1983 County v8 engine swap to 4.6 p38

[1983 110 county v8]

Hey guys,

 

Im new with Land Rover defenders, so I need to learn stuff from people with experience so I though this is the place to be. 

I have a RHD 110 county 3.5 v8 1983. I'm planning to put a p38 4.6 engine in, so I have more power and its economically better on cruising speed.

I think the standard engine mount in a 1983 county v8 is already good to fit a p38 4.6 engine, so engine wise that's not bad. I need to make the steering from RHD to LHD because for a daily driver in Amsterdam I think its not a bad idea. 

My main question is what gearbox should I use? I think the ZF4HP22 is the easiest option, because it belongs to the engine. But I going to make a lot of kilometers on the highway so a r380 with a gear extra sounds good in my opinion, but as I sad im a beginner so I have no idea. Maybe someone can tell what is the best set up for the 4.6 in a defender.

 

Thanks,

Mees

IMG_7210.HEIC

[Bowie69]

Gearbox will very much be down to what you prefer, I like an auto, and would run an Hp22 behind it -it is an overdrive transmission anyway (0.7:1 or something like that), so you won't gain much with an R380 in that respect.

The auto will be quieter, and probably won't leak as much, and as you say it is a gearbox well suited to the engine. Great for crawling about off-road.

One caveat, I *think* all the 4.6s came with an HP24, which is electronic, and quite tied to the body, suspect it is not as easy to get running properly out of the original vehicle (not that I have done this!)

I have a tuned 4.0 in front of an HP22 and they do fine. If you do break things you can upgrade an HP22 to a HP24 with bits from Ashcroft, but retain the hydraulic nature of the box. But I doubt you will, it is a fairly strong box.

[1983 110 county v8]

Thanks, Im going to buy the 4.6 with top hat liners and the gearbox separately, but I thought that the zf4hp22 also easy fitted to the 4.6, and it’s not as much electronics as the 24. The electronics are the big differences between the 2 right?

[smallfry]

All 4.6 engines came with a 4HP24, and they are all electronically controlled. You can get round this by using something like Compushift, which is a stand alone programmable module, but its quite expensive (to me) and you may not want to spend that sort of money.

If so, you will want a hydraulically controlled 4HP22, which needs no electronics apart from the shifter switch. Beware though, as some 4HP22s are electronic.

The giveaway is the downshift (kickdown) cable. Electronic gearboxes do not have this.

All the 4.6 engines will need aftermarket engine management systems, unless you are going to convert to the old Hotwire system, or carburettor/s. 

These systems will also need a different engine front cover and pulleys etc. Also an ignition distributor and coil.

It can be quite an expensive conversion, and not quite as simple as it seems !   

[Chicken Drumstick]

Think the HP24 is stronger. But probably not a real world issue on a single vehicle. Lots run the 22. 
 

Really depends what you want. For me the manuals are a lot more fun and in theory should offer better cruising mpg. Autos tend to make the RV8 feel lazy IMO. 
 

But lots of people like autos. 

[FridgeFreezer]

LR never put the 4.6 in front of the R380 or 4HP22 as far as I'm aware, but it's only a Rover V8 so you can bolt it to anything that bolts to a Rover V8 and just accept it's not quite as strong as it could be.

Gearbox honestly just run whatever you like, it's only an internet holy war of manual Vs auto anyway

The 4.6 should fairly well drop in where the 3.5 came out although there's a few details which I covered in my 127 conversion thread doing exactly the same swap - PAS pipes, oil filter, oil cooler ports, exhaust manifolds, flywheel if you're going manual, crank sensor for engine management depending what you're doing for that, coolant hoses & heater lines, and air filter off the top of my head.

[Escape]

As above, the engine will fit, but need some work on wiring and piping. Even more so if you get a later 4.6, with the Bosch/Thor engine management (identifiable by the banana manifold instead of the traditional brick plenum). Those also require a different fuel pump for the injectors to work properly.

The gearbox side is easier. I have driven and know of several 4.6 V8s with the (old) ZF 4HP22, as well as with the R380. That's purely down to personal preference, if you don't trash it they'll all handle the power without problems.

[Escape]

To add: top gear is identical, 0.732 for the R380 V8 and 0.728 for the ZF, so there shouldn't be much difference in mpg on the motorway. On slower roads where the lock-up doesn't engage or in start/stop the autobox will suffer.

[landroversforever]

On 2/3/2023 at 7:17 PM, smallfry said:

All the 4.6 engines will need aftermarket engine management systems, unless you are going to convert to the old Hotwire system, or carburettor/s. 

These systems will also need a different engine front cover and pulleys etc. Also an ignition distributor and coil.

I thought the later engines lost the space for the distributor. Not that I'd want to take that backwards step.

[FridgeFreezer]

1 hour ago, landroversforever said:

I thought the later engines lost the space for the distributor. Not that I'd want to take that backwards step.

Yep, 4.0 and 4.6 lost the distributor but gained cross-bolted mains and bigger crank journals.

[Bowie69]

.....and a waaaaaay better oil pump, which the serp-belted 3.9 also had, I understand.

Once you start down this road, you realise just how many iterations there were..... and how you can never really be sure of anything!

[Chicken Drumstick]

22 minutes ago, Bowie69 said:

.....and a waaaaaay better oil pump, which the serp-belted 3.9 also had, I understand.

Once you start down this road, you realise just how many iterations there were..... and how you can never really be sure of anything!

I have a late 3.9 serp like that in my TR7, it came out of a 1996 Disco 1.

 

It really screams, lovely engine. Have noticed it before, the earlier 3.9's just feel a bit more lazy compared to the last of the line.

[smallfry]

On 2/6/2023 at 1:27 PM, landroversforever said:

I thought the later engines lost the space for the distributor. Not that I'd want to take that backwards step.

They did. Thats why he will need a different front cover and distributor if using the Hotwire system in order to "save" money over an aftermarket management system.