Quick question for the gurus.

I was watching a video on YouTube of a guy who put a 4.3 Chevy in his Disco II. It was early stage but it ran (the engine). He was using the rover ECU. He pointed out a little bracket he made over a cam on the main pulley that had a rover crank sensor mounted. I think I saw a throttle position sensor too. He relocated the rover coils and I don't know what else he did.

So here's the question...

What's sensors can you do without and the Disco II still allow you to start the truck and drive regardless of the engine? Assume an old mechanical diesel or a distributor driven gas engine. No need for fuel injection or coils. It runs in its own with a wire from the battery. Assume dash lights are irrelevant. Assume I have no need for fuel trim information, advance, or any other engine control except throttle, start, and stop, and don't need anything else from the ECU except what it takes to turn the key and get power to the starter, and shift gears. Assume I have another way to turn the engine off, if necessary.

As I understand it, the CPS is crucial because you can't start without it and it reports RPMs to the ECU, BCU (dash), and transmission. The transmission wants RPMs, transmission oil pressure, and transmission temperature. I don't know whether it wants speed but that's from wheel sensors if I remember right (please correct me).

I've turned the key in my truck with just about every imaginable sensor disconnected, melted off, loose, and forgotten, and only the CPS was a show stopper, if I remember correctly. But when I was in that pickle I never tried to change gears.

So, if I wanted to turn my key to send a signal to the starter and then drive down the road, but had magic beans turning the crank, what would have to be hooked up?

This is not another build thread. I'm just thinking about possibilities. The usual criticisms of swap ideas are electronics, weight, and drivetrain. Most of the things in my truck (windows, locks, windshield wipers, blower, lights) work when the engine is off. If instead of meshing electronics you just did as the man in the video did and used the rover electronics and sensors (but cut that back to a minimum with an engine that didn't need management), it seems that just about any basic engine would work. And maybe the transmission too.

 

Why not use the Rover V8? It's a Buick 215 that ran since 1960 with no electronics at all. It's been in Rovers since 1970 running with no sensors whatsoever. It's a hell of a lot better motor than the Chevy 4.3. I've had both.

The Rover V8 doesn't need anything special compared to a Chevy or Buick engine. They are actually the same thing. The Rover is most closely related to the Buick V6, and while few parts remain interchangeable after nearly 60 years that included a lot of minor changes, they do have essentially the same design.

Fuel injected engines with electronic ignition need a CPS to tell the ECU when to inject fuel and when to fire spark. Before this, engines had distributors that were mechanically driven off the camshaft. Rover V8's worked that way too and the boss for the distributor is still on the front cover. Ignition advance could be done with vacuum. Fueling was done mechanically with a carburettor and vacuum or mechanical secondaries. As for the transmission, even my late model D1 uses mechanical/hydraulic shifting with no electronics.

If you want to go back in time, all the parts are there to do it with the Rover V8. Personally, I like fuel-injection on an offroad rig because it doesn't stall and fail to run when it's at extreme angles. I feel good about the GEMS on my D1 and don't see any shortcomings on it. It's been a little hard to understand because of how arcane and foreign it is, but it certainly works better than any carburetted engine I've ever had (notwithstanding a Honda motorcycle engine).

I don't have any experience with them, but I think the hotwire 14CUX injection on earlier D1's and RRC's might be even better than GEMS. I don't know about the Bosch on DII's. If it's bad, that's a pity, because the GEMS units are good.

The only legitimate upgrade to a Rover V8 is to a larger size. In my opinion, not even an LS is an upgrade except by reason of the increased displacement. Per cubic inch, the LS doesn't really offer any more power or torque on the low end. They breathe far better, and so they make a lot of power at high speeds, but on the low end they're not really any better than a Rover V8 except by virtue of their bigger size. I've heard they do get really good mileage, but that's no concern of mine since I don't commute.

 

That is a great, thoughtful post. Thank you. And please add to it if a thought arises.

I have had my Disco II for 16 years and it has been a great little suv. I still like it and I have several other vehicles to drive. When I bought it I had no mechanical knowledge because I got a new car every year. As it has aged I've decided that the one weakness of it is the engine. Now, it would be fair to say that I'm no great mechanic even though I now own 3 engines for this vehicle. That's fair. And true. But I am able to piddle with the Fords, the Nissan, the Mercedes, the Kenworth, the Volvo... when they ever need any piddling (rarely). The Mercedes is 33 years old and has never blown a head gasket or done anything bad except leak a little oil. Moreover, when they have a problem parts are easy to get and the solutions straightforward. If there was a graph of the types of questions posed on this very active forum, a plurality if not a majority would be head gaskets, cooling problems, misfires, and other problems related to the engine and Bosch electronics. I admit, my rover ran great for three years. Perfect. But it has been an up and down battle since it first had head gasket problems. Maybe the worst thing land rover ever did was turn the water temperature gauge into a "you're fine/you're screwed" gauge. But, whether it is me being a sorry mechanic or the engines being garbage doesn't matter, the result is that for me and many others the engine is a weak link and a pain in the butt. I don't care about going faster or towing more, really. If I stuffed a v12 engine in my rover I'd never break the (spider gears) or anything else because I drive it like I plan to keep it. I drive slow and I don't tow with it. I've taken pride in keeping this truck going without resort to the dealership. But it is becoming a job. And I didn't buy mine for 4000 dollars. I bought it for closer to 40000 dollars, so I don't mind spending some money on it. The constant drain in time and a general lack of dependability is the issue. Everything else on the truck is durable and dependable, or easy to fix.

