Oh what to do **sigh**

[disco2hse]

Patient presents as Stage 1 V8 ex NZ army. Body is adequately ok. Chassis has *no rust*. Gearbox is a little noisy but otherwise in pretty good nick. Salisbury is fine, new universals in front and rear props but cardan will need attention some time in the near future. Had to replace front diff recently due to a heavy application of foot while traction denegerated. New tyres and rides really well. Also has PTO with Thomas 8000lb winch. But...

The 3.5l donk is on its way out. After nearly 250000 km and 6000 hours of operation it is pretty much rooted.

Carbs just rebuilt with new gaskets and needles, properly tuned and balanced, and the engine runs like a pig. Compression test shows that cylinders 3 and 6 are weak. Has a good spark, the plugs are newish (6 months old) and have good terminals. No sign of a blown head gasket.

The cams have been on their way down for the past couple of years, but I think it is more than that without lifting the heads. Possibly the valve lifters are leaking out, rings are probably shot by now, and the valves themselves are probably not seating anymore as a result.

It is an old engine and the prospect of a full rebuild offers no joy (silk purse and all that). You know how it is. You start at the top and eventually everything ends up being replaced, and you still end up with an old and worn out block.

Perhaps I need to look at a 3.9 Disco with SUs (don't want EFI). I would like to keep the Mallory dizzy and Pertronix Flamethrower gear. That part works a treat. I also want to keep it at 24V, so keep the 24V alternator.

One main complicating factor is the starter and whether it will fit a Disco. Another is the probable condition of the clutch. Then there's the gearbox.

**sigh**

[rusty_wingnut]

why not just locate a spare engine and rebuild that? Tbh if it just worn out rather than abused out it will be rebuild-able. Sometimes you've just got to suck it up and get on with it.

[Maverik]

why not just locate a spare engine and rebuild that? Tbh if it just worn out rather than abused out it will be rebuild-able. Sometimes you've just got to suck it up and get on with it.

Here here, kind of agree. there are heaps of folk binning perfectly good V8's here as TDI have got the "econamy edge" - can you not pick up another similar lump, swap it out and slowly re-build the original engine to spread cost?

Mav

[FridgeFreezer]

A dead V8 is no reason to scrap a solid landy, pick any other V8 and bolt it in, the short engine is the same all the way through, only the crank nose got about 1" longer with the P38 but that can be worked round.

I'd say it's a massive backwards step to rip EFI off a later lump and bolt carbs on, you lose so much performance, but the 24v factor is a can of worms so if you're not electrically inclined it's probably best to leave the can unopened in the name of expediency. If the SU's will run a bigger lump they're probably the best choice as the performance 4-barrel stuff just sucks for reliability in my experience.

I also wouldn't bother rebuilding an old carbed 3.5 as it's likely to be a low-compression version anyway (~110bhp to the Range Rover / Disco's 135bhp in carb form, or 165bhp in EFI form). They make good coffee tables though

[tacr2man]

I would just retrofit a lowish mileage 3.9 efi unit ex disco (I did) , its an easy fit and not very technically difficult to run the efi off a 12v tap into your 24V system . What is the reason to stay with 24V ? The 3.9 starts very easy on 12v . Rebuilding high mileage V8 is not very cost effective IMHO .

[rusty_wingnut]

Seems to me like all you really need is to have the block bored, crank ground and some work on the heads. While you're at it you could have some skimming done and give yourself a little extra performance. The fact the cams are worn is easily solved, and a chance to buy a fresh profile for a bit extra "go", heads are easily reworked. It sounds like simple work just a bit time consuming.

The engine I rebuilt for my Series 1 required many new parts and machine work, but I saw it as an opportunity to put my stamp on it and build something different. It goes better now than when it left the factory, no doubt. I could of fitted any other engine but I like retaining a hint of originality. I don't see why you couldn't start with your 3.5 and improve on the base spec. The fact you want to keep it 24V suggests you want to keep it fairly original?

[Bowie69]

Changing the whole truck to 12V is a right pain actually, engine is great, but then you also need to change out heaters, instrument bulbs, instruments in a lot of cases, wiper motors, etc. The 24V FFR is a nice system, so don't just dump it I say

If you did convert then a new loom would be the way I would do it, as FFRs tend to have pretty radically altered schematics... I really advise against it!

I don't know how good 24-> 12V droppers are WRT to noise on signal lines, but get a good enough one there should be no problem running the EFI system at all.

Keep the 24V starter motor, less amps in cold weather = more likely to start

EFI would be worth it for sure, otherwise wave bye bye to ~30-50BHP.

