FridgeFreezer

I'd agree - 1/8" NPT is a super common thread for sensors and fittings, not hard to find a tap or die even here in metric land a lot of tap kits come with one by default.

TBH having to do a few weld repairs every decade or so is not the end of the world, if you give it a good dousing in cavity wax that could easily stretch out to every 20 years which is not too onerous! We did very minimal repairs to my bulkhead when we put the truck together in (yikes) 2006 and it's starting to show a few rust spots now, I can live with that sort of rate.

I think you get about the same whatever you fit - the MPG is largely decided by your right foot, and the 4.6 gives you the most torque which is what you need to move a 2-ton brick about the place. Certainly I can get the same or better MPG from the 4.6 as I ever did from the 3.5, and I sure as hell have a more relaxed drive and get there faster

I'm sure they've lovely but for the price of the conversion I can run my V8 for years...

4.6 - there's no substitute for displacement especially if you've got a 110.

If you just want to save a bit of fuel, mad ideas like supercharging are not what you need - you should be doing as honitonhobbit and td5tov8110 suggest - just do the basics and maybe make minor improvements like servicing & adjusting everything, getting the carb & ignition set up properly (or fitting upgraded versions), and there are improved cylinder heads available for the 2.5 such as the gasflowed performance one Turners sell: https://www.turnerengineering.co.uk/cylinder-head-lfhp-225-25-petrol-metric-cou-exchange-c2x28348429 If you are not carrying heavy loads you *could* look at the gearing (even just tyre size) but the 2.5 does not have a lot of power to spare so taller gearing may not work out.

I think we already had this discussion a while ago... the 2.25 does have some scope for improvements as they were very under-tuned from the factory but adding turbos or superchargers is not a very practical idea, it's a bit like strapping rockets to a horse to make it go faster. A 110 will accept any of the Rover V8's although you'll need the right gearbox and modify the wiring & cooling system etc. (but mostly using standard Defender V8 parts) but you can get ~2x the power of the 2.5 by just dropping a 4.0 or 4.6 in there, and with fuel injection it will not use any more fuel than the old 2.5 did unless you drive it like an idiot. Of course anything is possible - you *can* stick a turbo or supercharger on anything, just like you can put any engine into any car if you're willing to pay. You need to define what you're actually trying to achieve here - a 2-ton brick is never going to get fantastic MPG or be super fast. If you want much better MPG fit a turbo diesel engine. If you want to go everywhere at 100mph fit an LSx V8. But you won't achieve both at the same time.

There weren't a lot of EFI vehicles around when the system was designed. Blame Bosch.

These days it's far easier to find a crusty D2 or P38 with 4.0 / 4.6 than a classic Range Rover or D1 with a 3.9 in it. And the later blocks have numerous improvements like larger journals, cross-bolted mains, better oil pump, single serp belt, and composite head gaskets. The 4.0 is basically the best version of the 3.9. @Mediamab I understand the dilemma about retaining originality but you can (if you're reasonably careful) drop a 4.6 + R380 into your truck with zero permanent modifications, it's just some wiring & plumbing and maybe a swap of the transmission tunnel moulding. The original 3.5 from our 127 is under a tarp at the back of the lock-up should we ever want to revert it to standard or sell it to a collector who values originality.

Swapped wires would cause a false "double-gap" situation yes. You shouldn't need to mess with the VR settings, I'd suggest trying to start from the defaults / whatever Nige uses by default and not get too far into the weeds from there as there's 100 ways to confuse the issue with this stuff.

If you live somewhere sunny with a beach it would definitely work in the summer season, probably not so much in rainy Basingstoke.

2k is a lot for a 4.0 lump given how many rusty MOT failed D2 and P38's there are out there for no money - that way you can drive it & check it out before you do the swap too. Know nothing about the holley sniper, if the price is right it may well bolt onto your intake manifold and give you more reliable fuelling but that LC 3.5 is never going to be a beast. At least the Holley would be transferrable across engines.

