Range Rover 4.6 into Rover P6 3500

TVRTASMIN · Post by **TVRTASMIN** » Tue Sep 20, 2011 6:47 pm

Any advice much appreciated on what i will require from the donor vehicle (1995 Rangey) apart from the obvious.
I have quite a bit of the loom as i intend to keep it injection , plus the large box which was fitted under the driver seat and what i think is the ECU under the passenger seat.

I am going to remove the PAS and air con pumps and will be using electric fans, so will be removing the viscous fan too.
I will retain the original auto box presently fitted to my 1971 P6 , so i hope there will be no problems in bolting that on along with the P6 torque converter etc.

Anyway if anybody has any advice, i would greatly appreciate it.

ChrisJC · Post by **ChrisJC** » Tue Sep 20, 2011 7:07 pm

You have got a pretty major job on your hands!

If you want to run the P38 engine 'standalone' the only factory option that did that was the Defender 50th anniversary. Even then, the engine ECU talked to the alarm I think.

You will need a 'sorted' ECU from the likes of Mark Adams. Not cheap.

Physically, you can mix / match / modify the bits to set it all up. The blocks have all got the same mountings / bellhousing pattern, and the cranks are all the same at the end. Might have to remove a dowel though, not sure.

The large box from under the drivers seat is the BECM, you won't need that.

There is an in-tank fuel pump I think, you will need that.

Chris.

DaveEFI · Post by **DaveEFI** » Tue Sep 20, 2011 7:10 pm

The B-W 35 won't handle the torque of a 4.6, and the final drive won't either.

Best mod for the P6 is a Vitesse engine. That gives more power without straining things too much.

TVRTASMIN · Post by **TVRTASMIN** » Tue Sep 20, 2011 9:10 pm

I was considering trying to make things more basic without going back to carb(s).
Possibly use a suitable Megasquirt in conjunction with the existing loom to the engine maybe?
If the BW35 goes pop, i've always got an LT 77 2wd manual box to fall back on.

As you rightly say, there might be complications with trying to use the existing ECU and other bits interfering.

Can an external high pressure pump be used as i do not wish to try and modify the fuel tank or replace it?

I know Mark Adams ain't cheap. I've been down a similar but albeit easier route when i went from a 4.0 litre to 5.2 in a TVR over 10 years ago.

RoverP6B · Post by **RoverP6B** » Wed Sep 21, 2011 6:14 am

DaveEFI wrote,...

The B-W 35 won't handle the torque of a 4.6, and the final drive won't either.

Sorry Dave, that is not true.

I have a 4.6 in my 1974 Rover P6, engine went in during July 2007, engine now has 48,000 Miles on it with no problems.

I do however live in Australia, and the BW35 available here is not the same as those in the U.K. Our transmissions saw development with Ford up until the early 1990s so no problem with handling the power or torque from the 4.6. My final drive now has 252,000 Miles on it, the last 48,000 behind the 4.6, no problems.

Common sense though is important, don't go driving like a teenager and the Rover will last you for years.

Ron.

RoverP6B · Post by **RoverP6B** » Wed Sep 21, 2011 6:20 am

TVRTASMIN,

There is no problem with the Rover torque converter bolting up nor with the transmission bolting to the engine.

There is however a problem in that the later timing cover that incorporates the crank driven oil pump as you have on your 95 Range Rover 4.6, won't fit into the engine bay of the P6. There is insufficient clearance between the timing cover and the front cross member, and between the front of the engine and the radiator. You will need to retro fit either a P6 or SD1 timing cover which means running a distributor (in order to drive the oil pump) and the applicable water pump.

Ron.

ChrisJC · Post by **ChrisJC** » Wed Sep 21, 2011 6:59 am

TVRTASMIN wrote:
Can an external high pressure pump be used as i do not wish to try and modify the fuel tank or replace it?

You can, but I think there is some kind of evaporation control on the tank which reduces the pressure a bit. I'm not sure how it works, and if the engine ECU gets the hump if it isn't working. Certainly my P38 hisses when you remove the petrol cap.

Chris.

DaveEFI · Post by **DaveEFI** » Wed Sep 21, 2011 8:31 am

RoverP6B wrote:DaveEFI wrote,...
The B-W 35 won't handle the torque of a 4.6, and the final drive won't either.
Sorry Dave, that is not true.

I have a 4.6 in my 1974 Rover P6, engine went in during July 2007, engine now has 48,000 Miles on it with no problems.

I do however live in Australia, and the BW35 available here is not the same as those in the U.K. Our transmissions saw development with Ford up until the early 1990s so no problem with handling the power or torque from the 4.6. My final drive now has 252,000 Miles on it, the last 48,000 behind the 4.6, no problems.

