The V8 Owners Forum -

Hi Everyone,

Over the last two years I have completely restored a 1987 Range Rover Classic. The original car had a very tired 3.5 V8 with the Flapper EFi system so I decided to replace it with an engine that would give better performance.

I wasnt after a race car just something that had good performance and was fun to drive. I had RPI Engineering build an engine which I thought would give me this and spent quite a lot of money with them. They recommended the following spec -

Fully rebuilt, top hat liners etc 4.6 ltr Block
F85 Merlin high performance cylinder heads and adjustable pushrods
Piper 270i Camshaft
Hotwire EFi/Tornado ECU chip, new idle bypass and TPS sensors
Bosch 4 hole injectors
Bosch AFM
Ported intake and trumpet base
ACT Carbon fibre plenum
ACT Triple throttle bodies
RPI Ignition amplifier
Lucas coil
New distributor of unknown make
Magnacor leads

Stainless steel mainfolds and exhaust system is fitted

In all RPI where suggesting close to 300 BHP and a very driveable car.

The engine is fitted with the earlier front housing so it is not a serpentine belt type front end. Everything is basically new and I have no reason to suspect any individual component isnt working as it should.

This is how it looks fitted - I have a new Ashcroft built ZF4HP22 gearbox fitted with uprated internals and a large torque converter plus an uprated LT230 transfer box. All bearings, seals brakes etc have been replaced/uprated.

The car has done around 750 miles so I havent pushed the engine too much until recently. As it stands I am really disappointed in the cars performance, below 3500 RPM there is no real power or torque, not much better than the original 3.5 engine. Certainly, my wife's three-cylinder Fiesta is faster off the mark. The couple of times I have gone above 3500 RPM the car suddenly takes off and does develop some grunt but in terms of drivability this isnt much use as the auto gearbox has a tendency to change up through the gears before this point is reached unless I constantly use kickdown.

The engine runs well, no misfires etc, idles smoothly, runs cool and sounds good when revved, plugs look ok, timing is 8' BTDC (tried various other settings without any improvement). RoverGauge reports no errors, lambda's do minimal trimming, CO trimming is set a 1.5 volts and the correct tune resistor is fitted. Fuel pressure is 38 PSI (tried higher and lower without any effect) Smoke test shows no air leaks on intake or exhaust sides.

Unfortunately for me RPI ceased trading just as I was getting the engine fitted so I am not getting any help there. Tornado confirmed that the tune level on the chip provided was for a 4.2 engine (RPI didnt cutomise the map in any way I dont think) and recommended some time on their rolling road which I had intended doing once the engine was run in later in the summer.

The more I drive the car the more dissapointed in performance I am. I keep telling myself that its a heavy car and I should not expect too much but sometime ago I had a Discovery 2 with a TD5 engine which was much more powerful and drivable than what I have now which doesnt make sense.

Having gone through everything I can my feeling was that the map on the ECU isnt right so I considered fitting a Megasquirt system so it can be customised and contacted Shaun at MS2 Tuning. Shaun has been very helpful and has suggested due to the 'camy' nature of the engine that the cam timing may be out which I hadnt thought of. RPI had a mixed reputation but their engine builder I am sure would not have made such a rookie error but everyone can make a mistake I guess.

The Piper 270i camshaft is relatively mild so I cant see it causing such a loss of power at low RPM and being so camy if the timing is correct. The F85 Merlin heads are quite rare, perhaps this cam just isnt suited to the high flow nature of them, does anyone have any experience?

Right now I am at a loss as to what could be wrong any suggestions or help would be appreciated

Doesn't look like a very friendly engine bay to work around, so checking cam timing whilst yes a sensible idea...doesn't look so easy. But would be worth doing.

But equally, so would checking ignition timing is actually where you think, and also checking fuelling whilst driving, to ensure it isn't miles out.

And other obvious things like the throttle is actually opening correctly, no blocked exhaust etc.

As for any comments around fuel trims, largely meaningless. You need to establish what fuel is doing, not guessing or assuming based on something you don't know what any parameters really refer to.

Have you tried a rolling road, at least you could get a power run to see what performance it actually has.

Given that it's an '87 year vehicle does it run catalysts and hence a closed loop map? I'm assuming as you mention fuel trims that is must be but thought best to check.
What map are you running - Rover Gauge should indicate this.