If your 4-barrel carb is anything like the ones I had it will almost certainly be over-fuelling and the mixture screws will vibrate themselves loose every fortnight or so. I binned the 4-barrel and fitted the early flapper EFI (most basic of all the EFI systems) and it was night and day better for that alone. But then I got fed up with the low-comp lump with clockwork everywhere and threw a 4.6 in the hole, if you're curious how much work that is:

Alas I have promised myself and the boss that the only project car(s) are the existing fleet of Land Rovers...

If that is an original low-compression 3.5 unit there's little point spending money tuning it. And as Bowie says I would not jump straight to assuming a head gasket problem given that right now you don't even know how hot it's getting or appear to have a working cooling system. Whatever you do you'll eventually want a working temp gauge so that's a no-brainer - step #1. The fact it managed to overheat suggests the fan or rad or water pump is either not working or not being effective - you can test viscous fans by seeing if they "stiffen up" with temperature. Does it have a cowling on the fan? Is the rad in good nick? Anything making any noises? Anything leaking? Any collapsed or damaged hoses? Thermostat good? Heater getting hot? Next up is to actually do the basic checks of what else is wrong - is it losing water, is it mixing oil & water, is it pressurising the cooling system, does the cooling system pass a pressure test? Assuming the stock rad there's an easy 1/2" BSP port in the top of the rad you can use to pressurise the system and look for leaks. And, again as someone else said - always start with the cheap stuff. A decent stat is like £10 and 5 minutes to change, it's a damn sight easier to rule that out for £10 than spend a weekend and £250 doing head gaskets only to find out it was a £10 stat or a clogged radiator.

Reaaaaaaly tempted, despite how stupid it is...

Odds on your temperature gauge & sender were not made for each other. I gave up p*ssing about with mine and fitted a VDO vision gauge & sender. Once you know your real temperature next thing is to work out why it's getting hot - what flavour fan does it have fitted?

If you're being all proper about it, it needs to be very solidly on a very flat floor / levelling feet as in theory they can take on a slight twist if they're not. If you stand it up, I'd stand it on 4 solid pucks of something (assuming it has the aforementioned feet that can be levelled).

I still don't know which secure nuclear waste disposal site you sourced the paint from because I've still not seen anything manage to be quite so YELLOW. Anyway - not on eBay, an AI render, but lord I'm more tempted than I should be... @landroversforever I think this matches yours doesn't it?

ECU controls the pump, it won't run the pump if it doesn't think it needs to, which is based on various criteria. Do you have spark?

Does the gun know about different types of cheese?

I've found there's MTA and MTB versions of stuff, the ones with the tang are for lathes so you can pop them out, the ones without are for mills so you can wind the drawbar into the end & lock it in place. Although it sounds like Doug's has just been bucthered I guess you could weld a little tang on the back if you felt like it.

I suspect they'd be a lot better but there's got to be a limit to the side-load on a long thin thing before it bends...

Just to disagree with several of the points made so far - purely from my personal amateur idiot experience... A live centre is useful but those are like £15 from places like RDG or Chronos, and for light/hobby work the cheap stuff is likely more than good enough - and there's a ton of it out there these days that's better than it has any right to be. By the same token, I love my QCTP and I use cheap insert tooling from eBay china which means I don't have to sharpen or re-shim anything if I mess up (which I do often), I just throw the dead insert in the bin, screw in another one, and carry on. If I find the inserts don't last (which is no surprise) I'll look round eBay for people selling packs of NOS decent quality inserts or similar and it's an easy upgrade. I also find it useful to have a spare cheap crappy drill chuck that the centre spotting drill just lives in, saves time and cost all of about £10 - £15. It's a bit like how having an extra angle grinder or two can speed up work massively - technically you can keep swapping discs but it's so much easier if you just pick up the right thing and go.

I'm still amazed that with all the knowledge on this forum no-one's ever pointed out that Defender steering bars double as recovery points