Probably get away with a set of big end bearings.
This can be done through the side covers .
There are a lot of if's and but's with bearing fitment that is difficult to explain in a few short paragraphs.
The mains dont suffer the back and forth thrusts that the big ends are subject to and therefore less prone to failure.

Agree with Andrew
I would measure the journals and determine if a new set of bearings will return it to spec. I would also endeavor to check the condition and clearances of the main bearings that were easily accessible. With a suitable small bottle jack lifting the crank up next to the bearing being checked, a strip of plastigauge can be placed in the bearing cap and it installed temporarily to smash the stuff to gauge the clearance. In all honesty a close inspection of the main bearings will probably tell the tale, but since most of the bearings out of an engine will have some scratches etc from debris, it can be hard to ignore what your eye is telling you is bad, bad, bad and go with the clearance spec.

Connecting rod journals 3.624-3.625" I believe the undersizes are 0.025 and 0.050 on that engine
Max out of round 0.007"
Max journal wear 0.009"
Bearing clearance (measured vertically) 0.006-0.0085 Max 0.012
Torque on connecting rod bolts 5b913 150 lb ft. 4h9841 190 lb ft

The bolts will be cross drilled for cotter pins and castellated nuts used. It is permissible expected to advance to the next available hole/slot combination so the cotter pin can be installed after reaching the specified torque. Note this will be less than 30 degrees additional.

Main bearing cap nuts torque 5/8 = 58 lb ft 7/8 = 350 lb ft !!!!! Wow!

What is a good source for bearing inserts for mains and rod journals. Also gaskets? Can all of the main bearings and big end bearings be accessed with the oil pan removed?

I have had good luck with Off Road Equipment for parts on the older dozers I wouldn't worry too much about the sleeve's as they are harder than the hubs of hell, that engine is pretty much the same as the d73t's had' I am like the others just check the crank over good and if in good shape roll new bearing inserts in. and yes they can be done easier with the pan off altho they can be done thru the holes in the side of the block/pan

I think you have a pretty good shot at doing them through the side covers. Don't think there is a balancer unit in the way on that engine like the D7E 339 has. If I had to do mains, I might go ahead and drop the belly pan and go in from the bottom, but I sure would avoid that if possible.

I did an inframe overhaul on our 48a D7E and the biggest jobs were the belly pan and getting the rear section of oil pan out over the equalizer hard bar. Had to lift the engine in the frame a little for clearance. Once we got into it, then the balancer had to be removed to access some of the mains and rods. I wore an old pair of insulated coveralls and just threw them away when the job was done!

The 17A's do have a balancer.

I don't see how I could get the mains out thru the side covers. It is difficult to just get the rod bearings out?

Old Magnet how would I get the main bearings out working thru the side covers? This tractor has 24" pads and it was hard enough just getting to the rod bearings? Are there other covers that I have not seen?

The simplest way to get to the mains is to pull the sump imo.
Unbolt the spring saddle from the main frame and jack the chassis up to give your room to pull the sump.
You will have to take off the balancer also.

I have the engine out of one atm.

Good luck

Cheers djcat

"Dick wrote:

Old Magnet how would I get the main bearings out working thru the side covers? This tractor has 24" pads and it was hard enough just getting to the rod bearings? Are there other covers that I have not seen?

Oil pan removal is a must to access the mains. Also requires ability to raise the engine about 12 inches to get the pan to clear equalizer spring bracket. Also requires tooling/pullers to remove the main bearing caps. If you intend to proceed I'd recommend you acquire a service manual along with some capable assistance.