I'm talking about UK spec cars. The standard 35 was barely up to the 3.5 engine's torque. I didn't say they couldn't be modded. The final drive is a different matter.

Common sense though is important, don't go driving like a teenager and the Rover will last you for years.

Ron.

If you're only ever going to drive the car gently, what's the point of fitting a larger engine?

SuperV8 · Post by **SuperV8** » Wed Sep 21, 2011 11:22 am

There is however a problem in that the later timing cover that incorporates the crank driven oil pump as you have on your 95 Range Rover 4.6, won't fit into the engine bay of the P6. There is insufficient clearance between the timing cover and the front cross member, and between the front of the engine and the radiator. You will need to retro fit either a P6 or SD1 timing cover which means running a distributor (in order to drive the oil pump) and the applicable water pump.

Are you sure?
I now have a 4.6 with gems timing cover and it looks slimmer than my ols 3.5! I can do some measuring if you need? It has a much slimmer crank pulley and lower height water pump.

I could believe maybe the intermediate cover could be too big?

Tom.

RoverP6B · Post by **RoverP6B** » Wed Sep 21, 2011 12:53 pm

SuperV8 wrote,...

Are you sure?
I now have a 4.6 with gems timing cover and it looks slimmer than my ols 3.5! I can do some measuring if you need? It has a much slimmer crank pulley and lower height water pump.

Hello Tom,

Yes. Here is a link to my Rover... http://www.v8forum.co.uk/forum/viewtopic.php?t=4160

On the second page you will see a pic from underneath of the timing cover and oil filter. On the 4.6 gems cover, the oil filter faces directly downwards, right where the crossmember is situated. As you can see, they both cannot occupy the same space at the same time. There is also the problem of the water pump and the available space between it and the radiator. P6 water pumps have a short nose, the shortest of any Rover V8, and the clearance between the end of the pump and the radiator is between one and two cm only. This refers to the pumps available in Australia which run with a viscous coupling and 13 bladed fan. The P6 pumps available in the U.K have a different nose, no provison to attach a viscous coupling and run a fixed 4 bladed fan.

Ron.

SuperV8 · Post by **SuperV8** » Wed Sep 21, 2011 3:05 pm

Aha the clearence issue is with the oil pump not the depth of the timing cover. There is also a version of the P38 timing cover with an angled oil filter. Maybe this would fit? or you could use a remote oil filter housing.

Re water pump: looks like you're using an engine driven fan? An electric fan could free up a lot of space.

I will have a measure tonight, see how deep the water pump actually is?

Tom.

Dave3066 · Post by **Dave3066** » Wed Sep 21, 2011 3:31 pm

SuperV8 wrote:Re water pump: looks like you're using an engine driven fan? An electric fan could free up a lot of space.

Good luck getting a high capacity electric fan to fit between the water pump nose and the rad. At best there is around 40-50mm clearance and that's not nearly enough. You can just about get away with fitting an electric fan to the front of the rad but the front valance will need some fettling.

Dave

TVRTASMIN · Post by **TVRTASMIN** » Wed Sep 21, 2011 7:05 pm

I'd like at the very least to retain the GEMS coil pack even if this means getting a Megajolt unit.
I have a new inlet manifold and weber 4 barrell carb if all else fails on the fuelling side.
Interested in the oil filter facing backwards by fitting an alternative cover.
Although a remote take-off could be considered.

Thanks for the replies guys. Keep em coming.

RoverP6B · Post by **RoverP6B** » Thu Sep 22, 2011 3:55 am

The only timing covers that will fit as I say are the P6 or SD1. The clearance between the water pump tip and the facing surface of the radiator is only 17mm! All other timing covers accept a water pump with a different foot print and a much longer nose, so it is a non starter.

Now as far as driving hard is concerned, I can tell you breaking traction with the 4.6 will be extremely easy compared to the 3.5 and in this regard you WILL break diff drive axles. Downside is that you cannot buy them anymore, not new ones anyway. I drive with this in mind and have had no problems to date.

Ron.

RoverP6B · Post by **RoverP6B** » Thu Sep 22, 2011 5:53 am

Hello TVRTASMIN,

Another area to consider is the starter motor. There were two types fitted to the P6 and only one of them will clear the cross bolts to enable fitment. All Range Rover starter motors wont't fit as the solenoid is in the wrong position relative to the motor and it will hit against the base unit suspension point before it can be bolted up.

Your P6 engine number will point to which one you have fitted.

Ron.