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3.5 V8 to 3.9 V8


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I have a 1984 110 CSW which a factory fit 3.5 V8 with a 4 speed box and overdrive. I want to upgrade it a 3.9 EFI apart from the wiring what would require changing.

I was planning on buying an old Range Rover Classic complete so i have all parts i need. I was planning on keeping a manual.

Would it be a straight swap in terms of engine and transmission mounts?

Or is there going to be a lot of custom parts?

Any advice would be very helpful.

Thanks

Trevor

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If you are just changing the engine over and keeping your existing manual transmission, then not a lot. All I can think of is the radiator (because the RR 3.9 has oil cooler in the rad). Apparently the best rad for this sizewise is the Defender TD (not tdi), it may be worth checking hose connector sizes.

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I had no need to fit an oil cooler, or change radiator...

You can remove the oil cooler connection and just fit a standard oil filter. (It's just a blanking plate... Nut unscrews where the oil filter fits and plate comes away)

My 3.9 runs cooler than the 3.5 did with the same radiator. (Same sender unit so I know it's running cooler..)

I had tubular Janspeed manifolds and exhaust which fitted fine.. I'm guessing the standard 3.5 manifolds will also suffice unless anyone knows better.

The alternator sat in the wrong place on the 3.9 (Right as you look at it) but a plate off another 3.5 (or your old lump) will sort that. The old loom fitted perfectly and the man that fitted it all for me wired the three necessary wires from the 3.9 EFi loom into mine, one to the coil and it fired up first time ! ( I cannot claim the glory as I was mainly making coffee and passing tools around..)

Had to fit another bottom pulley wheel but you should be able to swap off the 3.5... (Mine was sold as turnkey engine with all ancilliaries left in-situ.)

If you need any pictures or specifics, ask in here or PM me.

Neil.

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I had no need to fit an oil cooler, or change radiator...

You can remove the oil cooler connection and just fit a standard oil filter. (It's just a blanking plate... Nut unscrews where the oil filter fits and plate comes away)

My 3.9 runs cooler than the 3.5 did with the same radiator. (Same sender unit so I know it's running cooler..)

I had tubular Janspeed manifolds and exhaust which fitted fine.. I'm guessing the standard 3.5 manifolds will also suffice unless anyone knows better.

The alternator sat in the wrong place on the 3.9 (Right as you look at it) but a plate off another 3.5 (or your old lump) will sort that. The old loom fitted perfectly and the man that fitted it all for me wired the three necessary wires from the 3.9 EFi loom into mine, one to the coil and it fired up first time ! ( I cannot claim the glory as I was mainly making coffee and passing tools around..)

Had to fit another bottom pulley wheel but you should be able to swap off the 3.5... (Mine was sold as turnkey engine with all ancilliaries left in-situ.)

If you need any pictures or specifics, ask in here or PM me.

Neil.

Did a garage do the work for you? Or was it a friend doing the job?

Some pics would be great.

What transmission did you start with and what transmission did you finish up with?

Thanks everyone for the replys so far.

Trev

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I was guided towards a man who could do the work for me...

Started and finished with the same gearbox etc. (LT85)...

All I had changed was the engine...

Not much in the way of pictures to show I'm afraid...

Engine out....

post-1475-1173824109_thumb.jpg

Engine in....

post-1475-1173824452_thumb.jpg

About all I have... Sorry....

Neil

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I'd describe it as sprightly....

Used to cruise well at 65 and make 90 at a push..

Now will cruise easily at 70 and make 90 quite easily..

It's much smoother power right through. The carb gave a sort of power band and performed well at low revs and at high (5k) revs. Now I have a much smoother spread of power.... Apart from the times I'm sticking my foot down, I believe the 3.9 to be as economical if not slightly better than the 3.5....

It may be that someone who knows the Weber 500 can set it up better than it was and make a better power delivery all round but I don't posess that expertise...

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Guest diesel_jim

I fitted a 3.9 efi into a 110, in place of a rather ashmatic 3.5 carb V6.5 (it was running on about 6.5 cylinders!)

so, needless to say, it was considerably more spritly!

I had the v8 running with just 4 wires for the ECU (ign feed, permanent +ve, fuel pump feed and coil feed i think), that was enought to make it "run", although you'll need the temparature sensor and lambda (if yours has that), but still nothing too bad.

