You got the engine for practical nothing, salvage everything you can and find your-self another block.
While “Top Hot liners” may be the cat’s meow, they also cost about $100.ea so you’re going to be into this block for $800 just in liners, then add in the machine work.
You obviously need new pistons; then keep adding everything else, block surfacing, line boring, machining the crank. You’re going to have $2500-3000 in that thing before you know it and you haven't even touched the heads yet.
While I’m sure Top Hats are great and are the savior of LR blocks, I haven’t seen any postings from anyone who has actual paid the $$$$ to have them installed.
A possible other route could be OKLAHOMA EUROPEAN LLC which sells a COMPLETE rebuilt 4.0 long block w/ heads for $3600 (I’ve seen used 4.0 for close to that) and they also sell a rebuilt 4.6 long block for $4000.00.
OKLAHOMA EUROPEAN LLC's standard limited warranty for a remanufactured engine is 12 months unlimited miles.
Just another veiw point.

 

Definitely possible. That why I asked about seeing the rod and writs pin under that cylinder. If it was hydrolocked, you'll see the signs of it under there.

 

So here's the piston now that I've got it out. The whole side of it seems ground down, the rings and all near 'the damage'.

Photocrimes; I like your 2 cents as it makes sense with the water jacket so close to where all the business is happening, as well as that the head gaskets seem so new in that the previous owner fixed the water leakeage but not the real problem.

I don't think that hydrolock is a concern, everything spins freely and no visible issues with the rod.

I knew that this forum was good, but guys...you're knowledge humbles me! So what next?? Full strip down for pressure test? All liners still seem exact so new piston and back in it goes?

 

You're most likely not going to see any issue with the rod because the piston gave way. Everything your looking at now is the result of continuing to drive it with the broken piston, the combustion blow by has eroded down the side where the original break occurred. My money is still on coolant in the cylinder. It doesn't have to be enough to cause hydro-lock, it only has to be a quantity very slightly greater than the capacity of the combustion chamber because liquid is incompressible and the aluminum piston is the weakest link in the chain. I've seen it before and in fact, when it happens, you're not really going to notice other than possibly hearing a slight chirp when the piston gives. Even after the piston breaks, on a V8 it's very likely that you may not really notice it, especially at speed.

 

Wow, I'm honestly not sure I would trust that cylinder. If you pressure test it and it looks ok absolutely make sure that cylinder is round! There will be uneven wear on that part of the sleeve now and I can guarantee the rings will probably not seal there. Might not even be visible to the eye. You will get blow by, and then down the road this will happen again.

 

Thanks for all the help so far guys. I ended up taking the block to the shop to cylinder relined, no problems with the block, no slipped liners, all back together now. Heads rebuilt, new piston, new gaskets all around, cleaned out all the gunk that was built up in the intake. Everything else looked good.

Now about to drop the engine back in, but have come across 3 pipes running across the top of the tranny. Each seems to have been melted at the end close to the back of the engine. One goes to the driver's side of the tranny, one goes to the transfer canse, and one just ends about halfway back the top of the tranny.

Any idea where they go, come from, what I need to have them connect to at the engine end?

Here's a link to a youtube video of the situation:

Land Rover mystery pipes - YouTube

Thanks!

 

That's normal. They are vent tubes. They are curved over like that to keep things from getting in them.

 

Not melted, but should be open. If they clog, or the banjo bolt they go to is plugged with mud, the oil in various items will evaporate, fumes will not have a way out, makes minor pressure, and cause seals to leak.

 

So it's been a while..... The Disco is done! What a great feeling of anticipation it was turning the key for the first time on the restart. And then the second time, and a few more times until - it started! WOW! first full engine rebuild and the thing works.

Since then to pass the safety i put on a new hub, brakes all around, a new rad and thermostat and a couple other odds and ends. Passed the emission test also, luckily. The new method (as of Jan 1) here in Ontario requires a hook up to scan for readiness of the electrical sensor systems? Or something like that as the mech said. They did the old test, just the sensor in the tailpipe and it passed that one, not the new one. Apparently my service engine soon light has been disconnected? I'll have to tear appart the dash to see what I can see.

Now to the next challenge. Had the car out and about around town a few times. Popped the tranny cooler line off at the rad connection and lost all the tranny fluid, again - those quick connections are crap. Once that was propperly attached it ran well. A little rough idle but not too bad. Took it on a 2 hour highway trip, sat for 2 hours then wnet to leave and it wouldn't stay idling, only crank, almost start for a couple seconds then stumble and stall. If I gas it a bit, (1000rpms) it stays on no problem. Warmed it up for a few minutes and made it 2 hours home.

Since then, I have to gas it to at least 1000rpms to have it stay running. If I coax it out of the garage and up to the end of the street it will stay running, but return to the starting issue when shut off.

Codes that were returning are: 1510(Idle Air Control Valve fault (opening) Drive cycle A:Signal missing.),
172 and 175 (running too rich, both banks),
455 evap emissions leak,
and 141 O2 sensor bank 1 sensor 2.
(Thanks aarongregor for the great list of codes.)

Any help in solutions to these codes would be greatly appreciated. Ive seen a couple of posts that may suggest the 455 is related to the 141 O2 sensor and may go away with a new sensor, or search around the gas tank for leaks? Solutions for the other ones...not sure?

I've cleaned the MAF and the IAC with no real positive results.

As always, thanks in advance for help in solving. The truck sits a little higher with just me in the engine bay instead of the 4.6

 

I'd be on the hunt for a vacuum leak. Most people end up fixing a rear O2 code by fixing a vacuum leak. That may also be related to your evap leak, and can lead to poor idle.