I hadn't considered older rover engines but that's a a great suggestion. While simplicity is a goal, I think I'd be asking the same questions about sensors for them as anything else... they would just fit better. Fit is easily solved, within limits, by moving motor mounds, shortening or lengthening lines, and making an adapter. A 300tdi kit would work and be cheaper than a new rover v8. But what would I do when I needed parts or service that I couldn't handle?

I have buddies with old ford broncos. The drive them on the weekends. They never worry about the engines and modifications and upgrades are cheap and plentiful. With old carburated Ford 302s (older than my rover, by double) they get the same gas mileage as me, and I have fuel injection, but without the headaches and expense. We all drive the same speed. I just have air conditioning. Swapping their engines takes 4 hours, start to finish and turn the key.

My old Mercedes has the vaunted om617 in it, and I have a spare one, too. They are underpowered, simple, durable motors. They rev like a gasoline engine and don't blow head gaskets. They will run on used motor oil, transmission fluid, diesel or just about anything you have laying around that can be coaxed to a flame under extreme pressure. The parts are mechanical. There are no connectors with wires. They don't require fancy tools or electronics. They work submerged. They don't generate much heat. They can idle all day on ounces of fuel. Most importantly, I can understand their functions and not have to read tea leaves from a code reader. They just run. Some of this can be said for simpler gas and older diesel engines, too.

Like you, I don't commute. I don't care what gas costs until it gets to 4 dollars. I don't care what diesel costs. I'm not trying to save money. I'm not worried about recouping an investment (I'm on year 16 with this truck so I'm way ahead). I has become a big, fun toy. I don't go offroad but I like knowing that I can.

So while many including me have failed to implement a real swap, I'm starting to feel like I have the time, money, and some of the information that I need. Putting a Mercedes diesel, an isuzu diesel, or a Chevy v8 in a Discovery II has been done and there are enough details available to start the big work. What seems to stop most is the issue of electronics, both for engine management and transmission function, leaving alone hill descent and whatever else that I either don't use or could live without. So after viewing that video it occurred to me: why fight the electronics? Make them happy by mounting sensors by whatever means. Put a cam on the crank pulley and dangle a crank sensor over it. Get a throttle position sensor and bandaid it to your throttle cable. Why not? A compushift does that. A compushift is a bunch of wires and even a temperature sensor braised onto the transmission pan. The smarts are all dedicated to talking to the ECU. The worst thing that can happen is yet another failed experiment. It won't bankrupt me or make me feel like a failure. I'm successful in some things and fail at others. On balance I get by.

The other thing that bogs and stops people is the "why would you want to do that" crowd and I'm glad you aren't one of those. But to anyone else I'm not saying I am going to do it or making any great claims. I'm just curious what sensors I'd need to make the computers happy enough to start my truck and change gears.

 

I know the Disco II ECU will turn the starter and run (poorly) without one knock sensor connected. I don't know about two.

I'm reasonably sure knock sensors gave nothing to do with transmission shifting.

 

I'm sure my Disco II will run fine with no oil sender hooked up. No impact on transmission.

 

To start . Crank and Cam position Sensors.

Running condition wont be great without the others.

I've had that idea, kep the electronics and swap a different block in there. I asked the question a few years ago, but got no responses. That being said, what sensors do our trucks have to begin with.

Cam Position?
Crank Position
Coolant Temp
Oil Pressure
Knock Sensors
O2 sensors

What else am I missing?

 

I guess idle air and purge.

A v8 would run badly off of the rover ECU but my thought was if you have an engine with its own ECU (suggested by Dro) or didn't have an ECU then what would it take to make our ECU and transmission work. All I can come up with is crank sensor and throttle sensor.

Build threads get bogged on several issues but it seems the electronic objection is that you'd have to get Chevy or ford sensors to talk to the rover ECU, reprogram, engineer, etc. Why couldn't you have two crank sensors? One to the engine ECU and one to the rover ECU? Or an old diesel like mine that doesn't have an ECU, but graft a TPS and CBS on the engine to make the rover ECU (and transmission) happy.

 

forgot about those.....

ok, so who responds to the cluster....or transmission....or the BCU
Clarify this for me, are you sugggesting two separate systems, keep the rover electronics to keep the ECU happy, but run a second set to run the engine?

Where are you going to put all the excess rover sensors?

Not trying to be difficult here, just trying to understand your concept a little better.

 

I'm not taking it that way. I appreciate your input.

Let's take two possibilities. One guy puts an old diesel engine in his Rover that has roughly the same rpm band as a rover gas engine. He puts a crank sensor on it and a throttle position sensor. Both are genuine land river sensors and hooked up to the ECU. No other sensors are attached. They are just dangling. Could he start it and drive down he road if he didn't care about SES lights? The diesel has no electronics at all in its stock form.

The second example is a Chevrolet v8. It has its own ECU and sensors. You hook it up to power and fuel, use its coils, etc. But you add a rover CPS and TPS on top of the Chevy ones and let the other Rover connectors dangle unused. Assuming it doesn't need alarm input and can be told by wire that the ignition has been turned could he start the truck and drive down the road?

OR would other sensors be required to be in position for the land rover ECU to say okay, you've turned the key so I'm going to activate the starter. Now here's your speed and RPMs and throttle position and I'll pass that on to the transmission controller so it will shift.

Obviously you'd have to deal with turning the engine off. The rover ECU is not going to be positioned to stop the spark.

In my list of sensors I forgot MAF. But I know that my rover engine will run (badly) with it disconnected.

 

You should be able to by-pass everything, if you don't care about gauges. The BCU provide the ground for the starter relay, but if you don't care about that, the just ground the relay at the fuse box. Probably something similar with the fuel pump relay.