Basic rod & main bearings repair older engine w/162K

[Good Sport]

I'm doing some bearing replacement while I have my oil pan off (replacing oil pump). Original '92 C1500 5.7 with 162k. I'm in the process of removing the bearings, and checking the crank journals. The 1st main bearings and journal are worn and have some scoring. The other mains look ok, but I'll still replace the bearings. Have only removed #1 & #2 rod caps, those have some scoring, but I was able to tidy up the journal quite well. At this time, I am not interested in pulling the engine, or replacing it, just a basic repair.

Here is what I want to know. For an older crankshaft with nominal wear, what size bearings should I go for? Regular, undersize, or what? Any suggestion for measuring tools that will work with engine in place?

 

[SAATR]

I'm doing some bearing replacement while I have my oil pan off (replacing oil pump). Original '92 C1500 5.7 with 162k. I'm in the process of removing the bearings, and checking the crank journals. The 1st main bearings and journal are worn and have some scoring. The other mains look ok, but I'll still replace the bearings. Have only removed #1 & #2 rod caps, those have some scoring, but I was able to tidy up the journal quite well. At this time, I am not interested in pulling the engine, or replacing it, just a basic repair.

Here is what I want to know. For an older crankshaft with nominal wear, what size bearings should I go for? Regular, undersize, or what? Any suggestion for measuring tools that will work with engine in place?

Inspect your current bearings for part number and undersize markings, and purchase bearings equivalent to them.

The rod journals could be checked with a micrometer if you can unbolt the rod and push the piston up the bore and out of the way. Otherwise, plastigauge is your only option, especially for checking main bearing clearances. The accessory belt, timing chain, and torque converter will apply forces to the crank that may skew clearance measurements, so be aware of that if you choose to do so.

Also, be aware that factory bearings are not always "standard". Some have slight variations (.0005" undersize, for example) to make up for production variations. Installing standard bearings without these "adjustments" may cause more problems than they solve.

 

[Good Sport]

Thanks SAATR. The number on one of the rod bearings reads: GK4 (or 6K4?), 5453695 and 38 G 232.

I'm going to try some measuring w/crank in place, as long as can physically get a micrometer small enough. Serpentine belt is off. TC and Timing chain are still in place.

I'm obviously concerned about the proper replacement bearing sizes, so I'll take as long as I need before purchasing/installing.

Yes, rods 1&2 are unbolted moved up:

You must be registered for see images attach

 

[Scooterwrench]

Thanks SAATR. The number on one of the rod bearings reads: GK4 (or 6K4?), 5453695 and 38 G 232.

I'm going to try some measuring w/crank in place, as long as can physically get a micrometer small enough. Serpentine belt is off. TC and Timing chain are still in place.

I'm obviously concerned about the proper replacement bearing sizes, so I'll take as long as I need before purchasing/installing.

Yes, rods 1&2 are unbolted moved up:

You must be registered for see images attach

That crank looks good! Determine the journal size and buy the appropriate bearings to fit. Be very careful to keep it clean,one grain of sand will ruin a new bearing,ten grains will destroy it and the crank immediately on fire up.

 

[Good Sport]

That crank looks good! Determine the journal size and buy the appropriate bearings to fit. Be very careful to keep it clean,one grain of sand will ruin a new bearing,ten grains will destroy it and the crank immediately on fire up.

Well, I worked 3-4 hours yesterday on that rod journal with various sandpaper wraps (600-2000 grits) and compound/polish. PITA, as horrible access, plus, I'm in my 70s, lol. Used a long sock instead of shoestring. I've got to figure out a way to do the #1 main journal, as it has some scoring as well.

 

[Scooterwrench]

Well, I worked 3-4 hours yesterday on that rod journal with various sandpaper wraps (600-2000 grits) and compound/polish. PITA, as horrible access, plus, I'm in my 70s, lol. Used a long sock instead of shoestring. I've got to figure out a way to do the #1 main journal, as it has some scoring as well.

Pull the front main cap and push the insert out. That should give you enough room to slip your abrasive paper up and around the main journal. Make sure you get the abrasive grit out of the oil passages in the crank.

 

[Good Sport]

Pull the front main cap and push the insert out. That should give you enough room to slip your abrasive paper up and around the main journal. Make sure you get the abrasive grit out of the oil passages in the crank.

Yeah, I was thinking about trying that approach. The good news is that journal is not too bad, but the lower bearing looks like a vinyl record! Thanks.

 

[Schurkey]

Pull the engine out, do the work with the engine flipped-over on an engine stand.

Better than flipping the MAN over, so he's working on his back like a prosti-tute.

 

[DerekTheGreat]

Better than flipping the MAN over, so he's working on his back like a prosti-tute.

Depends on who's working on top of you.

 

[Erik the Awful]

You're replacing the bearings because the engine has 162k miles but don't want to pull the engine because it's too much work?

If the rods aren't knocking and the bearings aren't showing copper, you're good to go. Either pull the engine and do a full rebuild or just run it.