking? They don't do so because they like to.......

The most obvious answer would be ......poor oil pressure.

which bearing is the one that has the knock? Front of the engine or rear.......

 

Idk which one it is and I dont really want to run the engine any longer to risk damaging the crank or the rod..

It noticed it knocking at 2000rpms after I went full throttle to avoid an accident on the interstate on the way home from work...

Motor has high mileage so i bet it just didnt have enough oil pressure to keep the bearing lubricated at 5200ish rpms.

Time to roll in some new bearings if the crank isnt damaged but I doubt it is because you can only hear the knock over 2k rpms

[55trucker]

Pick up a stethoscope, get under the car & search for the loudest point under & alongside the oilpan for the knock volume.

At idle there won't be a significant amount of damage outside of what already has happened.

you should really find out what the engines oil pressure is, seeing as you say this IS a high mileage item, ALL of the bearing (both crank & cam) clearances are more than likely opened up, the pump may be a question mark, replacing just the con rod shells won't be the cure.

[mycarsucks]

20 minutes ago, 55trucker said:

you should really find out what the engines oil pressure is, seeing as you say this IS a high mileage item, ALL of the bearing (both crank & cam) clearances are more than likely opened up, the pump may be a question mark, replacing just the con rod shells won't be the cure.

 i dont see why it would matter which bearing is making noise if im taking the pan off im replacing all rod and main bearings and also polishing the crank,,, 

ive seen bearing rolls on 350 small blocks with louder knocks and higher mileage and never had an issue so this shouldnt be much different i just want to know if you can in this motor because some motors you cant push the bearing around to the other side of the crank

Edited May 3, 2024 by mycarsucks

[Schurkey]

Doing that "in the chassis" would never happen in MY driveway.

That engine would come OUT, so I didn't have to work on my back like a prostitute for the whole job.  Flip the engine over on an engine stand, rather than flipping the worker over on the concrete.

Likely get a better job done with the main seal, pan gaskets, etc.  High mileage?  Timing set, rings, head gaskets and valve job.  MAYBE bore + pistons, crank grind, block decking...

[mycarsucks]

since its such a pain in the ass to take the stupid oil pan off I put 2 quarts of Lucas and another 2 quarts of 10w40 in and that seemed to quiet it down a little. gonna baby It until I have the time to swap a jy motor in