Oh, that it was! Thanks for the correction.

 

Get a used engine and slap that turd in. Don't overthink it or over pay for it.

Full disclosure: this is my usual rant

 

Nah. It is a whole lot less effort, and much less cost, and much greater quality to just drop the oil pan on a working motor and replace the rod+main bearings than it is to gamble that a used motor will be better so you pull the used motor from one vehicle, pull your motor from your vehicle, and install the used motor into your Disco.

With hand tools, it took me 3 full days to pull my Disco motor whereas it took just 6 hours to drop the oil pan and replace the rod bearings... and when you do that, you've got a motor with new rod bearings which you will never have in a donor used motor in an engine swap.

Keep in mind that the OP above has a running Disco motor that has oil pressure when running 20W50 oil and isn't overheating.

I say drop that oil pan and replace the rod+main bearings. That's barely more effort/expense than an oil change.

 

Okay, I understand how to replace both halves of the rod bearings, but how do you replace the top halves of the main bearings with the crankshaft in place?

 

You can push the old out and the new one in.
Wear on the crank and bearing will help because it slightly increased the gap between them(even though it's a very small amount).
The cap also increases the pressure on the crank, so there is less bearing resistance with the caps off.
Some bearings push in and out easily, others can be a pain, but it's doable.
It's kinda like if you've ever done a 2 piece rear main seal with an engine in the vehicle(not a 4.0/4.6 which use a one piece rear main seal).

 

The main bearings are in 2 halves. Friction-wise, it makes no difference if you are turning the crank or turning (pushing) a bearing.

You lube the new top half of your main bearing and use it to push the old main-bearing top half around until it drops, leaving your new main-bearing top half up in the motor as desired.

My memory is foggy on if the Main bearings have a catch. The above might only work in one, not both, directions.

 

Just to follow up on the above: the hard part is pulling the motor.

Now, once the motor is pulled, the rebuild is pretty easy.

So if you do have a donor used motor on hand that has already been pulled, by all means put it on your engine stand, open it up, and replace the bearings. Even better if you replace the piston rings.

Obviously check the crank and cam.

Replace the oil pump and timing chain.

Bonus points if you pull off the heads, lap the valves, and replace the valve stem seals plus reassemble with all-metal head gaskets and ARP studs, but that's just a top end job that can be done later with the motor left in the vehicle if desired.

Button it back up and then install it into your Disco.

 

Thanks for all the input everyone! Definitely going to do the rods and main bearings this Spring.

What's the difference between having my engine rebuilt by someone like Joe Robison and having a different rebuilt engine placed in my truck, like the Turner engine? Kind of seems easier just to have an engine shipped to me, but I might be missing some key differences in quality of outcome.