jgray152

Im going to be putting an engine in a truck I just bought and just for "preventative measures" I just got thinking of replacing the connecting rod bearings. Engine has 120K on it. The engine that is in the truck has unknown millage as it was replaced but it has a bad connecting rod bearing along with other issues...Today the oil pressure dropped to near zero since the engine got to around 400 rpm...then heard some awful screeching noises timed with the rod knock. O well.

So is there anything special I should do when replacing the rod bearings in the new engine im going to be putting in? If its too much trouble I'll just leave the original ones in. Not sure if there is any "wear" patterns I need to remove off the shafts or anything.

Amale97

Do not do anything to the crank shaft, all journals should be smooth if one has grooves on it you will need to have shaft turned or replace with a new one.
Installing rod bearings is not to difficult if engine is out of vehicle. Be sure to check each bearing you remove to see if the bearings are standard (std) or maybe undersized?
Remove cap from rod and you should be able to to push piston down enough to be able to remove rod end of bearing and replace. Be sure to pay attention to how the bearings come out they have a notch on one side that fits into a grove on the block and cap, be sure to line them up correctly. You need to turn the crank shaft so journals are up. Be sure to lube new bearings when installing them.
If your going to install new rod bearing I would install Main bearing also. If you put in new mains. loosen all the main bolts a few turns first and then remove each one, one at a time. you can turn out the block side around the crank shaft and turn in the new one the same way. A screwdriver helps get the old bearing started out. Again be sure to lube the new bearings when installing them. Also be sure to retorque all bearing bolts with torque wrench to proper amount.

jgray152

Awesome thanks for the info!

Aubrey Daigle

[QUOTE=Amale97;208359]Do not do anything to the crank shaft, all journals should be smooth if one has grooves on it you will need to have shaft turned or replace with a new one.
Installing rod bearings is not to difficult if engine is out of vehicle. Be sure to check each bearing you remove to see if the bearings are standard (std) or maybe undersized?
Remove cap from rod and you should be able to to push piston down enough to be able to remove rod end of bearing and replace. Be sure to pay attention to how the bearings come out they have a notch on one side that fits into a grove on the block and cap, be sure to line them up correctly. You need to turn the crank shaft so journals are up. Be sure to lube new bearings when installing them.
If your going to install new rod bearing I would install Main bearing also. If you put in new mains. loosen all the main bolts a few turns first and then remove each one, one at a time. you can turn out the block side around the crank shaft and turn in the new one the same way. A screwdriver helps get the old bearing started out. Again be sure to lube the new bearings when installing them. Also be sure to retorque all bearing bolts with torque wrench to proper amount.what is the proper torque for a Chevrolet 4.3 or vortex 6 rod bearings cap on 96 chevy cheyenne truck without using the 70 degrees mark

Little Bear

I might pop the caps and take a look at them, if they look good leave them alone and put it back together. If you find one or more bad then the crank is most likely going to be hosed and you'll have to pull the whole thing apart to have it turned.

bubbam

[QUOTE=jgray152;208346]Im going to be putting an engine in a truck I just bought and just for "preventative measures" I just got thinking of replacing the connecting rod bearings. Engine has 120K on it. The engine that is in the truck has unknown millage as it was replaced but it has a bad connecting rod bearing along with other issues...Today the oil pressure dropped to near zero since the engine got to around 400 rpm...then heard some awful screeching noises timed with the rod knock. O well.

So is there anything special I should do when replacing the rod bearings in the new engine im going to be putting in? If its too much trouble I'll just leave the original ones in. Not sure if there is any "wear" patterns I need to remove off the shafts or anything.[/QUOTE or you could just go ahead and do a i frame drop the oil pan take the heads off spark plugs out push the pistons out the top and do a rebuild if I’m going as far as replacing main bearings I would just do a rebuild it could be the cam