Greetings from the city of brotherly love.
Just picked up an 03 discovery s7. We were aware of the tick and whining power steering. After reading for days on here and trying the easy solutions (band-aids), still a tick or piston slap or slipped liner or whatever names it's given. It's all currently beside the point here. What I want to know is this:

Recently sourced a used 4.0 to put in instead of the terrible 4.6. Very little is known about the 4.0, basically only that it came out of a 1999-2002 Discovery and is only 350$U.S.. mileage=unknown function=unknown basically all is unknown. block looks stamped "HRC2411" and "WYF 11 HRC2411".
I think the 4.0 is comparable to the 4.6 thats a ticking time bomb, in fit and function and computer. Am I right? And what else would i need to worry about? i.e. upgrading trans or t-case.
It's still too cold here for me to start digging in and checking lifters, rods, caps etc. all the usual suspects. Planning on a lower thermo and replacing oil pump. but for the price of the 4.0, is it worth while to pick it up just in case with the 4.6 it's slipped liners or worse?

(The tick*, like so many others comes when warm, narrowed down to right rear. Will be pulling plugs soon to determine exact location, followed by cooling that cylinder to see if it stops; when the temps get above freezing again.)

 

Mine was squeaking, that turned into ticking, that turned into puffing. Ended up being a head gasket leaking out the exhaust side. Seen quite a few instances of this in the internet when researching my problem. Basically sounded like compression noise coming from a spark plug eventually. Originally when I heard the ticking, I thought it was going to either be slipped sleeves or worn main bearings (kind of a knocking sound) but I couldn't pinpoint the noise cuz I wasn't looking (or listening) by the exhaust manifold.

It's a shot in the dark.

 

4.0 is a direct swap, nothing needs to be changed.

 

Ok. So we've had a few warm weekend days and I've done a little digging. Firstly, had the 3 amigos and did the option b fix/mod. It's been a week and probably 500 miles and so far they haven't come back. Secondly, have an exhaust leak somewhere near manifold, haven't seafoamed the truck yet so I haven't pinpointed leak, nor am I overly concerned about it currently. Thirdly, stechascoped all around trying to narrow the knock down. It resonates throughout but seemed to be on driver rear.haven't pulled plugs to check for signs of coolant. Did put a hose to block, briefly so please don't beat me up over that, knocking stopped briefly on either #5 or #7 cylinder. This plus the steam in my exhaust, I'm fairly certain its a liner or cracked block, or combination of both. I'm no genius but am thinking of doing an inline thermo mod to keep block cool enough that the liner doesn't let go. Does this make sense or even possible. I will post video on YouTube and attach link tomorrow so y'all can hear what I hear.
fyi I'm not in the vin death range.
I will post oil pressure numbers asap

 

is it worth it not knowing a single thing about the 4.0?

 

depends on how much you value your time.