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V8 Engine swap


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Good Morning Chaps,

Swapping my old V8 3.5 injection Rover engine (the one that went bang!) for a V8 3.9 Range Rover Engine, all has been going well up to the point of putting all the injector leads back on, I dont have the ECU for the new 3.9 lump, so was planning on using all the ECU, lume and stuff off the old one. problem being they are quite different, the old one has an injector/cold start fitted in the air intake and the new one hasn't. plus the distributor on the new one has a digital thingy on the side of it? and the old one dosn't.

Am I best taking all the injection system off the old one from the intake manifold and just using the 3.9 block, and swapping distributors? or is there another way round my predicament.

My Father always told me "If it runs leave it alone" why didn't I listen to him!

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it sounds like the old engine is running flapper EFI and the new one is hotwire

Hotwire is the better system out of the two, so perhaps getting the ECU for it is the more sensible option?

If not then swapping the manifolds or whatever over should work, but you'll then be fuelling a 3.9L engine with a map for a 3.5, which while it might work, wont be ideal...

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You can run the 3.9 from the 3.5 setup, that's one plus point of a MAF system. However, it won't be quite right as the engine characteristics are different. Don't take the flapper kit off the old lump, it's not quite as good as the hotwire hardware (injectors require a resistor pack).

You can ignore the cold start injector, it's not needed even on flappers.

The dizzy is no big problem, you connect the white/black wire that goes to the ECU to the coil -ve terminal (on the flapper it would've come out of the ignition amp on the inner wing). That should see you running.

The idle stepper valve won't connect to the flapper setup but they're cr*p anyway, I find they run fine without so if you can handle it being slightly lumpy for a minute or two on cold mornings just forget about it and adjust the idle screw down to compensate.

I'd look at Megasquirt'n'EDIS with a PWM idle valve to get it all running nicely, but then I would say that :P

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