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3.9 into 3.5 rangie

Posted: Wed Jul 22, 2009 5:39 pm
by whitt
hi all just signed up
I have a 93 3.9 disco aswell as 87 3.5 rangie, I have blown up rangie it is on gas and was wanting to put engine from disco into it.As i recently done heads up and only has 170k on it.Should it be a straight swap,and can i use intake of 3.5 on 3.9 so i dont have to swap ecu or anything for gas
cheers for any replies

Posted: Wed Jul 22, 2009 7:19 pm
by RangingRover
Yes and yes. Biggest thing you should have to deal with is which ancillaries to swap (alt, p/s, a/c etc). From memory 93 disco has the multiple V belts on it still, so in theory you should be able to drop it in complete and all your powersteering hose etc would fit onto the disco pump. Probably easier to keep the rangie pump hooked up and use that on the disco motor though, may have to swap a bracket or two depending on pumps. Disco alternator MAY put out more juice, but wiring might be different - up to you which way to go there as well. A/c compressor might be different.... All of these should be straight bolt over swaps though if needed.

Far as the ECU goes, yes you CAN run the 3.9 fine on the 3.5 injection (with the intake manifold and plenum swapped), with a little tweaking of the AFM, but if you have the complete Disco, and want to run on petrol at all, I'd swap the 3.9 ECU + loom in as well - its a much better system (assuming hotwire, no 3.9s had flappers did they?). You'd ideally want to get the gas retuned for the bigger engine anyway (definitely don't want gas running lean especially on a rover v8), and depending on your gas system it should only be hooked into the engine loom in one or two spots - meaning it would be pretty cheap to get a gas place to hook those couple of wires back up into the 3.9 loom.

That'd be the way I'd go about it anyway.

Posted: Wed Jul 22, 2009 7:24 pm
by whitt
cheers mate some good info their,Should keep me busy..

Posted: Thu Jul 23, 2009 4:45 pm
by nottie
I thought all 3.9 discos had the serpantine belt.

I would be inclined to fit the complete 3.9 with its injection and computer.