Given some of the parts RPI have sold you it seems like the engine has been geared towards high end power rather than low down grunt (and probably un-necessary even there), the kind of engine I'd expect to see in a TVR rather than a rangie. Typical of RPI though.
Not really fair to compare to a Diesel version as this is the opposite end of the scale with good low down grunt but not so much high RPM power.

8° of advance seems a bit conservative and you say you don't have any information regarding what the distributor is.
Do you know what the advance characteristics are?
Also worth checking that the timing pointer is in the correct place relative to the pulley markings many different pulleys and pointers available, get the wrong combination and it won't read right.

I'd resist jumping to a new ECU, that's going to be a lot of work, cost and a whole new set of problems to solve and the 14CUX is not as evil as many people like to make out, it is also mappable and tweakable these days so no need to replace just to get that capability. having said that one benfit would be mappable ignition
I must admit I've never been too impressed with the MA/Tornado tune, and before anyone asks I do have one and reverted to standard and then to a modified version, much better.

Thanks for your help everyone.

No Cats but RPI fitted the white tune resistor in order for some fuel trimming to take place. RoverGauge reports R3116 which when looked up was for a 4.2 engine. Speaking to Tornado though they implied the actual tune on the chip can be quite different to whats reported.

Should have said 10' advance sorry not sure why I said 8'. I have improved things today taking it to 12' definitily more responsive and power is building from 2500 RPM. Strange I thought I had tried this before without any result. No sign of any pre-ignition do you think its worth advancing a little further?

No idea of the advance characteristics of the distributor, looking at the pulley and reving the engine I would say its advancing around 12' at 3000 RPM which probably isnt enough? The distributor is something I am not entirely happy with, looks cheap but probably the same as all the others available now.

The engine is a bit of a mish mash isnt it various parts thrown together with a different front cover to the original 4.6 one so it can run a distibutor. So who knows what sort of curve it actually needs to perform. This is the reason I am thinking about megasquirt, at least then on a rolling road with someone who understands megasquirt this can be mapped to give the best results.

Let me know what you think about advancing further.

it's n/a, chances of you harming it by advancing more are pretty slim ( without going nuts of course )

So give it a try.

Or take the vehicle to a suitable dyno who can play with timing as well as confirm ( and perhaps adjust ) fuelling for you if you are unable to do this yourself, and your setup allows making alterations.

heli_madken wrote: ↑Thu Feb 06, 2025 4:02 pm Thanks for your help everyone.

No Cats but RPI fitted the white tune resistor in order for some fuel trimming to take place. RoverGauge reports R3116 which when looked up was for a 4.2 engine. Speaking to Tornado though they implied the actual tune on the chip can be quite different to whats reported.

So you do have lambda sensors fitted?

heli_madken wrote: ↑Thu Feb 06, 2025 4:02 pm
Should have said 10' advance sorry not sure why I said 8'. I have improved things today taking it to 12' definitily more responsive and power is building from 2500 RPM. Strange I thought I had tried this before without any result. No sign of any pre-ignition do you think its worth advancing a little further?

No idea of the advance characteristics of the distributor, looking at the pulley and reving the engine I would say its advancing around 12' at 3000 RPM which probably isnt enough? The distributor is something I am not entirely happy with, looks cheap but probably the same as all the others available now.
[/quote]

If I've understood correctly there you have 12° of centrifugal advance so 22° total (including the 10° base advance)?
That seems very low.

heli_madken wrote: ↑Thu Feb 06, 2025 4:02 pm The engine is a bit of a mish mash isnt it various parts thrown together with a different front cover to the original 4.6 one so it can run a distibutor. So who knows what sort of curve it actually needs to perform. This is the reason I am thinking about megasquirt, at least then on a rolling road with someone who understands megasquirt this can be mapped to give the best results.

I wouldn't necessarily say a mish-mash, I think it's quite common to run the older front cover in order to get the distributor drive but that distributor doesn't sound right. Can't understand the concept of selling someone fancy carbon fibre parts and a nondescript distributor. But that's RPI for you!

Thanks yes I think the distributor is the source of the problem.

Had a drive out today and with the 12' timing it is much better to drive, still feels a little flat low down but improved.

