My turn to ask for help!

Right you lot, I've given alot of you tons of advise about ya landy, now it's my turn...........

As ya'll probably know I'm a landy tech but when it comes to rangie classics and the like, well they're a bit before my time and noone at work knows the answer to my questions. Workshop manuals for these have long since been thrown out as we never see them in the dealer.

hotwire Vs flapper...........

I'm converting my 3.5 V8 powered cortina to efi and sourcing the bits off ebay. Most people on ebay sell an efi "kit" in bits or incomplete rather than the whole lot.

I know that the differences between hotwire and flapper are the ecu and air flow meter (MAF) but are the inlet manifolds/plenum etc the same. Can I use the inlet & plenum off a flapper system and the wiring,ecu & MAF off a hotwire?

Another thing thats baffling me is there is no crank sensor on the early efi V8's so where the hell does the engine position/speed come from?

Eightinavee, you should know this!!!!!!!!! Well I hope so!

Cheers all.

clutchdust said:

Another thing thats baffling me is there is no crank sensor on the early efi V8's so where the hell does the engine position/speed come from?
Cheers all.

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With a distributor, there's no need for the position sensor(s) as the ignition timing is done purely by mechanical means. There's no need for a speed sensor as the injection is based on airflow,Lambda's and throttle opening etc. I haven't checked the schematics, but assume that there is a feedback from the distributor to the ECM to synchronise the injector firing.

The THOR and GEMS engines are the only ones with what you would call an engine management system as such.

Peter

There is no crank sensor on 3.5 or 3.9 flapper/hot wire systems. The ECU gets a signal off the rev counter which is provided by the alternator.

I think you'll find the inlet manifolds are basically the same between hot wire and flapper but the later ones (hot wire) mount the injectors slightly differently - they have small "o" rings not the big rubber grommets.

I think you will also find the hot wire engines typically have a bigger alternator (Lucas A133/80). The hot wire injection system is slightly more advanced than the flapper although by modern standards a bit of a dinosaur.

To the best of my belief, you should be able to use 3.5 flapper hardware (plenum, inlet manifold, injectors etc) hooked up to hot wire MAF and 14CUX ECU. Like you say, eightinavee is likely to know for sure.

classic kev said:

The hot wore injection system

Click to expand...

That could be taken the wrong way!

Peter

listerdiesel said:

That could be taken the wrong way!

Peter

Click to expand...

:hysterically_laughiOOOOPS:doh: Have edited

I would stick to Hotwire stuff if its a long term project,the flapper stuff was not much cop,and if you are running it open loop I dont know if the flow rates of the two types of injector are the same.If you use the flapper plenum you'll need to blank off the ninth cold start injector - it caused more problems in use than it solved.
The Hotwire ecu gets its pulse from the switched side of the LT on the ignition coil.
If you use Hotwire stuff its more reliable and was made/used until the end of WA in Disco 1's so there is still alot around compared to flapper stuff.Thinking about it you would have alot of messing around to make the stepper motor work on a flapper plenum,on the flapper the extra air bi-metallic valve was at the front,the stepper and pipework is at the back of the hotwire plenum.
The nice thing for special building like your Cortina is that the hotwire loom comes out of the car in one piece and is dead easy to set up.If you want it as a street/daily driver I'd run it closed loop with twin Oxy sensors but no Cats.
The other thought is to go the whole hog and build your own system with Megasquirt for the fuel and Megajolt for the ignition with the Ford Edis coil packs.There is a bloke on LR4x4.com called Fridge Freezer who is well into it and it seems to have a big following - may be worth a look.
Thing is for you,as with me its very easy to use standard LR stuff as its plug and play - and T4 to check it with.Be good fun tho,a mate of mine has an RS2000 shell in the barn with no engine/box..... Often wondered what it would go like with a 4.6 in it.

Get your self a Haynes Manual 606 for the Range Rover 1970 to Oct 1992 both the 3.5 and 3.9 engines are fully expland there, unlike the Haynes Manuals of today.

Inlet manifold is the same, plenum chamber is different in as much as the flapper has an inlet for a cold start injector the hot wire has inlet for an air bypass valve (stepper motor).

If you were going for a hot wire system then you would then have to fit a speed sensor, fuel temp sensor, stepper motor also there's a few things to remove such as the inline air bypass valve of the flapper and few other things which are not a problem such as a thermotime switch.

Ive fitted a flapper V8 into my 90 and wired it in with no problems and it runs fine and when you get to no how its all works its easy to work on . ive also got the flapper on my V8 hybrid racer and never had any problems with it and ive give that some stick on comps