[Team Idris]

I've just re-built my 3.5 RV8 and it was quite expensive, as I did the vernier cam/chain, Piper max-torque cam, and ARP mains-n-head studs. But that should be a good engine now, with many failings addressed.

It is a re-build of the V8 I bought in to replace my old engine. And guess what? It was stuffed, so still needed the full monty. I say 'better the devil you know'

[TheRecklessEngineer]

Being down where you are, you should have access to many american lumps and drivetrains.

I'd be inclined to hunt around a scrappy and see if you can find something that will fit. There might be some fun with the electrics, but nothing that can't be got around.

[disco2hse]

I have combined my responses

Edited October 7, 2011 by disco2hse

[disco2hse]

Thanks for the very good replies. Just a point about rebuilding this. Perhaps if it were a rare example of a series 1 or had some intrinsic value I would consider that, but literally there are hundreds of these things rolling around at the moment and there are much better examples than mine that have been restored into show ponies. They will still be on show long after mine has shuffled off its electronic coil.

A dead V8 is no reason to scrap a solid landy, pick any other V8 and bolt it in, the short engine is the same all the way through, only the crank nose got about 1" longer with the P38 but that can be worked round.

I'd say it's a massive backwards step to rip EFI off a later lump and bolt carbs on, you lose so much performance, but the 24v factor is a can of worms so if you're not electrically inclined it's probably best to leave the can unopened in the name of expediency. If the SU's will run a bigger lump they're probably the best choice as the performance 4-barrel stuff just sucks for reliability in my experience.

I also wouldn't bother rebuilding an old carbed 3.5 as it's likely to be a low-compression version anyway (~110bhp to the Range Rover / Disco's 135bhp in carb form, or 165bhp in EFI form). They make good coffee tables though

Thanks. That reflects my thinking too. I have thought about rebuilding it and in fact last year I was about to start replacing cams, but realised the lifters were something less than optimal, which would mean new valves, rings,... and in the end it is an engine that has done nearly 150000 miles.

Yes it is low compression and lowered further for the army use too (to allow for variable quality fuels to be used).

I am thinking of a straight rip it out chuck it in and get moving scenario. The vehicle as a whole is pretty damn good even if it looks rough from the outside.

I would just retrofit a lowish mileage 3.9 efi unit ex disco (I did) , its an easy fit and not very technically difficult to run the efi off a 12v tap into your 24V system . What is the reason to stay with 24V ? The 3.9 starts very easy on 12v . Rebuilding high mileage V8 is not very cost effective IMHO .

That's the general plan at the mo'. The main reason for staying 24V is everything on it is 24V except the ignition system. I have a rather clever charge equalising system between the two 12V batteries and run the Pertronix gear from one of them. Ignition is 12V now so that part is easy. Fires like Donald Trump on meth.

Changing the whole truck to 12V is a right pain actually, engine is great, but then you also need to change out heaters, instrument bulbs, instruments in a lot of cases, wiper motors, etc. The 24V FFR is a nice system, so don't just dump it I say

Until you actually get inside the wiring you don't realise how much different it is. Everything from split charging systems to convoy lighting means there are all kinds of weird little idiosyncrasies that have taken me years to figure out. And yes it is pretty good as a whole.

If you did convert then a new loom would be the way I would do it, as FFRs tend to have pretty radically altered schematics... I really advise against it!

hahaha ya think! I have thought (dreamed) about having a new loom installed but that can wait until the time comes for a complete ground up rebuild. Oh I know people have got away with replacing just bulbs, gauges and motors but that still leaves all the weirdo bits behind that can bite you in the bum later, like the split charge diodes that control three battery banks.

I don't know how good 24-> 12V droppers are WRT to noise on signal lines, but get a good enough one there should be no problem running the EFI system at all.

Keep the 24V starter motor, less amps in cold weather = more likely to start

EFI would be worth it for sure, otherwise wave bye bye to ~30-50BHP.

Tried the dropper option after the original army unit fried itself and fried two of them. Yes too much feedback and they didn't like it, even an industrial grade unit cut out. Gave up and found a more stable solution with the charge equaliser. The army units are known to be unreliable too. They have a noise filter and ballast to try to absorb spikes and other noise. I have found using one of the batteries as a kind of "sump" works better. Putting a meter on it and it is interesting to watch the current and voltage fluctuate

I want to keep the 24V starter if only for the fact that I paid so much damn money for it three years ago. But really for the reason already mentioned.

I know I will be dropping the power output of the engine, but then the donk in there now has served pretty well and anything will be an improvement on that.