Everything appears fine with the distributor but it clearly isnt advancing as it should. The problem is all the original good distributors have gone now replaced by chinese stuff so its where to get a decent distributor.

The 123 programmable one fits the bill but it is expensive. My intention now is, as suggested, to get the car on a rolling road as is so I know I have a good state of tune with the 14CUX then maybe look at the Megasquirt system so not sure I want to pay out £800 on a distributor at the moment.

Anyone know of a decent distributor?

Yes lambda's are fitted

I spoke to someone a while ago who had a 123 distributor although I can't remember who it was now, he seemed quite happy with it, from what I could tell this is a programable electronic system for the spark control with high tension distributor on top. Seems like a good 'half way house' between old style dizzy and wasted spark or COP system. They seem to be about £500 which is probably going to be a cheaper than going for a megasquirt (particularly the later ones) or similar and certainly a lot less work. Obviously this depends on your capability and how much you want to be working on your vehicle.

It is tempting, found one for £580 including the gear and it would be a good option alongside a rolling road tune.

If only I didnt have my daughters wedding to pay for and a new Grandson on the way in two weeks

heli_madken wrote: ↑Fri Feb 07, 2025 4:10 pm Thanks yes I think the distributor is the source of the problem.

Had a drive out today and with the 12' timing it is much better to drive, still feels a little flat low down but improved.

Everything appears fine with the distributor but it clearly isnt advancing as it should. The problem is all the original good distributors have gone now replaced by chinese stuff so its where to get a decent distributor.

The 123 programmable one fits the bill but it is expensive. My intention now is, as suggested, to get the car on a rolling road as is so I know I have a good state of tune with the 14CUX then maybe look at the Megasquirt system so not sure I want to pay out £800 on a distributor at the moment.

Anyone know of a decent distributor?

Yes lambda's are fitted

Mechanical advance setups in a dizzy are pretty simple, Take it apart and see if it works, or can work. Likewise a vac advance can if fitted.

A slightly poor video, overly long, but it does show the workings.



And narrowband lambdas are all but useless for tuning, as they only give a reference to stioch, , or rich/lean either side of it.

For tuning you need a wideband setup.

The camshaft doesn't seem like an unreasonable choice:
https://www.pipercams.co.uk/product/v8bp270ib

I would advance the timing until you can hear it pink. Then retard a fraction. Forget the timing lights and all that crap. That'll give you maximum power from the ignition system.

Chris.

I would like to get my new 4.6 on a rolling road but everyone I talk to here only know of axle dynos. I would also like to Mao my timing, I rebuilt my disco distributor myself and have a couple of spares, I would probably send one to the distributor doctor to be set up once I get the map of the curve I need. I do have a new one from Rimmer bros in storage too but like you I am unsure of the quality. I have a 3.5 distributor in the shed which has cut itself in half after the advance springs have failed so wanted to be sure of the one I fitted.

My RRC/Series 3 Landy hybrid with 37x14.5-15 mud tyres will accelerate 8.5s 0-100km/h.
It has got 4.6 top hat liner engine with home ported heads with stage 4 valves. 72mm plenum. LT95 4SPD Manual.

Some wheel spin also..


My L322 4.2SC is slower 0-80km/h.. Then it will go.

heli_madken wrote: ↑Fri Feb 07, 2025 4:10 pm Thanks yes I think the distributor is the source of the problem.

Had a drive out today and with the 12' timing it is much better to drive, still feels a little flat low down but improved.

Everything appears fine with the distributor but it clearly isnt advancing as it should. The problem is all the original good distributors have gone now replaced by chinese stuff so its where to get a decent distributor.

The 123 programmable one fits the bill but it is expensive. My intention now is, as suggested, to get the car on a rolling road as is so I know I have a good state of tune with the 14CUX then maybe look at the Megasquirt system so not sure I want to pay out £800 on a distributor at the moment.

Anyone know of a decent distributor?

Yes lambda's are fitted

I would double check your pointer & TDC crank pulley mark is actually at real TDC.
Mine was out quite a bit!
Use a piston stop tool in no1 cylinder (I made one out an old spark plug) and mark BTDC and ATDC on the pully - and the centre of these two marks is your real TDC. does this line up with your pointer?