With the stock rangie engine wiring loom, there was enough slack in the cable to mount the ECU between the front seats in my 110, with the loom coming through a hole i cut in the middle inspection plate thing (under the cubby box)

When i fitted the same engine into my 90, on 7.50's with a 1.4 transfer box..... jeez that was quick!! would spin the inside tyres on a roundabout very easily, and annoy rangie drivers who thought that they were "quick" off the mark... :lol:

although driving like that you could almost watch the fuel guage go down. one green laning day,where i was driving pretty gently, it gave me 8mpg.. :o:o

and if i even drank a glass of water nearby, it would cough and splutter.

so now i have a 90 and a 110 that run on proper fuel...... :ph34r: DIE sel :ph34r:

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Guest diesel_jim
Would the manual 5 speed off the range rover be a better gear box than the the 4 speed?

If so would it be a direct fit conversion?

The info has been great so far.

The gearbox would fit straight onto your engine no problem, however, i'm, sure that the rangies have the main gearstick and transfer gearstick in the opposite place, and it's a big stripdown job to swap them over.

you;d be far better with an LT85, much stronger than the rangie LT77

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20 litres that won't last very long :P

Answer .....Yes he [Les] does prefer diesel :D

Now hang on Ralph.... You personally saw my V8 in that little 1 mile long Ford we did together... Up to it's armpits in water... I don't remember the WD40 coming out then... No cough or splutter, infact, just a normal day out of the office I remember... (Apart from nearly killing my inverter !)

I don't know if the 3.9 is going to be so manly as there are now things like sensors and wires and the like involved... Only time and a damp patch on the pavement outside will tell...

I think you are all just taking the problems Nige talks about and suggesting that all RV8's are alike.. Not totally fair I would like to suggest ! (Having said that, I doubt my engine gets anywhere near 1% of the use/abuse Nige gives his....)

Come on Nige.. Defend the V8 in here with me.. Pleeeeeeaaaase ! (or maybe we should have a separate V8 forum where we can live in bliss in our little world of trouble free, dry V8 motoring.....)

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I don't know yet to be honest Trev...

I've driven it in torrential rain and it ran fantastic....

Took it across a friends farm, through quite a bit of water at speed.... When we sat on tick-over, admiring the mud patterns on the side of the 110, the steam was pouring out of the bonnet front and side vents..... Only ran on 7 for a while then but not had a problem since. (New plugs, leads, dizzy cap and rotor arm fitted as a matter of updating the old stuff tho....)

And I have to say folks... Replaced the vacuum advance unit yesterday.... Car accellerates MUCH better now with correct timing setting and advance mechanism working properly... I'd now describe it as great fun to drive.. Lively and amazing to pee most people off at the lights.. Faster acceleration and sounds sooooo much better than their 4 cylinders or diseasels....

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Don't fit carbs, they are an instant way to lose 30bhp and go back a century in technology. EFi doesn't have a problem in water, the weak point is always the dizzy. It's only if the loom is damaged/knackered with age or you allow water into the ECU/airflow meter that you will have problems. As long as you're sensible about it it will be fine.

I waded the 109 with EFi and the only thing that stopped it was the dizzy. Dad wades his flapper EFI RR regularly with no more than an ice-cream tub for waterproofing and it is fine, the dizzy doesn't like the condensation that follows but the EFI has been happy enough.

The 109 won't have a dizzy and the ECU is going to be bolted to the ceiling just to be sure ;)

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When changing the engine loom to suit the new 3.9 EFI is it easier to take the existing loom out and put the Range Rover one in?

Or is it best to just change the bits that you need to?

Where is the best place to mount the ECU?

Can you get dizzy-less ignition?

Trev

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The EFI loom should be one complete unit, it joins to the main loom through a small-ish connector that supplies things like +12v, ignition live, fuel pump connection etc. everything else (injectors, ECU, AFM) is in the EFI loom itself. The flapper ones are easy, not sure about hotwire you'd have to check the diagram.

You can get dizzyless using megasquirt, either with EDIS or directly driving coil packs. Check the tech archive for more than you ever wanted to know ;)

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