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4.6 V8 in a classic


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Afternoon everyone,

I have just got my hands on a good 4.6 V8 engine from a P38.

It does not use any water or such like and wanted to know what sort of work was needed to put it into my classic.

Any advise would be greatly appreciated.

Cheers Nick

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Afternoon everyone,

I have just got my hands on a good 4.6 V8 engine from a P38.

It does not use any water or such like and wanted to know what sort of work was needed to put it into my classic.

Any advise would be greatly appreciated.

Cheers Nick

Nick

I would think that you will retain all the injection and exhaust manifolds from your current car together with the alternator and air con if relevant. It should therefore be a simple case of unbolting one and bolting the new one in its place. Have you done an engine swap before? That is all you should be doing here the fact that one is either a 3.5 or a 3.9 and the new one is a 4.6 should be irrelevant beacuae they are both Range Rover V8. I once put a Rover SD1 V8 engine in a RR that required changes to the bracketry and the water pump but would not think that will be the case here.

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Yes the block is identical, but depending on the age of the 4.6 the ancillary mounting bracket points on the heads may differ …………. also late RV8 engines are serpentine (poly multi V) ancillary drive and the earlier engines are single V belts …………..

If its like for like then you will be OK ……………..i.e if both are pre 94/95 then fine.

:)

Ian

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Yes the block is identical, but depending on the age of the 4.6 the ancillary mounting bracket points on the heads may differ …………. also late RV8 engines are serpentine (poly multi V) ancillary drive and the earlier engines are single V belts …………..

If its like for like then you will be OK ……………..i.e if both are pre 94/95 then fine.

:)

Ian

BBC

Surely if you strip back to the bare block the mounting will be the same as the casting never changed. The difference between the SD1 and the RR was related to bolt on components line timing covers, alternator brakets etc.

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The 4.6 will have a longer crank nose, to bolt a non-serpentine front on you'll need a ~20mm spacer ring behind the crank pulley bolt to get it to tighten up. My 4.6 has a 3.5 V-belt front end and 3.9 inlet manifold and EFi.

The block isn't exactly the same as a 3.9 - it's cross-bolted, so if you have a remote filter replacement oil pump cover it will foul the cross-bolt (ask me how I know) :P apart from that - drop it in. What are you doing for fuelling?

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Morning Everyone,

Right my RRC is a 1990 3.9 while the engine i have got is from a 1995 P38, it does not have the serpentine belt arrangement.

Fuelling i am going to put LPG on it but i take it i will have to upgrade the fuel pump as well.

Cheers Nick

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Fuelling i am going to put LPG on it but i take it i will have to upgrade the fuel pump as well.

Not fuel pump, fuel injection. You might "get away" with it using the 3.9 hotwire system, but I wouldn't trust it on my engine. Then again, I don't trust anything with a Lucas sticker on it :P

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Not fuel pump, fuel injection. You might "get away" with it using the 3.9 hotwire system, but I wouldn't trust it on my engine. Then again, I don't trust anything with a Lucas sticker on it :P

Hi FridgeFreezer,

Right then, what choices do i have:

Please explain

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As I said, you may be able to get away with the hotwire system (before people tell me I'm being picky) however I would recommend MegaSquirt so you can tune it properly and keep an eye on things - a popular theory for the 4.6 liner slip/porus block problem is the lean cruise fuel map Rover run on them, hence why I would be wary of using a less-than-ideal setup on a 4.6.

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Morning Everyone,

Right my RRC is a 1990 3.9 while the engine i have got is from a 1995 P38, it does not have the serpentine belt arrangement.

Fuelling i am going to put LPG on it but i take it i will have to upgrade the fuel pump as well.

Cheers Nick

V8s have lots of tweaks mods and bits through the range that LOOK the same - until you do the mix n match when you go to assemble

A 4.6 Block has variants, is yours a serp crank or std. Then dependant on this it will give you a guide as to what you can fit, and as you have a 3.9 donor, again what EXACTLY is the spec, this will then give an idea of poss probs.

Also, what exhuast manifolds have you got, and is what it is going into std ?..ie rad cowling water pump viscous etc ?

Then the issue of getting it to run. A HW 3.9 system will NOT run a 3.9 without tweaks, the 3.9 ECU is not adjustable or reprogrammable so a EPROM from Mark Adams is one option, and he will then remap the fuel map for the ECU and tweak for you - Not exactly cheap

Megasquirt is a real option, if I can do it with the help of FF BBC and others - mnay on this forum - anyone can :lol:

Get a dmaned good look at both engines, and consider the options BEFORE you start, work out EXACTLY what you will need - or you will do a huge amount of screaming,.

Lastly if your using the top end of the 3.9 what the internal condition like ?. If its high mileage and not spotless, then pulling it apart for donor bits just makes things get more complicated - take apart to clean ..............then maybe valve guides.... re lapping... rocker shafts... pushrods...., cam shaft.... rockers.... Followers..... timing gears chain.... etc etc etc etc

Nige

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I had a RRC with a 4.6 .

It was brilliant, loads of torque.

I simply had the tired 3.9 rebuilt to 4.6 and had top hat liners put in.

Even with 235.85 tyres and standard gearing is was quick of the mark.

Fuel consumtion was good aswell, tottling along commuter style I got

about 17mpg. The best i got on a long run was 21.6mpg. That included

driving up 7 Km long tunnels with a 9% incline at 120Km/h in 3rd. :D

Sadly the car died when a lorry hit it in the rear. :(

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  • 7 years later...

Here we go again...I'm thinking of putting my 4.6 out of my p38, it rebuilt with top hat liners, big valve heads, adjustable pushrods, fast road can and some other nice bits, so let's talk fueling, I'm going to run LPG as its my daily, I think I will have to have a word with Mr megasquirt, also anybody know of anyone yo put the 4.6 auto internals into my classic box

Ta very much

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I think q-rover had the right idea with his top-hats NickSusy bearing in mind that, historically, the 4.6 seems to suffer the most from slipped liners, though installing one in the lighter Classic might help the reliability.

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  • 2 months later...

How much for the gearbox mod in UK, I just had mine done here in OZ me and a mate with plenty ZF experiance, with buying the doner box and every single moving part brand new geniune ZF parts $4000.00.

Yes I know it alot but to me its so wurth it.

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  • 2 months later...
  • 3 weeks later...

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